Flashcards
HDTD part 1
Cards in this deck (200)
- 1What is the result of using H&E stain on general tissue?Nuclei-purple/blue
basophilic cytoplasm and cartilage- purple
cytoplasm and collagen- pink
RBS's and eosinophil granules- bright red - 2What does the H&E stain contain?Haematoxylin: basic dye- stains blue
Eosin: acidic dye- stains pink - 3What is the result of using PAS (periodic acid Schiff) stain on tissue?Nuclei- blue
Mucus, GAG's and glycogen- magenta
RBC may be yellow.
Oxidises sugars and stains resulting in aldehydes being bright pink/purple - 4Name the three different types of cell proliferation.1. Continuously renewing
2. Conditionally renewing
3. Static/Non-Proliferative - 5What are some examples of continuously renewing cells?Epidermis of skin, intestinal epithelium, blood forming tissues.
- 6What are some examples of continuously renewing cells?Liver, kidneys and endocrine glands
- 7What are some examples of static/non-proliferative cells?Cardiac and nerve cells.
- 8What are the phases of the cell cycle?
- 9Define Karyokinesis.Nuclear division
- 10Define Cytokinesis.cell division
- 11Define interphase.The summation of all non-mitotic processes. The resting phase between successive mitotic divisions of a cell, or between the first and second divisions of meiosis.
- 12What stages of the cell cycle are classes as interphase?G1, S and G2.
- 13What does the S phase of the cell cycle represent?The replication of DNA, RNA, and protein
- 14What does the G1 phase of the cell cycle represent?cell maturation after being created and the cell life cycle starting
- 15What does the G2 phase of the cell cycle represent?Final preparation of the mature cell to undergo mitosis
- 16What does the M phase of the cell cycle represent?The process of cell replication and the distribution of the replicated DNA
- 17Define ChromatinThe material of which the chromosomes of organisms other than bacteria (i.e. eukaryotes) are composed, consisting of protein, RNA, and DNA
- 18In Interphase nuclei, what to forms does chromatin appear in?Heterochromatin and euchromatin
- 19What properties does Heterochromatin have?More condensed and densely staining. Tends to be found near a nuclear envelope. doesn't transcribe.
- 20What properties does euchromatin have?Less condensed and lightly staining. More central location. It is normally transcribed.
- 21What steps occur in prophase?1. Chromatin condenses and chromosomes become visible as paired chromatids
2. centrioles duplicate and move apart to form two poles.
3. Microtubules form spindle fibres - 22What steps occur in prometaphase?1. nucleoli regress and nuclear membrane disassembles.
2. chromosomes move toward the equator and interact with the microtubules.
3. each pair of sister chromatids attaches to kinetochore. - 23Define Kinetochoreanother term for centromere.
- 24What steps occur in metaphase?1. Central region of cell forms a metaphase plate
2. chromosomes arrange themselves on the plate as two sister chromatids joined together by the centromere.
3. Spindle fibres run from pole (centriole) to chromosome - 25What steps occur in Anaphase?1. Sister chromatids of each pair move apart to opposite poles of the cell.
2. These chromosomes are thought to be pulled by the microtubules - 26What steps occur in telophase?1. Chromosomes reach the centromeres and start to become less condensed.
2. Nuclear membrane reassembles.
3. The cleavage furrow begins around the equator.
4. spindles disappear and nucleoli appear. - 27What steps occur in cytokinesis?Eventually a slim bridge of cytoplasm is left. This breaks and marks the start of two new naughtier cells.
- 28Define Totipotent.Can give rise to all cell types in an adult organism, plus extraembryonic cells, e.g zygote.
- 29Define pluripotent.Can give rise to all three germ layers, but not extraembryonic cells.
- 30define multipotent.Can give rise to a restricted number of cells of different types.
- 31What is chromatin?A complex formed by chromosomal DNA&RNA, coupled with proteins in eukaryotic cells.
- 32What are the two different types of protein in chromatin?Basic (mainly histones) and Acidic
- 33How are chromosomes packed?They are packed into bead like structures called nucleosomes.
- 34What is the structure of a nucleosome?Two loops of DNA double-helix wrapped around a cluster of 8 histones
- 35How are chromosomes formed?Supercoiling and condensation of chromatin.
- 36What is a gene?Specialised function sites arranged along chromosomes.
- 37Define metacentric chromosome.Arms roughly equal and centromere across centre
- 38Define acrocentric chromosome.Arms unequal and centromere far away from the centre.
- 39How many sex chromosomes are expressed in females?Only one X chromosome is expressed in females, therefore one X is switched off
- 40Define lyonization.The process by which one x chromosome is switched off at random and made inactive.
- 41Define Facultative heterochromatisation.When the inactive gene can be switched back on.
- 42How does the female cat explain Facultative heterochromatisation?It is orange and black. One x chromosome carries the gene for black fur and the other for orange fur, yet the cat is multi-coloured. different genes inactivated at different places of the cats body.
- 43What is Kleinfelter's Syndrome?XXY- male with feminine features.
- 44What is Trisomy 21/Down's Syndrome?Extra 21st chromosome. causes heart defects, characteristic facial features and developmental features.
- 45What is Williams Syndrome?Deletion of 26 genes on chromosome 7, leading to mental impairment, heart problems etc.
- 46What is Aneuploidy?Abnormal number of chromosomes
- 47What are the different types of structural abnormalities in chromosomes?Inversion
deletion
duplication
translocation
rings
isochromosome - 48What is inversion? (chromosomal structural abnormality)Section of chromosome has broken off, inverted and reattached, resulting in genetic material being inverted.
- 49What are the different types of inversion? (chromosomal structural abnormality)Pericentric inversion: centromere included in inversion therefore break in each arm.
Paracentric inversion: Centromere not included, both breaks occur in one arm. - 50What is Deletion? (chromosomal structural abnormality)Section of a chromosome id deleted.
- 51What is translocation? (chromosomal structural abnormality)A section of chromosome transferred to another chromosome.
- 52What are the different types of translocation? (chromosomal structural abnormality)Reciprocal translocation: One arm swaps genetic material with another arm
Robertsonian translocation: An entire chromosome arm attached to another at the centromere. Can result in a loss of genetic material. - 53What are Rings? (chromosomal structural abnormality)End of chromosome breaks resulting in fusion of free ends. resulting structure can be stable but can also cause loss of genetic material.
- 54What are isochromosomes? (chromosomal structural abnormality)chromosome has a median centromere and two identical arms, the chromosomes therefore do not divide normally to form two daughter cells, as each isochromosome only has genetic material from one arm therefore genetic material will be absent
- 55Define Meiosis.Process of cell division for reducing the somatic quantity of DNA (2c) to that found in sex cells of gametes (1c)
- 56Define Spermatogenesis.Production of gametes in the testicles.
- 57Define Oogenesis.Production of gametes in the ovaries
- 58Why is meiosis needed to form gametes?Since DNA is duplicated in S phase, we start with 4c and not 2c therefore two reduction divisions are needed, meiosis I (4c-2c) & meiosis II (2c-1c).
- 59What are the stages of meiosis I?1. Prophase I
2. Metaphase I
3. Anaphase I
4. Telophase I - 60What are the 5 sub stages of prophase I?1. Leptotene
2. Zygotene
3. Phachytene
crossing over
4. Diplotene
5. Diakinesis - 61What happens during Leptotene?Chromatin condenses to form chromosomes (not yet split in to sister chromatids) with chromosomes visible along length
- 62What happens during Zygotene?Homologous chromosomes pair to form bivalents. Chromosomes now split into sister chromatids and local sites of alignment (synapsis) develop between sister chromatids.
- 63What happens during Pachytene?Synapsis complete, crossing over (chiasma formation) occurs. Very important point for genetic variation as genetic information is exchanged- more likely to happen between long stretches of chromatid arms than short ones.
- 64What happens during Diplotene?Chromatids held together by chiamasta as well as by centromeres.
- 65What happens during Diakinesis?Chiamasta move towards the end of the chromatids (terminalisation) and disappear.
- 66Define Chiasma.A point at which paired chromosomes remain in contact during the first metaphase of meiosis, and at which crossing over and exchange of genetic material occur between the strands
- 67Define bivalent.A pair of homologous chromosomes.
- 68What happens during Metaphase I?Each bivalent has to centromeres and these arrange themselves by chance on opposite side of this metaphase plate. This independent assortment of chromosomes results in genetic variation.
- 69What happens during Anaphase I?Chromosomes move to opposite poles giving a mixture of maternal and paternal chromosomes, also resulting in generic variation.
- 70What happens during Telophase IEach daughter cell has half the diploid number of chromosomes- nuclear envelope may reassemble.
- 71What occurs during Meiosis II?Morphologically similar to mitosis.
Centromeres split at kinetochores and move to opposite poles.
4 gametes formed at the end of divisions. - 72What factors contribute to genetic variation in meiosis?1. crossing over
2. independent assortment of maternal and paternal chromosomes in gamete.
3. random fusion of gametes. - 73What are the four basic tissues of the body?1. muscle tissue
2. nerve tissue
3. epithelia
4. connective tissue - 74How does epithelia receive nutrition?Diffusion
- 75What are the different shapes of epithelial cells?1.Squamus- flat, fried egg appearance
2. Cuboidal- looks like a cube
3. Columnar- cell taller than it is wide - 76Define stratified epithelia.Epithelia with layers upon the basement membrane.
- 77Define pseudostratified epithelia.cells which appear to be arranged in layers but all of which are in fact attached to the basement membrane, and so have nuclei at different levels
- 78Define cuboidal cells.Cuboidal epithelia are epithelial cells having a cube-like shape; that is, their width is approximately equal to their height. They may exist in single layers (simple cuboidal epithelium) or multiple layers (stratified cuboidal epithelium) depending on their location (and thus function) in the body
- 79Define squamous cell.Squamous cells are thin, flat cells that look like fish scales, and are found in the tissue that forms the surface of the skin, the lining of the hollow organs of the body, and the lining of the respiratory and digestive tracts
- 80What are the three morphological features epithelia are classified by?1. Whether its a single layer or several.
2. The shape of the cell.
3. Any specialisations that occur. - 81Define Ciliated cell.Something that's ciliated is covered in microscopic projections that look like tiny hairs. Ciliated cells use a sweeping motion to remove toxins from your lungs.
- 82Where are simple cuboidal epithelial cells found in the body?Found in many glands (e.g. sweat and thyroid glands
- 83Where are simple columnar epithelial cells found in the body?Found in the gall bladder, surface of the stomach, uterus and oviduct.
- 84Where are stratified columnar epithelial cells found?Found in the ducts of mammary glands and larger ducts of salivary glands.
- 85Where are stratified cuboidal epithelial cells found?Found in a few ducts of the sweat gland.
- 86Define transitional epithelium.Transitional epithelium is a type of tissue consisting of multiple layers of epithelial cells which can contract and expand. It is so named because of this function in the transition of degree of distension
- 87Where in the body are transitional epithelium found?They are found in the urinary tract, pelvis of the kidney, ureter, bladder ad part of the urethra.
- 88Define pseudostratified ciliated columnar epithelium.
- 89Where in the body are pseudostratified ciliated columnar epithelium found?They are found in the respiratory passages as far as the bronchioles. Also in the male reproductive tract from the efferent ducts to the vas deferens.
- 90What are the specialisations of simple epithelia?1. Cilia (oviduct)
2. Microvilli- Striate border (small intestine)
3. Microvilli- Brush border (proximal kidney tubules) - 91What is the function of simple epithelia?Absorption e.g. kidney and gut.
- 92What is the function of stratified epithelia?Protection e.g. Skin and lining of the oesophagus.
- 93What are some of the other functions of epithelia?Secretion of mucus, sensory perception, movement of materials, e.g. cilia, wound repair.
- 94What is the function of Microvilli?Apical plasma membrane, increase in surface area, core of microfilaments, anchored in terminal web.
- 95What is the function of cilia?Apical membrane, very numerous, transport material across surface, microtubules.
- 96What is the function of stereocilia?Non-motile, filament core, modified microvilli. (only really found in male testes with sperm processing. also found in parts of the ear)
- 97What is the function of basal in-foldings?It increases surface areas.
- 98GLANDSGLANDS
- 99What are glands derived from?Epithelia?
- 100What are the two different types of glands?Endocrine and exocrine.
- 101What is the function of Exocrine glands?They secrete out of the body via ducts.
- 102What is the function of endocrine glands?These glands do not have ducts but secrete directly into the body, into the blood capillaries.
- 103How are glands formed? (diagram)
- 104How are exocrine glands formed? (written)1. Cells from surface epithelium grow down into the underlying tissue. It is called the epithelial cord/tubule.
2. connecting cells persist to become a duct and the deepest cells become secretory. - 105How are endocrine glands formed?1. Cells from surface epithelium grow down into the underlying tissue. It is called the epithelial cord/tubule.
2. The connecting cells disappear and the deepest cells remain to secrete into capillaries. - 106What do serous glands secrete?Watery fluid.
- 107What do mucus glands secrete?The produce a more viscous fluid containing mucin
- 108What do mixed glands secrete?Produce a mixture of both serous and mucous fluids.
- 109What is the manner in which eccrine glands secrete?The glandular cell body is not injured or destroyed during secretion. there is a cycle of discharge, formation, discharge reformation etc.
- 110What is the manner in which holocrine glands secrete?Glands in which there's a build up of secretion within the cell cytoplasm. The cells die and are discharged along with the secretion contained within them. i.e. the cell has to die for the secretion to occur.
- 111What is the manner in which apocrine glands secrete?The secretion is gathered in the outer apical end of the secretory cell. The accumulated section is then pinched off alongside a small amount of cytoplasm, but most of the cell remains unaffected, after a refractory period the process can be repeated.
- 112How do endocrine glands store the products they make.They can store their products by intracellular storage in the form of intra-cellular cytoplasmic storage granules, or by extracellular storage within an intercellular follicle surrounded by secretory cells.
- 113CHROMOSOME STRUCTURECHROMOSOME STRUCTURE.
- 114Define Barr Body.A small, densely staining structure in the cell nuclei of females, consisting of a condensed, inactive X chromosome. It is regarded as diagnostic of genetic femaleness.
- 115Define aneuploidy.An abnormal amount of chromosomes
- 116What are the two main types of translocation?1. Reciprocal translocation
2. Robertsonian translocation - 117Define reciprocal translocation.When the sections of two different chromosomes have been exchanged.
- 118Define Robertsonian translocation.When the entire chromosome arm is switched and attached at the centromere. In humans it can only occur in chromosomes 13, 14, 15, 21, 22.
- 119Define Sister chromatid.A sister chromatid refers to either of the two identical copies (chromatids) formed by the replication of a single chromosome, with both copies joined together by a common centromere. In other words, a sister chromatid may also be said as 'one-half' of the duplicated chromosome.
- 120What do sister chromatids look like?
- 121CONNECTIVE TISSUESCONNECTIVE TISSUE
- 122Define connective tissue.Binds organs in place while allowing changes in size and shape and provides framework for other tissues, especially highly cellular tissues as epithelia.
- 123What is the function of the extracellular matrix.It fills the spaces between cell groups and capillaries and is the route by which exchange of soluble molecules takes place.
- 124What does connective tissue consist of?Connective tissue, in addition to cells, also consists of fibres and ground substance (known as extracellular matrix)
- 125What are the characteristics of connective tissue?1. Cells often separated by connective tissue.
2. Contain blood vessels and nerves.
3. Cells may communicate.
4. cells often have a slow turnover - 126Define Fibroblast.A cell in the connective tissue that produces collagen and other fibres.
- 127What mind of cells are there in the connective tissue?1.Fibroblasts.
2. Adipocytes
3. Defence cells - 128Define Adipocytes.Adipose cell: storage of fat. also acts as a mechanical cushion in places like the sole of your foot.
- 129Look at the bottom of page 74. highlighted bitLook at the bottom of page 74. highlighted bit
- 130Define Basement membrane.A thin, delicate membrane of protein fibres and mucopolysaccharides separating an epithelium from underlying tissue.
- 131Define mucopolysaccharide.Another name for glycosaminoglycan (GAG's). Any of a group of compounds occurring chiefly as components of connective tissue. They are complex polysaccharides containing amino groups.
- 132Define collagen.the main structural protein found in connective tissue. It is secreted as tropocollagen. There are at least 11 different types. Type I found in skin, tendons, ligaments and bone. Type II found in hyaline cartilage.
- 133Define elastin.An elastic, fibrous glycoprotein found in connective tissue. Tropoelastin polymerises into elastin.
- 134Look over diseases of connective tissue on pg 76.Look over diseases of connective tissue on pg 76
- 135CARTILAGECATILAGE
- 136Define Hyaline Cartilage.A translucent bluish-white type of cartilage present in the joints, the respiratory tract, and the immature skeleton.
- 137Define Cartilagefirm, flexible connective tissue found in various forms in various parts of the body, e.g. the joints. they are able to withstand compression forces.
- 138Components of cartilageExtracellular matrix:
ground substance- GAG's and large proteoglycans complexed with collagen fibres.
fibres- type II collagen, type 11 and type I collagen
Cells- chondrocytes and chondroblasts. - 139Define extracellular matrix.In biology, the extracellular matrix (ECM) is a collection of extracellular molecules secreted by cells that provides structural and biochemical support to the surrounding cells.
- 140Define Chondrocytes.A cell which has secreted the matrix of cartilage and become embedded in it.
- 141Define chondroblasts.Chondroblasts, or perichondrial cells, is the name given to mesenchymal progenitor cells in situ which, from endochondral ossification, will form chondrocytes in the growing cartilage matrix.
- 142Why don't there tend to be blood vessels in cartilage.Due to its dense structure. Therefore Relies on Diffusion via extracellular fluid.
- 143what are the different ways in which cartilage grows?It grows by both interstitial and appositional growth.
- 144Define Appositional growth.Growth accomplished by the addition of new layers to those previously formed; for example, the addition of lamellae in the formation of bone.
- 145Define interstitial growth.Growth from a number of different centres within an area.
- 146What are the different types of cartilage?Hyaline: most common, articular surfaces, tracheal rings etc.
Fibrocartilage: Intervertebral discs, pubic symphysis.
Elastic cartilage: External ear, auditory canal, epiglottis etc. - 147BONEBONE
- 148Define Ground substance.The ground substance is an amorphous gel-like substance surrounding the cells. In a tissue, cells are surrounded and supported by an extracellular matrix.
- 149What are the different components of bone.Ground substance: GAG's and minerals Ca++ and PO4 (2-)
Fibres: Type I Collagen
Cells: Osteoprogenitor cells (stem cells), Osteoblasts- Produce and maintain matrix, Osteocytes -Maintains matrix, Osteoclasts- Removes matrix. - 150Describe the growth and maintenance of bone.Mineralized matrix impermeable to water and small molecules. Needs intimate blood supply- Key to structural organisation. Grows by appositional growth only.
- 151Define intramembranous ossification.The process by which cartilage is transformed into bone.
- 152Describe the 1st part of the process of intramembranous ossification.It begins when groups of mesenchymal cells in embryonic connective tissue differentiate into osteoblasts and begin to lay down osteoid, the term for bone matrix before its mineralized. ossification traps the cells within the matrix and they become osteocytes.
- 153Describe the 2nd part of the process of intramembranous ossification.Spicules of the bone form 3D network around invading blood vessels producing typical spongy bone, some of which is later replaced with compact bone. The earliest bone is laid down as woven bone (primary bone) and later replaced by lamellar (secondary bone)
- 154What are the stages of ossification of long bones?pg92.
- 155What factors affect bone growth?Mechanical forces: shape of bone indicates function. Cells must be able to respond to mechanical stress.
Nutrition: Deficiencies- Vitamin D- reduced calcification. Vitamin C- collagen disrupted. Vitamin A- Endochondral growth reduced - 156What other factors affect bone growth?Hormones: Growth hormone- growth plate increases.
adrenal androgens- prepubertal growth spurt.
Gonadal steroids- closure of epiphyses
Thyroxine- essential for osteogenesis
Parathormone- Ca From bone to plasma
Oestrogen- maintains bone density - 157What are some diseases of the bone.1. Osteoporosis.
2. Osteomalacia
3. Paget's disease
4. Osteogenesis imperfecta
5. gout
6. scoliosis.
7. Rheumatoid arthritis. - 158Outline what Osteoporosis is.Loss of bone mass.
Reduced ability to weight bare- wheelchair bound.
Reduced oestrogen-menopause.
Reduced gravity- Astronauts. - 159Outline what Osteomalacia is.Bone softening.
Vit D deficiency- poor calcification.
Rickets in Children- permanent deformity. - 160Outline what Paget's disease is.Paget's disease disrupts the normal cycle of bone renewal and repair, causing bones to become weakened and deformed. The control of reabsorbtion and formation is uncoupled.
It is a mosaic of over and under production. The bone is woven and therefore weak. - 161Outline what osteogenesis imperfecta is.Brittle bones.
Genetic defect in type I collagen.
Poor mineralisation. - 162NERVOUS TISSUENERVOUS TISSUE
- 163Define astrocyte.Cover all the surfaces of the neuron that are not occupied by synapses or myelin. They are master supporters of the CNS. Their 'feet' touch neurons, other glial cells and capillaries. They also form the seal on the CNS surface.
- 164Define oligodendrocyte.They make myelin. each oligodendrocyte can make 40-50 myelin sheaths around different axons. They are the most abundant glial cells in the CNS
- 165Define Glial cell.… Glial Cells: Defined and MajorIntermediates between … - Götz - Cited by 231
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The glial cells surround neurons and provide support for and insulation between them. Glial cells are the most abundant cell types in the central nervous system. Types of glial cells include oligodendrocytes, astrocytes, ependymal cells, Schwann cells, microglia, and satellite cells. - 166Why are some neurones myelinated?myelinated nerves have salutatory axonal conduction, which is much faster (more than 100x) than unmyelinated axons.
- 167How are myelin Sheaths formed?Myelin sheaths are insulators. They are formed by tightly spiralled very thin layers of oligodendrocytes, or Schwann cells in the PNS
- 168Define Microglia.Microglia cells are the principle arm of the immune system in the CNS. If they detect an infectious agent they will attract other defence cells with soluble attracting factors (cytokines). They can phagocytose and act as local antigen presenting cells.
- 169Describe the cellular makeup of the CNS.It is tightly packed with cellular projections, glial cells, and neurones. There is virtually no intracellular space on an electron micrograph. no basement membranes. Glial cells outnumber the neurones by about 10-1.
- 170Define nodes of Ranvier.a gap in the myelin sheath of a nerve, between adjacent Schwann cells
- 171Define Nissl Body.A Nissl body, also known as Nissl substance, is a large granular body found in neurons. These granules are of rough endoplasmic reticulum (RER) with rosettes of free ribosomes, and are the site of protein synthesis.
- 172Describe what makes up the CNS.Brain and spinal cord. Surrounded by cerebrospinal fluid.
- 173Describe what makes up the PNS.Peripheral nerves and ganglia. Surrounded by interstitial tissueand interstitial fluid.
- 174Define Ganglia.A structure containing a number of nerve cell bodies, typically linked by synapses, and often forming a swelling on a nerve fibre.
- 175Describe the location of afferent and efferent nerve fibres in the PNS and CNS.Efferent fibres have their perikarya (cell bodies) in the CNS and their axons in the PNS. Afferent neurons have their cell bodies and dendrites in the PNS and most of their axons in the CNS
- 176Define pseudounipolar neurone.Dendrite and axon as uninterrupted strand for maximal speed of transduction. Perikaryon moved to side
- 177Define monosynaptic reflex.When the reflex arc only contains one synapse.
- 178Define dorsal root ganglion.A dorsal root ganglion is a cluster of nerve cell bodies in a posterior root of a spinal nerve. The dorsal root ganglia contain the cell bodies of sensory neurons (afferent).
- 179Define somatic peripheral nervous system.The somatic nervous system (SoNS or voluntary nervous system) is the part of the peripheral nervous system associated with skeletal muscle voluntary control of body movements. The SoNS consists of afferent nerves and efferent nerves.
- 180SKELETAL, CARDICAC AND SMOOTH MUSCLE.SKELETAL, CARDIAC AND SMOOTH MUSCLE.
- 181Define endomysium.Results
The endomysium, meaning within the muscle, is a wispy layer of areolar connective tissue that ensheaths each individual myocyte (muscle fiber, or muscle cell). It also contains capillaries and nerves. It overlies the muscle fiber's cell membrane: the sarcolemma. - 182Define Perimysium.Mixed connective tissue, surrounding a bundle of muscle fibres.
- 183Define Epimysium.A sheath of fibrous elastic tissue surrounding a muscle.
- 184Define Sarcomere.is the basic unit of striated muscle tissue. Skeletal muscles are composed of tubular muscle cells (myocytes called muscle fibers) which are formed in a process known as myogenesis. Muscle fibers are composed of tubular myofibrils.
- 185Outline the structure of a sarcomere.
- 186What motion do heart muscles undertake when going about contraction?When the cardiac ventricles contract, they go about a wringing motion. The is a result of the spiral, fibre like arrangement of the heart muscle cells.
- 187What is the structure of cardiac cells.On closer inspection, it is revealed that cardiac muscle cells are single cells (myocytes), not syncytia, and therefore are much smaller than skeletal muscle fibres, but they show cross striations.
- 188Compare the structure of, skeletal, cardiac and smooth muscle.Skeletal muscle = striated, voluntary, shaped like long fibers, multinucleated. Smooth muscle = nonstriated, involuntary, shaped like almonds (tapered ends), one nucleus per cell. Cardiac muscle = striated, involuntary, branched, shaped like fibers cross-linked to one another, typically one nucleus per cell.
- 189Define intercalated discs,Intercalated discs are microscopic identifying features of cardiac muscle. Cardiac muscle consists of individual heart muscle cells (cardiomyocytes) connected by intercalated discs to work as a single functional organ or syncytium.
- 190What makes intercalated discs function?Crucial features of the intercalated discs are desmosomes which allow longitudinal force transfer due to their strong adherence, and low resistance gap junctions, which allow transfer of membrane depolarisations, i.e. the action potentials.
Skeletal muscle fibres do not have gap junctions. - 191BLOODBLOOD
- 192Define haematocrit.It is the packed red cell volume. The ratio of the volume of the red blood cells to the total volume of the blood.
- 193Define serum.Plasma without any coagulation factors.
- 194What is a granulocyte?a white blood cell with secretory granules in its cytoplasm
- 195What are some examples of white blood cells?Neutrophils, eosinophils and basophils.
- 196Describe neutrophils.49-67% of white blood cells. Nucleus is in several lobes
- 197Describe eosinophils.1.5-5% of white blood cells. The nucleus is normally bi-lobed. Dominant, same sized granules
- 198Describe basophils.0.01-0.3% of white blood cells. Nucleus bi-orti-lobed. Dominant purple granules.
- 199Define agranulocyte.Also known as mononuclear leukocytes, are white blood cells with a one-lobed nucleus. They are characterized by the absence of granules in their cytoplasm, which distinguishes them from granulocytes.
- 200What are some examples of agranulocytes?Lymphocytes and monocytes.
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- Year 1 Medicine (HDTD) Flashcards on HDTD part 1 , created by Dan Aduakwa on 22/07/2016.
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