Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physiology > 4.7 Endocrine mineral homeostasis > Flashcards

4.7 Endocrine mineral homeostasis Flashcards

1
Q

what are the 3 hormones that control mineral homeostasis aka regulate calcium?

A

1) vitamin D
2) parathyroid hormone (PTH)
3) calcitonin (follicular cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

main places we regulate Ca?

A

1) gut = absorb in1st palce
2) kidney = reabsorb
3) bone = take Ca+ out of storage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what does calcitonin do?

A

lowers blood Ca levels and inhibits bone resorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

1) Vitamin D is synthesized where?
2) what type of hormone?
3) main role is located in?

A

1) synthesized in skin via UV light (or can ingest
2) steroid hormone (from cholesterol)
3) main role is in gut

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is active form of Vitamin D?

A

cholesterol + UV light + OH + OH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

exaplin vit D synthesis?

A
  • *7-dehyrocholesterol + UV light = Vit D3 aka cholecalciferol)
    1) 1st hydroxylation occurs in liver
  • *Vit D3 + OH= 25-hydroxyvitamin D3
    2) 2nd hydroxylation occurs in kidney
  • *25-hydroxyvitamin D3 + OH = 1,25-dihydroxyvitamin D3
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is active form of Vit D?

A

1,25-dihydroxyvitamin D3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

vit D synthesis must have TWO _______ events (one in liver, one inkidney)

A

hydroxylation events

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

enzymes used in 2nd hydroxilation are stimulated by?

A

PTH (parathyroid hormone)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

primary effect of vit D?

A

directly increase intestinal absorption of Ca

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

secondary effect on Vit D?

A

indirect effects on bone resoprtion (and possibly kidney reabsorption) of Ca via PTH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how does low Ca affect Vit D regulation?

A
  1. decrease plasma Ca++ =
  2. increase PTH =
  3. stimulation of kidney enzyme =
  4. final hydroxylation of Vit D
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Calcium in intestine?

A

1) increase Ca binding protein to keep free Ca low
2) increase active transport of Ca out of mucosal cell via vit D-dependent Ca pump
* *increase intestinal absorption of Ca

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Calcium in bone?

A

increase action of PTH = increase bone resorption

*may also directly cause bone resorption by itself

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Calcium in kidney?

A

increase action of PTH = increase Ca reabsorption and decrease in P reabsorption
*may have direct actions on kidney that cause Ca++ reabsorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

PTH and Vit D relationship???

A

PTH helps activatre Vit D

*so Vit D helps PTH by increasing the action of PTH on bone for resorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what all does Vit D help reabsrop?

A

Ca and phosphate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what type of hormone in PTH?

located?

A

parathyroid hormone is a protein

*CHEIF cells of parathyroids are imbedded intyroid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

why can’t the parathyroid be removed?

A

need at least ONE to regulate blood Ca! otherwise you die

20
Q

what is the MOST important hormone for raising blood Ca levels?

A

PTH

21
Q

PTH directly and indirectl raises blood ca how?

A
  • directly thru bone and kidney action

* indirect action on intestine via Vit D synthesis

22
Q

PTH regulates cell activites of?

A

osteoclasts, osteocytes, kidney tubule cells

23
Q

PTH stimulates enzyme in kidney that performs?

A

final hydroxylation of Vit D (intestinal absorption of Ca)

24
Q

how is PTH regulated?

A

feedback inhibition of Ca++ on parathyroids =negative feedback

25
Q

calcitonin is what type of hormone? secreted from what cell?

A

peptide hormone from parafollicular cells (aka C cells) of thyroid

26
Q

why is calcitonin NOT considered a thyroid hormone like T3 or T4?

A

it is coming from C cells that is found BETWEEN the functional follicles of thyroid; but still coming from thyroid

27
Q

primary effects of calcitonin?

***

A

Keep blood Ca levels low

  • inhibition of osteoclastic and osteocytic bone resorption
  • stimulationf of osteoblastic and osteocytic bone formation
28
Q

secondary effects of calcitonin?

A

decrease Ca and PO$ reabsorptionin kidney

29
Q

what INHIBITS secretion of calcitonin?

A

low levels of Ca+

30
Q

remember peptide hormones?

A

have cell membrane receptors

*acts via cAMP

31
Q

describe hypervitaminosis D

A

too much vit D

*increases action of PTH which increased resorption of bone

32
Q

vit D deficiency aka hypovitaminosis D names fro child and adutls?

A 
rickets= child
osteomalacia= adult
33
Q

describe rickets and osteomalacia?

A

vit D deficiency aka hypovitaminosis D

*decreases bone mineratlzation

34
Q

BOTH hypo and hypervitaminosis D causes soft, flexable bones why?

A

1) a lot of Vit D helps PTH take stuff out of bones = soft

2) not enough Vit D means we never had enought to mineralize bone to start with = soft bones

35
Q

secondary effects of rickets and osteomalacia? only occurs during?

A

dentinal and enamel HYPOPLASIA (only IF deficiency occurs DURING tooth development)

36
Q

PTH hyperparathyroidism primary effect?

A

secreting excess PTH (which main role is to resorb bone)

***osteitis fibrosa cystica= replacementof bone with fibrous tissue

37
Q

osteitis fibrosa cystica

A

= replacementof bone with fibrous tissue

**means one has bone demineralized by excess PTH and replaced with fibrous tissue

38
Q

PTH hyperparathyroidism secondary effect?

A

1) neuromuscular depression
- –due to excess plasma Ca+
2) cardiac spasm
- –due to excess plasma Ca+
3) metastatic calcification
- –due to excess Ca pyrophosphate, can;t keep ahead of it!

39
Q

metastatic calcification

A

due to excess Ca pyrophosphate, can;t keep ahead of it! because of PTH hyperparathyroidism secondary effect
**START to see mineralization of tissue that we don’t want!

40
Q

hypoparathyroidism primary effect?

A

decrease osteoclastic and osteocytic bone resorption

*due to tumor or removal of thyroif with malfunctioning parathyroid

41
Q

hypoparathyroidism secondary effect?

A

1) dentinal and enamel hypoplasia (if during tooth development)
2) hypocalcemia -low Ca in blood (and hyperphosphatemia)
3) hypocalcemis tetany = spasms starting in extremities

42
Q

what all causes hypocalcemic tetany??

A

1) hypoparathyroidism

2) low plasma Ca

43
Q

renal failure is associated iwth high or low Ca levels?

A

high

44
Q

what are otherfactors essentual for growth and maintenance?

A

1) thyroxine (growth)
2) growth hormone (growth)
3) estrogen (keeps Ca+ and PO4 in bone)
4) Vat A (for normal osteoclasts to remodel)
5) Vit C (for normal collagen)

45
Q

why do menopausal women have trouble with osteoporosis?

A

they have low levels of estrogen

46
Q

What all causes bone resorption when in EXCESS and HOW?

A

1) vit D, thyroxine, and Vit A all increase osteoclast activity
2) cortisol decreases osteoBlast activity
3) prostaglandins sometimes cause formation and sometimes resorption BUT if too high, cause more resorption

47
Q

what does fluoride do?

A

stabilizes bone minerals (make hydroxyapetie more stable)

*&may stimulate ostoblastic activity

Physiology (42 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions