Urinary System

• What are three major functions of the kidneys?

  1. Regulates blood pressure + osmolarity
  2. Secretes hormones (renin & erythropoietin)
  3. Filters blood plasma
• How many kidneys do we have?

  We have two kidneys
• What is a ureter?

  The ureter transports urine from the kidneys to the urine bladder.
• What is a urethra?

  A urethra transports urine from the bladder to the outside of the body.
• What is a bladder?

  A bladder stores urine, allowing urination to be infrequent and controlled.
• How many ureters, urethras, and bladders do we have?

  2 tubular ureters, 1 urethra, and 1 bladder.
• Trace the path of blood flow through the kidney. You should be able to name 10 blood vessels.

  Renal artery → Segmental artery → Interlobular artery → Arcuate artery → Cortical radiate artery → Afferent arteriole → Glomerular capillaries → Efferent arteriole → Peritubular capillaries → Cortical radiate vein → Arcuate vein → Interlobular vein → Renal vein
• Trace the path of filtrate flow through the kidney. You should be able to name 4 tubes between the glomerular capsule and the minor calyx.

  1. Glomerulus → 2. glomerular capsule (bowman's capsule) → 3. proximal convoluted tubule → 4. descending loop of henle → 5. ascending loop of henle → 6. distal convoluted tubule → 7. collecting duct → 8. minor calyces → 9. major calyces → 10. renal pelvis → 11. ureters → 12. urinary bladder → 13. urethra
• Name the two main regions of the kidney.

  The two main regions of the kidney are Renal cortex

  and Renal medulla.
• What structures are in the renal cortex?

  RENAL CORTEX: proximal convoluted tubule, distal convoluted tubule, collecting duct, peritubular capillaries, afferent arteriole, glomerulus, efferent arteriole, interlobular artery, interlobular vein, and renal columns
• What structures are in the renal medulla?

  RENAL MEDULLA: papilla, Renal columns, descending loop of henle, and ascending loop of henle
• What are nitrogenous wastes? Which is the most abundant one?

  -Nitrogenous waste is the nitrogen compounds through which excess nitrogen is eliminated from organism.

  The most abundant one is urea.
• Explain how the kidney uses filtration, secretion and reabsorption to clean waste from the blood while keeping all the good stuff.

  Renal filtration occurs when blood pressure forces water through membrane pores, and solute molecules small enough to pass through those pores are carried along.

  During secretion, water and other substances are taken from the filtrate in the tubules and returned to the blood. BACK TO BODY. During reabsorption, substances are taken from the blood and added to the filtrate. LEAVE BODY.
• How does tubular secretion (excretion) regulate the body’s pH when blood is too acidic?

  When blood is too acidic, hydrogen ions are reabsorbed and excreted in urine. When blood is too alkaline, hydrogen ions are secreted to bring pH levels down.
• In what part of the nephron does filtration happen?

  The part of the nephron where filtration happens is in the glomerulus and bowman's capsule.
• Where does MOST tubular reabsorption and secretion happen?

  MOST tubular reabsorption and secretion happens in the proximal convoluted tubule.
• What is filtrate?

  The fluid produced when blood is filtered by the filtration is membrane in the glomeruli of the kidneys.
• What is in filtrate?

  Filtrate consists of glucose, amino acids, water-soluble vitamins, H20, salts, urea, hydrogen ions, and carboxyl ions.
• What is NOT in filtrate?

  NOT in filtrate is red blood cells, white blood cells, platelets, albumin, fibrinogen, and other large proteins
• In what part of the nephron reabsorbs glucose?

  Proximal convoluted tubule reabsorbs glucose.
• What does the term ‘transport maximum’ mean?

  Transport maximum is when transport proteins of cell membrane are saturated and cant keep reabsorbing stuff.
• What happens when the transport maximum of glucose is exceeded during poorly controlled diabetes?

  When the transport maximum of glucose is exceeded during poorly controlled diabetes, glucose will remain in urine and power of osmosis will lead to glucose dragging a few water molecules with it.
• How does the body force filtrate out of the blood and into the glomerular capsule? Explain using the terms afferent arteriole, glomerulus, and efferent arteriole.

  To force filtration, net filtration pressure must be regulated. If afferent arteriole constricts, net filtration pressure decreases. If efferent constricts, blood backs up into the glomerulus and net filtration pressure increases.
• What part of the kidney regulates the concentration of your urine? (How watery or how dilute it is.)

  Collecting duct regulates the concentration of urine.
• How does the kidney make your urine more concentrated? Explain using the terms hormone, osmolarity hypothalamus, pituitary, aquaporin, renal medulla, collecting duct and ADH.

  In the medulla, concentration is 4x deep by osmolarity. In order to dilute urine, the collecting duct must be MORE permeable. When the hypothalamus senses salty blood it will tell the posterior pituitary to release antidiuretic hormone (ADH). The ADH then stimulates aquaporins the cells of the collecting duct. Then urine will become watery.
• What is the role of renin in regulating urine production and blood pressure?

  The role of renin is to maintain urine production and blood pressure.
• Where is renin made?

  Renin is made in the kidneys' juxtagomerular cells.
• How does renin affect the kidney and what is the mechanism by which it acts?

  It can help control tissue growth in the kidneys.

  Renin controls the production of the hormone aldosterone, and regulates blood pressure by increasing sodium reabsorption and water reabsorption and how much blood vessels constrict.
• Does renin make your blood pressure go up or down?

  Renin makes blood pressure go up.
• If your body asked the kidneys to make more urine, would your blood volume go up or down? If your blood volume goes down, does that make your blood pressure go up or down?

  To make more urine, blood volume goes down. To make less urine blood volume goes up. If blood volume goes down then blood pressure goes down too.
• Why is blood pressure in the glomerulus higher than the blood pressure in a typical capillary bed?

  Blood pressure in the glomerulus is higher than the blood pressure in a typical capillary bed because the diameter of the afferent arteriole is larger than the efferent arteriole.
• What is GFR? If the efferent arteriole constricts, would that

  make the GFR go up or down?

  GFR or Glomerulus filtration rate is a test to see if the kidneys are working / filtering.

  If efferent arteriole constricts then blood would back up into the glomerulus and filtration pressure increases.