Disorders of Excretory System in Humans

The following points highlight the eight major disorders of excretory systems in humans. 

Excretory System: Disorder # 1. Uremia:

In this condition there are high concentrations of non-protein nitrogen’s which include urea, uric acid, creatinine and a few less important compounds. Urea accu­mulation in blood is comparatively high in uremia. In such patients urea can be removed by a process called hemodialysis.

Excretory System: Disorder # 2. Renal Failure (RF) or Kidney Failure:

Renal failure is a decrease or cessation of glomerular filtration in humans. In acute renal failure (ARF), both the kidneys abruptly stop working. The main feature of ARF is either oligouria (scanty urine production) which is daily urine output less than 250 ml or anuria (daily urine output less than 50 ml).

Causes:

(i) Low blood volume (e.g., due to hemorrhage),

(ii) decrease cardiac output

(iii) damaged renal tubules

(iv) kidney stones

(v) the dyes used to observe blood vessels in angiograms.

(vi) non-steroid anti-inflammatory drugs and

(vii) some antibiotic drugs.

Effects:

(a) Oedema,

(b) Potassium level rises which can lead to cardiac arrest,

(c) No production of enough erythropoietin for adequate RBCs production and causing anaemia,

(d) Since kidneys are not able to convert vitamin D to calcitriol, which is needed for proper calcium absorption from the small intestine,

(e) Osteomalacia may also occur

Treatment:

Haemodialysis.

Excretory System: Disorder # 3. Renal calculi (Kidney Stones):

The stone gives rise to severe colic pain starting in the back and radiating down to the front of the thigh or the testicle or vulva on that side, insoluble mass of crystallized salts (oxylates, etc.) is formed within kidney.

Excretory System: Disorder # 4. Nephritis (Bright’s Disease):

It is inflammation of the kidney. Nephritis is a non- specific term used to describe a condition resulting from a variety of causes there is inflammation of the renal pelvis and the medullary tissue of the kidney. In Glomerulonephritis there is inflammation of glomeruli of the kidney and they become engorged with blood. If a large number of glomeruli become nonfunctional, the individual must use an artificial kidney.

Excretory System: Disorder # 5. Hypertension caused by Secretion of Renin:

Secretion of large amounts of renin ids to the formation of angiotensin which in turn leads to hypertension.

Excretory System: Disorder # 6. Renal Tabular Acidosis:

In this condition the person is unable to secrete adequate antities of hydrogen ions and as a result, large amounts of sodium bicarbonate are consciously lost into the urine.

Excretory System: Disorder # 7. Oedema (= Dropsy):

Accumulation of excess fluid in tissues is called oedema. It is an increase in the volume of extracellular (interstitial) fluids without a change in their osmo­lality. It is usually caused by an excess of sodium ions, which in turn causes water retention.

Excretory System: Disorder # 8. Diabetes Insipidus:

Cause:

Deficiency of Antidiuretic hormone (ADH) leads to diabetes insipidus. ADH is released from posterior lobe of pituitary gland.

Why is ADH so called?

Diuresis is urine production. ADH facilitates reabsorption of water by the distal parts of the kidney tubules (nephrons) and thereby prevents diuresis.

Symptoms:

Diabetes insipidus is characterised by excessive dilute urine and intense thirst. The name itself (diabetes = overflow; insipidus – tasteless) distinguishes it from diabetes mellitus (mel = honey), in which insulin deficiency causes large amounts of blood sugar to be lost in the urine.