TNPSC Free Notes Biology – Function of pancreatic harmones

இந்தக் கட்டுரையில், TNPSC குரூப் 1, குரூப் 2, குரூப் 2A, குரூப் 4 மாநிலப் போட்டித் தேர்வுகளான TNUSRB, TRB, TET, TNEB போன்றவற்றுக்கான  முறைகள் இலவசக் குறிப்புகளைப் பெறுவீர்கள்.தேர்வுக்கு தயாராவோர் இங்குள்ள பாடக்குறிப்புகளை படித்து பயன்பெற வாழ்த்துகிறோம்.

Function of pancreatic harmones

A balance between insulin and glucagon production is necessary to maintain
blood glucose concentration.
Insulin

 Insulin helps in the conversion of glucose into glycogen which is stored in
liver and skeletal muscles.
 It promotes the transport of glucose into the cells.
 It decreases the concentration of glucose in blood.
 Insulin also inhibits the breakdown of glycogen to glucose, the
conversion of amino acids or fats to glucose, so insulin is rightly called a
hypoglycemic hormone.
 Insulin is called a hypoglycemic hormone.
 Insulin: The half-life period of insulin (in plasma) is 6 minutes.
 It is cleared from the circulation within 10 – 15 minutes.
Glucagon
 Glucagon helps in the breakdown of glycogen to glucose in the liver.
 It increases blood glucose levels
 Since glucagon reduces the cellular uptake and utilization of glucose it is
called a hyperglycemic hormone.
Diabetes mellitus
 The deficiency of insulin causes Diabetes mellitus.
 It is characterized by
 Increase in blood sugar level (Hyperglycemia).
 Excretion of excess glucose in the urine (Glycosuria)
 Frequent urination (Polyuria).
 Increased thirst (Polydipsia).
 Increase in appetite (Polyphagia).

Adrenal Gland
 The adrenal glands are located above each kidney.
 They are also called supra renal glands.
 The outer part is the adrenal cortex and the inner part is the adrenal medulla.
 The two distinct parts are structurally and functionally different.
Adrenal Cortex

The adrenal cortex consists of three layers of cells. They are
 Zona glomerulosa,
 Zona fasciculata
 Zona reticularis
Hormones of Adrenal Cortex
The hormones secreted by the adrenal cortex are corticosteroids. They are
classified into
 Glucocorticoids
 Mineralocorticoids
Functions of adrenocortical hormones Glucocorticoids
The glucocorticoids secreted by the zona fasciculata are cortisol and
corticosterone
 They regulate cell metabolism.
 It stimulates the formation of glucose from glycogen in the liver.
 It is an anti-inflammatory and anti-allergic agent.
Mineralocorticoids
 The mineralocorticoids secreted by zona glomerulosa is aldosterone
 It helps to reabsorb sodium ions from the renal tubules.
 It causes increased excretion of potassium ions.
 It regulates electrolyte balance, body fluid volume, osmotic pressure and
blood pressure.
Adrenal Medulla
 The adrenal medulla is composed of chromaffin cells.
 They are richly supplied with sympathetic and parasympathetic nerves.
Hormones of Adrenal Medulla
It secretes two hormones namely
 Epinephrine (Adrenaline)

 Norepinephrine (Noradrenaline)
 They are together called as “Emergency hormones”.
 It is produced during conditions of stress and emotion.
 Hence it is also referred as “flight, fright and fight hormone”.

Functions of adrenal medullary hormones Epinephrine (Adrenaline)
 It promotes the conversion of glycogen to glucose in liver and muscles.
 It increases heart beat and blood pressure.
 It increases the rate of respiration by dilation of bronchi and trachea.
 It causes dilation of the pupil in eye.
 It decreases blood flow through the skin.
Norepinephrine (Noradrenalin)
Most of its actions are similar to those of epinephrine.

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