Endocrine system contains two types of glands.
Exocrine glands : These glands convey their secretion to the place of their action.
Endocrine glands : These glands secrete hormones and send them into blood stream. Blood carries these hormones to the place of action. But pancreas and gonads are of mixed nature.
Hormones : These are the chemicals produced in endocrine glands. These control the activity of the body organs. Hormones are usually made up of proteins, amino acids, peptides, steroids etc. They coordinate activities of different organs and tissues.
Endocrine glands : Following are the endocrine glands.
1. Pituitary gland
2. Thyroid gland
3. Parathyroid gland
4. Adrenal gland
5. Pancreas
6. Gonads
7. Pineal Body
1. Pituitary Gland : This is the master gland of the body. This is a small gland that lies just interior to the hypothalamus. The anterior pituitary produce several hormones some of which control other endocrine glands. The posterior pituitary produces oxytocin and autidiuretic hormones.
The hormones which are produced by anterior pituitary are :
(a) Growth hormone (GH)
(b) Thyroid stimulating hormone (TSH)
(c) Aderno corticotropic hormone (ACTH)
(d) Follicle stimulating Hormone (FSH)
(e) Luteinizing Hormone (LH or ICSH)
(f) Prolactin hormone (PRL)
The secretion of anterior pituitary depends upon the age, external stimuli and feedback system of hormones.
The hormones produced by posterior pituitary are.
(a) Oxytocin hormone needed for the contraction of smooth muscles.
(b) Antidiuretic hormone (ADH). It regulates urination.
- Thyroid gland
This gland secretes thyroxin and tri-iodothyroxin. These two hormones regulate the metabolic rate, body growth etc. This is a large gland situated in the neck. - Parathyroid
This gland is embodied in the posterior surface of the thyroid gland. It produces the parathormones and calcitonin which increases the blood calcium level by increasing the bone calcium. This also reabsorbs calcium from the urine. - Adrenal Gland
A gland that lies at the top of the kidney. This gland produces the hormones epinephrine and norephine phrin. Epinephrine is also called Adrenalin. Adrenal medulla and sympathetic nervous systen together work in a co-ordinated way. - PANCREAS
This is an abdominal organ. This produces digestive enzymes and the insulin hormone. This also produces glucagon hormone. Alpha cells produce glucagon hormone. Beta cells produce insulin. This hormone controls the sugar level in the blood. - GONADS
This gland secretes testosterone. It stimulates growth. In overy it also secretes estrogen and progesterone hormones respectively. The former stimulates the female secondary sexual characterstics whereas the pregnancy changes are controlled by progestrone. - PINEAL BODY
A gland-either at the skin surface (fishefe) or in the third ventricle of the brain that produces melatonin. This hormone regulates the monthly cycle, reproductive cycle and related physiology.
Mucous Membrane of stomach and Duodenum : This membrane secretes gastrin, secretin, pancreozymin, enter-oknin and enterogestrin. These hormones are used by various organs of the body. Gastrin gland secretes the gastric juice. Secretin stimulates pancreas. Chlolecystokinin contracts gall bladder. Enterokinin stimulates intestinal mucosa. Enterogastrin regulates gastric secretion.
Endocrine gland system is very useful for the body health.
