Topic 13: Urinary System

• What are the main structures contained in the renal cortex?

  Glomerulus, Bowman’s capsule, tubules
• What structures are found in the renal medulla?

  Loop of Henle and collecting duct
• Where does the ureter join the kidney?

  Renal pelvis
• How does blood enter and leave the kidney?

  Enters through renal artery, leaves via renal vein
• What are the functional units of the kidney?

  Nephrons
• What are the three main functions of the nephron?

  Filtration, reabsorption, and secretion
• What two parts make up a nephron?

  Renal corpuscle and renal tubule
• What occurs in the renal corpuscle?

  Blood plasma is filtered
• What is the order of fluid passage through the renal tubule?

  Proximal tubule, nephron loop, distal tubule
• What is the glomerulus?

  A loop of capillaries for filtration
• What is the role of podocytes in the nephron?

  They form filtration slits to prevent large molecules
• What does the juxtaglomerular apparatus do?

  Regulates blood pressure and sodium concentration
• What triggers renin secretion from juxtaglomerular cells?

  Low sodium concentration in tubular filtrate
• What is the function of angiotensin II?

  Stimulates reabsorption of sodium and chloride
• What is the pathway of blood supply to the kidneys?

  Renal artery to segmental artery to renal vein
• What happens to interlobar veins in the kidneys?

  They merge to form the renal vein
• What are the three basic processes performed by nephrons?

  Glomerular filtration, tubular reabsorption, secretion
• What is glomerular filtration?

  Blood pressure forces water and solutes across capillary walls
• What is tubular reabsorption?

  Returning filtered water and solutes to the blood
• What substances are primarily excreted by tubular secretion?

  Wastes, drugs, and excess ions
• Where does tubular reabsorption primarily occur?

  In the proximal convoluted tubule
• What is the role of the loop of Henle?

  Concentrates urine by creating a salty environment
• What does the distal convoluted tubule do?

  Facilitates osmosis and diffusion of solutes
• How does antidiuretic hormone (ADH) affect the nephron?

  Increases permeability of the distal convoluted tubule
• What does angiotensin II do in the kidneys?

  Enhances reabsorption of sodium and chloride
• What hormone stimulates the release of aldosterone?

  Angiotensin II
• What is the effect of aldosterone on the kidneys?

  Stimulates reabsorption of sodium and chloride
• What are the components of the urinary system and their functions?

  • Kidneys: filter blood and produce urine
  • Ureters: transport urine to the bladder
  • Urinary bladder: stores urine
  • Urethra: expels urine from the body
• How does the urinary system contribute to homeostasis?

  • Regulates water balance
  • Maintains electrolyte levels
  • Controls blood pressure
  • Eliminates waste products
• What disorders can affect the urinary system?

  • Urinary tract infections (UTIs)
  • Kidney stones
  • Chronic kidney disease
  • Bladder cancer
• What effects does aging have on the urinary system?

  • Decreased kidney function
  • Reduced bladder capacity
  • Increased risk of incontinence
  • Higher likelihood of urinary tract infections
• What is the glomerular filtration rate (GFR) and its significance?

  • Volume of filtrate formed per minute
  • Indicator of kidney function
  • Regulated by multiple mechanisms
• What are the main sections of the renal tubule and their functions?

  • Proximal convoluted tubule: reabsorbs nutrients
  • Loop of Henle: concentrates urine
  • Distal convoluted tubule: regulates solute balance
• What is the filtration barrier in the glomerulus?

  • Endothelial cells of capillaries
  • Glomerular basement membrane
  • Epithelial cells (podocytes) of Bowman’s capsule
• What is the role of the macula densa in the juxtaglomerular apparatus?

  • Detects low sodium concentration
  • Stimulates renin secretion
  • Helps regulate blood pressure
• What is the significance of tubular secretion in the nephron?

  • Removes wastes and excess ions
  • Occurs mainly in the distal convoluted tubule
  • Helps maintain acid-base balance
• What is the process of tubular reabsorption?

  • Returns filtered water and solutes to blood
  • Primarily occurs in the proximal convoluted tubule
  • Involves passive and active transport mechanisms
• What is the role of the loop of Henle in urine concentration?

  • Creates a salty environment in the medulla
  • Allows water to osmose out of the nephron
  • Concentrates urine for excretion
• How does sodium reabsorption occur in the nephron?

  • Most sodium is reabsorbed actively
  • Water follows sodium due to osmotic gradients
  • Occurs mainly in the proximal convoluted tubule
• What is the function of the collecting duct in the nephron?

  • Transports urine to the renal pelvis
  • Regulates final concentration of urine
  • Responds to hormones like ADH