BL correction fc Flashcards
what is the role of ATP in the sliding filament theory of contraction?
ATP binding causes the release of the myosin head from the actin
ATP hydrolysis that causes the resetting of the myosin head to the original position, making this the correct answer.
Which type of muscle contains calmodulin in the place of troponin in its light chain?
smooth muscle only
what is present in the M line of the sarcomere?
only myosin
which area of the sarcomere decreases in size during contraction?
The I band is the portion of the sarcomere with only actin present. Since myosin causes the darker colour, when the muscle contracts and the overlap increases, the A band (darker) stays the same length, and the I band shrinks. The H zone (not H band) is the area of the A band with only myosin present, but this is not obvious as the actin does not contribute much to a colour change. The Z line (not Z band) is the centre of the I band.
what is the primary glycosaminoglycan (GAG) in collagen?
hyaluronic acid
What is oogenesis?
differentiation of the ovum into a cell competent to further develop when fertilized. It is developed from the primary oocyte by maturation
How many pairs of Somites and associated spinal nerve remain at the end of segmentation?
31
how is bone marrow distributed in bones?
long bones = in the medullary region, but during ageing the yellow marrow replaces red marrow in epiphyses packed between trabeculae
corticol bone = no bone marrow, just has osteocytes trapped within lamellae and trabeculae of bone
how is bone marrow distributed in bones?
long bones = in the medullary region, but during ageing the yellow marrow replaces red marrow in epiphyses packed between trabeculae
corticol bone = no bone marrow, just has osteocytes trapped within lamellae and trabeculae of bone
through which vasculature do cells leave the bone marrow?
intracellular gaps in sinusoidal vessels
how long does it take RBC to fully develop in circulation?
1-2 days
what are the different layers of the arteries and veins?
outer layer = tunica adventitia
external elastic lamina
tunica media
internal elastic lamina
inner layer = tunica intima
where are osteoprogenitor cells normally found in developing bone?
part of periosteum
which component of bone slows done / impedes distribution of nutrients and oxygen to osteocytes?
extrcellular matrix
What are the 3 parts of the mesoderm?
Paraxyl
Intermediate
Somatic and Splanchnic
What are the 2 cells that function as part of the mucocillary escalator?
Goblet and ciliated cells
Which ion allows for the attachment of epithelial cells to one another?
Calcium
What causes malignant hyperthermia?
Mutation in ryanodine receptors
In the neuromuscular junction where are vesicles containing acetylcholine stored?
Synaptic bouton
What is galactosemia?
due to deficiencies in enzyme galactose 1-phosphate uridyltransferase
results in accumulation of galactose in blood and galactosuria which causes kidney damage, cataracts, heptomegaly and cirrhosis
through which blood vessel does lymph drain into the bloodstream?
left subclavian vein
What contractory cells aid secretion from exocrine glands?
Myoepithelial cells
In which layer of the epidermis is keratin synthesised?
Occurs when lamellar bodies appear in differentiating keratinocytes
stratum spinosum
In which epidermis layer is keratohyalin granules occur?
Stratum granulosam
(These granules cause thickening of the skin)
Which sensory receptor detects vibrations?
Pacinian corpuscles
What histological changes occur in epidermis of patients with psoriasis?
Aconthosis = thickening of epidermis
what are the differences between the different muscle fibres in terms of the following:
1. capillary supply
2. myoglobin levels
3. num of mitochondria
4. num of chytochrome
5. colour
slow twitch type 1 VS fast twtich type 2A VS fast twitch type 2B
1. rich VS rich VS poor
2. high VS high VS low
3. lots VS lots to intermediate VS few
4. lots VS lots VS few
5. red VS red to pink VS white
what are the different causes of lymphodema?
Primary:
1. milroys disease
2. meige’s disease
3. tarda
Secondary:
1. neoplasia
1. surgery
1. radiotherapy
1. autoimmune
1. infection
milroys disease causes prmary lymphodema, what are its features?
- onset within 2 years
- causes mutate FLT4 gene
- small or missing endothelial cells in vessel wall
meige’s disease causes prmary lymphodema, what are its features?
- onset 2 - 35 years
- cause is unknown
tarda disease causes prmary lymphodema, what are its features?
- inset after 35 years
- cause is unkown
how does neoplasia causes secondary lymphoedma?
- pelvic masses
- neoplasia metastises + infiltrate lymph node
how does surgery causes secondary lymphoedma?
- node involvement
- accidental removal
how does radiotherapy causes secondary lymphoedma?
- nodal fibrosis = obstruction of blood vessel
how does autoimmune disease causes secondary lymphoedma?
- rheumatoid arthritis
- eczema
how does infection causes secondary lymphoedma?
- cellulitis - obstruction of vessels
- filariasis = parasititc worm that invades and survives in lymphatic vessels
what are the different types of salivary gland?
serous cells = dark in colour, mucosal cells = paler in colour
1. submandibular glands = produces both serous and mucous (so contains paler and darker cells)
2. sublingual glands = produces only mucous so much paler
3. parotid glands = produce only serous so much darker
what are the different types of salivary gland?
serous cells = dark in colour, mucosal cells = paler in colour
1. submandibular glands = produces both serous and mucous (so contains paler and darker cells)
2. sublingual glands = produces only mucous so much paler
3. parotid glands = produce only serous so much darker
what causes liver cirrhosis in chronic alcohol users?
2 hit system:
1. kupffer cells - activation of Toll-like and CD14 receptors on kupffer cells results in the internalisation of endotoxins, stimulates production of ROS and pro-inflammatory cytokines (e.g. TNF), kupffer cells undergo apoptosis
2. stellate cells - TNF causes stellate cells to synthesis collagen = liver fibrosis, fibrosis of liver progresses to cirrhosis
how do most glands develop?
in utero approx 5 weeks after fertilisation:
1. fibroblast growth factor is produced in mesenchymal cells
2. FGF stimulus is recieved by epithelal cells, causing them to proliferate downwards towards source of FGF
3. migrating epithelial cells produce extracellular protein degrading enxyme allowing them to move further down
4. next step depends on if gland is endocrine or exocrine:
* endocrine = epithelail cells in centre of downward growth undergo apoptosis, leaves a duct in middle of growth, cells at base of growth differentiate into secretory cells
* exocrine = cells which link migratory cells to original epithelium apoptose, leaving a group of cells sorrounded by extracellular matrix, these epithelial cells differentiate into secretory cells + induce the formation of capillaries around the gland
what is the role of the hepatic portal system?
supplies deoxygenated blood that is full of toxins and nutrients from the small intestine to the liver
the toxins are neutralised by hepatocytes and the nutrients are used by liver tissue
what is the bloos supply to the long bone in adults vs in children?
adults = epiphyseal + metaphyseal artery
children = just epiphyseal
what site do pathogens enter the spine?
vertebral body via haematogenous spread
what is the difference between fatty acid oxidation and synthesis?
synthesis:
cycle of reactions that adds C2
C2 atoms added as malonyl CoA
occurs in cytoplasm
reductive - reduces NADPH
oxidation:
cycle of reaction that removes C2
C2 atoms removed as acetyl-CoA
occurs in mitochondria
oxidative - produces NADH and FADH2
what is the developmenal period of human gestation between 3 - 8 weeks after fertilisation?
what is the developmenal period of human gestation between 9 - 38 weeks after fertilisation?
- embryonic period
- foetal period
