Thyroid Gland

-

The thyroid gland is a butterfly-shaped organ that is located at the front of the neck.

The thyroid gland produces three hormones:
  • Triiodothyronine, also known as T3
  • Tetraiodothyronine, also called thyroxine or T4
  • Calcitonin

Image result for thyroid gland


Here, the highlighted portion is the Thyroid Gland.





Hormonal output from the thyroid is regulated by Thyroid Stimulating Hormone (TSH) secreted from the Anterior Pituitary gland, which itself is regulated by Thyrotrophin-Releasing Hormone (TRH) produced by the hypothalamus.


The thyroid may be affected by several diseases. Hyperthyroidism occurs when the gland produces excessive amounts of thyroid hormones, the most common cause being Graves' disease, an autoimmune disorder. In contrast, hypothyroidism is a state of insufficient thyroid hormone production. Worldwide, the most common cause is iodine deficiency.




Comments

Post a Comment

Popular posts from this blog

Pituitary Gland

-
Image
Pituitary gland is also called as master gland... The pituitary is a pea-sized gland that is housed within a bony structure (sella turcica) at the base of the  brain . The sella turcica protects the pituitary but allows very little room for expansion. It has 3 parts:  1.Anterior lobe (Adenohypophysis)                         2.Intermediate lobe (Pars intermedia)                         3.Posterior lobe ( Neurohypophysis ) It secretes 11 hormones Hormone Target Organ or Tissue Adrenocorticotropic hormone (  ACTH ) Adrenal glands Beta-melanocyte–stimulating hormone Skin Endorphins Brain and immune system Enkephalins Brain Follicle-stimulating hormone Ovaries or testes Growth hormone Muscles and bones Luteinizing hormone Ovaries or testes Oxytocin * Uterus and mammary glands Prolactin Mammary glands Thyroid-stimulating hormone Thyroid
Read more

Parathyroid Gland

-
Image
Parathyroid glands  are small   endocrine   glands  in the neck of humans and other  tetrapods . Humans usually have four parathyroid glands, located on the back of the  thyroid gland  in variable locations.   The parathyroid gland produces and secretes  parathyroid hormone  in response to a low blood calcium, which plays a key role in regulating the amount of calcium in the blood and within the bones .  Parathyroid hormone (also known as parathormone) is a small   protein   that takes part in the control of calcium and phosphate   homeostasis , as well as bone physiology. Parathyroid hormone has effects antagonistic to those of   calcitonin . Calcium . PTH increases blood calcium levels by directly stimulating osteoblasts and thereby indirectly stimulating  osteoclasts  (through RANK/RANKL mechanism) to break down bone and release calcium. PTH increases gastrointestinal calcium absorption by activating  vitamin D , and promotes calcium conservation (reabsorption) by the  ki
Read more

Pancreas

-
Image
Pancreas is a heterocrine gland ( mixed gland) found in the folds of the duodenum. A portion of pancreas acts like an exocrine gland and another portion like an endocrine gland. The group of cells of endocrine pancreas is called islets of Langerhans. The cells of islet are of three types, with respect to kind of hormones they secrete. 1. Alpha cells :-     These cells secrete glucagon hormone which causes the breakdown of glycogen to release glucose in the blood. Thereby glucose becomes available to the tissues and organs of the body. 2. Beta cells :-      These cells secrete insulin hormone, which controls the formation of glycogen from glucose in the liver. If insulin is not secreted properly, blood glucose level will keep on rising and after a limit, the kidney will allow the glucose to go out in the urine. This happens in people suffering from diabetes mellitus, who are unable to secrete insufficient amounts of insulin. 3. Delta cells :-     These cells secrete soma
Read more