Lecture 2 - Urinary System A+P 2
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Questions and Answers

What is the primary function of the urinary system in regard to waste management?

  • Conserving sodium in the blood
  • Excreting metabolic waste products (correct)
  • Maintaining blood pressure
  • Regulating blood pH levels

    • What is the role of the kidney in regulating blood pressure?

  • Secretion of aldosterone to conserve sodium
  • Secretion of renin to increase blood pressure (correct)
  • Filtration of chloride ions
  • Reabsorption of potassium ions

    • What is the significance of sodium in the urinary system?

  • It is essential for the reabsorption of water
  • It is a key electrolyte in maintaining blood volume (correct)
  • It is a waste product excreted in the urine
  • It helps in regulating blood pH levels

    • What is the net effect of the urinary system on blood pH levels?

    <p>It helps to conserve bicarbonate ions</p> Signup and view all the answers

    What is the primary function of the urinary system in regard to blood composition?

    <p>Regulating electrolyte levels</p> Signup and view all the answers

    What is the relationship between the kidney and blood volume?

    <p>The kidney regulates blood volume by conserving or eliminating water</p> Signup and view all the answers

    What is the function of the kidneys in regulating electrolytes?

    <p>To maintain a balance of potassium and sodium levels in the body</p> Signup and view all the answers

    What is the function of Calcitriol in the kidneys?

    <p>To regulate calcium homeostasis</p> Signup and view all the answers

    What is the name of the outermost layer of the kidney that connects it to the abdominal wall and diaphragm?

    <p>Renal fascia</p> Signup and view all the answers

    What is the term for the dropping of the kidney from the supine to erect position?

    <p>Ptosis</p> Signup and view all the answers

    What is the name of the functional unit of the kidney that is responsible for filtering waste and excess substances from the blood?

    <p>Nephron</p> Signup and view all the answers

    What is the name of the tube that connects the kidney to the bladder and allows for the passage of urine?

    <p>Ureter</p> Signup and view all the answers

    What is the function of the renal cortex in the kidney?

    <p>To filter waste and excess substances from the blood</p> Signup and view all the answers

    What is the name of the indented area on the medial side of the kidney where the renal artery, renal vein, and ureter enter?

    <p>Renal hilum</p> Signup and view all the answers

    What is the term for the movement of the diaphragm during inhalation that helps to facilitate the flow of urine through the kidneys?

    <p>Respiratory excursion</p> Signup and view all the answers

    How many pyramids are typically found in the renal medulla of the kidney?

    <p>8-18</p> Signup and view all the answers

    What percentage of the resting cardiac output does the kidneys receive?

    <p>20-25%</p> Signup and view all the answers

    Which part of the nephron is not located in the renal cortex?

    <p>Loop of Henle</p> Signup and view all the answers

    What is the function of the Juxtaglomerular Complex?

    <p>Regulation of blood pressure within the kidney</p> Signup and view all the answers

    What is the name of the artery that supplies each segment of the kidney?

    <p>Segmental Artery</p> Signup and view all the answers

    What is the main function of the Glomerular Capsule?

    <p>Collection of filtrate</p> Signup and view all the answers

    What is the term for the process of filtering blood plasma in the glomerulus?

    <p>Glomerular Filtration</p> Signup and view all the answers

    What is the approximate thickness of the filtration membrane in the glomerulus?

    <p>0.1 mm</p> Signup and view all the answers

    What is the term for the pressure that drives filtration in the glomerulus?

    <p>Net Filtration Pressure</p> Signup and view all the answers

    What is the name of the cells that relax or contract to regulate the surface area of the glomerulus?

    <p>Mesangial cells</p> Signup and view all the answers

    What is the term for the process of reabsorbing water and electrolytes from the filtrate back into the bloodstream?

    <p>Tubular Reabsorption</p> Signup and view all the answers

    What is the primary force responsible for the formation of filtrate in the glomerulus?

    <p>Glomerular Blood Hydrostatic Pressure (GBHP)</p> Signup and view all the answers

    What is the result of the Net Filtration Pressure (NFP) equation?

    <p>NFP = GBHP - CHP - BCOP</p> Signup and view all the answers

    What happens to the Glomerular Filtration Rate (GFR) if the afferent arteriole dilates?

    <p>GFR increases</p> Signup and view all the answers

    What is the function of the renal autoregulation mechanism?

    <p>To maintain a constant GFR</p> Signup and view all the answers

    What is the purpose of the tubuloglomerular feedback mechanism?

    <p>To maintain a constant GFR</p> Signup and view all the answers

    What is the result of a Glomerular Filtration Rate (GFR) that is too high?

    <p>Needed substances may be lost in the urine</p> Signup and view all the answers

    What is the role of the stretch receptors in the myogenic mechanism?

    <p>To detect changes in blood pressure</p> Signup and view all the answers

    What is the effect of chronic kidney disease on renal autoregulation?

    <p>Renal autoregulation is disrupted</p> Signup and view all the answers

    What is the purpose of the eGFR calculation?

    <p>To estimate the Glomerular Filtration Rate (GFR) based on creatinine levels</p> Signup and view all the answers

    What is the relationship between the Glomerular Filtration Rate (GFR) and the Net Filtration Pressure (NFP)?

    <p>GFR is directly proportional to NFP</p> Signup and view all the answers

    What is the effect of increased sodium and chlorine ions on the glomerulus?

    <p>It inhibits the release of nitric oxide from the juxtaglomerular apparatus.</p> Signup and view all the answers

    What is the effect of sympathetic nerve stimulation on renal blood flow and GFR?

    <p>It decreases renal blood flow and GFR.</p> Signup and view all the answers

    What is the role of angiotensin II in renal autoregulation?

    <p>It causes vasoconstriction of the afferent and efferent arterioles.</p> Signup and view all the answers

    What is the primary function of tubular reabsorption?

    <p>To conserve water and ions in the body.</p> Signup and view all the answers

    What is the function of the antiporter Na+-H+ in the proximal convoluted tubule?

    <p>It promotes the absorption of sodium and secretion of hydrogen ions.</p> Signup and view all the answers

    What is the role of the loop of Henle in tubular reabsorption?

    <p>It generates a concentration gradient for water and ions in the loop of Henle.</p> Signup and view all the answers

    What is the function of the principal cells in the collecting duct?

    <p>They control facultative water reabsorption by responding to ADH.</p> Signup and view all the answers

    What is the effect of atrial natriuretic peptide (ANP) on renal blood flow and GFR?

    <p>It increases renal blood flow and GFR.</p> Signup and view all the answers

    What is the role of the macula densa in tubuloglomerular feedback?

    <p>It detects changes in sodium and chlorine ions and adjusts glomerular filtration rate accordingly.</p> Signup and view all the answers

    What is the role of the intercalated cells in the collecting duct?

    <p>They regulate blood pH levels by secreting hydrogen ions.</p> Signup and view all the answers

    Which hormone stimulates the release of aldosterone?

    <p>Angiotensin II</p> Signup and view all the answers

    What is the primary function of the urinary bladder?

    <p>To temporarily store urine</p> Signup and view all the answers

    Where does the ureter enter the bladder?

    <p>Through the posterior wall</p> Signup and view all the answers

    What is the effect of high Antidiuretic Hormone (ADH) levels on urine output?

    <p>It decreases urine output</p> Signup and view all the answers

    Which structure is responsible for moving urine from the kidney to the urinary bladder?

    <p>Ureter</p> Signup and view all the answers

    What is the function of the renal cortex?

    <p>To filter waste and excess substances from the blood</p> Signup and view all the answers

    Which hormone has a role in regulating facultative water reabsorption?

    <p>Antidiuretic Hormone (ADH)</p> Signup and view all the answers

    What is the location of the ureteropelvic junction?

    <p>Where the ureter meets the renal pelvis</p> Signup and view all the answers

    What is the effect of Angiotensin II on the glomerular filtration rate (GFR)?

    <p>It decreases GFR</p> Signup and view all the answers

    Which structure is anterior to the symphysis pubis?

    <p>Urinary bladder</p> Signup and view all the answers

    If GBHP passes below ___... no filtration

    <p>45</p> Signup and view all the answers

    Glomerular Blood Hydrostatic Pressure should = Capsular Hydrostatic Pressure should = Blood Colloid Osmotic Pressure should =

    <p>55mmHg 15mmHg 30mmHG</p> Signup and view all the answers

    NFP Increases if afferent arteriole ____ and efferent arteriole _____.

    <p>Dilates Constricts</p> Signup and view all the answers

    Would not inject contrast in patient who's eGFR is?

    <p>30-44</p> Signup and view all the answers

    eGFR of kidney failure is?

    <p>&lt;15</p> Signup and view all the answers

    Two mechanisms of renal autoregulation are?

    <p>Myogenic mechanism and Tubeuloglomerular feedback</p> Signup and view all the answers

    T or F, Tubulorglomerular feedback inhibits the release of nitric oxide from cells, causing constriction of of afferent artieroles

    <p>True</p> Signup and view all the answers

    Angiotension II is a _____

    <p>Vasoconstrictor (reduces blood flow in afferent and efferent arterioles)</p> Signup and view all the answers

    T or F, Angiotenson II increases GFR

    <p>False</p> Signup and view all the answers

    Atrial Natriuretic Peptide does what?

    <p>Released from the heart when its too stretched (too much blood volume) causes afferent to get bigger</p> Signup and view all the answers

    T or F ANP (atrial natriuretic peptide) increases GFR

    <p>True</p> Signup and view all the answers

    T or F antiporters are mb proteins that move 2 or more substances in opposite directions and symporters move in same direction

    <p>True</p> Signup and view all the answers

    Obligatory water resorption (90%) occurs where? and Facultative water resorption (10%) happens where?

    <p>PCT and Descending loop of Henle</p> <p>DCT and collecting ducts</p> Signup and view all the answers

    Majority of water is absorbed?

    <p>PCT</p> Signup and view all the answers

    Descending loop of henle is permeable to ____while ascending is permeable to _____

    <p>water sodium and chloride ions</p> Signup and view all the answers

    Study Notes

    Urinary System Overview

    • The urinary system excretes waste products in the urine, regulates blood volume, blood composition, blood pressure, and blood pH.
    • It also regulates blood glucose levels and produces hormones that regulate calcium homeostasis and stimulate the production of red blood cells.

    Functions of the Urinary System

    • Excrete waste products in the urine, including:
    • Urea (breakdown of amino acids)
    • Creatinine (breakdown of creatine phosphate in muscles)
    • Uric acid (catabolism of nucleic acids)
    • Bilirubin (catabolism of hemoglobin)
    • Regulate blood volume by conserving or eliminating water in the urine
    • Regulate blood composition by controlling levels of:
    • Sodium
    • Potassium
    • Calcium
    • Chloride
    • Phosphate ions
    • Regulate blood pressure by secreting renin, which increases blood pressure
    • Regulate blood pH by excreting H+ ions and conserving bicarbonate ions in the blood
    • Regulate blood glucose levels by producing and releasing glucose into the blood
    • Produce hormones that regulate calcium homeostasis (calcitriol) and stimulate the production of red blood cells (erythropoietin)

    Important Electrolytes

    • Sodium: regulates osmotic gradients and fluid flow, and is involved in action potentials in muscles and nerves
    • Potassium: involved in repolarizing membrane potential
    • Calcium: important for bone health, blood clotting, and neurotransmitter release
    • Magnesium: important for bone health and metabolic reactions
    • Phosphate: important for bone health, cell membrane structure, and ATP production
    • Bicarbonate: regulates pH and CO2 transport

    Renal Anatomy

    • Kidneys are located in the abdominal and pelvic cavities
    • Right kidney is more inferior than the left kidney
    • Kidneys are surrounded by:
    • Renal capsule (innermost layer)
    • Adipose capsule (middle layer)
    • Renal fascia (outermost layer)
    • Renal cortex is the outer layer of the kidney, and the renal medulla is the inner layer
    • Renal columns are structures that anchor the cortex
    • Renal pyramids are cone-shaped structures in the medulla that drain urine into minor calyces
    • Minor calyces merge to form major calyces, which merge to form the renal pelvis
    • The renal pelvis is the funnel-shaped structure that collects urine from the kidney

    Nephron Structure

    • The nephron is the functional unit of the kidney
    • Each kidney contains approximately 1 million nephrons
    • The nephron consists of:
    • Renal corpuscle ( Bowman's capsule and glomerulus)
    • Renal tubule (proximal convoluted tubule, loop of Henle, and distal convoluted tubule)
    • The glomerulus is a network of capillaries that filters the blood
    • Bowman's capsule is the double-walled cup that surrounds the glomerulus
    • The renal tubule is where reabsorption and secretion of substances take place

    Glomerular Filtration

    • Glomerular filtration is the process of filtering the blood in the glomerulus
    • The net filtration pressure (NFP) is the force that pushes water and solutes out of the blood and into the Bowman's capsule
    • NFP is influenced by:
    • Glomerular blood hydrostatic pressure
    • Capsular hydrostatic pressure
    • Blood colloid osmotic pressure
    • The glomerular filtration rate (GFR) is the amount of filtrate formed by both kidneys each minute
    • GFR is regulated by:
    • Renal autoregulation
    • Neural regulation
    • Hormonal regulation

    Hormonal Regulation

    • Hormones that regulate GFR include:
    • Angiotensin II
    • Antidiuretic hormone (ADH)
    • Aldosterone
    • Atrial natriuretic peptide (ANP)
    • Parathyroid hormone (PTH)

    Ureters

    • Ureters are muscular tubes that transport urine from the kidney to the urinary bladder
    • The ureters have a smooth muscle wall that contracts to propel urine through the ureter
    • The ureters have a narrow lumen and a thick muscular layer

    Urinary Bladder

    • The urinary bladder is a temporary storage site for urine
    • The bladder has a smooth, trabeculated wall and a trigone that is the point of entry of the ureters
    • The bladder has a rugose appearance when empty, and becomes smooth and rounded when full

    Urethra

    • The urethra is the tube that carries urine from the bladder out of the body

    • The urethra is shorter in females than in males

    • The urethra has a sphincter that controls the flow of urine### Renal Autoregulation

    • Renal autoregulation maintains a constant GFR despite changes in blood pressure

    • There are three mechanisms: myogenic, tubuloglomerular feedback, and neural regulation

    Tubuloglomerular Feedback

    • Macula densa provides feedback to the glomerulus
    • Detects increased sodium and chloride ions and water in the filtrate
    • Inhibits release of nitric oxide, causing constriction of the afferent arterioles
    • Operates much slower than the myogenic mechanism

    Neural Regulation

    • Sympathetic ANS supplies nerves to the kidneys
    • At rest, this system is not controlling GFR (renal autoregulation)
    • Sympathetic nerve stimulation causes vasoconstriction of the afferent and efferent arterioles
    • Decreases renal blood flow and GFR, reducing urine output (conserves water)
    • Permits greater blood flow to heart and brain during hemorrhage or severe dehydration

    Hormonal Regulation

    • Angiotensin II is a potent vasoconstrictor
    • Reduces renal blood flow in both afferent and efferent arterioles, reducing GFR
    • Atrial Natriuretic Peptide (ANP) relaxes mesangial cells, increasing GFR

    Tubular Reabsorption

    • In 45 minutes, more fluid has entered the PCT than there is total blood volume
    • Most of the filtrate is reabsorbed from the tubules back into the bloodstream
    • Water, glucose, proteins, urea, ions (Na+, Cl-, Ca2+, K+) are reabsorbed
    • Passive transport: no energy required
    • Active transport: requires energy, uses symporters and antiporters

    Water Reabsorption

    • 99% of water is reabsorbed
    • Solute reabsorption drives water reabsorption
    • Occurs via osmosis (passive transport)
    • Obligatory Water Reabsorption (90%): PCT and descending Loop of Henle
    • Facultative Water Reabsorption (10%): regulated by ADH in the DCT and collecting ducts

    Tubular Secretion

    • Movement of substances from the capillaries into the filtrate
    • Occurs at a site other than the filtration membrane
    • Controls pH by secreting hydrogen and ammonium ions and conserving bicarbonate
    • Regulates sodium, potassium, magnesium, phosphate, and sulfate ions

    Reabsorption in Different Segments

    • PCT: 65% of glucose and amino acids, active transport of sodium, potassium, magnesium, phosphate, and sulfate ions
    • Loop of Henle: sodium, potassium, chloride, calcium, and magnesium ions
    • DCT: 95% of water and solutes reabsorbed, regulated by ADH and aldosterone

    Hormones and Homeostasis

    • Five hormones affect the extent of Na+, Cl-, Ca2+, and water reabsorption as well as K+ secretion by the renal tubules
    • Hormones involved in homeostasis: ADH, aldosterone, and others

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    Description

    Test your knowledge on the anatomy and physiology of the urinary system, including its relational anatomy, blood and urine flow, and glomerular filtration. This quiz covers the objectives of Chapter 26 from Merrill's Volume 2, 12th Edition.

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