Urinary

• What is the primary function of the urinary system?

  To filter and remove waste products and excess substances from the blood through urine production and excretion.
• What are the four main components of the urinary system?

  • Kidneys
  • Ureters
  • Urinary Bladder
  • Urethra
• What is the function of the kidneys in excretion?

  To filter blood, reabsorb needed substances, and form urine to eliminate metabolic wastes, toxins, and excess ions.
• How do the kidneys regulate blood volume and pressure?


  By altering urine concentration based on hydration levels.
• What role do the kidneys play in regulating blood solute concentrations?


  They control the levels of major ions and other solutes in the blood.
• How do the kidneys manage extracellular fluid pH?

  By adjusting hydrogen ion secretion.
• What is the function of erythropoietin released by the kidneys?

  To promote red blood cell production.
• How do the kidneys activate vitamin D?

  By helping regulate calcium levels in the blood.
• Where are the kidneys located?

  In the retroperitoneal space, positioned between the T12 and L3 vertebrae.
• What is the average size of an adult kidney?

  About 4-5 inches long, 2.5 inches wide, and 1 inch thick.
• What is the weight of an adult male and female kidney?

  Adult male: 150 g; Adult female: 135 g.
• What is the hilum of the kidney?

  The medial indentation where the ureter, blood vessels, lymphatics, and nerves enter and exit the kidney.
• What is the function of the renal capsule?

  It is the outer connective tissue layer surrounding the kidney.
• What is the role of the perirenal fat capsule?


  It provides cushioning and support to the kidney.
• What is the renal fascia?

  It is dense connective tissue anchoring the kidney to surrounding structures.
• What are the two main regions of the kidney?

  The cortex and the medulla.
• What is the function of the renal pyramids?

  They are cone-shaped tissues that lead to the minor calyx.
• What are renal columns?

  Tissues between the renal pyramids that support and separate them.
• What is the renal pelvis?

  A funnel-shaped cavity that collects urine and leads into the ureter.
• What are nephrons?


  Functional units of the kidney responsible for filtering blood and forming urine.
• How many nephrons does each kidney contain?

  Over 1 - 1.3 million nephrons.
• What are the parts of a nephron?

  • Renal Corpuscle
  • Renal Tubules
  • Collecting Duct
• Where is the renal corpuscle located?

  In the renal cortex.
• What is the glomerulus?


  A tuft of fenestrated capillaries that filters blood to form protein-free filtrate.
• What is the function of the glomerular (Bowman's) capsule?

  It surrounds the glomerulus and regulates what enters the nephron.
• What are juxtaglomerular cells?


  Specialized smooth muscle cells surrounding the afferent arteriole that detect changes in blood pressure.
• What is the macula densa?

  A group of specialized cells in the distal convoluted tubule that sense sodium concentration in the filtrate.
• What is the main function of the juxtaglomerular apparatus?

  To regulate blood pressure and filtrate formation.
• What enzyme does the juxtaglomerular apparatus secrete when blood pressure is low?

  Renin.
• What is the filtration membrane in the nephron?

  A barrier that allows water and small molecules to pass while blocking blood cells and larger proteins.
• What is the filtration fraction?

  19% of plasma is filtered by the glomerulus.
• What is the glomerular filtration rate (GFR)?

  The amount of plasma entering the Bowman's capsule per minute, approximately 125 mL/min.
• What is the renal plasma flow rate?

  Renal blood flow rate multiplied by 55%, approximately 650 mL/min.
• What is the role of the peritubular capillaries?

  They surround the PCT and DCT of cortical nephrons and are adapted for reabsorption of water and solutes.
• What is the function of the vasa recta?


  It surrounds the nephron loops of juxtamedullary nephrons and maintains the osmotic gradient in the medulla.
• What is the first step in urine production?

  Filtration, which occurs in the renal corpuscle.
• What drives the filtration process in the renal corpuscle?

  Hydrostatic pressure.
• What is the composition of filtrate?

  Similar to plasma but lacks proteins and blood cells.
• What is the approximate amount of filtrate produced per minute?

  Approximately 125 mL/min.
• What is the renal fraction of cardiac output?

  Approximately 21-25% of cardiac output.