PARATHYROIDS

By Afra Nehal and Nida Madni

LOCATION

Parathyroid glands are 4 small glands of the

endocrine system which are embedded in posterior

surface of the thyroid gland.

HORMONES THAT ARE PRODUCED

The parathyroid glands release a hormone called parathyroid hormone (PTH). This hormone controls the levels of: calcium, phosphorus and magnesium. Parathyroid hormone has a number of effects in the body.

AFFECTS OF HORMONES ON BODY

It causes the release of calcium from bones.

It causes calcium to be absorbed (taken up into the

blood) from the intestine.

It stops the kidneys from excreting (getting rid of)

calcium in the urine.

It causes the kidneys to excrete phosphate in the urine.

It increases blood levels of magnesium.

HOMEOSTASIS

PTH has many effects on the bones and the kidneys.

 It stimulates osteoblasts to pump Ca++ ions out of the fluid. Over a

longer time course, PTH stimulates bone reabsorption

Stimulates [Ca++] on the kidney. First, it decreases the loss of Ca+

+ ions in the urine by stimulating Ca++ reabsorption. "Reabsorption"

means the transfer of substances from the forming urine back into

the ECF. Reabsorption, which is performed by the cells of the kidney

tubules, allows the recovery of those useful small molecules such as

sugars, amino acids, and Ca++ ions. As well as stimulating Ca+

+ reabsorption, PTH also inhibits phosphate reabsorption in the

kidney.

EXAMPLES OF HORMONES

FEEDBACK MECHANISMS AND ANTAGONISTIC HORMONES

A negative feedback system involving 2

antagonistic hormones, calcitonin and parathyroid

hormone (PTH), play the major roles in calcium

(Ca2+) in order to maintain homeostasis in

mammals. 

RELEASING HORMONES AND GLANDS

Hormone Released: Parathyroid hormone (PTH)

Hormone Structure: Peptide

Hormone Function: Increases blood calcium

concentrations by stimulating calcium release from bone,

promoting calcium uptake from intestinal tract and

decreasing calcium excretion by the kidney; Decreases

blood phosphate level 

Hormone Regulator: Calcium concentrations in blood

IMPROPER FUNCTION

Hyperparathyroidism occurs when the parathyroid

hormone is produced by an overactive parathyroid

gland. This is called hyperparathyroidism.

 Hyperparathyroidism occurs when one or four

parathyroid glands grows into a tumor and behaves

inappropriately by making excess parathyroid hormone

which harms the body. Too much calcium in the

bloodstream causes damage to the nervous system, and

cause higher risk of cancer.

TREATMENTS

There are no pills nor drugs to cure this disease.

The only way to solve/remove hyperparathyroidism is

by having surgery.

The average operative time to remove the diseased

parathyroid gland using this technique is about 25

minutes

PARATHYROID VIDEO

http://www.youtube.com

/watch?v=sD9st1ZPFrQ

#t=302

SOURCES

http://courses.washington.edu

www.parathyroid.com

http://classes.biology.ucsd.edu

http://faculty.clintoncc.suny.edu