L9A: Urinary system (anatomy and renal physiology)

• What is the primary function of the urinary system?

  Excretion of waste products
• How does the urinary system maintain acid-base balance?

  By filtering blood and forming urine
• What hormone is produced by the kidneys for red blood cell synthesis?

  Erythropoietin
• What is the role of renin in the body?

  Regulates blood pressure
• What is the function of the bladder?

  Stores urine for secretion
• Where are the kidneys located in the body?

  Below diaphragm on posterior wall
• Why is the right kidney lower than the left kidney?

  Due to the position of the liver
• What shape are the kidneys?

  Bean shaped
• What is the average size of a kidney?

  11cm long, 6cm wide, 3cm thick
• What is the hilum of the kidney?

  Concave medial border for transport
• What is the renal pelvis?

  Where urine collects
• What is the function of the ureters?

  Drain urine to the bladder
• How does the structure of the urinary bladder change?

  Size and position change with volume
• What is the urethra?

  Tube from bladder to exterior
• How does the length of the urethra differ between genders?

  Shorter in females than males
• What is the capsule of the kidney?

  Fibrous outer layer
• What color is the renal cortex?

  Reddish brown
• What is the medulla of the kidney?

  Innermost layer with conical striations
• What is a nephron?

  Functional unit of the kidney
• What does the glomerular capsule contain?

  Contains glomerulus
• How long is the nephron tubule?

  3 cm long
• What type of endothelium lines the capillaries in the glomerular capsule?

  Fenestrated endothelium
• What is the role of the basement membrane in the glomerulus?

  Main site of filtration of proteins
• What are podocytes?

  Cells that wrap around capillaries
• What percentage of nephrons are cortical nephrons?

  80-85%
• What is the function of juxtamedullary nephrons?

  Concentrate urine
• What percentage of cardiac output do the kidneys receive?

  20%
• What happens to the afferent arteriole in the nephron?

  Enters each glomerulus
• Why do afferent arterioles have a larger diameter than efferent arterioles?

  Increases pressure inside glomerulus
• What is the role of peritubular capillaries?

  Wrap around loop of Henle for exchange
• What are the three factors affecting fluid dynamics?

  Diameter, length of tube, viscosity
• What is urea?

  Breakdown product of protein
• What is the role of urobilin?

  Excreted as stercobilin or urobilin
• What is creatinine a product of?

  Regeneration of ATP
• What are the cations found in urine?

  Sodium, potassium, calcium, ammonia
• What is the process of urine formation?

  Filtration, selective reabsorption, tubular secretion
• What is ultrafiltration?

  Process through glomerulus and capsule
• What types of molecules pass easily through the glomerulus?

  Water and small molecules
• What happens to large molecules during filtration?

  They stay in capillaries
• What is the filtration membrane composed of?

  Capillary endothelium and basement membrane