Question

Define the term 'uropoiesis". Where does it take place? Name the processes involved in the formation of urine.

Answer 1

Uropoiesis:

1. Uropoiesis is the term for the process of urine formation.
2. The production of urine happens in the kidneys.
3. The filtration of blood through the nephrons results in three phases in the production of urine.

Involved processes in the formation of urine:
Glomerular filtration:

1. The glomerular filtrate is formed when blood is filtered from the glomerulus before entering Bowman's capsule and generating urine.
2. The afferent arteriole that enters the glomerulus is larger in diameter in comparison to the efferent arteriole.
3. This assists with filtration by increasing blood pressure within the glomerulus.
4. Except for corpuscles and plasma proteins, the glomerular filtrate is made up of all blood elements.

Selective reabsorption:

1. The essential nutrients are reabsorbed when the glomerular filtrate reaches the proximal tubule.
2. The glomerular filtrate contains glucose, amino acids, water, and ions such as sodium, potassium, chloride, bicarbonate, magnesium, and calcium, which are reabsorbed.
3. When the filtrate reaches the collecting duct, ADH (anti-diuretic hormone) takes effect, reabsorbing the extra water and lowering urine volume.

Tubular secretion:

1. Uric acid is secreted in the proximal tubule creatinine when the glomerular filtrate is present.
2. Urea, potassium ion, and some hydrogen ions are secreted in the form of urine when the filtrate reaches the distal portion.