By Yoon Kim and Allen Shin
Introduction
 Urinary System removes certain slats and nitrogenous
wastes
 Helps maintain the normal concentrations of water and
electrolyses within body fluids, regulates pH and volume
of body fluids, and help control red blood cell production
and blood pressure
 Pair of kidneys – remove substance from blood
 Pair of tubular ureters- transport urine from kidney
 Tubular urethra- conveys urine to the outside of the body
Kidneys
 Kidney is a reddish-brown, bean-shaped organ
 Kidneys are located on either side of the vertebral column
and are positioned retroperitoneally (behind parietal
peritoneum)
 Connective tissues and adipose tissues
surround the kidneys to hold
them in position
Structure of the kidneys
 Medial depression caused by the lateral and medial
surface of the kidneys creates a depression into hollow
chamber called renal sinus
 Inside the renal pelvis, a funnel-shaped sac expands from
the end of the ureter.
Functions of the Kidneys
 Secretes hormone erythropoietin to help control the rate
of red blood cell production
 Activates vitamin D
 Helps maintain blood volume and blood pressure by
secreting the enzyme renin
Renal Blood Vessels
 Renal arteries : Supply blood to the kidneys
 Afferent arterioles : the final branches of the interlobular
arteries; lead to the nephrons
 Renal Vein: joins the inferior vena cava as it courses
through the abdominal cavity
Nephrons
 Kidney contains 1 million nephrons
 Nephrons consists of renal corpuscle and renal tubule
 Fluid flows through renal tubules out of the body
Nephrons
 Renal corpuscle is composed of glomerulus blood
capillaries.
 Glomerulus capillaries filter fluids
 Thin walled, saclike structure called glomerular capsule
surrounds the glomerulus
Nephron Blood Supply
 After passing through the glomerular capillaries, blood
enters efferent arteriole
 Efferent arteriole resists blood flow which then backs up
blood into the glomerulus
 Peritubular capillary system surrounds the renal tubule
Juxtaglomerular Apparatus
 Juxtaglomerular cells: smooth muscle cells attached to
the walls of arterioles near glomerulus
 Juxtaglomerular apparatus: fuction in the control of renin
secretion
Review Questions
Review Questions
 1. Kidneys activates vitamin ____
 2. __________: Supply blood to the kidneys
 3. _______________: the final branches of the interlobular
arteries; lead to the nephrons
 4. ________: joins the inferior vena cava as it courses
through the abdominal cavity
 5. ________ capillaries filter fluids