Write short notes

Question 13 Marks

peritoneal dialysis.

Answer

In this method, the dialyzing fluid is introduced in abdominal cavity or peritoneal cavity.
The peritoneal membrane acts as semipermeable dialyzing membrane.
Toxic wastes and extra solutes pass into the fluid.
This fluid is drained out after a prescribed period of time.
Peritoneal dialysis can be repeated as per the need of the patient.
It can be carried out at home at work or while travelling. But it is not as efficient as haemodialysis.

Question 23 Marks

nephritis.

Answer

Nephritis is the inflammation of kidneys characterised by proteinuria.
It is caused due to increased permeability of glomerular capsular membrane, permitting large amounts of proteins to escape from blood to urine.
This leads to change in blood colloidal osmotic pressure, leading to movement of fluid from blood to interstitial spaces.
It is reflected as edema.

Question 33 Marks

Juxta Glomerular Apparatus.

Answer

Some smooth muscle cells of the wall of afferent arteriole are modified in such a way that their sarcoplasm is granular. These cells are called juxtaglomerular (JG) cells.
In each nephron, initial part of DCT makes contact with the afferent arteriole of same nephron.
Cells in the wall of DCT in this region are packed more densely than those in other region of DCT. This is called macula densa.
Macula densa and the JG cells together form Juxta Glomerular Apparatus (JGA).
The JGA plays an important role in blood pressure regulation within the kidney.

Question 43 Marks

nephron.

Answer

Nephrons are structural and functional units of kidney.
Each nephron consists of a 4 – 6 cm long, thin-walled tube called the renal tubule and a bunch of capillaries known as the glomerulus.
The wall of the renal tubule is made up of a single layer of epithelial cells.
Its proximal end is wide, blind, cup-like and is called as Bowman’s capsule, whereas the distal end is open.
The nephron is divisible into Bowman’s capsule, neck, proximal convoluted tubule (PCT), Loop of Henle (LoH), distal convoluted tubule (DCT) and collecting tubule (CT).
The glomerulus is present in the cup-like cavity of Bowman’s capsule and both are collectively known as renal corpuscle or Malpighian body.

Question 53 Marks

micturition.

Answer

The process of release of urine from the urinary bladder is called micturition.
The average capacity of urinary bladder is 700 ml.
When urinary bladder is almost half filled, stretch receptors in urinary bladder transmit impulses to spinal cord, initiating a conscious desire to expel urine.
Micturition reflex center of spinal cord transmit impulses to the wall of urinary bladder and internal urethral sphincter.
Bladder muscles contract and muscles of internal urethral sphincter relax.
The external sphincter receives impulses from conscious centre of brain and relaxes.
This leads to elimination of urine from the bladder.

Question 63 Marks

deamination.

Answer

Deamination is the process of breakdown of excess amino acids.
It is an essential process, since the body of an organism is unable to store excess amino acids.
In this process, amino group is separated from the amino acid and ammonia is formed.
Toxic ammonia is either excreted or converted to less toxic forms like urea or uric acid before excretion.

Biology Write short notes