Urinary System Flashcards
What are the functions of the urinary system & kidneys? (6)
filters the blood, removes waste, regulates blood volume, produces renin and EPO, metabolizes vitamin D, and maintain salt and pH balance
Which kidney sits lower?
the right one
Where is the juxtaglomerular apparatus located?
distal part of the ascending limb against the afferent arteriole
What three things does the juxtaglomerular apparatus regulate?
GFR (rate at which plasma is filtered), BP, sodium & chloride
Where is the filtration membrane located?
between blood & interior of glomerular capsule
What are the three layers of the filtration membrane?
capillary endothelium, podocytes, and a shared basement membrane (between the two)
What does the filtration membrane do?
allows passage of water and solutes smaller than plasma proteins
What are the 3 processes of urine formation?
glomerular filtration, tubular absorption, and tubular secretion
What is glomerular filtration?
forming filtrate (pre-urine) - movement from glomerular capillary into capsule space
What is tubular absorption?
reabsorbing back water and nutrients - movement from renal tubules into peritubular capillary bed
What is tubular secretion?
removing waste from blood stream - movement of substances into renal tubules
What is net filtration pressure?
10 mm Hg
What force is in FAVOR of making filtrate?
glomerular hydrostatic pressure (BP) - 55 mm Hg
What forces are AGAINST making filtrate? (2)
- blood osmotic pressure - 30 mm Hg
- capsular hydrostatic pressure - 15mm Hg
Where are all substances your body wants back reabsorbed the most?
proximal convoluted tubule
What % of water is reabsorbed by the proximal convoluted tubule?
65%
What % of water is reabsorbed via the descending loop?
15%
What is the countercurrent multiplier?
- descending loop is permeable to water but not Na & Cl
- ascending loop is permeable to Na & Cl but not water
- this creates an osmotic gradient
What hormone is the distal convoluted tubule sensitive to?
ADH
When will you produce ADH and what happens?
- ADH is produced when you’re dehydrated
- ADH causes aquaporins to open in the DCT, causing the reabsorption of water
What substances are removed during tubular secretion?
metabolic waste, excess ions (H+ ions), metabolized drugs
What is the pH of urine?
6, slightly acidic
What is a normal urine volume per day?
1-2 liters
Urine should not contain what? (7)
RBC, glucose, plasma proteins, ketones, bile pigments, proteins, leukocytes (pus)
