Chapter
26 Notes
The Urinary System
Examination
of the kidneys
1. Functions
- remove and restore selected solutes and wastes
- forms erythropoietin
- controls body pH
- regulates blood pressure
2. Organs
- kidneys at T12 through L3
- ureters
- urinary bladder
- urethra
-
web anatomy
3. Layers
- renal fasciae - anchor
- adipose capsule - protection
- renal capsule - barrier
- renal cortex - contains nephrons
- cortical zone, 85% of nephrons remain in cortex
-juxtamedullary zone, 15% of nephrons reach into medulla
- renal medulla
- pyramids - contains collecting ducts
- papillae - drain urine into calyces
- renal columns - between pyramids contains Loop of Henle
- renal pelvis
- major and minor calyces - cups to drain urine
- gross
anatomy online
4. Blood flow at nephron
- afferent arteriole-->glomerulus-->efferent
arteriole--> peritubular
capillaries (or vasa recta in medulla)
- afferent arteriole has largest diameter
- juxtaglomerular cells near it monitor blood pressure
- note blood supply through entire kidney
5. Nephron
- renal corpuscle
- Bowman’s capsule
1. double walled cup
2. parietal layer - squamous epithelium
3. visceral layer - podocytes: leaky star-shaped cells that
filter plasma
- glomerulus
1. 50 capillary loops
2. filters plasma into Bowman's
capsule
-
microscopic anatomy online
- renal tubules
- proximal convoluted tubule
- descending limb
- loop of Henle
- ascending limb
- distal convoluted tubule
- collecting duct - drains into renal
pelvis
- nephron
online
-
microscopy online
-
online quiz
of nephron
6. Pathway of filtrate
- CORTEX
- here filtrate is formed from plasma and most chemicals
are reabsorbed back into blood at peritubular
capillaries
- afferent arteriole to glomerulus to Bowman's capsule to proximal convoluted
tubule
- MEDULLA
- here urine either is concentrated or diluted
- descending limb
- Henle’s loop
- ascending limb
- BACK to CORTEX
- under influence of hormones, ADH and aldosterone
- distal convoluted tubule
- INTO MEDULLA
-collecting duct