overview of kidney

• How many kidneys do humans have?

  Two kidneys
• What are the two main blood vessels associated with the kidneys?

  Renal artery and renal vein
• What are the main structures of the kidney?

  • Capsule
  • Cortex
  • Medulla
  • Nephron

  
• What is the pathway for urine collection in the kidneys?

  1. Collecting duct
  2. Minor calyx
  3. Major calyx
  4. Renal pelvis
  5. Ureter
• What do kidneys do with plasma as it is filtered?

  Keep valuable substances and eliminate waste
• What are the three major functions of the kidneys?

  1. Excretion
  2. Homeostasis
  3. Endocrine organ
• What is the primary component of urine?

  Water
• What waste products do kidneys eliminate?

  Urea and uric acid
• How do kidneys maintain homeostasis?

  By regulating water balance and pH
• What hormone do kidneys produce to stimulate RBC production?

  Erythropoietin
• What is the blood flow rate to the kidneys?

  1200 ml/minute
• Why do kidneys have a high blood supply?

  To maintain body fluid volume and composition
• How many nephrons are in each kidney?

  1-1.5 million nephrons
• What are the components of a nephron?

  • Vascular component
  • Tubular component
  • Renal cortex
  • Renal medulla

  
• What does the afferent arteriole do?

  Carries blood to the glomerulus

  
• What is the role of the glomerulus?

  Filters plasma into the tubular component
• What happens to blood in the efferent arteriole?

  It carries unfiltered blood away
• What do peritubular capillaries supply?

  Blood supply to renal tissue
• What factors affect renal blood flow?

  • Vasoconstriction decreases blood flow
  • Glomerular blood flow determines filtration rate
  • Constant renal blood flow maintains GFR

  
• What is autoregulation in renal blood flow?

  Myogenic response constricts afferent arteriole

  
• What is the function of Bowman’s Capsule?

  Collects glomerular filtrate

  
• What occurs in the Proximal Convoluted Tubule (PCT)?

  Absorption and secretion of substances
• What is the role of the Loop of Henle?

  Establishes an osmotic gradient
• What does the Distal Convoluted Tubule (DCT) control?

  Reabsorption of Na+ and water
• What is the function of the Collecting Duct?

  Takes fluid into the renal pelvis
• What are the basic renal processes performed by the nephron?

  1. Glomerular filtration
  2. Tubular reabsorption
  3. Tubular secretion
  4. Excretion
• What is the formula for excretion?

  Excretion = Filtration - Resorption + Secretion
• Where does urine flow after the collecting ducts?

  Into the renal pelvis
• What is the structure of the ureters?

  Two smooth muscle layers
• What type of epithelium lines the ureters?

  Transitional epithelium
• What is the function of the detrusor muscle?

  Contracts to help empty the bladder
• What is micturition?

  The process of bladder emptying

  
• What nervous systems are involved in micturition?

  Sympathetic, parasympathetic, and somatic

  
• What are the steps in urination?

  1. Contraction of the detrusor muscle
  2. Relaxation of internal sphincter
  3. Relaxation of external sphincter

  
• What does the pelvic nerve do in bladder innervation?

  Enables micturition by contracting detrusor

  
• What does the hypogastric nerve do in bladder innervation?

  Prevents micturition by relaxing detrusor

  
• How much plasma is filtered per minute?

  125 ml
• How much filtrate forms per day?

  1. 180 litres
• What is the typical daily urine output?

  ~1.5 litres/day
• What is the composition of urine?

  • Water
  • Urea
  • Uric acid
  • Creatinine
  • Ions (Na+, K+)