Exam 4 extra help Flashcards
somatic motor (causes contraction), stimulated during filling, inhibited during micturition
external urethral sphincter (skeletal)
parasympathetic - calming after arousal (causes contraction), inhibited during filling, stimulated during micturition
detrusor muscle (smooth)
sympathetic - arousal (causes contraction), stimulated during filling, inhibited during micturition
internal urethral sphincter (smooth)
- active process
- occurs everywhere but in the descending limb
- ascending limb is permeable
Na (salt) reabsorption
- osmosis
- dependent upon sodium reabsorption
- NaCl in the interstitial fluid will drive reabsorption
- descending limb is freely permeable
water reabsorption
1.Disposing of drugs and drug metabolites
*this is why most drug tests are urine tests
2.Eliminating undesired substances or end products that have reabsorbed by passive processes (urea and uric acid).
3.Removing excess potassium ions
4.Controlling blood pH
Tubular secretion is an important mechanism for:
- passive process
- more efficient filter bc has a larger SA & very permeable to water and solutes
- higher pressure
glomerular filtration
water is drawn out by osmosis because the interstitial fluid is hypertonic (so it wants to go from H to L concentrations)
- impermeable to ions
- passive transport
descending limb
- Na+ move from the thick portion to the epithelial cells via electrochemical gradient, this drives the secondary active transport of Cl- and K+.
- K+ diffuses back into filtrate, Na is pumped into interstitial fluid, Cl- passively follows
- active transport
- reabsoprtion of Na+, Cl-, K+
- impermeable to water
ascending limb