4/29- Urinary System (Exam 4) Flashcards
What are the 3 basic functions of the urinary system?
1) removal of nitrogenous waste
2) water balance (regulating water levels)
3) ion regulation or electrolyte balance of salt balance
Where does nitrogenous waste come from?
Amino acids
What is deamination?
Amino groups (NH2) is removed from amino acid
Takes place in liver
Produced waste product that is toxic and needs to be removed
What are the 3 molecules that can be derived from the amino group (NH2)?
1) ammonia- highly toxic
2) uric acid
3) urea
What is uric acid?
Insoluble in water
Crystallizes
Tiny amounts in humans
What is gout?
When uric acid crystallizes in joint capsule of big toe
Need to cut down protein
What is urea?
Human waste product
Insoluble in water
Must be removed from body
What is the nephron and it’s 3 basic functions?
Basic functional unit of kidney
Microscopic
1) filtration- filters blood (Bowmans capsule)
2) reabsorption- proximal and distal convoluted tubule
3) secretion- Na+ out, K+ and H+ in
What do mammals have and why?
Loop of Henle
Makes urine more concentrated that blood plasma
What is the Bowmans capsule and it’s 2 layers?
Where filtration takes place
2 layers
1) parietal layer- outer
2) visceral layer- inner
What are podocytes?
Cells visceral layer of bowmans capsule
Fit over glomerulus
Have pedicels
What are pedicels?
Finger like process inside podocytes
Interfinger each other
What are filtration slits?
Spaces between pedicels where water gets through
What are fenestrated capillaries?
Found in glomerulus
Have pore like openings
Water goes out and into filtration slits than to hollow interior of bowmans capsule
What is the proximal convoluted tubule?
Reabsorbs useful material
Cells that form wall- simple cuboidal epithelium
Microuilli increase absorption
What is the counter- current exchange system?
Happens in loop of henle
Filtrate flowing in opposite direction
What is the efferent arteriole?
Brings things in and out of nephron
What is the peritubular capillaries?
Wraps around nephron leaving afferent arteriole
Pumping in from this blood supply
Pumping out goes to thia blood supply
What is the vasa recta?
Capillary coming out of the efferent arteriole
Capillary loops around loop of henle and water is picked up by the blood
What is the Antidiuretic hormone (ADH)?
Secretion of posterior pituitary gland
Cause kidney to conserve water
Affects collection duct to become more permeable to water- allows more water than usual to leave the urine and vasa recta conserves the water
What is the glomerular hydrostatic pressure (GHP)?
Pushing water and dissolved material out of the blood into bowmans capsule
Greater pressure
Bp in glomerulus
What is the capsular hydrostatic pressure (CsHP)?
Liquid that is collecting inside the bowmans capsule is generating a force of its own
What is the net hydrostatic pressure (NHP)?
NHP= GHP- CsHP
What is the blood colloid pressure (BCOP)?
Suspended plasma proteins
Draws water into the blood
What is the filtration pressure (FP)?
Overall force moving material in or out of the blood
FP = NHP- BCOP
What is the glomerular filtration rate (GFR)?
Important measure of the health of the kidney
Amount of filtrate the kidney produces each minute
What is creatinine?
Breakdown of creatine phosphate
Leaches out of the blood and is filtered out by kidneys
What is the creatinine clearance test?
Combo of blood test and urine analysis
Analyze blood to see how much creatinine is in the blood
Measure how much is in the urine (collected over 24hrs)
What are 3 ways to regulate the GFR?
1) auto regulation
2) hormonal or other chemical regulations
3) autonomic regulation
What is auto regulation?
Self regulation in kidney
Dilate afferent arteriole- more blood to rush in under high pressure in glomerulus
Constrict efferent arteriole- builds up pressure when closed and raises GFR
What is hormonal regulation?
Renin- angiotestin system
Antiotensinogen—> angiotensin 1—> angiotensin 2 (vasoconstrictior)
What is the juxtaglomerular apparatus?
Where renin comes from
Consists of 2 things
1) juxtaglomerular cells
2) macula Densa
Cells measure bp drops
N-+ ion levels drop in filtrate
——-renin is produced
What are juxtaglomerular cells?
Thick cells that surround walls of afferent arteriole
Measures bp
What is macula densa?
Columnar cells in wall of distal convoluted tubule
Measure Na+ ion levels in filtrate
What is autonomic regulation?
Visceral motor
Sympathetic nerves connecting to arteries and raIses bp and GFR
Bp raises GFR raises
What does angiotensin 2 do?
Stimulates the zoma glomerulosa of the adrenal cortex
Secretes aldosterone
What is aldosterone?
Sodium regulator
Causes rest of distal convoluted tubule to save even more sodium to the body and not lose it in the urine
