Kindey and the Nephrons Flashcards
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Where does blood initially enter the nephrons
Through the Bowman’s capsule at an osmotic pressure of 300. Blood enters the glomerulus via the afferent arteriole and exits in the efferent arteriole.
What components make up the kidney
Blood enters through the renal pelvis, filtered through nephrons which are in the renal cortex - every nephron has a glomerulus, kidney medulla - the inner part of the kidney, and finally pass through the ureter to the bladder
how is hydrostatic pressure used in the kidneys
The process that moves the blood plasma forced fluid and solutes through glomerular capillaries in the bowman’s capsule (which is a passive process)
What is ultrafiltration
Blood is filtered in the kidney under high pressure
What diameter is too big for molecules to pass through the capillary pores in endothelium and podocyte split pores?
4.2nm
What is the sum of glomerular ultrafiltrate?
blood plasma - plasma proteins
What is the glomerular hydrostatic pressure? And what is the net filtration pressure?
55mmHg
10mmHg
Describe the limbs of the nephrons and molecular
The descending limb is permeable to water and not to ions. The ascending limb is impermeable to water. NaCl ions are actively transported out into the surrounding interstitial fluid.
What releases ADH and what does it affect?
The pituitary gland. ADH causes kidney tubules to become more permeable.
What is the final part of the loop of Henle called?
The collecting duct
What is the Renal Threshold?
The maximum amount of a substance (such as glucose or salt) is absorbed and the rest is excreted.
What is diabetes mellitus, and what is an indication for it?
High blood glucose that exceeds threshold, resulting in glucose appearing in the urine.
What quantities pass through the kidney?
1.25L of blood passes through kidneys every minute. 625ml of this is plasma. 125ml of plasma is filtered into kidney tubules per minute.
How much urine do we need to produce a day to rid the body of urea?
0.5L
What kind of transportation is reabsorption?
Active
What system is used for water reabsorption?
Through a counter current multiplier system
How is Urea used by the medulla?
To maintain high osmotic pressure
How is heat trapped?
in the counter current heat exchanger in the body core.
What is the osmotic pressure in the connecting distal tubule between limbs?
100 mOsm/L
What are the 3 functions of the kidneys?
-The removal of nitrogenous waste
-Osmoregulation
-Regulation of salt balance
How much cardiac output do the kidneys receive?
25% due to controlling the chemical composition of blood in our body
What is the name of the capillary network in the kidneys?
Peritubular capillaries
What are the two kinds of nephrons?
-Juxta-medullary which produce very concentrated urine (only present in mammals and birds)
-Cortical which produces less concentrated urine (makes up ~85% of the nephrons in the human body)
What are the vasa recta?
Blood vessels that run parallel to the loop of Henle
What is the osmotic pressure in capillaries
10 mm Hg
What is the glomerular colloid osmotic pressure
30 mm Hg
How much water is reabsorbed by the kidneys?
~98-99%
What are the distal and proximal convoluted tubules?
- Proximal connects bowman’s capsule to descending limb
-Distal connects ascending limb to collection duct
What kind of urine do reptiles have?
Isosmotic means it contains the same osmotic pressure. The epithelium of cloaca (urogenital opening) reabsorbs water and uric acid paste is excreted
