Urinary Tract Flashcards
what are the 6 homeostatic roles of the kidney?
- regulation of extracellular fluid volume
- Regulation of blood osmolarity
- Maintenance of electrolyte balance
- Regulation of blood pH
- excretion of waste
- hormone production
The homeostatic roles are achieved in 3 main events conducted in the nephrons.. which are?
- Glomerular filtration
- Tubular reabsorption
- Tubular secretion
What does glomerular filtration do?
removes solutes from the blood
- receives 12-30% of cardiac output
What happens in the glomerulus?
filtration of solutes from the blood
What covers the glomerulus?
Bowman’s capsule
What happens to the osmolarity as you descend into the renal medulla?
it increases
What happens at the proximal convoluted tubule?
Reabsorption of ions, water, and nutrients into the blood
removal of toxins and adjustment of filtrate pH
What is the proximal convoluted tubule lined with?
Simple cuboidal brush border epithelium
What proportion/% of nutrients/water/electrolytes are reabsorbed in the PCT?
nearly all of the essential nutrients and 70-80% of
electrolytes and water are reabsorbed
How does the PCT help to maintain the pH and ionic balance of body fluids?
by selective secretion of hydrogen ions, ammonia, and K+ into the filtrate and absorption of HCO3
What happens in the descending loop of Henle? What does this require
Aquaporins allow water to pass from the filtrate into the interstitial fluid
- concentrate the filtrate
- requires energy
What happens in the ascending loop of Henle?
Reabsorption of Na and CL from the filtrate into the interstitial fluid
- active or passive
What is the main role of the loop of Henle as a whole? (2 things actually)
to maintain high osmolarity of the interstitial fluid
production of concentrated urine
What happens to the filtrate as it passes up through the ascending loop of Henle?
it gets diluted due to the passage of electrolytes to the medullary fluid
What is the lining of the distal tubule like?
lined with simple cuboidal cells that lack a brush border
What happens in the distal tubule?
selective secretion and absorption of various ions in maintain blood pH and electrolyte balance
- Ca2+, K+, Na+
What does the collecting duct connect?
the nephron to the ureter
What happens in the collecting duct? (secretion/resorption)
The secretion of K+ and the resorption of Na+
What hormones regulate the collecting duct?
vasopressin and aldosterone
What are 4 hormones that are made in the kidney?
- Calcitriol
- Klotho
- Renin
- EPO