Karteikarten
Anatomy and physiology basics: systems, homeostasis, chemistry
Karten in diesem Stapel (467)
- 1AnatomyThe study of structure
- 2Subdivisions of anatomy1) Gross or macroscopic (IE regional, surface, and systemic)
2) Microscopic (IE cytology and histology) - 3PhysiologyThe study of function at many levels
- 4Subdivisions of physiologybased on organ systems (IE renal system, cardiovascular physiology, nervous system, etc)
- 5Principle of ComplementarityAnatomy and Physiology are inseparable; function always reflects structure
- 6The hierarchy of structural organizationOrganism
Organ System
Organ
Tissue
Cell
Organelle
Macromolecule
Molecule
Atom - 7Integumentary SystemForms the external body covering and protects deeper tissues from injury. Synthesizes vitamin D and houses cutaneous (pain,pressure, etc) receptors and sweat and oil glands
- 8Skeletal SystemProtects and supports body organs and provides a framework the muscles use to cause movement. Blood cells are formed within bones. Bones store minerals.
- 9Muscular SystemAllows manipulation of the environment, locomotion, and facial expression. Maintains posture and produces heat
- 10Nervous SystemAs the fast-acting control system of the body it responds to interal and external changes by activating appropriate muscles and glands
- 11Endocrine SystemGlands secrete hormones that regulate processes such as growth, reproduction, and nutrient use (metabolism) by body cells
- 12Cardiovascular SystemBlood vessel transport blood, which carries oxygen, carbon dioxide, nutrients, wastes, etc. The heart pumps blood
- 13Lymphatic System/ImmunityPicks up fluid leaked from blood vessels and returns it to blood. Disposes of debris in the lymphatic stream. Houses white blood cells (lymphocytes) involved in immunity. The immune response mounts the attack against foreign substances within the body
- 14Respiratory SystemKeeps blood constantly supplied with oxygen and removes carbon dioxide. The gaseous exchanges occur through the walls of the air sacs of the lungs
- 15Digestive SystemBreaks down food into absorbable units that enter the blood for distribution to body cells. Indigestible foodstuffs are eliminated as feces.
- 16Urinary SystemEliminates nitrogenous wastes from the body. Regulates water, electrolyte and acid-base balance of the blood
- 17Male Reproductive SystemOverall function is production of offspring, Testes produce sperm and male sex hormones, and male ducts and glands aid in delivery of sperm to the female reproductive tract.
- 18Female Reproductive SystemOverall function is offspring. Ovaries produce eggs and female sex hormones. The remaining female structures serves as sites for fertilization and development of the fetus. Mammary glands of female breasts produce milk to nourish the newborn.
- 19HomeostasisMaintenance of a relatively stable internal environment despite continuous outside changes; a dynamic state of equilibrium
- 20Homeostatic Control MechanismsInvolve continuous monitoring and regulation of many factors (variables); Nervous and endocrine systems accomplish the communication via nerve impulses and hormones
- 21Components of a control mechanismReceptor, Control Center, and effector
- 22Receptor (sensor)Monitors the environment, responds to stimuli (changes in controlled variables)
- 23Control CenterDetermines the set points at which the variable is maintained, receives input from receptor, and determines appropriate response
- 24EffectorReceives output from control center, provides the means to respond, and response acts to reduce or enhance the stimulus (feedback)
- 25Negative FeedbackThe response reduces or shuts off the original stimulus; regulation of body temperature (a nervous mechanism) and a regulation of blood volume by ADH (an endocrine mechanism)
- 26Negative Feedback: Regulation of blood volume by ADHReceptors sense decreased blood volume, Control center in hypothalamus stimulates pituitary gland to release antidiurectic hormone (ADH); ADH causes the kidneys (effectors) to return to more water to the blood (water retention by body)
- 27Positive FeedbackThe response enhances or exaggerates the original stimulus; may exhibit a cascade or amplifying effect; usually controls infrequent events (i.e. enhancement of labor contractions by oxytocin; platelet plug formation and blood clotting)
- 28Homeostatic ImbalanceDisturbance of homeostasis: Increases risk of disease, contributes to changes associated with aging, may allow destructive positive feedback mechanisms to take over (Ie heart failure)
- 29MatterAnything that has mass and occupies space
- 30States of matterSolid, Liquid, and Gas
- 31SolidDefinite shape and volume
- 32Liquiddefinite volume, changeable
- 33Gaschangeable shape and volume
- 34EnergyCapacity to do work or put matter into motion
- 35Types of energyKinetic and Potential
- 36KineticEnergy in action
- 37Potentialstored (inactive) energy
- 38Rules of energyEnergy may be converted from one form to another; conversion is inefficient because some energy is "lost" as heat
- 39AtomsUnique building blocks for each element
- 40Atomic SymbolOne or two letter chemical shorthand for each element
- 41About 96% of body massOxygen (O), Carbon (C ), Hydrogen (H), and Nitrogen (N)
- 42About 3.9% of body massCalcium (Ca), Phoshorus (P ), Potassium(K), Sulfur (S), Sodium (Na), Chlorine (Cl), Magnesium (Mg), Iodine (I), and Iron (Fe)
- 43Trace Elements <0.01% of body massparts of enzymes, e.g. chromium (Cr), Manganese (Mn), and Zinc (Zn)
- 44Atomic StructureDetermined by numbers of subatomic particles, nucleus consists of neutrons and protons, protons (positively charged; mass=1 amu), neutrons (no charge; mass= 1 atomic mass unit (amu)
- 45ElectronsOrbit nucleus, equal in number to protons in atom, negatively charged, 1/2000 the mass of a proton (O amu)
- 46Identifying elementsAtoms of different elements contain different numbers of subatomic particles
- 47Atomic Numbernumber of protons in nucleus
- 48Mass Number (Atomic Mass)Mass of the protons and neutrons
- 49Mass numbers of atoms of an element might varyIsotopes are structural variations of elements that differ in the number of neutrons they contain
- 50RadioisotopesValuable tools for biological research and medicine; cause damage to living tissue: useful against localized cancers; radon from uranium decay causes lung cancer
- 51MoleculeTwo or more atoms bonded together
- 52CompoundTwo or more different kinds of atoms bonded together
- 53Three Types of MixturesSolutions, Colloids, Suspensions
- 54SolutionsHomogeneous Mixtures; usually transparent
- 55SolventPresent in greatest amount, usually a liquid
- 56SolutePresent in smaller amounts
- 57Colloids (Emulsions)Heterogeneous translucent mixtures (IE cytosol); large solute particles that do not settle out; undergo sol-gel transformations
- 58SuspensionsHeterogeneous mixtures (i.e. blood); large visible solutes tend to settle out
- 59MixturesNo chemical bonding between components; can be separated physically, such as by straining or filtering, heterogenous or Homogeneous
- 60CompoundsCan be separated only by breaking bonds; all are homogeneous
- 61Chemical BondsElectrons occupy up to seven electron shells (energy levels) around nucleus
- 62Octet RuleExcept for the first shell which is full with two electrons, atoms interact in a manner to have eight electrons in their outermost energy level (Valance shell)
- 63Chemically Inert ElementsStable and unreative, outermost energy level fully occupied or contains eight electrons
- 64Chemically Reactive ElementsOutermost energy level not fully occupied by electrons; tend to gain, lose, or share electrons (form bonds) with other atoms to achieve stability
- 65Ionic BondsIons are formed by transfer of valence shell electrons between atoms; attraction of opposite charges results in an ionic bond
- 66Anionsnegative charge; have gained one or more electrons
- 67CationsPositive Charge; Have lost one or more electrons
- 68Covalent BondsFormed by sharing of two or more valence shell electrons; allows each atom to fill its valence shell at least part of the time
- 69Covalent Bonds (II)Sharing of electrons may be equal or unequal; equal sharing produces electrically balanced non polar molecules
- 70Covalent Bonds (III)Unequal sharing by atoms with different electron-attracting abilities produces polar molecules
- 71Electronegativeatoms with six or seven valence shell electrons are electronegative
- 72ElectropositiveAtoms with one or two valence shell electrons are electropositive
- 73Hydrogen BondsAttractive force between electropositive hydrogen of one molecule and an electronegative atom of another molecule; common between dipoles such as water; also acts as intramolecular bonds, holding a large molecule in a 3D shape
- 74Chemical ReactionsOccur when chemical bonds are formed, rearranged, or broken; represented as chemical equations
- 75Synthesis ReactionsA+B ---> AB
Always involve bond formation
Anabolic - 76Decomposition ReactionsAB ----> A+B
Reverse Synthesis Reactions
Involve breaking of bonds
Catabolic - 77Chemical ReactionsAll chemical reactions are either exergonic or endergonic
- 78Exergonic ReactionsRelease Energy
IE Catabolic Reactions - 79Endergonic ReactionsProducts contain more potential energy than did reactants
IE Anabolic Reactions - 80Inorganic CompoundsWater, Salts, and many acids and bases
- 81Organic CompoundsCarbs, Fats, Proteins, and Nucleic Acids, Contains carbon and hydrogen, usually large and are covalently bonded
- 82Water60-80% of the volume in living cells; most important inorganic compound in living organisms because of its properties
- 83Properties of WaterHigh Heat Capacity (absorbs and releases heat w/little temp change; prevents sudden temp changes) High Heat of Vaporization (Evaporation requires large amnts of heat; useful cooling mechanism) Polar Solvent Properties (Dissolves and dissociates ionic substances; body's major transport medium) Reactiviy (a necessary part of hydrolysis and dehydration synthesis reactions) Cushioning (protects certain organs from physical trauma i.e. cerebrospinal fluid)
- 84Acids and BasesBoth are electrolytes; Acids are proton (hydrogen ion) donors (release H+ in a solution) while bases are proton acceptors (take up H+ from solution)
- 85pHThe negative logarithm of H+ in moles per liter; pH of pure water is 7; all neutral solutions have a pH of 7
- 86Acid-Base HomeostasispH change interferes with cell function and may damage living tissue; slight change in pH can be fatal; pH is regulated by kidneys, lung, and buffers
- 87BuffersMixture of compounds that resist pH changes; convert strong (completely dissociated) acids or bases into weak (slightly dissociated) ones
- 88SaltsIonic compounds that dissociate in water; contain cations other than H+ and anions other than OH-; Ions (electrolytes) conduct electrical currents in solution; Ions play specialized roles in body functions
- 89Organic CompoundsUnique to living systems including carbs, lipids, proteins, and nucleic acids; many are polymers-chains of similar units (monomers of building blocks); they are synthesized by dehydration synthesis, broken down by hydrolysis reactions
- 90CarbohydratesSugars and starches; contain C,H, and O; three classes: monosaccharides, disaccharides, and polysaccharides; functions: major source of cellular fuel, structural molecules
- 91Monosaccaridessimple sugars containing three to seven C atoms
- 92Disaccharidesdouble sugars; too large to pass through cell membranes
- 93Polysaccharidespolymers of simple sugars (i.e. starch and glycogen); not very soluble
- 94LipidsContain C,H, O and sometimes P; insoluble in water; main types: neutral fats or triglycerides, phospholipids, steroids, and eicosanoids
- 95TriglyceridesNeutral fats- solid fats and liquid oils; composed of 3 fatty acids bonded to a glycerol molecule; main functions: energy storage, insulation, and protection
- 96Saturated Fatty Acidssingle bonds between C atoms; maximum number of H; solid animal fats (i.e. butter)
- 97Unsaturated Fatty Acidsone or more double bonds between C atoms; reduced number of H atoms (i.e. plant oils, olive oil)
- 98Phospholipidsmodified trigylcerides (glycerol + two fatty acids and a phosphorus containing group); "head" and "tail" regions have different properties; important in cell membrane structure
- 99Steroidssteroids; interlocking four-ring structure; cholesterol, vitamin D, steroid hormones, and bile salts
- 100EicosanoidsMany different ones; derived from a fatty acid (arachidonic acid) in cell membranes; prostaglandins
- 101Proteinspolymers of amino acids (20 types); joined by peptide bonds; contain C,H,O,N and sometimes S and P
- 102Primary Structure of a Proteinthe primary structure of any protein is simply its sequence of amino acids; this sequence determines everything else about the proteins final shape
- 103Secondary Structure of ProteinsStructural motifs, such as the corkscrew- like alpha helix, beta pleated sheets, and the less organized "random coils" are parts of many polypeptid chains, forming their secondary structure
- 104Tertiary StructureThese motifs may persist through a set of larger- scale turns that make up the tertiary structure of the molecule
- 105Quaternary StructureSeveral polypeptide chains may be linked together in a given protein, in this case hemoglobin, with their configuration forming its quaternary structure
- 106Fibrous (structural) proteinsstrandlike, water insoluble, and stable
Examples: keratin, elastin, collagen, and certain contractile fibers - 107Globular (functional) proteinscompact, spherical, water-soluble and sensitive to environmental changes; specific functional regions (active sites)
Examples: antibodies, hormones, molecular chaperones, and enzymes - 108Enzymesbiological catalysts; lower the activation energy, increase the speed of a reaction (millions of reactions per minute)
- 109Nucleic AcidsDNA and RNA (largest molecules in body); contain C, H, O, N and P; building block = nucleotide, composed of N- containing base, a pentose sugar, and a phosphate group
- 110DNAhereditary material/genetic material
double stranded helical molecule in the cell nucleus
provides instructions for protein synthesis
replicated before cell division, ensuring genetic continuity - 111RNAsingle stranded molecule mostly active outside the nucleus
Three varieties of RNA carry out the DNA orders of protein synthesis (messenger RNA, transfer RNA, and ribosomal RNA) - 112ATPadenosine containing RNA nucleotide with two additional phosphate groups; energy currency system in the body
- 113Cell TheoryThe cell is the smallest structural and functional unit of life
Functions of an organism depend on individual and collective cell functions
Biochemical activities of cells are dictated by their specific subcellular structures
Continuity of life has a cellular basis - 114Generalized CellThere are over 200 different types of human cells
Types differ in size, shape, subcellular components, and functions
Still all cells have some common structures and functions
Human cells have three basic parts:
-Plasma membrane-Flexible outer boundary
-Cytoplasm-intracellular fluid containing organelles
-Nucleus- control center - 115Plasma MembraneBimolecular layer of lipids and proteins in a constantly changing fluid mosaic
Plays a dynamic role in cellular activity
Separates intracellular fluid (ICF) from extracellular fluid (ECF)
-Interstitial Fluid (IF)= ECF that surrounds cells - 116Membrane Lipids75% phospholipids (lipid bilayer)
>phosphate heads:polar and hydrophilic
>Fatty acid tails: non polar and hydrophobic
5% glycolipids
>lipids with polar sugar groups on outer membrane surface
20% cholesterol
>increases membrane stability and fluidity - 117Lipid Rafts20% of the outer membrane surface
Contain phospholipids, sphingolipids, and cholesterol
May function as stable platforms for cell-signaling molecules - 118Integral ProteinsFirmly inserted into the membrane (most are transmembrane)
Functions: transport proteins (channels and carriers), enzymes, or receptors - 119Peripheral ProteinsLoosely attached to integral proteins
Functions: enzymes, motor proteins, cell-to-cell links, provide support on intracellular surface, and form part of glycocalyx - 120Functions of Membrane Proteins1)Transport
2) Receptors for signal transduction
3) Attachment to cytoskeleton and extracellular matrix
4)Enzymatic Activity
5)Intercellular Joining
6) Cell-to-Cell Recognition - 121Three Types of Membrane JunctionsTight Junction, Desmosome, and Gap Junction
- 122Tight JunctionPrevent fluids and most molecules from moving between cells
- 123Desmosome"Rivets" or "spot-welds" that anchor cells together
- 124Gap JunctionTransmembrane proteins form pores that allow small molecules to pass from cell to cell
- 125Membrane TransportPlasma membranes are selectively permeable
some molecules easily pass through the membrane; others do not - 126Types of Membrane TransportPassive and Active
- 127Passive ProcessNo cellular energy (ATP) required
Substance moves down its concentration gradient - 128Active ProcessEnergy (ATP) required
Occurs only in living cell membranes - 129Passive ProcessesSimple Diffusion
Carrier-Mediated Facilitated Diffusion
Channel-Mediated Diffusion
Osmosis - 130Simple DiffusionNonpolar lipid-soluble (hydrophobic) substances diffuse directly through the phospholipid bilayer
- 131Facilitated DiffusionCertain lipophobic molecules (ie glucose, amino acids, and ions) use carrier proteins or channel proteins, both of which:
>exhibit specificty (selectivity)
>Are saturable; rate is determined by number of carriers or channels
>Can be regulated in terms of activity and quantity - 132Facilitated Diffusion using carrier proteinsTransmembrane integral proteins transport specific polar molecules (Ie sugars and amino acids)
Binding of substrate causes shape change in carrier - 133Facilitated Diffusion using channel proteinsAqueous channels formed by transmembrane proteins selectively transport ions or water
Two types:
>Leakage channels (always open)
>Gated channels (controlled by chemical or electrical signals) - 134OsmosisMovement of solvent (water) across a selectively permeable membrane
Water diffuses through plasma membrane
>through the lipid bilayer
>through water channels called aqua porins (AQPs) - 135Osmosis (II)Water concentration is determined by solute concentration bc solute particles displace water molecules
When solutions of different osmolarity (the measure of total concentration of solute particles) are separated by a membrane, osmosis occurs until equilibrium is reached - 136TonicityThe ability of a solution to cause a cell to shrink or swell
- 137IsotonicA solution with the same solute concentration as that of the cytosol
- 138HypertonicA solution having greater solute concentration than that of the cytosol
- 139HypotonicA solution having lesser solute concentration that that o the cytosol
- 140CytoplasmLocated between plasma membrane and nucleus
- 141CytosolWater with solutes (proteins, salts, sugars, etc)
- 142Cytoplasmic OrganellesMetabolic machinery of cell
- 143InclusionsGranules of glycogen or pigments, lipid droplets, vacuoles, and crystals
- 144Membranous Cytoplasmic OrganellesMitochondria, Peroxisomes, Lysosomes, Endoplasmic Reticulum, and Golgi Apparatus
- 145Nonmembranous Cytoplasmic OrganellesCytoskeleton, Centrioles, and Ribosomes
- 146MitochondriaDouble-membrane structure with shelflike cristae
Provide most of cell's ATP via aerobic cellular respiration
Contian their own DNA and RNA - 147RibosomesGranules containing protein and rRNA
SIte of protein synthesis
Free ribosomes synthesize soluble proteins
Membrane-bound ribosomes (on rough ER) synthesize proteins to be incorporated into membranes or exported from the cell - 148Endoplasmic Reticulum (ER)Interconnected tubes and parallel membranes enclosing cisternae
Continuous with nuclear membrane
Two Varities: Rough ER and Smooth ER - 149Rough ERExternal Surface studded with ribosomes
Manufactures all secreted proteins
Synthesizies membrane integral proteins and phospholipids - 150Smooth ERTubules arranged in a looping network
Functions:
>In the liver-lipid and cholesterol metabolism, breakdown of glycogen, and along with kidneys detox of drugs, pesticides, and carcinogens
>synthesis of steroid based hormones
>In intestinal cells-absorption, synthesis, and transport of fats
>In skeletal and cardiac muscle- storage and release of calcium - 151Golgi ApparatusStacked and flattened membranous stacks
Modifies, concentrates, and packages proteins and lipids
Tranport vessels from ER fuse with convex cis face of GA
Proteins then pass through GA to trans face
Seretory vesicles leave trans face of Golgi stack and move to designated parts of cell - 152Lysosomesspherical membranous bags containing digestive enzymes (acid hydrolyses)
Digest ingested bateria, viruses, and toxins
Degrade nonfunctional organelles
Break down and release glycogen
Destroy cells in injured or non useful tissue (autolysis) - 153PeroxisomesMembranous sacs containing powerful oxidases and catalyses
Detoxify harmful or toxic substances
Neutralize dangerous free radicals (highly reactive chemicals with unpaired electrons) - 154CytoskeletonElaborated series of rods throughout cytosol: microtubules, microfilaments, and intermediate filaments
- 155Centrosome"cell center" near nucleus
generates microtubules; organizes mitotic spindle
contains centrioles: small tube formed by microtubules - 156Cilia and FlagellaWhiplike, motile extensions on surfaces of certain cells
Contain microtubules and motor molecules
Cilia move substances across cell surfaces
Longer flagella propel whole cells (tail of sperm) - 157NucleusGenetic library with blueprints for nearly all cellular proteins
Responds to signals and dictates kinds and amounts of proteins to be synthesized
Most cells are uninucleate
Red blood cells are a nucleate
Skeletal muscle cells, bone destruction cells, and some liver cells are multinucleate - 158Nuclear EnvelopeDouble-membrane barrier containing pores
Outer layer is continuous with rough ER and bears ribosomes
Inner lining (nuclear lamina) maintains shape of nucleus - 159NucleolusDark-staining spherical bodies within nucleus
Involved in rRNA synthesis and ribosome subunit assembly - 160TissuesFormed by a group of cells performing similar functions
- 161Four primary types of tissuesEpithelium
Connective
Muscular
Nervous - 162HistologyThe study of tissues
- 163Nervous Tissueinternal communication
Loc: Brain, spinal cord, and nerves - 164Muscle TissueContracts to cause movement
Loc: Muscles attached to bones(skeletal)
Muscles of heart (cardiac)
Muscles of walls of hollow organs (smooth) - 165Epithelial TissueForms boundaries between different environments, protects, secretes, absorbs, filters
Loc: skin surface (epidermis)
Lining of the GI tract organs and other hollow organs - 166Connective Tissuesupports, protects, binds other tissues together
Loc: bones, tendons, and fat and other soft padding tissue - 167SkinConsists of three major regions (2 layers in the skin and one underneath these layers)
- 168Layers of skinEpidermis-superficial region
Dermis-middle region
>Hypodermis (superficial fascia)-deepest region
^subcutaneous layer deep to skin (not technically part of skin); mostly adipose tissue - 169EpidermisKeratinized stratified squamous epithelium
- 170Cells of epidermisKeratinocytes, Melanocytes, Epidermal Dendritic (Langerhans) Cells, and Tacticel (Merkel) Cells
- 171KeratinocytesProduce fibrous protein keratin
- 172Melanocytes10-25% of cells in lower epidermis
Produce pigment melanin - 173Epidermal Dendritic (Langerhans) CellsMacrophages that help activate immune system
- 174Tactile (Merkel) CellsTouch receptors
- 175DermisStrong, Flexible Connective Tissue
Cells include fibroblasts, macrophages, and occasionally mast cells and white blood cells
2 Layers: Papillary and Reticular - 176Papillary Layer of DermisAreolar Connective Tissue with collagen and elastic fibers and blood vessel
Dermal Papillae contain:
-Capillary Loops
-Meissner's Corpuscles
-Free nerve endings - 177Reticular-80% of the thickness of dermis
Collagen fibers provide strength and resiliency
Elastic Fibers provide stretch-recoil properties - 178Skin ColorThree pigments contribute to skin color:
Melanin, Carotene, and Hemaglobin - 179MelaninYellow to reddish-brown to black, responsible for dark skin colors
Produced in melanocytes; migrates to keratinocytes where it forms "pigment shields" for nuclei
Freckles and pigmented moles
^Local Accumulations of melanin - 180CaroteneYellow to orange most obvious in the palms and soles
- 181HemoglobinResponsible for the pinkish hue of skin
- 182Appendages of the skinDerivatives of the Epidermis
-Sweat glands
-Oil glands
-Hairs and hair follicles
-Nails - 183Sweat GlandsTwo main types of sweat (sudiferous) glands:
Eccrine and Apocrine - 184Eccrine (merocrine) sweat glandsAbundant on palms, soles and forehead
-Sweat: 99% water, NaCL, Vitamin C, antibodies, dermeiden, metabolic wastes
-Ducts connect to pores
-Function in thermoregulation - 185Apocrine sweat glandsConfined to axillary and anogenital areas
-Sebum: sweat+fatty substaces and proteins
-Ducts connect to hair follicles
-Functional from puberty onward(as sexual scent glands)
-Specialized apocrine glands
-Ceruminous glands-in external ear canal; secrete cerumen
-Mammary Glands - 186Sebaceous (oil) glandsWidely distributed
Most develop from hair follicles
Become active at puberty
Sebum:
-Oily holocrine secretion
-Bactericidial
-Softens hair and skin - 187HairFunctions: Alerting the body to presence of any objects on the skin, Guarding the scalp against physical trauma, heat loss and sunlight
Distrubution: Entire surface except palms, soles, lips, nipples, and portions of external genitalia - 188Hair (cont.)Consists of dead keratinized cells
Contains hard keratin; more durable than soft keratin of skin
Hair pigments: melanins( yellow, rust brown, black)
>Gray/white hair: decreased melanin production, increased air bubbles in shaft - 189Hair FollicleExtends from the dermis to the epidermal surface
Two-layered wall: outer connective tissue root sheath, inner epithelial root sheath
Hair bulb: expanded deep end
Hair follicle receptor (root hair plexus)
>sensory nerve endings around each hair bulb which are stimulated by bending a hair
Arrector Pili
>Smooth muscle attached to follicle; responsible for "goose bumps" - 190Alopeciahair thinning in both sexes after age 40
- 191True (Frank) BaldnessGenetically determined and sex-influences condition
Male pattern baldness is caused by follicular response to DHT - 192Functions of the Integumentary System1)Protection-Physical and Chemical Barriers
2) Body Temperature Regulation
3) Cutaneous Sensations- Temperature, Touch, and Pain
4) Metabolic Functions-synthesis of vitamin D precursor and collagenase; chemical conversion of carcinogens and some hormones
5) Blood Reservoir-up tp 5% of body's blood volume
6) Excretion-nitrogenous wastes and salt in sweat - 193Skin CancerMost skin tumors are benign (do not metastasize)
Risk Factors: Overexposure to UV radiation, Frequent irritation of the skin
Some skin lotions contain enzymes in liposomes that can fix damaged DNA - 194Three Major Types of Skin CancerBasal Cell Carcinoma (Least malignant, most common)
Squamous Cell Carcinoma (Second most common)
Melanoma (Most dangerous) - 195MelanomaInvolves melanocytes, Highly metastatic and resistant to chemotherapy, treated by wide surgical excision accompanied by immunotherapy
- 196BurnsHeat, electricity, radiation, certain chemicals Lead to burn (tissue damage, denatured proteins, cell death)
Immediate threat: dehydration and electrolyte imbalance, leading to renal shutdown and circulatory shock - 197First Degree BurnEpidermal Damage only
Localized redness, edema (Swelling) and pain - 198Second Degree BurnEpidermal and upper dermal damage
Blisters appear - 199Third Degree BurnEntire thickness of skin damaged
Gray white, cherry red, or black
No initial edema or pain (nerve endings destroyed)
Skin grafting usually necessary - 200Fetal Developmental AspectsEctoderm ----> Epidermis
Mesoderm-----> Dermis and Hypodermis
Lanugo Coat: covering of delicate hairs in 5th and 6th month
Vernix Caseosa: sebaceous gland secretion; protects skin of fetus - 201Adolescent to Adult Developmental AspectsSebaceous gland activity increases
Effects of cumulative environmental assaults show after age 30
Scaling and dermatitis become more common - 202Old Age Developmental AspectsEpidermal replacement slows, skin becomes thin,dry, and itchy
Subcutaneous fat and elasticity decrease, leading to cold intolerance and wrinkles
Increased risk of cancer due to decreased numbers of melanocytes and dendritic cells - 203Two main groups of the bones of the skeleton by locationAxial and Appendicular
- 204Long BonesLonger than they are wide
- 205Short BonesCube-shaped bones (in wrist and ankle)
Sesamoid Bones (within tendons, IE patella) - 206Flat BonesThin, flat, slightly curved
- 207Irregular BonesComplicated Shapes
- 208Functions of BonesSupport-for the body and soft organs
Protection-For brain, spinal cord, and vital organs
Movement- levers for muscle action
Storage- minerals (calcium and phosphorus) and growth factors
Blood Cell Formation (Hematopoiesis) in marrow cavities - 209Bone MarkingsBulges, depressions, and holes serve as:
Sites of attachment for muscles, ligaments, and tendons
Joint surfaces
Conduits for blood vessels and nerves - 210TuberosityRounded projection
- 211Crestnarrow, prominent ridge
- 212Trochanterlarge, blunt, irregular surface
- 213LineNarrow ridge of bone
- 214TubercleSmall rounded projection
- 215EpicondyleRaised area above a condyle
- 216Spinesharp, slender projection
- 217ProcessAny bony prominence
- 218HeadBony expansion carried on a narrow neck
- 219FacetSmooth, nearly flat articular surface
- 220CondyleRounded articular projection
- 221RamusArmlike Bar
- 222MeatusCanal-like passageway
- 223SinusCavity within a bone
- 224FossaShallow, basin like depression
- 225GrooveFurrow
- 226FissureNarrow, slitlike opening
- 227ForamenRound or oval opening through a bone
- 228Compact BoneDense outer layer
- 229Spongy (Cancellous) boneHoneycomb of trabeculae
- 230Diaphysis (shaft)Compact bone collar surrounds medullary (marrow) cavity
Medullary cavity in adults contains fat (yellow marrow) - 231EpiphysesExpanded Ends
Spongy bone interior
Epiphyseal Line (remnant of growth plate) - 232PeriosteumOuter Fibrous Layer
Inner Osteogenic Layer
>Osteoblasts (Bone forming cells)
>Osteoclasts (Bone destroying cells)
>Osteogenic (Stem cells)
Nerve fibers, nutrient blood vessels, and lymphatic vessels enter the bone via nutrient foramina
Secured to underlying bone by Sharpey's fibers - 233EndosteumDelicate membrane on internal surfaces of bone
Also contains osteoblasts and osteoclasts - 234Location of Hematopoietic TissueRed Marrow Cavities of Adults
>Trabecular cavities of the heads of the femur and humerus
>Trabecular cavities of he dipole (spongy bone) of flat bones
Red Marrow of Newborn Infants
>Medullary cavities and all spaces in spongy bone - 235Osteogenic (Oteoprogenitor) CellsStem cells in periosteum and endosteum that give rise to osteoblasts
- 236OsteoblastsBone-forming cells
- 237OsteocytesMature bone cells
- 238Osteoclastscells that breka down (resorb) bone matrix
- 239Compact BoneHaversian system or osteon- structural unit of bone; formed by:
>Lamellae
-Weight-bearing
-Column-like matrix tubes
>Central (Haversian) canal
-Contains blood vessels and nerves - 240Compact Bone (cont.)Perforating (Volkmann's) Canals
>At right angles to the central canal
>Connects blood vessels and nerves of the periosteum and central canal
Lacunae- small cavities that contain osteocytes
Canaliculi-hairlike canals that connect lacunae to each other and the central canal - 241Spongy BoneTrabeculae
>Align along lines of stress
>No osteons
>Contain Irregularly arranged lamellae, osteocytes, and canliculi
>Capillaries in endosteum supply nutrients - 242Organic BoneOsteogenic Cells, Osteoblasts, Osteocytes, Osteoclasts
Osteoid- organic bone matrix secreted by osteoblasts
>Ground substance (proteoglycans, glycoproteins)
>Collagen Fibers
-Provide tensile strength and flexibility - 243Inorganic BoneHydroxyapatites (mineral salts)
>65% of bone by mass
>Mainly calcium phosphate crystals
>Respsonsible for hardness and resistance to compression - 244Osteogenesis (Ossification)Bone tissue formation
- 245Stages of Bone DevelopmentBone formation- begins in the 2nd month of development
Postnatal Bone Growth-Until early adulthood
Bone modeling and repair- Lifelong - 246Intramembranous OssificationMembrane bone develops from fibrous membrane
Forms flat bones (Ie clavicles and cranial bones) - 247Endochondral OssificationCartilage (endochondral) bone forms by replacing hyaline cartilage
Forms most of the rest of the skeleton - 248Endochondral OssificationUses hyaline cartilage models
Requires breakdown of hyaline cartilage prior to ossification - 249Interstitial GrowthIncreases the length of long bones
- 250Appositional GrowthIncrease thickness and remodeling of all bones by osteoblasts and osteoclasts on bone surfaces
- 251Hormonal Regulation of Bone GrowthGrowth hormone stimulates epiphyseal plate activity
Thyroid hormone modulates activity of growth hormone
Testosteron and estrogens (at puberty)
>promotes adolescent growth spurts
>end growth by inducing epiphyseal plate closure - 252Bone ResorptionOsteoclasts Secrete
>Lysosomal Enzymes (digest organic matrix)
>Acids (convert calcium salts into soluble forms)
Dissolved matrix is transcytosed across osteoclast, enters interstitial fluid and then blood - 253What controls continual remodeling of bone?Hormonal Mechanisms that maintain calcium homeostasis in the blood
- 254Calcium is necessary for:Trasmission of nerve impulses
Muscle contraction
Blood coagulation
Secretion by glands and nerve cells
Cell division - 255Hormonal Control of Blood Ca2+Primarily controlled by parathyroid hormone (PTH)
low blood ca2+ levels lead to parathyroid glands release PTH which leads to PTH stimulates osteoclast to degrade bone matrix and release ca2+ which then leads to increase in blood ca2+ - 256Hormonal control of blood ca2+May be affected to a lesser extent by calcitonin
increase in blood ca2+ levels leads t oparafollicular cells of thyroid release calcitonin which leads to osteoblasts deposit calcium salts which leads to a decrease in blood ca2+ levels
Leptin has also been shown to influence bone density by inhibiting osteoblasts - 257Wolff's LawA bone grows or remodels in response to forces or demands placed upon it
- 258Homeostatic ImbalancesOsteomalacia and Rickets
>Calcium salts not deposited
>Rickets (childhood disease) causes bowed legs and other bone deformities
>Cause: vitamin D deficiency or insufficient dietary calcium - 259OsteoporosisLoss of bone mass-bone resorption outpaces deposit
Spongy bone of spine and neck of femur become most susceptible to fracture
Risk factors: lack of estrogen, calcium or vitamin D; petite body form; immobility; low levels of TSH; diabetes mellitus - 260Developmental Aspects of BonesNearly all bones completely ossified by age 25
Bone mass decreases with age beginning in 4th decade
Rate of loss determined by genetics and environmental factors
In old age bone resorption predominates - 261Three Types of Muscle TissueSkeletal, Cardiac, and Smooth
- 262Skeletal Muscle TissueAttached to bones and skin
Striated
Voluntary (ie conscious control)
Powerful - 263Cardiac Muscle TissueOnly in the heart
Striated
Involuntary - 264Smooth Muscle TissueIn the walls of hollow organs (i.e. stomach, urinary, bladder, and airways
Not striated
Involuntary - 265Muscle Contraction and MovementThe skeleton and muscles interact to produce movement
Muscles can only contract
Anatagonistic pairs of muscles
>Reverse actions
> Relengthen muscles - 266Excitability of IrritabilityThe ability to receive and respond to a stimulus
- 267ContractilityThe ability to contract forcible when stimulated
- 268ExtensibilityThe ability to be stretched
- 269ElasticityThe ability to resume the cells' original length once stretched
- 270Muscle Function 1Produce movement by acting on the bones of the skeleton, pumping blood, or propelling substaces though out hollow organ systems
- 271Muscle Function 2Aid in maintaining posture by adjusting the position of the body with respect to gravity
- 272Muscle Function 3Stabilize joints by exerting tension around the joint
- 273Muscle Function 4Generate heat as a function of their cellular metabolic processes
- 274Muscle fibersare cells consist of bundles of myofibrils
- 275Myofibrils containing overlappingThick (myosin) filaments and thin (actin) filaments
- 276SarcomeresThe contractile unit- the fundamental unit of muscle action
Formed by repeating groups of thick and thin filaments - 277The sliding-filament model-explains muscle contraction
-a muscle contracts when thin filaments slide across thick filaments
-Myosin heads of the thick filaments
>bind ATP and
>extend to high-energy states
-Myosin heads then
>Attach to binding sites on the actin molecules and
-Pull the thin filaments toward the center of the sarcomere - 278Motor NeuronsCarry action potentials
That initiate muscle contractions - 279The axon of a motor neuronForms synapses with a muscle at a neuromuscular junction
- 280Acetylcholineis released from the synaptic terminal of a motor neuron
& diffuses to the plasma membrane of the muscle fiber - 281Muscle ContractionAn action potential
>passes along T tubules
>into the center of the muscle fiber
Calcium Ions
>are released from the endoplasmic reticulum
>initiate muscle contraction by moving regulatory proteins away from the actin binding sites - 282A motor unit consists ofA neuron and the set of muscle fibers it controls
- 283Principles of Muscle Mechanics1) same principles apply to contraction of a single fiber and a whole muscle
2) contraction produces tension, the force exerted on the load or object to be moved
3) contraction does not always shorten a muscle
4) Force and duration of contraction vary in response to stimuli of different frequencies and intensities - 284Isometric Contractionno shortening, muscle tension increases but does not exceed the load
- 285Isotonic ContractionMuscle shortens because muscle tension exceeds the load
- 286Aerobic Respirationprovides most of the ATP used to power muscle movement during exercise
-Requires a steady supply of
>Glucose
>oxygen - 287Anaerobic ExerciseGenerates ATP faster and is much less efficient at producing ATP
- 288Muscle fibers can be classified as:Slow Fibers
Intermediate Fibers
Fast Fibers - 289Types of Muscle FibersMost muscles have a combination of muscle fibers
The proportion of fiber types can be affected by exercise
Muscle fiber characteristics affect athletic performance - 290Muscles adapt to exercise by increasingLevels of myoglobin
Number of mitochondria
Number of capillaries going to muscles - 291All or none principleSeen on the cellular level, concerning one muscle fiber
Stimulated the muscle fiber
>stimulus will be strong enough to generate an action potential --> contraction (all)
> stimulus will not be strong enough to generate an action potential ---> no contraction (none)
No mechanism to control the gradation on the cellular level
>influenced by number of cross bridges involed (degree of overlap)
>availability of Ca2+ enzymes
See gradations on the organ level
>organ made up of many fiber types - 292A muscle twitchProduced in a lab setting
One contraction in response to a threshold stimulus - 293MyographMachine that is used
- 294Myogram tracingRecording of the response
- 295Phases of a muscle twitch1) Latent Period
Events of excitation-contraction
2) Contraction Phase
Interaction of myosin and actin
3) Relaxation Phase
Ca2+ are falling, active sites are being covered - 296Muscle twitcheesTwitches of different muscles
See different responses
Some muscles contract fast, others more slowly
Fast twitch and slow twitch fibers have different roles in the body - 297TreppeFrequent stimulation results in a slightly stronger contraction due to more ca2+ and heat (warm up for athletes)
- 298Wave SummationStimulate before relaxation, subsequent contraction builds on previous
- 299TetanusA sustained contraction due to constant stimulation
A normal physiological response that allows for normal use of muscles in the body
In lab: wave summation--> incomplete tetanus --> tetanus
<> - 300Rigor MortisUpon death production of ATP stops
Ca2+ leaks out of the SR
Actin and myosin interact
No ATP to detach the myosin head
Muscles become locked in the contracted state
Lasts 15-20 hours - 301Functions of the nervous system1) Sensory Input
2) Integration
3)Motor Output - 302Sensory InputInformation gathered by sensory receptors about internal and external changes
- 303IntegrationInterpretation of sensory input
- 304Motor OutputActivation of effector organs (muscles and glands) produces a response
- 305Divisions of the nervous systemCentral Nervous System (CNS) and Peripheral Nervous System (PNS)
- 306Central Nervous SystemBrain and spinal cord
Integration and command center - 307Peripheral Nervous SystemPaired spinal and cranial nerves carry messages to and from the CNS
- 308Two functional divisions of the peripheral nervous system1) Sensory (Afferent) Division
2) Motor (Efferent) Division - 309Sensory (Afferent) DivisonSomatic afferent fibers- convey impulses from skin, skeletal muscles, and joints
Visceral afferent fibers- convey impulses from visceral organs - 310Motor (Efferent) DivisionTransmits impulses from the CNS to effector organs
- 311Motor Division of PNS1) Somatic (Voluntary) Nervous System
>Conscious control of skeletal muscles
2) Autonomic (Involuntary) Nervous System (ANS)
>Visceral motor nerve fibers- regulates smooth muscle, cardiac muscle, and glands
>Two functional subdivisions
-Sympathetic
-Parasympathetic - 312Two Principle Cell Types in Nervous Tissue1) Neurons
2) Neuroglia - 313NeuronsExcitable cells that transmit electrical signals
- 314Neuroglia (Glial Cells)Supporting Cells
>Astrocytes (CNS)
>Microglia (CNS)
>Ependymal Cells (CNS)
>Oligodendrocytes (CNS)
>Satellite Cells (PNS)
>Schwann Cells (PNS) - 315AstrocytesMost abundant, versatile, and highly branched glial cells
Cling to neurons, synaptic endings, and capillaries
Support and brace neurons - 316MicrogliaSmall, ovoid cells with thorny processes
Migrate toward injured neurons
Phagocytize microorganisms and neuronal debris - 317Ependymal CellsRange in shape from squamous to columnar
May be ciliated
>Line the central cavities of the brain and spinal column
>separate the CNS interstitial fluid from the cerebrospinal fluid in the cavities - 318OligodendrocytesBranched Cells
Processes wrap CNS nerve fibers, forming insulation myelin sheaths - 319Satellite CellsSurround neuron cell bodies in the PNS
- 320Schwann Cells (Neurolemmocytes)Surround peripheral nerve fibers and form myelin sheaths
Vital to regeneration of damaged peripheral nerve fibers - 321Special Characteristics of NeuronsLong Lived ( 100 years of more)
Amitotic (With few exceptions)
High Metabolic Rate (depends on continuous supply of oxygen and glucose)
Plasma membrane functions in:
>Electrical signaling
>Cell-to- cell interactions during development - 322Cell Body (Perikaryon or Soma)Biosynthetic center of a neuron
Spherical nucleus with a nucleolus
Well-developed Golgi Apparatus
Rough ER called Nissl Bodies (chromatophilic substance)
Clusters of cells bodies are called
>Nuclei in the CNS
>Ganglia in the PNS - 323Processes-Dendrites and axons
-Bundles or processes are called
>Tracts in the CNS
>Nerves in the PNS - 324DendritesStructure:
>Short, tapering, and diffusely branched
>Receptive (input) region of a neuron
Function:
>Convey electrical signals toward the cell body as graded potentials - 325The AxonStructure:
>One axon per cell arising from the axon hillock
>Long Axons (nerve fibers)
>Occasional branches (axon collaterals)
Function:
>Conductin region of a neuron
>Generates and transits nerve impulses (action potentials) away from the cell body - 326Myelin SheathSegmented protein-lipoid sheath around most long or large- diameter axons
It functions to:
>Protect and electrically insulate the axon
>Increase the speed of nerve impulse transmission - 327Myelin Sheaths in the PNSSchwann Cells wrap many times around the axon
>Myelin sheath- concentric layers of Schwann cell membrane
Neurilemma-peripheral bulge of schwann cell cytoplasm - 328Myelin Sheaths in the PNS (II)Nodes of Ranvier
>Myelin sheath gaps between adjacent schwann cells
>Sites where axon collaterals can emerge - 329Unmyelinated AxonsThin nerve fibers are unmyelinated
One schwann cells may incompletely enclose 15 or more unmyelinated axons - 330Myelin Sheaths in the CNSFormed by processes of oligodendroctyes, not the whole cells
Nodes of Ranvier are present
No neurilemma
Thinnest fibers are unmyelinated - 331Myelin Sheaths in the CNSFormed by processes of oligodendrocytes, not the whole cells
Nodes of Ranvier are present
No neurilemma
Thinnest fibers are unmyelinated - 332White MatterDense collections of myelinated fibers
- 333Gray MatterMostly neuron cell bodies and unmyelinated fibers
- 334Structural Classification of Neurons1)Multipolar-1 axon and several dendrites
>most abundant
>motor neurons and interneurons
2)Bipolar-1 axon and 1 dendrite
>Rare (ie retinal neurons)
3) Unipolar (pseudounipolar)-single, short process that has two branches
>peripheral process: more distal branch, often associated with a sensory receptor
>Central proess: branch entering the CNS - 335Functional Classification of Neurons1) Sensory (afferent)
-Transmit impulses from sensory receptors toward the CNS
2) Motor (Efferent)
-Carry impulses from the CNS to effectors
3)Interneurons (association neurons)
>shuttle signals through CNS pathways; most are entirely within the CNS - 336ArticulationsWhere two bones interconnect
- 337Functional Classification of JointsAmount of movement allowed
Range of motion - 338Structural Classification of JointsAnatomical Components
Bony, fibrous, cartilaginous, synovial - 339SynarthrosesImmovable joints
Fibrous/cartilageneous
Bony - 340AmphiarthrosesSlightly moveable joints
Fibrous/Cartilageneous - 341DiarthrosesFreely movable joints
Synovial - 342Four major types of synarthrosesSuture: skull bones bound together by dense CT
Gomphosis: teeth bound to bony sockets by periodontal ligaments
Synchondrosis: two bones bound by rigid cartilaginous bridge
Syntosis: two bones completely fused - 343Two major types of AmphiarthrosesSyndesmosis: Bones connected by a ligament
Symphysis: bone separated by fibrocartilage - 344DiarthrosesJoint is enclosed
Joint space is filled with fluid
Can also be called a synovial joint
Most joints of the appendicular skeleton - 345Components of a synovial jointArticular Capsule
>Encloses the joint
Articular Cartilage
>Hyaline cartilage
>Covers articulating surfaces
Synovial Membrane
>Lines the capsule
Synovial Fluid
>Consistency of egg whites - 346Synovial Fluid FunctionsLubrication
Nutrient Distribution
Shock Absorption - 347Additional Structures may includeMenisci (Knee)
Fat pads
Accessory Ligaments
Bursae - 348Gliding MotionTwo surfaces slide past one another
>Carpals, Tarsals - 349FlexionAngular Movement
Decreases the angle between two parts - 350ExtensionAngular Movement
Increasing the angle between two parts - 351HyperextensionAngular Movement
Extending beyond the anatomical position - 352AbductionMovement away from the body's midline
- 353AdductionMovement towards the body's midline
- 354CircumductionCombination of flexion, adduction, extension, abduction
- 355PronationPalms up to down
Front to back
Start in anatomical position - 356SupinationPalms down to up
Back to front
Return to the anatomical position - 357Plantar FlexionToes down, heel up (flexes plantar surface of the foot)
- 358DorsiflexionToes up, heels down
- 359Gliding JointsPermit movement in a single plane
- 360Hinge JointsMonoaxial joints permitting angular motion in one plane
- 361Ellipsoidal JointsBiaxial Joints that pit one bone in an oval depression of another
- 362Saddle JointsBiaxial Joints with one concave and one convex bone face
- 363Ball-And-Socket JointsTriaxial joints that permit rotation and other movements
- 364Central Nervous SystemConsists of the brain and spinal cord
- 365CephalizationEvolutionary development of the rostral (anterior) portion of the CNS
Increased number of neurons in the head
Highest level is reached in the human brain - 366Embryonic DevelopmentNeural plate is formed from ectoderm
Neural plate invaginates to form a neural groove and neural folds
Neural groove fuses dorsally to form the neural tube
Neural tubes gives rise to the brain and spinal cord - 367Anterior end of the neural tube gives rise to three primary brain vesiclesProsencephalon-Forebrain
Mesencephalon-Midbrain
Rhombencephalon-Hindbrain - 368Adult Brain RegionsCerebral Hemisphers
Diencephalon
Brain Stem (Midbrain, Pons, Medulla Oblongata)
Cerebellum - 369Ventricles of the BrainConnected to one another and to the central canal of the spinal cord
Contain cerebrospinal fluid
>Two C-Shaped lateral ventricles in the cerebral hemispheres
>Third ventricle in the diencephalon
>Fourth ventricle in the hindbrain, dorsal to the pons, develops from the lumen of the neural tube - 370Surface MarkingsRidges: Gyri
Shallow Grooves: Sulci
Deep Grooves: Fissures - 371Five Lobes of Cerebral HemispheresFrontal
Parietal
Temporal
Occipital
Insula - 372Surface Markings (cont)Central Sulcus: separates the pre central gyrus of the frontal lobe and the post central gyrus of the parietal lobe
Longitudinal Fissure: Separates the two hemispheres
Transverse Cerebral Fissure: Separates the cerebrum and the cerebellum - 373Cerebral CortexThin (2-4mm) superficial layer of gray matter
40% of the mass of the brain
Site of conscious mind:awareness, sensory perception, voluntary motor initiation, communication, memory stage, understanding
Each hemisphere connects to contralateral sides of the body
There is lateralizatin of cortical function in the hemispheres - 374LaterilizationDivision of labor between hemispheres
Left Hemisphere: controls language, math, and logic
Right Hemisphere: ingisht, visual-spatial skills, intuition, and artistic skills
Left and right hemispheres communicate via fiber tracts in the cerebral white matter - 375Cerebral DominanceDesignates the hemisphere dominant for language (left hemisphere in 90% of the people)
- 376Three types of functional areas of the cerebral cortexMotor Areas-control voluntary movement
Sensory Areas-conscious awareness of sensation
Association Areas- integrate diverse information
Conscious behavior involves the entire cortex - 377Motor Areas of cerebral cortexPrimary (somatic) motor cortex
>Allows conscious control of precise, skilled, voluntary movements
Premotor Cortex
Broca's Area
Frontal Eye Field - 378Sensory Areas of Cerebral CortexPrimary Somatosensory Cortex
Somatosensory Association Cortex
Visual Areas
Auditory Areas
Olfactory Cortex
Gustatory Cortex
Visceral Sensory Area
Vestibular Cortex - 379Broca's AreaPresent in one hemisphere (usually the left)
A motor speech area that directs muscles of the tongue and is active as one prepares to speak - 380Wernicke's AreaInvolved in understanding written and spoken language
- 381Limbic SystemProvides emotional impact that helps establish memories (works together with hypothalamus)
- 382DiencephalonThree paired structures:
Thalamus
Hypothalamus
Epithalamus
Pituitary Gland - 383ThalamusGateway to the cerebral cortex
Sorts, edits, and relays information - 384HypothalamusAutonomic control center for many visceral functions (i.e. blood pressure, rate and force of heartbeat, digestive tract motility)
Center for emotional response: involved in perception of pleasure, fear, and rage and in biological rhythms and drives
Regulates body temp, hunger, thurst, water balance, sleep and wake cycle
Controls release of hormones by the anterior pituitary
Produces posterior pituitary hormones - 385EpithalamusMost dorsal portion of the diencephalon; forms roof of the third ventricle
- 386Pineal GlandExtends from the posterior border and secretes melatonin (which helps regulate sleep-wake cycles)
- 387Three Regions of the Brain StemMidbrain
Pons
Medulla Oblongata - 388MidbrainLocated between the diencephalon and pons
Major areas:
Cerebrul Peduncles -contain pyramidal motor tracts
Cerebral Aqueduct- channel between 3rd and 4th ventricles
Nuclei that control cranial nerves III (oculomotor) and IV (trochlear)
Corpora Quadrigemnia-domelike dorsal protrusions
>Superior Colliculi- visual reflex centers
>Inferior Colliculu- auditory relay centers - 389PonsForms part of the anterior wall of the 4th ventricle
Fibers of the pons
>Connect higher brain centers and the spinal cord
>Relay impulses between the motor cortex and the cerebellum
Origin of cranial nerves V(trigeminal), VI (abducens), and VII (facial)
Some nuclei of the reticular formation
Nuclei that help maintain normal rhythm of breathing - 390Medulla OblongataAutonomic Reflex Centers
Cardiovascular Center
>Cardiac center adjusts force and rate of heart contraction
>Vasomotor center adjusts blood vessel diameter for blood pressure regulation
Respiratory centers
>Generate respiratory rhythm
>Control rate and depth of breathing, with pontine centers
Additional Centers regulate
>Vomiting, Hiccuping, Swallowing, Coughing ,Sneezing - 391The Cerebellum11 of brain mass, dorsal to the pons and medulla
Subconsciously provides precise timing and appropriate patterns of skeletal muscle contraction
Recognizes and predicts sequences of events during complex movements
Plays a role in non motor functions such as word association and puzzle solving - 392Spinal CordLocation:
Begins at the foramen magnum
Ends at conus medullaris at L1 vertebra
Functions:
Provides two-way communication to and from the brain
Contains spinal reflex centers
Protected by bone, meninges, CSF - 393Spinal Cord (cont)Spinal Nerves
>31 pairs
Cervical and Lumbar Enlargements
>the nerves serving the upper and lower limbs emerge here
Cauda Equina
> the collection of nerve roots at the inferior end of the vertebral canal - 394Peripheral Nervous SystemFormed by all neural structures outside the brain
>Sensory Receptors
>Peripheral Nerves and Associated Ganglia
>Motor Endings - 395Sensory ReceptorsSpecialized to respond to changes ni their environment (stimuli)
Activation results in graded potentials that trigger nerve impulses
Sensation (awareness of stimulus) and perception (interpretation of the meaning of the stimulus) occur in the brain - 396Classification of Receptors Based On:Stimulus Type
Location
Structural Complexity - 397MechanoreceptorsRespond to touch, pressure, vibration, stretch, and itch
- 398Thermoreceptorssensitive to changes in temperature
- 399Photoreceptorsrespond to light energy (i.e. retina)
- 400ChemoreceptorsRespond to chemicals (ie smell, taste, changes in blood chemistry)
- 401Nociceptorssensitive to pain-causing stimuli (i.e. extreme heat or cold, excessive pressure, inflammatory chemicals)
- 402Classification by LocationExteroceptors
Interoceptors
Proprioceptors - 403ExteroceptorsRespond to stimuli arising outside the body
Receptors in the skin for touch, pressure, pain, and temperature
Most special sense organs - 404Interoceptors (Visceroceptors)Respond to stimule arising in internal viscera and blood vessels
Sensitive to chemical changes, tissue stretch, and temp changes - 405ProprioceptorsRespond to stretch in skeletal muscles, tendons, joints, ligaments, and CT coverings of bones and muscles
Inform the brain of one's movements - 406Classification by Structural ComplexityComplex Receptors (Special Sense organs)
Simple Receptors for General Senses - 407Complex Receptors (Special Sense Organs)Vision, Hearing, Equilibrium, Smell, and Taste
- 408Simple Receptors for General SensesTactile Sensations (Touch, pressure, stretch, vibration) Temperature, Pain, and Muscle Sense
Unencapsulated (Free) or Encapsulated Dendritic Endings - 409Unencapsulated Dendritic EndingsThermoreceptors
Nociceptors
Light Touch Receptors - 410ThermoreceptorsCold Receptors (10-40 degrees celsius) in superficial dermis
Heat Receptors (32-48 degress celsius) - 411NociceptorsRespond to: Pinching, chemicals from damaged tissue, temperatures outside the range of thermoreceptors
- 412Light Touch ReceptorsTactile (Merkel) Discs and Hair Follicle Receptors
- 413Encapsulated Dendritic EndingsMeissner's (tactile) corpuscles
Pacinian (Lamellated) corpuscles
Ruffini Endings
Muscle Spindles
Golgi Tendon Organs
Joint Kinesthetic Receptors - 414Meissner's (Tactile) CorpusclesDiscriminative Touch
- 415Pacinian (Lamellated) CorpusclesDeep pressure and vibration
- 416Ruffini Endingsdeep continuous pressure
- 417Muscle SpindlesMuscle Stretch
- 418Golgi Tendon OrgansStretch in tendons
- 419Joint Kinesthetic ReceptorsStretch in articular capsules
- 420From Sensation to PerceptionSurvival Depends upon sensation and perception
- 421SensationThe awareness of changes in the internal and external environment
- 422PerceptionThe conscious interpretation of those stimuli
- 423Sensory IntegrationInput comes from exteroceptors, proprioceptors, and interceptors
Input is relayed toward the head, but is processed along the way - 424Sensory IntegrationLevels of neural integration in sensory systems:
1) Receptor Level- the sensor receptors
2) Circuit Level- ascending pathways
3) Perceptual Level-neuronal circuits in the cerebral cortex - 425Processing at the receptor levelReceptors have specifity for stimulus energy
Stimulus must be applied in a receptive field
Adaptation is a change in sensitivity in the presence of a constant stimulus
>Receptor membranes become less responsive
>Receptor potentials decline in frequency or stop - 426Phasic ReceptorsFast-adapting
Signal the beginning or end of a stimulus
ex: receptors for pressure, touch, and smell - 427Tonic ReceptorsAdapt slowly or not at all
Examples: nociceptors and proprioceptors - 428Processing at the circuit levelPathways of 3 neurons conduct sensory impulses upward to the appropriate brain regions
- 429First Order NeuronsConduct impulses from the receptor level to the second-order neurons in the CNS
- 430Second Order NeuronsTransmit impulses to the thalamus or cerebellum
- 431Third Order NeuronsConduct impulses from the thalamus to the somatosensory cortex (perceptual level)
- 432Processing at the Perceptual LevelIdentification of the sensation depends on the specific location of the target neurons in the sensory cortex
- 433Perceptual DetectionAbilty to detect a stimulus (requires summation of impulses)
- 434Magnitude EstimationIntensity is coded in the frequency or impulses
- 435Spatial DiscriminationIdentifying the site or pattern of the stimulus (studied by the two-point discrimination test)
- 436Structure of a NerveCordlike organ of the PNS
Bundle of myelinated and unmyelinated peripheral axons enclosed by CT
CT coverings include
>Endoneurium-loose CT that encloses axons and their myelin sheaths
>Perineurim- coarse CT that bundles fibers into fascicles
>Epineurium- tough fibrous sheath around a nerve - 437Classification of NervesMost nerves are mixtures of afferent and efferent fibers and somatic and autonomic (Visceral) fibers
Pure sensory (afferent) or motor (efferent) nerves are rare
Types of fibers in mixed nerves
>Somatic afferent and somatic effernt
>Visceral afferent and visceral efferent
Peripheral nerves are classified as cranial or spinal nerves - 438GangliaContain neuron cell bodies associated with nerves (IN PNS)
>Dorsal root ganglia (sensory, somatic)
>Autonomic Ganglia (motor, visceral) - 439Regeneration of Nerve FibersMature neurons are amitotic
If the soma of a damaged nerve is intact, axon will regenerate
Involves coordinated activity among:
>macrophages: remove debris
>schwann cells: form regeneration tube and secrete growth factors
>axons: regenerate damaged part
CNS oligodendrocytes bear growth-inhibiting proteins that prevent CNS fiber regeneration - 440Cranial NervesTwelve Pairs of nerves associated with the brain
Most are mixed in function; two pairs are purely sensory
Each nerve is identified by a number (I through XII) and a name
"On Occasion Our Trust Truck Acts Funny- Very Good Vehicle Anyhow - 441Spinal Nerves31 pairs of mixed nerves named according to their point of issue from the spinal cord
8 cervical (C1-C8)
12 thoracic (T1-T12)
5 lumbar (L1-L5)
5 sacral (S1-S5)
1 coccygeal (C0) - 442Autonomic Nervous System (ANS)The ANS consists of motor neurons that:
>Innervate smooth and cardiac muscle and glands
>Make adjustments to ensure optimal support for body activities
>Operate via subconscious control
Other names
>involuntary nervous system
>General visceral motor system - 443The two systems differ inEffectors
Efferent pathways (and their neurotransmitters)
Target organ responses to neurotransmitters - 444EffectorsFor somatic nervous system- skeletal muscles
For ANS- cardiac muscle, smooth muscle, and glands - 445Efferent PathwaysSomatic Nervous System
>A thick heavily myelinated somatic motor fiber makes up each pathway from the CNS to the muscle - 446ANS Pathway is a two-neuron chain1) Preganglionic neurgon (IN CNS) has a thin, lightly myelinated preganglionic axon
2) Ganglionic neuron in autonomic ganglion has an unmyelinated postganglionic axon that extends to the effector organ - 447Somatic Nervous SystemAll somatic motor neuron release actetylcholine (ACh)
Effects are always stimulatory - 448ANSPreganglionic fibers release ACh
Postganglionic fibers release norepinephrine or ACh at effectors
Effect is either stimulatory or inhibitory depending on type of receptors - 449Divisions of the ANS1) sympathetic division
2) parasympathetic division
>Dual innervation
-almost all visceral organs are served by both divisions, but they cause opposite effects - 450Role of the Parasympathetic DivisionPromotes maintenance activities and conserves body energy
Its activity is illustrated in a person who relaxes, reading, after a meal
>blood pressure, heart rate, and respiratory rates are low
>gastrointestnal tract activity is high
>pupils are constricted and lenses are accommodatd for close vision - 451Role of the sympathetic divisionMobilizes the body during activity: is the "fight-or-flight" system
Promotes adjustments during exercise or when threatened
>blood flow is shunted to skeletal muscles and heart
>bronchioles dilate
>liver releases glucose - 452Sympathetic DivisionOrigin of Fibers: Thoracolumbar region of the spinal cord
Length of fibers: short preganglionic and lost postganglionic
Location of ganglia: close to the spinal cord - 453Parasympathetic DivisionOrigin of Fibers: Brain and sacral spinal cord (craniosacral)
Length of Fibers: Long preganglionic and short postganglionic
Location of Ganglia: In visceral effector organs - 454NeurotransmittersCholinergic Fibers release the neurotransmitter ACh
> All ANS preganglionic axons
>All parasympathetic postganglionic axons
Adrenergic FIbers release the neurotransmitter NE
>most sympathetic postganglionic axons
>exceptions: sympathetic postganglionic fibers secrete ACh at sweat glands and some blood vessels in skeletal muscles - 455Receptors for Neurotransmitters1) Cholinergic Receptors for ACh
2) Adrenergic Receptors for NE - 456Cholinergic ReceptorsTwo types of receptors bing ACh
1)Nicotinic
2) Muscarinic
Names after drugs that bind to them and mimic ACH effects
Effect of ACh at nicotinic receptors is always stimulatory
The effect of ACh at muscarinic receptors can be either inhibitory or excitatory - 457Adrenergic ReceptorsTwo Types
>Alpha
>Beta
Effects of NE depend on which subclass of receptor predominates on the target organ - 458Effects of drugsOver the counter drugs for colds, allergies, and nasal congestion
>stimulates a-adrenergic receptor s
Beta Blockers
>drugs that attach to beta 2 receptors to dilate lung bronchioles in asthmatics; other uses - 459Control of ANS functioningHypothalamus- main integrative center of ANS activity
Subconscious cerebral input via limbic lobe connections influences hypothalamic function
Other controls come from the cerebral cortex, the reticular formation, and the spinal cord - 460Hypothalamic ControlControl may be direct or indirect (through the reticular system)
Centers of the hypothalamus control
>Heart activity and blood pressure
>Body temp, water balance, and endocrine activity
>emotional stages (rage, pleasure) and biological drives (hunger, thirst, sex)
>reactions to fear and the "fight-or-flight" system - 461Developmental Aspects of the ANSDuring youth, ANS impairments are usually due to injury
In old age ANS efficiency declines partially due to structural changes at preganglionic axon terminals - 462The three parts of the earInner, Middle, and External Ear
- 463The external and middle earInvolved with sound wave transmission
- 464The inner earFunctions in both hearing and equilibrium
- 465Receptors for hearing and equilibriumRespondto separate stimuli
Are activated independently - 466The route of sound to the inner ear follows this pathwayExternal Ear-pinna, external acoustic meatus, tympanic membrane
Middle Ear-malleus, incus, and stapes to the oval window. Learn middle ear bones by proper name
Inner Ear- scala vestibuli and scala tympani to the cochlear duct
>Stimulation of the spiral organ (organ of corgi)
>Cochlea is the structure for hearing
>Generation of impulses in the cochlear nerve - 467Vestibular ApparatusEquilbrium receptors in the semicircular canals and vestibule
>Maintains our orientation and balance in space
>Vestibular receptors monitor static equilibrium and linear acceleration
>semicircular canal receptors monitor dynamic equilibrium
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