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22 spring: Physiology > Test 3: lecture 10 > Flashcards

Test 3: lecture 10 Flashcards

1
Q

functions of calcium

A

Contraction of muscles

Blood coagulation

Enzyme activity (as a second messenger)

Neural excitability

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2
Q

Hypocalcemia causes nervous system excitation and muscle____

A

tetany

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3
Q

Hypercalcemia ____ nervous system and muscle activity

A

depresses

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4
Q

___ provides the tensile strength to bones

A

Organic matrix of bone (30%)

  • Collagen fibers
  • Tensile strength
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5
Q

___ provides the compressional strength of bones

A

Crystalline salts of bone (70%)

  • Hydroxyapatite Ca10(PO4)6(OH)2
  • Compressional strength
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6
Q

what inhibits the formation of hydroxyapatite?

A

high levels of PPi (pyrophosphate)

formed by PC-1 (plasma cell membrane glycoprotein 1 )(non bone tissues)

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7
Q

how to form hydroxyapatite

A

PPi (TNAP) → hydroxyapatite

if bones don’t have TNAP they will form soft bones (uncalcified)

TNAP = tissue non-specific alkaline phosphatase (bone)

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8
Q

remodeling of bones is done by

A

osteoblasts- make new bone

osteoclasts- breakdown and resorb bone

GH stimulates osteoblasts

Fracture stimulates osteoblasts

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9
Q

New organic matrix (___) maintains the bone strength.

A

collagen fiber

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10
Q

regulation of calcium metabolism is by ___

A

Vitamin D

Parathyroid hormone (PTH)

Calcitonin (Thyroid C cells)

that target the: GI, kidneys and bone

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11
Q

how to form vit D

A

1-25 (OH)2D3 is the active form of Vit D made in the kidney

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12
Q

Cholecalciferol (D3) can be stored in the ___ for months

A

liver

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13
Q

effects of 1,25(OH)2D3

____ Ca2+ and PO43- intestinal absorption

Increase renal ____ absorption

Promote bone ____ (small quantities)

Increase bone ____ (extreme quantities)

A

increases

Ca2+ and PO43-

calcification

resorption

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14
Q

how does vit D work in intestine

A

stimulates the production of calcium binding proteins → promotes calcium absorption

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15
Q

types of cells in the parathyroid gland

A

chief cells → make PTH

oxyphil cells → increase amount with age (old chief cells?)

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16
Q

how to make PTH

A

peptide hormone

has a precursor (pre-proparathyroid hormone) with a signal peptide that is cleaved (pro-parathyroid), then another part is cleaved (parathyroid hormone)

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17
Q

rapid phase of PTH:

A

Rapid phase of absorption: PTH activates calcium pump to pump Ca2+ and PO43- into ECF.

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18
Q

slow phase of PTH

A

Slow phase of bone resorption by activation of osteoclasts.

19
Q

two stages of PTH

A

PTH increases Ca2+ and PO43- absorption from the bone

Rapid phase of absorption: PTH activates calcium pump to pump Ca2+ and PO43- into ECF.

Slow phase of bone resorption by activation of osteoclasts.

20
Q

rapid phase of PTH will effect ____ to release Calcium into the ECF

A

osteoblasts

21
Q

how are osteoclasts stimulated by PTH

A

indirect

PTH binds to osteoblasts, osteoblasts release unknown substance and stimulates osteoclasts to break down bone and release Ca and phosphate

(paracrine secretion)

22
Q

effect of PTH on bone vs kidney vs the GI

A

Increase Ca2+ and PO43- absorption from the bone

Decrease Ca2+ excretion and increase PO43- excretion by kidney

Increase intestinal Ca2+ and PO43- absorption via [1,25(OH)2D3]

23
Q

PTH will

___ Ca2+ and PO43- absorption from the bone

____ Ca2+ excretion and increase PO43- ____ by kidney

Increase intestinal Ca2+ and PO43-____via [1,25(OH)2D3]

A

Increase

Decrease. excretion

absorption

24
Q

high PTH causes ____ and ___

A

hypercalemia but hypophosphatemia

25
Q

____ activates Vit D into 1,25 (OH)2D3

A

1 alpha hydroxylase

stimulated by low serum Ca, and Pi, and high PTH

26
Q

____ inactivates Vit D in the kidney

A

24-hydoxylase

stimulated by high Ca diet, High serum Ca, serum Pi and high Calcitonin

27
Q

high calcitonin →

high PTH →

A

inactivates Vit D= too much calcium in blood → storage in bones

activates Vit D = caused by too low calcium in blood → break down of bones for Ca and Phosphate release

28
Q

C cells are found ___

A

in the thyroid gland

29
Q

C cells in the thyroid produce

A

calcitonin (peptide hormone

30
Q

calcitonin will cause the ___

A

decrease of plasma calcium concentrations

decreases osteoclasts (breakdown of bone)

decreases formation of new osteoclasts

31
Q

___ and ___ have opposite effects on Caclium

A

calcitonin

PTH

32
Q

increased serum calcium triggers ____

decrease serum calcium triggers ___

A

calcitonin

PTH

33
Q

Ultimobranchial glands of lower animals (fish, amphibians, reptiles, and birds) is similar to ___ in mammals

A

C cells → make calcitonin → decrease serum Calcium

34
Q

control of Calcium concentration is by the ___ function of exchangeable Ca in the bones and then by the ___ control of Ca concentration by ___

A

buffer

hormonal

PTH

35
Q

how is Vit D balanced in the blood

A

PTH increases serum Calcium

Calcitonin decreases serum Calcium

36
Q

Primary Hyperparathyroidism

A

Hypercalcemia- depresses nervous system and muscle activity (muscle weakness)

Hypophosphatemia

High PTH

Cause: Adenoma of Chief cell → abnormal PTH will increase serum Calcium too much

Symptoms

Bone absorption (bone cysts)

Soft tissue mineralization

Depression, muscle weakness (lethargy), vomiting, constipation

37
Q

symptoms of primary hyperparathyroidism

A

abnormal PTH → causes too much calcium in serum

Symptoms

Bone absorption (bone cysts)

Soft tissue mineralization- crystals can form in soft tissues from excess Ca

Depression, muscle weakness (lethargy), vomiting, constipation

38
Q

secondary hyperparathyroidism

A

Diagnosis: Hypocalcemia, High PTH, Hypertrophy of parathyroid glands

Caused by

Renal - chronic renal diseases

Nutritional -Vitamin D deficiency (Rickets), low Ca diet

39
Q

primary Hyperparathyroidism leads to ___

secondary Hyperparathyroidism leads to ____

A

high Ca, low P, high PTH → caused by tumor of chief cells

low Ca, High PTH, hypertrophy of parathyroid glands → caused by low Ca diet and chronic kidney issues (low Ca causes nervous system excitation and muscle tetany)

40
Q

vit D toxicosis causes ___

A

Hypercalcemia → depressed nervous system and muscle activity

Hyperphosphatemia

Parathyroid atrophy

Hyperplasisa of C cells

1,25(OH)2D3

41
Q

osteoporosis decreased ___ activities. Decreased ___ bone matrix

A

osteoblast

organic

42
Q

what are some protein/peptide hormones:

A

Hypothalamus: TRH, CRF, GHRH, GHIH, GnRH

Anterior pituitary: TSH, ACTH, GH, LH, FSH

Pancreas: insulin, glucagon, somatostatin

PTH, Calcitonin

43
Q

what are some steroid hormones

A

mineralocorticoid - aldosterone

glucocorticoids - cortisol

Androgens

Vitamin D

44
Q

what hormones are derivatives of tyrosine

A

thyroid hormones

epinephrine and norepinephrine

22 spring: Physiology (34 decks)

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