parathyroid gland

Question 1

eclampsia
puerperal tetany
milk fever

Answer 1

life-threatening drop in blood levels of calcium that strikes some nursing dogs, cats and cows

Question 2

hypocalcemia tetany is due to

Answer 2

Increase in excitability of nerve and muscle cells due decrease calcium
spastic skeletal muscle contraction

Question 3

calcium decrease causes what channels to be unblocked?

Answer 3

NA channels
NA increases and depolarization threshold is more atteinable causing activation of neurons
neurons are unstable and fire spontaneous action potentials that trigger the involuntary contraction of muscle leading to tetany

Question 4

what hormone does the parathyroid gland secretes?

Answer 4

parathyroid hormone (PTH)

Question 5

major hormone to raise blood calcium level

Answer 5

parathyroid hormone (PTH)

Question 6

calcium is needed for

Answer 6

blood coagulation
secretion
cell function
neural transmission
muscle contraction

Question 7

Three hormones regulate blood calcium level

Answer 7

parathyroid hormone (PTH)
active vitamin D3
calcitonin

Question 8

PTH is produced and secreted by what cells is the parathyroid gland?

Answer 8

chief cells

Question 9

in chief cells PTH is first synthesized as

Answer 9

Pre-proPTH

Question 10

chief cells become active in response to

Answer 10

decreased calcium levels

Question 11

mechanism of activation of chief cels

Answer 11

chief cells detect low blood calcium levels and in response increase secretion of PTH

Question 12

t/f PTH raises blood Ca2+ levels without promoting the deposition of calcium phosphate crystals in bone

Answer 12

true

Question 13

PTH is increased by two causes

Answer 13

decreased Calcium or increased calcium phosphate crystals in BLOOD

Question 14

3 mechanism of action of PTH

Answer 14

1. stimulates activity of osteoclasts to promote reabsorption to release calcium
2. stimulates kidneys to reabsorb calcium from renal filtrate while inhibiting the reabsorption of PO43
3. stimulates kidney to convert D3 to it’s active form raising blood calcium levels indirectly
   promoting : Ca2+ and PO43- absorption in small intestine and reabsorption in kidney

Question 15

synthesis of active vitamin D3 =1,25(OH)2D3= calcitriol

Answer 15

1. vitamin D3 is produced in the skin under influence of sunlight
2. converted to active form in liver and kidney

Question 16

PTH stimulates the activity of what enzyme in the kidneys to help converting vit. D3 to calcitriol?

Answer 16

hydroxylation enzyme

Question 17

what promotes calcitriol?

Answer 17

Ca2+ and PO43- absorption in small intestine and reabsorption in kidney

Question 18

t/f The effect of simultaneously raising the blood concentrations of Ca2+ and PO43- results in the increased tendency of these two ions to precipitated as hydroxyapatite crystals in bone

Answer 18

true

Question 19

mechanism of PTH activation of osteoclast for reabsorption and release of calcium

Answer 19

1. PTH has receptors on osteoblasts, but NOT in osteoclasts.
2. PTH stimulate osteoblasts to produce RANKL (Receptor-Activator of Nuclear Factor κB Ligand).
3. Binding of RANKL to RANK on preosteoclast promote its differentiation into mature osteoclast, thereby causes bone resorption.

Question 20

t/f PTH has receptors on osteoblasts, but NOT in osteoclasts.

Answer 20

true

Question 21

PTHrP parathyroid hormone related protein functions

Answer 21

acts on PTH receptor to mimic the role PTH
increases bone resorption, stimulating the renal reabsorption of Ca2+
promotes renal excretion of PO43+ causes hypercalcemia

Question 22

t/f PTHrP is also secreted by many types of cancers

Answer 22

true

Question 23

t/f PTHrP causes hypocalcemia

Answer 23

false
cause HYPERCALCEMIA

Question 24

in Malignancy-Related Hypercalcemia (Pseudo-hyperparathyroidism) how are the levels of PTH and PTHrP?

Answer 24

PTH normal or low
PTHrP high

Question 25

2 types of hyperparathyroidism

Answer 25

primary and secondary

Question 26

occurs within parathyroid glands in Parathyroid tumor or cancer Hypercalcemia =elevated level of blood Ca2+ causes kidney stones

Answer 26

Primary hyperparathyroidism

Question 27

occurs outside parathyroid glands, through hypocalcemic Ca2+ negative feedback in Rickets /Osteomalacia Vitamin D3 deficiency Chronic renal or celiac disease Lack of dietary calcium Hypocalcemia =decreased level of blood Ca2+)

Answer 27

secondary hyperparathyroidism

Question 28

Lack of dietary calcium can cause

Answer 28

secondary hyperparathyroidism

Question 29

weakening of the bones due to excessive resorption of bones

Answer 29

osteoporosis

Question 30

In hypothyroidism how are the levels of PTH?

Answer 30

LOW = low levels of calcium

Question 31

What can cause hypoparathyroidism?

Answer 31

Accidental injury to or removal of parathyroid glands in thyroidectomy surgery Cancer radiation treatments Autoimmune reactions

Question 32

In pseudo-hypoparathyroidism, how are going to be the levels of PTH?

Answer 32

normal or high

Question 33

clinical signs of hypoparathyroidism

Answer 33

Muscle aches or cramps Muscle spasms, especially around the mouth Tingling, burning, or numbness in the fingertips, toes, and lips. Seizures Osteoporosis

Question 34

calcitonis is produced by ________in response to _________

Answer 34

parafollicular cells increased blood calcium

Question 35

calcitonin is the contraregulatory hormone of

Answer 35

PTH

Question 36

Inhibits osteoclastic activity = inhibits bone resorption Inhibits Ca2+ absorption in the intestines Inhibits of Ca2+ reabsorption in the kidneys

Answer 36

calcitonin

Question 37

what is the hypothesis for the use of calcitonin?

Answer 37

useful during Calcium stress protecting bone growth pregnancy inihibiting postpandrial hypercalcimia

Question 38

inhibits postpandrial hypercalcimia

Answer 38

calcitonin

Question 39

t/f salmon can be used to treat hypercalcimia

Answer 39

true

Question 40

disease induced by excessive bone remodeling, caused by osteoclastic activity

Answer 40

Paget's disease

Question 41

decrease in extracellular Ca2+ concentrations or an increase in phosphate (PO43-) concentrations leads to

Answer 41

PTH secretion from the parathyroid glands

Question 42

increases renal reabsorption of Ca2+ renal activation of vitamin D3 urinary PO43- excretion bone resorption

Answer 42

PTH

Question 43

increases intestinal absorption and renal reabsorption of Ca2+ and PO43-

Answer 43

active vitamin D3

Question 44

An increase in Ca2+ concentration stimulates the thyroid gland to secrete _____ to inhibit ____

Answer 44

calcitonin to inhibit osteoclastic bone resorption