Flashcards
Exam 1 (part 1)
Flashcards do conjunto (200)
- 1Parenchyma vs. StromaP: cells that make up the functional elements of an organ
S: structural framework of an organ (background tissue) - 2Tissue typesBlood
Connective tissue
Epithelium
Muscle
Nervous Tissue - 3Tissue preparation1. Fix with formalin
2. Place cut tissue in cassettes
3. Dehydrate via series of alcohol baths
4. Clear with xylene
5. Embed in liquid paraffin or plastic resin
6. Microtome (6-7 microns)
7. Mount on slides
8. Remove paraffin
9. Rehydrate with alcohol and xylene
10. Stain and add coverslip - 4What does formalin do?Cross-links proteins to preserve tissue for slides
- 5Hematoxylin vs. EosinH: blue, BASIC, stains acids (basophilic materials like nuclei)
E: red/pink, ACIDIC, stains bases (eosinophilic materials like proteins) - 6What are special stains used for slide prep?Gram (bacteria), GMS, silver stain (fungi)
- 7Layers of the cell membraneHydrophilic:
-contains pos-charged N groups and neg-charged phosphate groups
-present on both inside and outside of membrane
Hydrophobic:
-contains two long-chain FA's that are covalently linked to glycerol - 8What is responsible for the tri-laminar appearance of the cell membrane on EM?2 electron dense layers (hydrophilic phospholipid heads) separated by the electron lucent layer (hydrophobic FA tails)
- 9What is the fluid-mosaic model?The fluidity of the membrane increases with increased temperature AND decreases with saturation of FA's
- 10What does cholesterol do?Helps regulate fluidity and stabilize the membrane
If you have more cholesterol, you increase stiffness in membrane and decrease fluidity - 11What are the types of membrane proteins?Extrinsic (peripheral): on surface of membrane
Intrinsic (integral): within the membrane
Transmembrane (transmural): type of intrinsic protein that extends from one side of the membrane to the other - 12Pores vs. ChannelsBoth openings in transmembrane proteins
Pores: always open
Channels: can open and close
Used for active or passive transport of hydrophilic molecules - 13Categories of membrane proteinsPumps: serve to transport ions across membrane
Channels: allow passage of water-soluble molecules via diffusion
Receptor Proteins: allow for cell recognition and binding on cell membrane
Transducers: initiate enzymatic reactions following binding with ligand molecules
Enzymes: components of ion pumps and digestive action
Structural proteins: add mechanical stability to membrane - 14What is the glycocalyx?Short polysaccharide chains containing glucose molecules conjugated to membrane to form glycoproteins and glycolipids
Protects surface of cell membrane, may be involved in cell recognition, and important in mediating exchange b/w internal and external cell environment - 15Types of membrane transportSimple (passive) diffusion
Facilitated diffusion
Active transport
Bulk (vesicular) transport - 16What is simple diffusion?Diffusion that occurs down a concentration or ionic gradient
Some pass directly through plasma membrane (lipids, gases, water, urea, bicarbonate)
Larger water-soluble molecules use pore or channels in transmembrane proteins - 17What is facilitated diffusion?Diffusion that is passive and concentration-dependent, but requires "carrier molecules"
Reversible binding and unbinding to transport water-soluble, hydrophilic molecules (e.g. glucose and amino acids)
Uses ion channels in integral proteins (either gated or ungated) and requires presence of stimulus to open - 18What is the affect of membrane folding on diffusion?BOTH passive and facilitated diffusion is enhanced by increased surface area of membrane via folding (e.g. microvilli)
- 19What kinds of stimuli can affect facilitated diffusionChange in membrane potential (voltage-gated)
Binding of signaling molecule or neurotransmitter (chemical-gated) - 20Aquaporinsimportant type of channel that uses facilitated diffusion
Allows water to cross plasma membrane faster than by simple diffusion alone - 21What is active transport?Transport that is independent of concentration (usually against concentration gradient)
Requires energy (ATP -> ADP, Na/K pump)
Occurs at specialized "dynamic pore sites" (usually transmembrane proteins) - 22What is bulk (vesicular) transport?Transport that requires energy and consists of the engulfment of molecules/particles by cytoplasmic extensions
AKA endocytosis
Results in formation of membrane-bound, endocytic vacuoles called endosomes or phagosomes - 23Types of endocytosisPhagocytosis: engulfment of solid, particulate matter
Pinocytosis: engulfment of liquids - 24What is receptor-mediated endocytosis?Types of endocytosis in which extracellular molecules (ligands) bind to receptor proteins (clathrins) located in coated pits (caveolae) of cell membrane
- 25What is exocytosis?Any bulk transport or vesicular movement from the cytoplasm to the extracellular space
- 26What is transcytosis?transport of material across or through a cell via sequential endocytosis followed by exocytosis
- 27What are the two major categories of organisms?Prokaryotes (no nucleus)
Eukaryotes - 28Differences b/w prokaryotes and eukaryotesEukaryotes have a nucleus, organelles, histones, chromosomal DNA, and axonemal flagella
Prokaryotes have plasmids and cell walls - 29What is protoplasm? Types?~70-85% water + electrolytes, proteins, lipids, and carbohydrates
Cytoplasm: between cell membrane and nuclear membrane
Nucleoplasm: within nucleus - 30How much of the nuclear mass is consisted of DNA?<20%
- 31Chromatin vs. ChromosomesChromatin: DNA complexed with nucleoproteins
Chromosomes: packaged chromatin - 32GenesSegments of DNA within individual chromosomes that code for particular traits
- 33AllelesDifferent forms of the same gene
- 34Diploid vs. HaploidTypes of homologous pairs in chromosomes
Diploid in humans: 2n =46
Haploid in humans: n = 23 (eggs and sperm) - 35Karyotypingsorting of chromosome pairs according to size and shape
- 36HeterochromatinElectron-dense, darkly-staining, INACTIVE DNA & nucleoproteins
In females, find Barr body (permanently inactive DNA; degenerate X chromosome)
Most chromatin in nucleus is heterochromatin - 37EuchromatinDispersed DNA that is ACTIVE in transcription (RNA synthesis)
Cells active in translation will have a prominent nucleolus and abundant euchromatin - 38What are lamp brush chromosomes?Active portions of chromosomes that unravel to to undergo transcription and become visible
- 39HistonesMost of DNA-associated proteins in eukaryotes
Assist with DNA folding => chromatin organization into chromosomes - 40NucleosomesSegments of DNA wrapped around several histones
Regulate DNA activity - 41Non-histonesadditional category of nucleoproteins
may also be involved in regulation of gene activity - 42Nuclear envelopeSurrounds nucleus and separates the nucleoplasm from the cytoplasm
Contains inner and outer nuclear membrane separated by perinuclear cisterna - 43What is a nuclear pore complex?~70-80 nm diameter channels that connect the inner and outer nuclear membranes
Regulate the exchange of macromolecules between the nucleus and cytoplasm - 44Difference between the inner and outer nuclear membranesInner: associated with network of lamin filaments for support (called nuclear lamina)
Outer: studded with ribosomes, continuous with rER - 45RibosomesBipartite (two subunits, 40S & 60S)
Proteinaceous structures (contain rRNA)
Synthesized and assembled in nucleolus, then migrates to cytoplasm where it's found free and attached to rER and outer nuclear membrane
Often grouped together as polyribosomes or polysomes (aggregates or ribosomes and mRNA)
Sites of protein synthesis - 46MitochondriaProduce energy (ATP) via Kreb's cycle and oxidative phosphorylation (both aerobic)
Vary greatly in size, shape, and number within cell
Oblong to oval, move freely within cytosol
present in all cells except RBCs and keratinocytes - 47What is porin?Pore-forming protein found in the permeable outer membrane of mitochondria
- 48What are cristae?Folds in the inner membrane of mitochondria
Lined with elementary particles that contain enzymes for oxidative phosphorylation - 49What is in the inner cavity of mitochondrion?Amorphous matrix material that contains dense granules (thought to be binding/storage sites for Ca2+)
- 50How do mitochondrion replicate?Possess circular DNA and are self-replicating
Reproduce by binary fission, similar to bacterial division - 51How are mitochondrion replicated?Maternally inherited but unique from the rest of DNA
Structurally similar to bacterial ribosomes - 52What is cellular respiration?Energy released from chemical breakdown of organic molecules from diet and stored in the form of ATP
- 53Where does cellular respiration occur?Begins in the cytosol (glucose -->pyruvate) via anaerobic glycolysis
Then diffuses into mitos where aerobic respiration occurs in the matrix via Kreb's cycle (pyruvate --> CO2+H2O+ATP) - 54How is most ATP produced in the cell?Via oxidative phosphorylation by cytochromes of the electron transport system
- 55What are cytochromes?Enzymes on the inner membrane of cristae in the mitochondria
- 56What is the endoplasmic reticulum?Series of membranous sheets and tubules throughout the cytoplasm
Can be smooth or rough - 57Smooth vs. rough ERRough: has surface receptor molecules for ribosomal attachment; specializes in protein synthesis
Smooth: functions in lipid synthesis, transport of proteins from rER to Golgi, membrane formation & recycling, synthesis of cholesterol & steroid hormones; principle organelle involved in detoxification and conjugation of drugs & toxins - 58What are coated vesicles?Vesicles that surround and coat proteins for transport, bud off the sER, then transport proteins between sER and Golgi and between Golgi and cell surface
Act as "taxi" for proteins - 59Golgi apparatusComplex of flattened, stacked, membrane-bound cisternae
Functions in post-translational modification, packaging, & sorting of proteins synthesized in rER (e.g., sulfation, phosphorylation, glycosylation) - 60Cis vs Trans GolgiCis: "forming face"; convex; where proteins arrive from rER in coated transfer vesicles
Trans: "maturing face"; concave; where proteins are packaged into clathrin-coated vesicles for secretion - 61How does the Golgi complex work?Vesicles bud off maturing face as condensing vacuoles, sorted into secretory vesicles for extracellular export via exocytosis or as membrane-bound vesicles for intracellular use, or as secretory granules for long-term storage
- 62What is membrane trafficking?During exocytosis and secretion, large amounts of intracellular membrane are incorporated into outer cell membrane
These are recycled by the Golgi - 63LysosomesMembrane-bound vesicles containing hydrolytic enzymes (e.g. acid phosphatase)
Used to degrade organelles and cells with finite lifespans during apoptosis or programmed cell death (aka autophagy) - 641' lysosomesNewly-formed lysosomes produced by rER and Golgi
INACTIVE - 652' lysosomesWhat occurs when 1' lysosomes fuse with phagocytic vesicles (phagosomes)
AKA phagolysosomes
ACTIVE
Function in intracellular digestion - 663' lysosomeResult of hydrolytic breakdown
AKA residual body
May be excreted or remain in cells for life (e.g., lipofuscin pigment granules in neurons) - 67Endosomestype of endocytic vesicle with acid pH in the lumen due to proton pumps in membrane which pump H+ into interior
- 68PeroxisomesMembrane-bound organelles containing oxidative enzymes (oxidases)
Resemble lysosomes (also contain catalase and peroxidase)
Use enzymes, free radicals, and hydrogen peroxide to oxidize toxic metabolites - 69What are inclusions?Non-living components of the cell
Include neutral fat droplets, lipids, glycogen, secretory & pigment granules
Also viral inclusions (can be found in cytoplasm or in nucleus) - 70Intracytoplasmic pigmentsMelanin: black, brown, granular pigment; produced by melanocytes and transported to other cells
Lipofuscin: gold-brown granules; frequently seen in neurons; sometimes called "old age pigment" - 71Functions of cytoskeletonProvide structural support for plasma membrane and cell organelles
Intracellular movement/transport of substances (large molecules/organelles)
Cell locomotion (amoeboid movement, embryonic development, cilia, flagella)
Muscle contraction (specialized cells) - 723 main elements of cytoskeletonMicrofilaments, intermediate filaments, and microtubules
- 73MicrofilamentsDistributed in 3D network throughout cytoplasm
Important in maintaining cell shape; facilitate shape changes during movement (e.g., wound contraction during healing and muscle contraction) - 74What is actin?Type of microfilament
AKA thin filament; 6-8 nm in diameter
Made up of smaller G-actin subunits (small, globular protein monomer that polymerizes to form protofilaments)
Two protofilaments twist together to form a double helix (F-actin), then these combine to form larger actin filaments - 75What is the terminal web?Support meshwork that prevents cell from deformation
Formed by actin linking with filamin protein - 76MyosinType of microfilament
AKA thick filament; ~15 nm in diameter
Also classified as "motor protein" along with dynein and kinesin
Long and rod-saped with globular heads; form thick "cables" with myosin heads sticking out sides
Myosin heads form cross-bridges between adjacent filaments - 77What is required for movement of myosin filaments for muscle contraction?Ca2+ and ATP
- 78Intermediate filaments8-10 or 10-15 nm in diameter
1' structural function
Heterogenous group, so molecular make-up varies between cells (generally form large filaments that bind with intracellular structures)
Several different classes, each expressed in different cell types (1 cell may produce more than 1 type of filament)
Useful in immunohistochemistry and tumor ID - 79Types of intermediate filamentsCytokeratin: all epithelial cells; forms tonofibrils in epidermis
Vimentin: found in mesodermal cells
Desmin: unique to muscle cells
Neurofilament proteins: nerve cells
GFAP: found in glial cells
Lamin: forms layer on inside of nuclear membrane - 80MicrotubulesLarger than microfilaments or intermediate filaments (~24 nm diameter)
Composed of 2 types of globular protein subunits (alpha and beta tubulin) arranged in a coiled, spiral pattern that polymerize to form hollow tubes so they can readily assemble and disassemble
Involved in cell movement, maintenance of cell shape, and intracellular transport of substances - 81How does microtubule movement occur?Via addition or subtraction of tubulin subunits from microtubules
Motor proteins dynein and kinesin attach them to organelles and allow movement in the cytoplasm - 82What provides microtubules with energy?Microtubule-associated proteins (MAPs) as ATPase
Stabilize microtubules along with capping proteins - 83What drugs affect microtubules?Colchicine, vincristine, and vinblastin
Inhibit polymerization of microtubules and therefore cell division - 84Where are microtubules found?Cilia and flagella, centrioles, basal bodies of cilia, and mitotic spindles
- 85Axoneme9 pairs of microtubules (peripheral doublets) containing dynein arms arranged in a circle with a central doublet in the middle (9+2)
Central doublet connects to peripheral doublets by radial spokes and peripheral doublets connect to each other via nexin protein
In cilia, grows from basal body and is derived from a modified centriole - 86CentriolesNormally located in region of cell called centrosome near nucleus
Function in cell division
Each consists of 9 triplets of microtubules arranged in a cylinder - 87Function of centrioles in cell divisionPair of centrioles (diplosome) oriented at right angles to each other within centrosome acts as a nucleation center for microtubules
Centrioles divide and go to opposite poles, forming mitotic spindle which controls distribution of chromosomes - 88How does movement of chromosomes occur during cell division?Addition and subtraction of tubulin subunits and attachment proteins (dynein and kynesin) to chromatids at kinetochore (aka centromere)
- 89Interphase"resting phase" between divisions
Occupies most of the life of the cell
Three subphases: G1, S, G2 - 90G1 phasePart of interphase
Longest of the cell phases (lasts hours to days)
When cell growth, maturation, and differentiation occur - 91What is hypertrophy?Increase in cell size
Occurs in G1 phase - 92What is hyperplasia?Increase in cell number
Occurs during mitosis - 93S phasePart of interphase
Replication of DNA prior to division
At beginning, chromosome # is 2n, at end is 4n for a brief period of time
Prior to replication, each chromosome has a single chromatid with attached centromere, but afterward each contains 2 chromatids connected by centromere
Replication of centrioles also occurs in S (=> 2 diplosomes)
Takes several hours - 94G2 phasePart of interphase
Preparation for mitosis
Synthesis of ATP and tubulin for mitotic spindle
"last minute prep stage"
Takes several hours - 95M phaseCell division portion
Characterized by karyokinesis (nuclear division) followed by cytokinesis (cell division)
Results in 2 daughter cells
Takes several hours - 96Go phaseOccurs when cells lose capacity for cell division
May be permanent (terminally differentiated) or reversible (facultative dividers), depending on cell type - 97Phases of mitosisProphase:
-microfilaments & microtubules of cytoskeleton disaggregate
-centrioles migrate to poles of cell and form spindle apparatus w/ interpolar microtubules
Prometaphase:
-Nuclear membrane and nucleoli disappear
-Mitotic spindle attaches to chromosomes at kinetochore
Metaphase:
-Chromosomes line up at equator
Anaphase:
-Centromeres split apart and chromosomes are pulled by MTs connected to centriole
Teloophase:
-Mitotic spindle disintegrates, nuclear envelope reassembles, nucleoli reappear
-Plasma membrane forms cleavage furrow and cytokinesis begins - 98What is mitotic index?Proportion of cells in a tissue in mitosis at any given time (normally <1)
Important in tumors - 99Differences in meiosis from mitosisDuring prophase I, homologous pairs of chromosomes form tetrads with exchange of chromatin via crossing over (chiasmata formation) that results in hybrid chromatids different from parents
Centromeres don't split during anaphase I - 100Second meiotic division stepsBrief interphase II (interkinesis) with NO replication of DNA
NO crossing over during prophase II
During anaphase II centromeres split
During telophase II cytokinesis yields four haploid gametes, each genetically unique - 101What is produced during gametogenesis?In male, 3-4 viable gametes (sperm) produced
In female, 1 functional gamete (ovum) and 2-3 non-functional polar bodies - 102What is the process of oogenesis?Begins during fetal development
Germ cells enter prophase I ~5th month gestation and then remain there until ovulation (12-50 years later) - 103What triggers apoptosis?Timing in fetal development (programmed cell death)
Some cells have finite, predetermined lifespans
Growth and regression of ovarian follicles and CL
Destruction of virus/tumor-infected cells
Clonal deletion in thymus (removal of t-cells that react to self molecules - 104What is pyknosis?Shrinkage of nucleus that occurs during apoptosis
- 105Process of apoptosis1. Condensation of nuclear chromatin and shrinkage of nucleus
2. Cell swells as result of water influx due to loss of ATP to maintain cell membrane pumps
3. Lysosomes release catalytic enzymes into cytoplasm (autolysis)
4. Cytoplasm becomes bright pink (eosinophilic) as membranes start to break apart and leak
5. Final pathway initiated by caspace cascade (which are usually inactive enzymes)
6. Chromatin in nucleus begins to degenerate (karyolysis)
7. Nuclear material begins to fragment and nuclear membrane disintegrates (karyorhexis)
8. Dead, necrotic cells are later phagocytosed by neutrophils and macrophages - 106ErythropoeitinHormone secreted by the kidney that controls blood cell production
- 107Where does hemopoiesis occur?IN adult humans, occurs in vascular sinuses of bone marrow (especially in flat bones)
2.5 billion RBCs/day
In fetus, first in blood islands in wall of yolk sac (1st trimester) then in liver and lymphatic tissue (2nd trimester) then in bone marrow (last month of pregnancy) - 108Bone marrowRed marrow is active and contains large #'s of mature RBCs
Yellow (fatty) marrow is inactive - 109ErythropoiesisStem cell (CFU-E) -> proerythroblast -> erythroblast/normoblast -> reticulocyte -> mature RBC
Overall trends: progressive decrease in cell size, loss of nucleus and organelles, increase in hemoglobin concentration - 110What are Howell-Jolly bodies?Occasional, basophilic nuclear remnants visible within the cytoplasm
- 111What are reticulocytes?Immature RBCs with stippled cytoplasm (still have some rRNA)
Slightly larger than mature RBCs - 112What is reticulocytosis?Increase in reticulocytes in circulation associated with chronic blood loss and/or hemolytic anemia
AKA left shift
Also seen in severe/chronic infections - 113What is megaloblastic anemia?Anemias where there are large numbers of erythrocyte precursors in peripheral blood
Lots of free stem cells in blood! - 114What is the makeup of blood?Plasma: liquid, extracellular matrix that makes up 55% of blood volume
-91-92% water, 1-2% electrolytes (Na, Ca, K, HCO3), 7-8% protein
Serum: plasma-clotting factors - 115Plasma proteinsAlbumins: bulk of plasma proteins, all synthesized in liver; function as transport proteins for insoluble metabolites; responsible for colloid osmotic pressure in blood vessels b/c of large size
Globulins: large molecules used as transport proteins for lipids and heavy metal ions; largest fraction are immunoglobulins (antibodies synthesized by plasma cells)
Fibrinogens: largest proteins; soluble, synthesized by liver; polymerize to form insoluble fibrin during clotting (prothrombin -> thrombin catalyzes fibrinogen -> fibrin) - 116Formed elements of bloodHematocrit (volume of RBCs)
-45% in males, 42% in females
Plasma
Buffy coat (WBCs and platelets)
-1-2%
Hematocrit +/- buffy coat = packed cell volume - 117What is the modified Romanovsky method?Process of producing a blood smear
Uses Wright, Giemsa stain - 118Erythrocytes~6-8 microns in diameter
Biconcave discs (--> deformability and increased surface area for gas exchange)
Primary structural protein is spectrin (binds to inner surface of plasma membrane and provides both resiliency and defomability) - 119What is sickle cell anemia?Disease caused by single amino acid substitution (valine for glutamic acid @ position 6 of beta-globulin chain) that leads to a change in the 3D structure of hemoglobin
Causes conformational change in cell to "sickle" shape that is more fragile and easily damaged
Can also cause damage to endothelial cells of capillary walls b/c of rough edges
Confers resistance to malaria - 120What is the lifespan of a RBC?~120 days
- 121How can RBCs make ATP?anaerobic glycolysis
- 122What happens to senescent RBCs?They are removed from the circulation by the liver and the spleen
- 123PlateletsSmall non-nucleated cells containing organelles (2-4 micron diameter)
Formed from megakaryocytes (huge cells with multi-lobed nucleus) in bone marrow
Lifespan of 8-12 days
Function in blood clotting
Impaired by aspirin (inhibits clotting) - 124What are demarcation channels?Pleated channels in megakaryocyte cytoplasm
Where platelets "tear off" - 125What is coagulation?Result of cascade interaction between plasma proteins and coagulation factors
Occurs ONLY if endothelial lining of vessel is injured
Extrinsic (Faster, initiated by thromboplastin) and intrinsic (slower, initiated by exposure of collagen and requires clotting factors) pathways - 126Process of coagulation1. Wall of blood vessel breaks
2. BV releases thromboplastin to initiate extrinsic and exposes collagen to initiate intrinsic
3. Platelets adhere to exposed collagen and release serotonin (vasoconstrictor)
4. Extr. and intr. pathways converge to form common pathway (at point where Factor X activated) which results in prothrombin -> thrombin which converts soluble fibrinogen into insoluble fibrin
5. Platelets and RBCs trapped - 127What stops clotting?Exhaustion of fibrinogen and removal of thrombin from blood during conversion of fibrinogen to fibrin
Also anticoagulants antithrombin III and heparin - 128What is hemophilia?Deficiency in clotting factor(s), so blood can't clot; defect in intrinsic pathway
Sex-linked, in males; present on X chromosome - 129Types of hemophiliaA: deficiency of clotting factor VIII
B: Factor IX
C: Factor XI
Von Willebrand's disease: von Willebrand's factor - 130What is pseudopodia?Process by which WBCs stick to endothelial cell surface and then squeeze between endothelial cells of capillaries and venules
- 131What is chemotaxis?Attraction of WBCs to endothelial surface of BVs at inflammatory sites
Occurs via cytokines - 1321' granulesFound in ALL WBCs
AKA azurophilic granules (stain blue)
Contain lysosomal enzymes (e.g., acid hydrolases) - 1332' granulesAKA specific granules
Found only in granulocyte WBCs
Contain lysozyme and alkaline phosphatases
Exhibit variable staining
Includes: neutrophils, basophils, and eosinophils - 134NeutrophilsMost common WBC
12-14 micron diameter
Multi-lobed nucleus (aka polymorphonuclear cells or PMNs)
Lifespan: several hours to days
Few mitochondria, so use 1' anaerobic glycolysis
1' granules contain antimicrobial myeloperoxidase, 2' granules contain inflammatory mediators, proteases, defensins, lactoferrin, and lysozyme, 3' granules contain gelatinase - 135When are neutrophils released?During inflammatory reaction via degranulation
Associated with acute inflammation, generally lasts several days
Attracted to bacteria and damaged tissue by chemotactic factors - 136How do neutrophils move?Amoeboid movement
- 137What is the primary function of neutrophils?Phagocytosis
Leads to formation of phagolysosome to digest bacteria and enhanced via opsonization (coating of bacteria with antibodies) - 138What is respiratory burst?Bacterial killing by generating hydrogen peroxide and hypochlorous acid
Assoc. with neutrophils - 139what are Stab cells?AKA band cells
Immature (u-shaped nucleus) neutrophils - 140What is a Barr body?Inactive X chromosome in females
Presents as "drumstick appendage" in neutrophil nuclei - 141BasophilsLeast common WBC
14-16 micron diameter, bilobed nucleus
May be the same as mast cells, lifespan uncertain
Characterized by large, basophilic specific granules
Used in Type I hypersensitivity reactions and counteracted by eosinophils - 142What is found in the specific granules of basophils?Hydrolytic enzymes, heparin sulfate (anticoagulant), chondroitin sulfate (proteoglycan), histamine, and leukotrienes (e.g., slow reacting substance of anaphylaxis which causes asthma attacks; eosinophilic chemotactic factor)
- 143Eosinophils1-6% of WBCs; 16 micron diameter, bilobed nucleus
Remain in circulation 3-6 hours before entering tissue and have a tissue lifespan of 8-12 days
Have surface receptors for IgE - 144What is found in specific granules of eosinophils?Hydrolytic enzymes
E.g. histaminase (neutralizes histamine), eosinophil peroxidase, lysosomal enzymes, and major basic protein (neutralizes heparin and kills parasites) - 145How do eosinophils counteract basophils?Chemotactically attracted to basophils/mast cells via eosinophilic chemotactic factor
Release eosinophil-derived inhibitor (inhibits basophil/mast cell degranulation)
Major basic protein destroys parasites and Ag-Ab complexes - 146MonocytesLargest WBCs
2-10% of WBCs, 16-20 micron diameter
Abundant lavendar cytoplasm and kidney bean-shaped nucleus
Present in bloodstream 2-3 days, then enter tissue and become macrophages where lifespan is several months (remains in same tissue)
Highly mobile and phagocytic (contains hydrolytic enzymes)
Active in subacute to chronic infections
Also function as antigen presenting cells in lymphoid organs - 147What are epithelioid giant cells?Fused macrophages in chronic granulomas
- 148LymphocyteMost common type of agranulocyte WBC (20-45%)
Active in subacute to chronic infections
Lifespan of days to years
Round, densely staining nucleus surrounded by thin rim of cytoplasm
Primary cell of immune system
2 Types: b-cells and t-cells (90% t) - 149B-cellsType of lymphocyte that is formed and matured in bone marrow
Functions in humorally-mediated immune response and produces antibodies (as plasma cells)
Can also function as antigen-presenting cells (have HLA Type II surface markers and surface immunoglobulins) - 150What is clonal expansion?AKA amplification
After b-cells encounter an antigen, they undergo multiple divisions to produce clones of antibody-producing plasma cells - 151T-cellsType of lymphocyte formed in bone marrow but matured in the thymus
Have paratopes (receptors on cell surface that recognize foreign proteins of antigens, called epitopes)
Also have CD molecules on surface that recognize HLA receptors on surface of other cells to prevent self-destruction - 152Types of T-cellsCytotoxic: AKA killer; primary effectors in cell-mediated immunity; recognize cells with foreign surface antigens/receptors and kill them by punching holes in plasma membranes
Suppressor: suppress activity of b-cells, dampen immune response (especially to self molecules; loss of control of these in autoimmune diseases
Helper: detect invaders by recognizing antigens (usually presented by macrophage or b-cells) then secrete lymphokines that stimulate antibody production and/or arrival of killer T cells - 153What are Null cells?Lymphocytes that possess Fc receptors but lack specific cell surface markers of either b or t-cells
Includes natural killer cells and possibly some pleuripotential stem cells
Responsible for nonspecific cytotoxicity against virus-infected and tumor cells (also in antibody-dependent cell-mediated cytotoxicity) - 154What does an increase in WBC count tell you?Infection/tumor
Neutrophils: acute, bacteria
Lymphocytes/monocytes: subacute, viral
Eosinophils: allergies, parasites - 155What does a decrease in WBC count tell you?Immune suppression/tumor
- 156What is the function of connective tissue?Provides structural/metabolic support for tissues and organs; carries blood vessels; tissue repair; nutrient/metabolite/waste exchange between tissue and circulation
- 157What is connective tissue derived from?Mesodermal mesenchyme
- 158WStellate to spindle-shaped cells, jelly-like extracellular matrix, and occasional fibers
Cells and extracellular material (determines physical properties of tissue) secreted by cells - 159FibroblastsPointed, elongate, spindle-shaped cells in connective tissue
Synthesize and maintain proteinaceous ground substance and connective tissue fibers (collagen, elastin, and reticular fibers) - 160What are myofibroblasts?Fibroblasts with contractile ability
- 161Reticular cellsType of fibroblast found in lymph nodes and bone marrow
Morphologically similar to primitive mesenchymal cells (look like branched fibroblasts)
Synthesize reticular fibers made of reticulin
May have phagocytic function - 162AdipocytesConnective tissue cells responsible for storage and metabolism of lipids
Generally large, balloon-shaped, clear spaces filled with "lipid" - 163What is ground substance?AKA extracellular organic matrix
Amorphous material made of long unbranched polysaccharide chains of repeating disaccharide units (one of these is always an amino sugar)
Various fibers embedded within (e.g. collagen, reticulin, and elastin) - 164CollagenPrincipal type of fiber in extracellular matrix
67-68 nm banding pattern
Provides tensile strength - 165Types of collagenType I: 90% of collagen in body; loose & dense connective tissue of skin, tendons, ligaments, bone, and fibrocartilage; supports blood vessels; MOST important protein in the body
Type II: i.e. hyaline and elastic
Type III: AKA reticulin; thin, branching, net-like fibers for structural support in organs; produced by reticular cells in lymph nodes and bone marrow and by fibroblasts elsewhere; argyrophilic (stains black with silver stain)
Type IV: found in basement membrane
Type V: cornea
Type VII: dermoepidermal junctions - 166What is Ehlers-Danlos syndrome?Collagenopathy characterized by hyperextension of joints, skin fragility, and poor wound healing
- 167How is collagen made?1. Precursor proteins produced by fibroblasts
2. Initially synthesized as procollagen, composed of three alpha polypeptide chains, form triple helix
3. Packed into secretory vesicles and secreted into the extracellular space
4. Extracellular enzymatic modification to form tropocollagen monomers
5. Polymerization of tropocollagen into larger bundles results in final formation of collagen microfibrils
6. Several microfibrils combine to form larger collagen fiber, then several fibers make up the collagen bundle - 168Elastic fibersHighly branched refractile fibers synthesized by fibroblasts as tropoelastin precursor that polymerizes in ECM to form elastin
Composed of elastin (protein core similar to collagen) and fibrillin (structural glycoprotein microfibrils) - 169What is Marfan's syndrome?Autosomal dominant condition resulting in abnormal elastic fibers
Characterized by tall stature, long limbs, and long thin fingers
Enlarged aorta with increased regurgitation and risk of developing a dissecting aneurysm - 170Structural glycoproteinsIncludes fibrillin and fibronectin
Large polypeptides with branched polysaccharide side-chains
Fibronectin found in BM; aids in adhesion b/w cell membrane and ECM via interaction of adhesion molecules (INTEGRINS) - 171What is laminin?Non-filamentous sulfated glycoprotein
Major component of basement membrane
Produced by most epithelial and endothelial cells - 172What is entactin?Non-filamentous sulfated glycoprotein
Binds with laminin - 173What is tenascin?Non-filamentous glycoprotein
Binds cells to extracellular matrix
Thought to be important in cell migration in developing nervous system - 174What are GAGs?Glycosaminoglycans
Disaccharide sugar usually covalently bound to proteins to form proteoglycans
Most are sulfated!
Negatively charged due to sulfate and carboxyl side groups (=> hydrophilic)
Incompressibility of water provides the turgor pressure of connective tissue
Reinforced with fibrous proteins - 175Types of GAGsHyaluronic acid: found in most connective tissue; predominant GAG in loose CT; longer than most GAGs; not bound to proteins; destroyed by hyaluronidase from bacteria
Chondroitin sulfate: found in cartilage and bone
Keratan sulfate: found in cartilage, bone, cornea, and intervertebral disk
Dermatan sulfate: found in dermis of skin, blood vessels, and heart valves
Heparan sulfate: found in BM, lungs, and liver - 176Loose connective tissueSparse fibers and abundant ground substance, so has a viscous gel-like consistency
Has supportive function
Located beneath epithelia and around nerves and vessels - 177Dense connective tissueProvides structural support with abundant fibers, moderate # of cells, and lesser ground substance
Regular: collagen fibers oriented parallel to each other and densely packed
Irregular: collagen fibers oriented randomly with moderate number of fibers and few cells - 178Adipose tissueWhite fat: AKA unilocular; distributed in dermis and around intraperitoneal organs; 20% of weight in males (25% in females)
Brown fat: AKA multilocular; highly specialized; present in infants and hibernating animals; many smaller vacuoles to store triglycerides; used in thermoregulation; lots of mitochondria; located in adrenals - 179What characterizes epithelial cells?Production of keratin intermediate filaments
Different epithelia produce different keratin - 180Histogenesis of epitheliaEctoderm --> epidermis, cornea, enamel, anterior pituitary, inner ear
Neuroectoderm --> neural tube (posterior pituitary), neural crest (ganglia, nerves, glial, adrenal medulla)
Mesoderm --> kidneys, mesothelium, endothelium, adrenal cortex
Endoderm --> respiratory epithelium, alimentary epithelium, liver, pancreas, thyroid, bladder, parathyroid, thymus - 181Types of epitheliumMucosa: lines cavities that connect with outside; contains ectoderm, BM, lamina propria, and sometimes smooth muscle
Serosa: lines closed body cavities; lacks smooth muscle layer
Endothelium: lines blood and lymph vessels (varies depending on which) - 182Components of basement membraneGAGs (heparan sulfate), type IV collagen, & structural glycoproteins (laminin, fibronectin, and entactin)
On EM, lamina densa (electron dense layer) and two electron-lucent layers (lamina lucida and lamina reticularis) - 183Types of cell junctionsOccluding: AKA tight junctions; located immediately beneath luminal surface of simple columnar epithelia; act as gaskets
Adhering: AKA anchoring junctions; bind cells together and act as anchoring points for cytoskeleton
Communicating: AKA gap junctions; focal adherent zones located on lateral border of cell; permit passage of small molecules between adjacent cells and allow transport of info and metabolites - 184What is the zonula occludens?Type of occluding junction
Portions of opposing cell membranes fuse together, forming continuous circumferential band around cell - 185What is a fascia occludens?Type of tight junction
Present between endothelial cells in wall of blood vessels
Discontinuous to allow for WBC movement - 186What is zonula adherens?Type of adhering junction
Continuous band characterized by transmembrane glycoproteins called cadherins (class of cell adhesion molecules) - 187What is macula adherens?AKA desmosomes
Small circular patches located on lateral surface of cell
Most common type of cell junction
Assoc. with attachment plaques containing attachment proteins (desmoplakins, desmogleins, and tonofilaments) - 188What are hemidesmosomes?Type of adhering junction
Found on basal surface of cell to anchor it to BM via integrins
Assoc. with high mechanical abrasion/shearing forces (e.g. skin) - 189What is the terminal bar?AKA junctional complex
Specialized, circumferential, intercellular connection
Hybrid between adhering and occluding junctions (forms diffusion barrier between cells
Consists of zonula occludens, zonula adherens, and macula adherens - 190What are connexons?Channels formed by ring of 6 integral proteins (connexins) surrounding 2 nm diameter pores
Part of communicating junctions - 191MicrovilliFinger-like cytoplasmic projections that contain actin filaments
Increase surface area for absorption or secretion
Supported by terminal web (network of actin at base) - 192StereociliaLong microvilli found in epididymis and inner ear
Non-motile
Contains actin filaments
Appear to function in fluid reabsorption - 193CiliaLong, motile cytoplasmic extensions
Possess axoneme (9+2 arrang. of microtubules with dynein arms)
Each arises from individual basal body developed from centrioles
Beat in synchronous metachronal rhythm - 194What happens if cilia microtubules lack dynein arms?Kartagener's syndrome: non-functional flagella on sperm
Dextrocardia (situs inversus): inverted location of organs
Hydrocephalus: cilia on ependymal cells can't circulate CSF - 195What type of gland is the parotid?SEROUS
- 196What type of gland is the palatal gland?MUCOUS
- 197What type of glands are the sublingual and submandibular?SEROMUCOUS
- 198Endocrine vs. exocrine glandsEndocrine: lack ducts; secrete products directly into bloodstream
Exocrine: secrete product onto epithelial surface via ducts; contain myoepithelial cells that lie between secretory cells and BM to assist in secretion; have Goblet cells that secrete mucus - 199What phase are all neurons in?Go
All are terminally differentiated and DO NOT divide - 200What are the three categories of supporting cells? Where are they found?Neuroglia in CNS
Schwann cells in PNS
Satellite cells in ganglia
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- DDS Histology - DDS (Exam 1) FlashCards sobre Exam 1 (part 1), criado por Brianne Schmiegelow em 19-09-2017.
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- Brianne Schmiegelow
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