LOCOMOTION AND MOVEMENT

 

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.

 

CBSE Biology (Chapter Wise) Class XI ( By Mr. Hare Krushna Giri ) 
Email Id : [email protected]