The following mechanism are involved in the formation of urine:
• Active transport : this is the mechanism that is mainly responsible for selective reabsorption of substances that the body needs and excretion of urea. The energy needed comes from cellular respiration.
• Varying permeability of tubule : various regions of the tubule are selectively permeable to water, ions and urea. For example, the descending limb of the loop of Henle is Kore permeable to water than the ascending limb.
• Passive diffusion and osmosis ions and water move in and put of the fluid in the tubule by diffusion and Osmosis respectively. These processes are controlled by concentration gradients and selective permeability of the regions of the tubule concerned.
• Hormonal control : Hormones act on various regions of the tubule to control reabsorption of ions and water.
No comments:
Post a Comment