ch 15 excretory sys overview
TRANSCRIPT
Chapter 15The Urinary System
Functions of the Urinary SystemFunctions of the Urinary System1. Elimination of waste
Nitrogenous wastes
Toxins
Drugs
2. Regulates homeostasis
Water balance
Electrolytes
Acid-base balance in the blood
Blood pressure
RBC production
Activation of vit. D
Organs of the Urinary systemOrgans of the Urinary system
Kidneys
Ureters
Urinary bladder
Urethra
Location of the KidneysLocation of the Kidneys
Against dorsal wall
Right lower than left
Attached to ureters, renal blood vessels, & nerves at renal hilus
Atop kidney is adrenal gland
Regions of the KidneyRegions of the Kidney
Renal cortex – outer region
Renal medulla – inside the cortex
Renal pelvis – inner collecting tube
NephronsNephrons Structural and
functional units of the kidneys
Forms urine
Main structures
a. Glomerulus
b. Renal tubule
GlomerulusGlomerulus
Glomerulus sits within a glomerular capsule (1st part of the renal tubule)
Specialized capillary bed
Arterioles on both sides (maintains high pressure)
- Large afferent arteriole
- Narrow efferent arteriole
Renal TubuleRenal Tubule Glomerular
(Bowman’s) capsule
Proximal convoluted tubule
Loop of Henle
Distal convoluted tubule
Urine FormationUrine Formation
Filtration
Reabsorption
Secretion
FiltrationFiltration Nonselective passive process
Water and solutes smaller than proteins are forced through capillary walls (Filtrate same as blood plasma)
Blood cells cannot pass out to the capillaries
Filtrate - collected in glomerular capsule and leaves via the renal tubule
ReabsorptionReabsorption Peritubular capillaries reabsorb
- Some water, Glucose, Amino acids, Ions
Some passive, most active
Most reabsorption occurs in proximal tubule
Nitrogenous waste products
- Urea
- Uric acid
- Creatinine
Excess water
Not ReabsorbedNot Reabsorbed
Secretion Secretion
Materials left in renal tubule move to ureter