Malfunctioning of kidneys can lead to accumulation of urea in blood, a condition
called Uremia, which is highly harmful and may cause kidney failure. In such
patients urea can be removed by a process called haemodialysis. The unit contains
a coiled cellophane tube surrounded by a dialysis fluid which has the same
composition as that of plasma except the nitrogenous wastes. The porous nature
of the cellophane acts as a semipermeable membrane and filters the nitrogenous
wastes.
(i) One of the following is not the function of kidneys
a) Maintenance of hydration in the body.
b) Removal of carbon dioxide
c) Removal of nitrogenous wastes
d) Maintenance of pH and ionic balance of the body fluids.
(ii) Identify the hormone which helps in water reabsorption in the nephron.
a) ADH
b) Growth hormone
c) Testosterone
d) Oestrogen
(iii) Why is Uremia dangerous ?
(iv) Why should the dialyzing fluid in the haemodialysis unit have the same
composition as that of blood ?
Answers
Answer:
(i) removal of Carbon dioxide as it is carried out by lungs
(ii) Water levels in the body are controlled by antidiuretic hormone (ADH), which is produced in the hypothalamus and triggers the reabsorption of water by the kidneys.
(iii)Uremia can lead to kidney failure when left untreated. Someone with uremia may have seizures, loss of consciousness, heart attacks, and other life-threatening symptoms. Some will need a kidney transplant. Kidney failure may also damage other organs, so untreated uremia can result in liver or heart failure.
(iv)Blood is removed from the patient and flows into the dialyzer where it is kept separated from dialysis fluid by a partially permeable membrane. The dialysis fluid contains the same concentration of glucose and salts as normal blood plasma so there is no net movement of glucose out of the blood by diffusion.