Lecture 29- Urine Flashcards
Countercurrent mechanism
When fluid flows opposite directions in two adjacent segments of same tube with hairpin turn
What can leave in descending limb?
Water, but solutes stay
What can leave in ascending loop?
Solutes, but water stays
Countercurrent multiplier
Uses gradients from movement of ions from ascending limb and water from descending limb to establish positive feedback cycle to multiply power of salt pumps
Countercurrent exchanger
Movement of water and solutes in and out of vasa recta
Diuretics
Increase urine output
Act as osmotic diuretic or inhibit Na+ and resulting obligatory water reabsorption
Renal clearance
Volume of plasma that is cleared of specific substance in a given time
Inulin
Dietary fibre from plants, used as clearance standard to measure glomerular filtration rate because it is not reabsorbed or secreted
Urochrome
Pigment from hemoglobin destruction
Urine pH
Slightly acidic (6) can vary based on diet
Ureters
Tubes that actively convey urine from kidneys to bladder
Urinary bladder
Muscular sac that expands as urine is produced by kidneys to allow storage for urine until voiding is convenient
Urinary bladder layers
Detrusor muscle, inner layer of transitional epithelium
Urethra
Muscular tube that drains urine from body
What are the two sphincter muscles associated with urethra?
Internal urethral sphincter- involuntary, formed from detrusor smooth muscle
External urethral sphincter- voluntary, formed by skeletal muscle at urogenital diaphragm
