Glands are sac like tissue structures in the body which play a vital role in the body physiology and homeostasis. Glands are quite numerous and regulate different physiological functions and activities. The glands can be differentiated based on their locations, based on their type of secretions, based on the organ systems they control etc. These glands mostly perform their function through release of secretions and these secretion can be hormones, enzymes and sometimes just fluid yet all of them have some important functions.
Types of Glands in human body:
Based on the way of secretion: Glands are two types based on secretion as
1. Exocrine glands: They secrete into a location or region of the body through a duct and their secretions are called enzymes mostly while some are non enzymes.
Examples of glands and their secretions include
- Salivary gland: In the buccal cavity secrete saliva. This saliva has many functions.
- Pancreas: Secrete amylase, trypsin, lipase.
- Sperm: Hyaluronidase.
- sweat glands: secrete sweat.
- Sebaceous gland: secrete sebum.
- Lachrymal glands: In eye secrete water to moisten the eye.
2. Endocrine glands: Secrete into blood flowing through them, so as to let the secretion function at distant parts of the body from the gland. They are ductless glands. Their secretions are called as hormones.
a) Pituitary Gland (of hypothalamus): This is a gland located below the hypothalamus in the brain which has many secretions like those from
i. Anterior pituitary gland
- leutinising hormone
- Thyroid stimulating hormone
- Adreno corticotrophic hormone
- Follicle stimulating hormone
ii. Posterior pituitary
- vasopressin (anti-diuretic hormone)
b) Thyroid gland: Produces thyroid hormones T3 & T4.
c) Parathyroid gland: Produces parathormone.
d) Adrenal gland:
- Cortex: secretes gluco-corticoids and mineralo-corticoids.
- Medulla: secretes adrenal hormone.
e) Pancreas: Pancreatic glands release their secretions like insulin, glucagon, somatostatin.
f) Kidneys: produce Renin angiotensin (controls blood pressure).
g) Pineal gland: Melatonin (sleep hormone)
g) Testes: Testosterone.
h) ovaries: Estrogen, progesterone.