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The concentration of calcium in the blood of mammals is?

~10 mg/dL

Calcium in plasma or serum exists in three forms or fractions:

1) Protein-bound calcium

2) Ionized or free calcium

3) Complexed or chelated calcium

accounts for approximately one-third of the total serum calcium concentration.

Protein-bound calcium

Protein-bound calcium cannot diffuse through membranes and thus is not

usable by tissues.

is the physiologically active form that accounts for 50%–60% of total calcium concentration

Ionized or free calcium

s bound to phosphate, bicarbonate, sulfate, citrate, and lactate and accounts for ~10% of the total calcium concentration.

Complexed or chelated calcium

Three major hormone

(PTH, vitamin D, and calcitonin)

is an essential intracellular signaling molecule and also plays a variety of extracellular functions, thus the control of body _____________concentrations is vitally important.

Calcium

is secreted by the parathyroid glands. Its main action is to mobilize calcium from bone and increase urinary phosphate excretion.

Parathyroid hormone (PTH)

is a steroid hormone formed from vitamin D by successive hydroxylations in the liver and kidneys.

1,25-Dihydroxycholecalciferol

1,25-Dihydroxycholecalciferol primary action

increase calcium absorption from the intestine

a calcium-lowering hormone that in mammals is secreted primarily by cells in the thyroid gland, inhibits bone resorption.

Calcitonin

PTH is synthesized and stored in the?

chief cells of the parathyroid glands

The primary function of PTH is to control?

calcium concentratio

are four tiny glands, located in the neck, that control the body's calcium levels.

Parathyroid Glands

Each PTH gland is about the size of?

grain of rice (weighs approximately 30 milligrams and is 3-4 millimeters in diameter).

is a 32-amino acid polypeptide hormone secreted by the parafollicular cells (C-cells) of the thyroid gland in mammals and by ultimobranchial tissue in avian and other nonmammalian species.

Calcitonin

the rate of secretion of calcitonin is increased greatly by rapid discharge of stored hormone from C-cells into interfollicular capillaries.

Hypercalcemia

of C-cells occurs in response to longterm hypercalcemia.

Hyperplasia

Calcitonin exerts its effects by interacting with target cells, primarily in?

Bone and kidney

Another major hormone involved in the regulation of calcium metabolism and skeletal remodeling is?

Vitamin D

Vitamin D includes?

cholecalciferol (vitamin D3) of animal origin, as well as ergocalciferol (vitamin D2) of plant origin.

vitamin D can be formed in the skin from a?

cholesterol metabolite (7-dehydrocholesterol)

a complication of chronic renal failure is a metabolic state characterized by an excessive, but not autonomous, rate of PTH secretion.

Secondary hyperparathyroidism

is produced in excess of normal by a functional lesion in the parathyroid gland.

primary hyperparathyroidism PTH

is a metabolic disorder in which PTHlike polypeptides or other bone-resorbing substances are secreted in excessive amounts by malignant tumors of nonparathyroid origin.

Hypercalcemia of Malignancy (PSEUDOHYPERPARATHYROIDISM)

is a metabolic disorder in which either subnormal amounts of PTH are secreted by pathologic parathyroid glands or the hormone secreted is unable to interact normally with target cells.

Hypoparathyroidism

Considerably less is known about the pathogenesis of hypocalcemic syndromes in the dog and cat than is known about their development in the cow

Hypocalcemic Syndromes Associated with Parturition

Clinical syndromes associated with abnormalities in the secretion of CT are recognized much less frequently than disorders of PTH in both animals and humans

Hypercalcitoninism

Specific disease syndromes resulting from a lack of CT secretion have not been recognized in either humans or animals.

Hypocalcitoninism

The kidneys produce three important hormones namely:

• erythropoietin,

• calcitriol (1, 25- dihydroxycholecalciferol)

• renin

is a peptide hormone which regulates erythropoiesis.

Erythropoietin

Erythropoietin is produced by?

interstitial fibroblasts in the kidney

Erythropoietin, also known as?

haematopoietin or haemopoietin

is a glycoprotein cytokine secreted by the kidney in response to cellular hypoxia; it stimulates red blood cell production in the bone marrow

Erythropoietin

Erythropoietin is a glycoprotein containing how many amino acid?

165

In adults, approximately __% of erythropoietin is synthesized in the kidneys

90%

The main stimulus of erythropoietin is a?

decrease in the partial pressure of oxygen

is produced in the cells of the proximal tubule of the nephron in the kidneys by the action of 25-hydroxyvitamin D3 1-alpha-hydroxylase,

Calcitrio

Calcitriol is produced in?

Outside the kidneys

Calcitriol's lifespan in the body is measured in?

Hours

stimulates the small intestine for protein synthesis allowing absorption of calcium ions and phosphates.

Calcitriol

• Treatment of hypocalcaemia – hypoparathyroidism, osteomalacia (adults), rickets (infants,

children), renal osteodystrophy, chronic kidney disease

• Treatment of osteoporosis

• Prevention of corticosteroid-induced osteoporosis

Calcitriol

the kidney (and also, possibly, by the placenta) that is part of a physiological system that regulates blood pressure.

Renin

In the blood, renin acts on a protein known as?

angiotensinogen

is cleaved by angiotensin-converting enzyme, splitting off two amino acids from the 10-aminoacid chain of angiotensin I, to form angiotensin II

Angiotensin I

acts via receptors to constrict arterioles, causing a rise in both systolic and diastolic blood pressure.

angiotensin II octapeptide (previously called hypertensin, or angiotonin)