module 4

Question 1

essential mineral component of the skeleton and plays a central role in maintaining the homeostasis of vertebrate animals.

Answer 1

calcium

Question 2

involved in a wide variety of physiological processes including muscular contraction, blood coagulation, enzyme activity, neural excitability, hormone secretion, and cell adhesion

Answer 2

ionized calcium

Question 3

synthesized and released by the chief cells of the parathyroid glands

Answer 3

parathyroid hormone

Question 4

secreted by the parafollicular or C-cells of the thyroid gland.

Answer 4

calcitonin

Question 5

the bioactive vitamin D metabolite derived from cholecalciferol (vitamin D3).

Answer 5

calcitriol

Question 6

active form of calcium

Answer 6

ionized form (ca²+)

Question 7

approximately 99% of calcium of the body that is present in the inorganic matrix of bone

Answer 7

hydroxyapatite

Question 8

reduce the concentration of Ca2+ in the serum

Answer 8

Calcitonin and stanniocalcin

Question 9

important regulators of total body calcium in terrestrial vertebrates

Answer 9

parathyroid glands and kidneys

Question 10

where Ca2+- bind to regulate cellular function, such as in parathyroid chief cells or renal epithelial cells.

Answer 10

G-protein-linked Ca2+-sensing receptor

Question 11

the concentration of ionized Ca2+ in the serum in most domestic animals

Answer 11

1.251.6 mmol/L (5.0 – 6.4 mg/dl)

Question 12

dependent on the pH of the serum and is principally bound to negatively- charged sites on albumin with smaller amounts bound to globulins

Answer 12

protein bound

Question 13

reabsorb approximately 40-fold more calcium than is absorbed by the intestinal tract due to the high degree of blood flow and ultrafiltration in the glomerulus

Answer 13

kidney

Question 14

carrier-mediated, vitamin D dependent process and occurs predominantly in the duodenal segment of the small intestine, and to a lesser degree in the cecum and colon.
- requires influx of calcium into intestinal epithelial cells via Ca2+ channels, movement and buffering in the cytoplasm, and basolateral exit by a Ca2+-ATPase.

Answer 14

saturable or transcellular transport

Question 15

responsible for sensing serum Ca2+ concentration and modifying parathyroid hormone secretion, calcitonin secretion, and calcium transport by renal epithelial cells

Answer 15

Ca2+ receptor

Question 16

the major intracellular anion existing in inorganic form

Answer 16

phosphate

Question 17

are the major regulators of the phosphate concentration in the serum

Answer 17

kidney

Question 18

range of Serum Pi in adult animals

Answer 18

2.5-6.0 mg/dl (0.8-1.9 mmol/L)

Question 19

most of the inorganic phosphate (80%) in the serum

Answer 19

Dibasic form (HPO4)

Question 20

the remaining 20%

Answer 20

Monobasic form (H2PO4)

Question 21

an unreliable indicator of body stores and may be higher in growing animals than in adults, especially the giant dog breeds, because growth hormone increases renal phosphate reabsorption

Answer 21

serum phosphate

Question 22

phosphate absorption takes place in ruminants

Answer 22

forestomach

Question 23

phosphate absorption takes place in monogastric animals

Answer 23

duodenum and jejunum

Question 24

phosphate absorption takes place in horses

Answer 24

large intestine

Question 25

enzyme in the rumen of ruminant species which release the phosphate from the sugar moiety

Answer 25

phytase