3 functions of the urinary system • Excrete nitrogenous wastes – Urea produced from the metabolism of proteins and nucleic acids • Other animals produce ammonia or uric acid • Regulate water balance • Regulate salt balance
3 functions of the urinary system
• Excrete nitrogenous wastes– Urea produced from the metabolism of proteins
and nucleic acids• Other animals produce ammonia or uric acid
• Regulate water balance• Regulate salt balance
Fig. 25-6d Bowman’scapsule
Artery
Artery
Glomerulus
Distaltubule
Proximal tubule
Branch ofrenal vein
Capillaries
Fromanothernephron
Loop of Henlewith capillarynetwork
Collectingduct
Everything in the blood smaller than blood cells or large proteins is filtered into the nephron at the glomerulus/bowman’s capsule Vital materials
-sugars-amino acids-water-NaClAre reabsorbed into the blood, so they do not leave the body
Salts are secreted into urine if their concentration in the blood is too high
Urine is excreted from the body
Fig. 25-8
Blood
Kidney tubule
Somedrugsand poisons
HCO3–
Nutrients
Medulla
Bowman’scapsule
Cortex
H+
NaClH2O
H2ONaCl
HCO3–
H+
UreaGlucoseAmino acidsSome drugs
Filtrate composition
NaCl
H2O
NaCl
NaCl H2O
NaCl H2O HCO3–
H+K+
Kidney tubule1
2
3
Reabsorption
Secretion
Filtrate movement
Loop ofHenle
Collectingduct
Urea
Urine (to renal pelvis)