Renal Physiology lab 1. Describe how the Loop of Henle and Collecting duct of th
ID: 3517716 • Letter: R
Question
Renal Physiology lab
1. Describe how the Loop of Henle and Collecting duct of the kidney work together to concentrate urine.
2. What is the effect of increased ADH (Antidiuretic Hormone) release on the collecting tube AND urine volume/concentration?
3. In the salt group, what can you conclude about the level of plasma osmolarity at the peak of salt excretion? What can you conclude about aldosterone level in the blood? ADH level?
4. Describe how the osmoreceptors lead to increased urine volume in the water only group
Explanation / Answer
1) The Loop of henle is U shaped tubule present between pct and dct. Here there is a mechanism called counter current mechanism occurs. Countercurrent multiplication in the kidneys is the process of using energy to generate an osmotic gradient that enables you to reabsorb water from the tubular fluid and produce concentrated urine. This mechanism prevents you from producing litres and litres of dilute urine every day, and is the reason why you don’t need to be continually drinking in order to stay hydrate.
In loop of henle it is divided into thin descending limb, thin ascending limb and thick ascending limb. Around this is capillary structure Vasa recta.
Now from collecting duct water is reabsorbed and urine is concentrated. Also absorbtion of urea occurs.
2) The urine can be made more concentrated or more dilute than plasma, depending on how hydrated you are. This process is mainly controlled by antidiuretic hormone, a hormone that is made in the hypothalamus of the brain and stored in the pituitary gland. The release of antidiuretic hormone by the pituitary gland is controlled by sensors in your heart and blood vessels that detect drops in blood pressure, or increased concentrations of salt in your bloodstream that may occur when you are dehydrated.
The collecting duct is present along cortex , outer medulla and inner medulla. It present in between the DCT and bunches of CD.
The action of ADH in the collecting tubule :
a) in the cortex ADH increases water permeability water reabsorbed
b) in the outer medulla as water is reabsorbed urine concentration increased
c) in the inner medulla ADH increases water and urea permeability .
Urea is reabsorbed.
3) The max osmolarity of tubular fluid is 1200 mosm/L.
4)insufficient h2o in the body ?? Increased blood osmolality ?? Osmoreceptors in hypothalamus ??Thirst ?? Drink
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Posterior pituatory ?? Increased ADH ?? Water retention by kidneys ?? Increased blood volume increased blood osmolarity