Question

1. How does the kidney regulate the pH balance of the blood? Include at least 2 pathways in your response.

2. Describe the events of filtration, reabsorption, and secretion in the kidney.

3. Explain how counter current multiplier and counter current exchange occur in the kidney.

Answer 1

1. kidney is the most important organ responsible for regulation of Blood pH.i.e. 7.35-7.45

The kidneys have two main ways to maintain the acid-base balance i.e. Blood pH

-Kidneys  cells reabsorb the HCO3-bicarbonate from the urine back to the blood and secrete hydrogen H+ ions into the urine.

The Kidney regulate the pH of the blood stream by changing the volumes reabsorbed and secreted.

2. Events of Urin formation

The kidneys remove toxic substances from the blood and collect urine for excretion. There are three main stages of urine formation:

glomerular filtration, reabsorption, and secretion.

These processes ensure that only waste and excess water is removed from the body.

a. Filtration:Growing kidney has more than 1 million tiny structures called nephrons. Every nephron has a glomerulus, the filtration site for the blood. The glomerulus is a network of capillaries surrounded by a cuplike structure called the glomerular capsule (or capsule of Bowman). Blood pressure forces water from the capillaries into the capsule through a filtration membrane, as blood passes through the glomerulus. This glomerular filtration begins the process of urinal formation.The filtration membrane in the bloodstream protects blood cells and large proteins

b. Reabsorption:The glomerulus extracts water out of the bloodstream, and small solutes. The resulting filtrate includes waste, but also other substances that are required by the body: vital ions, oxygen, amino acids and smaller proteins. When the filtrate leaves the glomerulus, it flows into a duct called the renal tubule in the nephron.When it passes, the substances and some water required are reabsorbed into adjacent capillaries through the tube wall. The second stage in urine formation is this reabsorption of essential nutrients from the filtrate.

c. Secretion: The filtrate accumulated in the glomerulus passes into the renal tubule, where it reabsorbs nutrients and water into capillaries. At the same time, the waste ions and hydrogen ions migrate into the renal tubule from the capillaries. This is called secretion. The secreted ions mix with the majority of the filtrate and transform into urine. The urine flows out into a collecting channel from the nephron tubule.It passes through the renal pelvis, into the ureter, and down to the bladder.

3. Explain how counter current multiplier and counter current exchange occur in the kidney.

Counter current multiplier system

kidneys have a amazing feature, called counter - current multiplication, to reabsorb water from the tubular fluid.Countercurrent kidney multiplication is the method of using energy to create an osmotic gradient that helps you to reabsorb tubular fluid water and to produce concentrated urine. This process stops you from producing liters and liters of diluted urine every day, which is why you don't need to be drinking continuously to remain hydrated.

Counter current exchange system

Mammalian kidneys use countercurrent exchange to extract water from urine so that the body can preserve water used for the transport of nitrogen waste.A fluid circuit in the Henle loop — an essential part of the kidneys enables the gradual build-up of urine concentration in the kidneys by the use of active transport on the exiting nephrons tubes containing liquid in the process of slowly accumulating the urea.The active transport pumps only need to conquer a steady and low concentration gradient, due to the countercurrent multiplier mechanism.