Renal-Chapter 26 Flashcards
What separates the glomerular and peritubular capillary beds?
Efferent arteriole
What does each nephron contain?
- Glomerulus (tuft of capillaries)
- Long tubule where filtered fluid is converted into urine
What’s the typical pressure in the glomerulus?
High hydrostatic pressure (60 mmHg)
2 types of nephrons
- Where
- Characteristics
Cortical nephrons
close to the surface of the kidney (AKA cortex)
Short LOH
Juxtamedullary nephrons
penetrate deep into medulla
Long LOH
Which nephrons surround the peritubular capillary network?
Cortical nephron
Which nephrons yield more concentrated urine?
Juxtamedullary
Which nephrons are located in the vasa recta
Juxtamedullary
Smooth muscle that lines the wall of the bladder
Detrusor muscle
- Has a lot of gap junctions
- Laced with large amounts of elastic tissue
Area of bladder that opens into the posterior urthera
Trigone (smooth mucosa)
Smooth muscle that prevents emptying of bladder (in the neck)
Internal sphincter
Skeletal muscle in bladder
External sphincter
-Under voluntary control
Pelvic nerve fibers
Sensory-detect stretch in bladder from increasing frequency of action potentials to sacral region (S1-S3)
Motor-Parasympathetic fibers from spinal cord innervate detrusor muscle to empty bladder
Pudendal nerves
Innervate external sphincter (skeletal muscle) under voluntary control.
Hypogastric nerves
Sympathetic innervation that stimulates blood vessels
Sensory-senses fullness,pain.
T/F Composition of urine changes once it leaves the kidneys
F
What happens when calyces are stretched in the kidney?
Increases inherent pacemaker activity
Initiates peristaltic contractions that spread along length of ureter
Ureter innervation
Smooth muscles
- Sympathetic=inhibitory
- Parasympathetic=enhances contractions
If there’s blockage in the ureters what will happen?
Ureterorenal reflex
-Sympathetic reflex to constrict renal arterioles in kidney.
-Decreases urine output
T/F Ureters have pain nerve fibers
T
Explain the micturition reflex
As bladder fills, receptors are stretched which sends a sensory signal through pelvic nerve to sacral segement (S1-S3) and back to bladder to contract detrusor muscle (parasympathetic)
If bladder does not empty, micturition contracts relax
As bladder fills more, reflexes become more frequent and stronger.
When threshold reached, 2nd reflex causes pudendal nerve to be inhibited (voluntary signal override) and external sphincter is relaxed to pee.
Renal blood flow is what percent of cardiac output
20
Urinary excretion rate formula
GFR- Reabsorption rate + Secretion rate
Reabsorption vs Secretion
Reabsorption
-Substance goes from renal tubules back into blood
Secretion
-Substance from blood stays in renal tubules
