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Med P1 > SUGAR > Flashcards

SUGAR Flashcards

1
Q

at what day does the developing embryo switch from using maternal RNA to using its own genetic code

A

day 5

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2
Q

what is the major thing that happens on cleavage, day 2

A

splitting of the ooplasm (cytoplasm). if one of the pronuclei failed to condense, it can results in mosaicism

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3
Q

what stage happens at day 4 of embryonic development in utero and what is its 2 key steps

A

compaction. flattening of cells and formation of tight junctions between cells

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4
Q

what happens in cavitation, day 5

A

tight junctions form between the outermost layer of cells, the trophectoderm.

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5
Q

at which of the 7 stages can the embryo be classed as a blastocyst and why

A

cavitation. it is formed of more than 80 cells

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6
Q

what happens at day 5/6 and give a key step in it

A

expansion. pumping of fluid into the blastocyst to cause the zona pellucida to become thinner

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7
Q

what are the 2 factors that cause hatching at day 6

A

enzymatic factors and expansion by the pumping of fluid in

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8
Q

what are the 3 stages of implantation

A

apposition, adhesion invasion

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9
Q

at which stage of implantation do receptor ligand integrations occur and what are the receptors called, and what are they on

A

adhesion, integrins, on the trophectoderm cells

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10
Q

what substance is produced as part of the decidual reaction, by the endometrial stromal cells, that prevents rejection of the embryo by maternal cells

A

interleukin 2

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11
Q

what are the 2 cell layers below the trophectoderm?

A

epiblast (directly under) and hypoblast

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12
Q

what does hCG stand for, where is it produced and what does it support

A

human chorionic gonadotropin, placenta, corpus luteum

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13
Q

where along the nephron is bulk phosphate reabsorption and is it active or passive

A

proximal, 80%, active using a sodium symporter

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14
Q

what 2 hormones increase serum calcium

A

1,25 (OH)2VD and PTH

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15
Q

where is PTH produced, be specific

A

in the parathyroid gland’s chief cells, these have receptors for calcium

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16
Q

where is calcitonin produced, be specific

A

C cells (parafollicular cells) of the thyroid gland

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17
Q

what 3 factors activate 1 alpha hydroxylase to produce more of the active vitamin d hormone

A

decreased active VD hormone, decreased FGF23, increased PTH

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18
Q

what are the 2 main effects of calcium homeostasis done by active Vitamin D

A

increased absorption by active transport in the gut (so jejnum and duodenum) and increased resorption of bone

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19
Q

what shape graph best describes the relationship between plasma calcium levels and PTH secretion

A

sigmoid

20
Q

what are the 3 types of calcium in the blood

A

ionised, complexed and protein-bound

21
Q

give 3 reasons why extracellular calcium must be kept at a constant level

A

nerve function, muscle function and normal blood clotting

22
Q

what is the main way by which phosphate levels can be altered in the blood

A

by the reabsorption in the kidneys

23
Q

what substance is a local regulator of FGF23 release

A

PHEX

24
Q

give 3 result of low vitamin D chemically

A

low serum calcium, low serum phosphate , low FGF23

25
Q

what do kinases do

A

add phosphate to a substance, so phosphorylation

26
Q

what do phosphatases do

A

remove phosphate from substances, so dephosphorlylation

27
Q

if PTH decreases reabsorption of phosphate by the proximal tubule, what is the fractional secretion of phosphate increased to?

A

20% from 10%

28
Q

does increased phosphate increase or decrease PTH production

A

increases it

29
Q

what cells do osteoblasts originate from and what other important cell also shares this origin

A

mesenchymal stem cells. monocytes

30
Q

what cells do osteoclasts originate from

A

haemopoietic stem cells. so are a differentiated form of macrophages

31
Q

what are the 4 paracrine/autocrine mediators of osteoclast differentiation and activity

A

prostaglandins, interleukin 1 and 6 and tumour necrosis factor (TNF)

32
Q

what substance binds to RANK-ligand, to stop it activating osteoclast precursors

A

osteoprotegrin (OPG)

33
Q

what are the 3 types of bone disease associated with rheumatoid arthritis

A

generalised osteoporosis, periarticular osteopenia (adjacent to inflammed joints) and focal bone loss

34
Q

closure of what means that bone growth can no longer take plate

A

the epiphyseal plate

35
Q

what are the 5 stages of bone remodelling in order?

A

quinesence, resorption, reversal, formation, mineralisation

36
Q

what 2 things are resultant from osteoclasts and osteoblasts communicating with eachother

A

balance and coupling (bone formation occurring at sites of previous resorption)

37
Q

what is the area in the middle of a long bone called, another word for shaft

A

diaphysis

38
Q

define modelling of bone

A

this is the changing of the gross shape of a bone, either by adding bone on to the existing or resorbing bone

39
Q

give the 5 types of bones as classified by shape

A

flat, long, short, sesamoid, irregular

40
Q

as well as being a scaffold, give 2 important functions of the ECM

A

to act as a basement membrane for the attachment of cells and so stop apoptosis. to have receptors (like collagen receptors and integrins) to allow self-surface signalling and cascades of reactions within the cell

41
Q

what is the name given to the tropocollagen before proteinases cleave its ends

A

procollagen

42
Q

give 3 structure that type 1 collagen is found in

A

tendons, bone and skin

43
Q

what type of collagen is in the basemnt membrane of cells

A

IV

44
Q

what 2 things are released by osteoclasts and what does each break down?

A
  1. protons (dissolves the bone mineral) 2. Cathepsin K (breaks down the collagen, so the matrix)
45
Q

give the 7 stages of endochondral ossification

A
  1. cartilage proliferator 2. collar formation 3. invagination of osteogenic bud 4. formation of the primary centre 5. establishment of the secondary centre 6. lengthening via growth plates 7. closure of the growth plates
46
Q

what is the name given to the pits that the osteoclasts reside in?

A

Howship’s lacunae

47
Q

what 2 ways can primary bone develop from

A
  1. mesenchyme (membrane bone) 2. cartilage proformer (endochondral bone)

Med P1 (15 decks)

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