Question

1. Know the following about Vitamin D, PTH and calcitonin: what stimulates them? What are their target tissues? Where are their receptors located in the target tissues (intracellular vs on the plasma membrane)? How do they regulate each other (if any)? The cells that secrete them. The roles of the small intestine, kidneys and bone in Ca²⁺homeostasis. How Ca²⁺regulates them.

Answer 1

vitamin D: Vitamin D is a group of fat-dissolvable secosteroids in charge of expanding intestinal retention of calcium, magnesium, and phosphate, and various other natural impacts. In people, the most vital mixes in this gathering are vitamin D3 (otherwise called cholecalciferol) and vitamin D2 (ergocalciferol). Cholecalciferol and ergocalciferol can be ingested from the eating routine and from supplements. Just a couple of nourishments contain vitamin D. The significant characteristic wellspring of the vitamin is a union of cholecalciferol in the skin from cholesterol through a synthetic response that is subject to sun presentation.

Vitamin D is also known as a hormone engaged in mineral metabolism and bone development. Its most sensational impact is to encourage intestinal retention of calcium, in spite of the fact that it likewise empowers assimilation of phosphate and magnesium particles. In cell societies, vitamin D empowers separation of osteoclasts.

PTH: Parathyroid hormone (PTH), also known as called parathormone or parathyrin, is a hormone discharged by the parathyroid organs that is critical in bone redesigning, which is a progressing procedure in which bone tissue is on the other hand resorbed and remade after some time. PTH is emitted because of low blood serum calcium (Ca2+) levels. PTH in a roundabout way fortifies osteoclast action inside bone marrow.

stimulators of PTH:

decreased levels of serum [Ca2+].

Gentle declines in serum [Mg2+].

An expansion in serum phosphate (expanded phosphate makes it complex with serum calcium, framing calcium phosphate, which lessens incitement of Ca-touchy receptors (CaSr) that don't detect calcium phosphate, setting off an increment in PTH). and hormones like Adrenaline and Histamine can also stimulate the PTH.

Calcitonin :

Calcitonin is a hormone that is generally produced in humans by the parafollicular cells (normally known as C-cells) of the thyroid organ. Calcitonin is engaged with controlling levels of calcium and phosphate in the blood, contradicting the activity of parathyroid hormone.

stimulators of calcitonin:

calcitonin is usually stimulated by:

1. an increased levels in serum [Ca2+]

2. gastrin and pentagastrin.

Targeted tissues of vitamin D, PTH, and calcitonin:

The best-considered target tissues for the vitamin D metabolites are bone, kidney, and digestive tract. and it also targets muscle, endocrine pancreas, parathyroid organ, pituitary, and skin.

The significant target end organs for parathyroid hormone (PTH) activity are the kidneys, skeletal system, and intestine system.

calcitonin usually targets bone tissues.

The roles of the small intestine, kidneys, and bone in Ca2+homeostasis.

Vitamin D and parathyroid hormone (PTH) help direct how much calcium is assimilated and how much calcium the kidneys dispense with. Solid kidneys transform vitamin D into a functioning hormone (calcitriol), which helps increment calcium ingestion from the digestion tracts into the blood. Calcium release from bone is controlled by parathyroid hormone. Calcitriol controls the levels of calcium and phosphorus in the blood and keeps up a sound skeletal system. Bone resorption by osteoclasts discharges calcium into the circulation system, which controls calcium homeostasis.

the physiological effects on [Ca++]ECF. [Ca++]ECF is impacted by dietary admission, Ca++ retention in the small digestive system, and by the release of Ca++ in the pee.