Function of adrenaline and nor-adrenaline.
- Increase alertness.
- Pupilary dilation.
- Piloerection (raising of hairs)
- Sweating.
- Increase heart rate,.
- The strength of heart contraction increased.
- Increase rate of respiration.
- Breakdown of glycogen into glucose
- Stimulate breakdown of proteins and fats.
- Adrenal cortex divided into three zones –
- Zona reticularis – inner layer ( mainly secretes sex steroids)
- Zona fasciculata – middle layer (mainly secretes glucocorticoids)
- Zona glomerulosa – outer layer (mainly secretes mineralocorticoids)
- Adrenal cortex secrete many steroid commonly called as corticoids.
- Corticoids regulate carbohydrate metabolism called glucocorticoids.
- Principal glucocorticoid is cortisol.
- Corticoids which regulate balance of water and electrolytes in our body are called mineralocorticoids.
- Principal mineralocorticoid is aldosterone.
- Sex steroids are called androgen.
Function of glucocorticoids :
- Stimulate gluconeogenesis (conversion of proteins and fats into glucose).
- Stimulate lipolysis (breakdown of fat)
- Promote proteolysis (conversion of protein into amino acids)
- Inhibit cellular uptake and utilization of amino acids.
- Cortisol maintains cardiovascular system as well as kidney function.
- Cortisol produces anti-inflammatory reactions and suppresses the immune response.
- Cortisol stimulates RBC production.
Function of aldosterone :
- Aldosterone acts mainly at the renal tubules.
- Stimulates the reabsorption of Na+ and water and excretion of K+ and phosphate ions.
- Aldosterone helps in maintenance of electrolytes, body fluid volume, osmotic pressure and blood pressure.
Function of androgen :
- Play a role in growth of axial hair, pubic hair and facial hair during puberty.
Pancreas :
- Pancreas is a myxocrine gland which acts as both exocrine and endocrine gland.
- The endocrine part consists of ‘Islets of Langerhans’.
- There are 1-2 millions of Islets of Langerhans in a pancreas representing only 1 – 2 percent of the pancreatic tissues.
- There are two principal cell type in Islets of Langerhans –
- α- Cells secretes Glucagon.
- β- Cells secrete Insulin.
Role of glucagon :
- Glucagon is a polypeptide hormone.
- Maintain normal blood glucose level.
- Stimulates glycogenolysis in hepatic cells, resulting increased blood sugar level called hyperglycemia.
- Stimulates gluconeogenesis.
- Reduce cellular glucose uptake and utilization.
- In general glucagon is a hyperglycemic hormone.
ole of Insulin :
- Insulin is a peptide hormone
- Regulate blood glucose homeostasis.
- Insulin acts mainly on hepatocytes and adipocytes.
- Enhance cellular glucose uptake and utilization.
- Stimulates rapid movement of glucose from blood to hepatocytes and adipocytes, resulting decrease in blood glucose level (hypoglycemia)
- Stimulates conversion of glucose into glycogen called glycogenesis.
- Stimulates synthesis of fat from glucose called lipogenesis.
Diabetes mellitus :
- Caused due to hyposecretion of Insulin.
- Prolonged hyperglycemia associated with Glycosuria (excretion of glucose in urine).
- Hyperglycemia leads to formation of ketone bodies.
- Diabetic patients are treated with insulin therapy.
