Physiology Exam 4
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What are the main functions of the kidneys?

Regulation of body fluid osmolality and volume, regulation of electrolyte balance, regulation of acid-base balance, excretion of metabolic products and foreign substances, and production and secretion of hormones.

What is being absorbed within the nephron of the kidney?

  • Urine
  • Water and ions (correct)
  • Glucose (correct)
  • Protein

    • What is being secreted by the nephrons of the kidneys?

  • Urine (correct)
  • Bile
  • Hormones
  • Digestive enzymes

    • Is the proximal convoluted tubule the primary site where toxins are secreted from a kidney nephron.

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

    What is the basic function of the nephron?

    <p>Filtering blood and removing waste via bladder as urine</p> Signup and view all the answers

    Each nephron has only one set of arterioles and capillaries.

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

    The nephron filters blood and removes waste via ______ as urine.

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

    Match the components of the nephron with their descriptions:

    <p>Afferent arterioles = Bring blood to the glomerulus Efferent arterioles = Take blood away from the glomerulus Bowman's capsule = Filters fluid that flows into the proximal tubule Collecting duct = Receives fluid from the distal tubule</p> Signup and view all the answers

    Match the following characteristics with the corresponding type of nephron:

    <p>Juxtamedullary nephron = Glomeruli near cortical medullary border Cortical nephron = Glomeruli in outer cortex Juxtamedullary nephron = Extended loop of henle in the renal pyramids Cortical nephron = Shorter loops of Henle Juxtamedullary nephron = 20% are juxtamedullary nephrons Cortical nephron = 80% are cortical variety Both = Both regulate solutes, water, and blood Juxtamedullary nephron = Concentrate and dilute urine Cortical nephron = Mainly perform excretory and regulatory function</p> Signup and view all the answers

    Which part of the nervous system controls the internal sphincter and Detrusor muscle?

    <p>Autonomic nervous system</p> Signup and view all the answers

    The external sphincter is a voluntary muscle under the control of autonomic nerves.

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

    What is the net pressure from the glomerulus that provides for filtration to the kidney nephron?

    <p>10 mmHg</p> Signup and view all the answers

    The presence of proteins in blood plasma slows down osmosis due to the _______________ pressure.

    <p>blood colloid osmotic</p> Signup and view all the answers

    Match the following pressures with their effects on filtration:

    <p>Glomerular blood hydrostatic pressure (GBHP) = Promotes filtration Capsular hydrostatic pressure (CHP) = Opposes filtration Blood colloid osmotic pressure (BCOP) = Opposes filtration</p> Signup and view all the answers

    What happens if the GFR is too high?

    <p>Fluid flows through tubules too rapidly to be absorbed</p> Signup and view all the answers

    There are 3 mechanisms that keep GFR at 10 mmHg.

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

    What is the primary function of albumin in the blood?

    <p>To keep water inside blood vessels</p> Signup and view all the answers

    What is the primary function of vasopressin in the collecting duct?

    <p>To conserve water by reducing urine production</p> Signup and view all the answers

    The descending limb of the loop of Henle is impermeable to water.

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

    What is the primary role of the carbonic acid bicarbonate buffer system?

    <p>To prevent pH changes caused by organic and fixed acids</p> Signup and view all the answers

    What percentage of most pH disturbances can be handled by the 2nd line of defense, which is ventilation?

    <p>75%</p> Signup and view all the answers

    The buffer system can eliminate hydrogen ions completely.

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

    The glomerulus allows smaller molecules, waste, and fluid, mostly ___________________, to pass into the tubule.

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

    What is the major source of hydrogen ions in the body?

    <p>Metabolism, breaking down 4 monomers, glucose, fatty acids, amino acids, and nucleic acids</p> Signup and view all the answers

    Match the hormones with their functions:

    <p>Vasopressin = Regulates water reabsorption in the collecting duct Aldosterone = Regulates electrolyte balance and blood pressure ANP = Lowers blood pressure and controls electrolyte homeostasis</p> Signup and view all the answers

    The act of breathing raises the blood oxygen level, lowers the blood ______________________ concentration and raises pH.

    <p>carbon dioxide</p> Signup and view all the answers

    What is the primary site of action for aldosterone?

    <p>Distal convoluted tubule</p> Signup and view all the answers

    Match the following lines of defense against pH changes with their corresponding actions:

    <p>Buffer system = Ties up assets and bases but cannot eliminate them, acts in seconds Ventilation = Handles about 75% of most pH disturbances, raises blood oxygen level, lowers carbon dioxide concentration and raises pH Renal regulation = Eliminates excess metabolic acids directly, takes hours to days</p> Signup and view all the answers

    The glomerular filtrate contains red blood cells.

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

    What stimulates the release of aldosterone?

    <p>An increase in potassium or low blood pressure</p> Signup and view all the answers

    The counter-current multiplier is driven by active transport of ____________________.

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

    What is the functional overview of a nephron?

    <p>Filter everything out and take back what is worth keeping</p> Signup and view all the answers

    What is the primary mechanism that regulates renal blood flow and glomerular filtration rate?

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

    The myogenic mechanism is a local mechanism that responds to changes in renal blood flow by constricting or dilating the afferent arteriole.

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

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

    <p>Macula densa cells act as sodium sensor receptors and trigger a signaling molecule that binds to the afferent arteriole, causing constriction or dilation.</p> Signup and view all the answers

    The countercurrent multiplier system in the loop of Henle is responsible for establishing a ____________________ environment in the renal medulla.

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

    Match the following mechanisms with their effects on glomerular filtration rate (GFR):

    <p>Myogenic mechanism = Decreases or increases GFR Tubuloglomerular feedback = Decreases GFR Neural regulation = Decreases GFR Hormonal regulation = Increases or decreases GFR</p> Signup and view all the answers

    Angiotensin II causes vasoconstriction of both afferent and efferent arterioles.

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

    What is the role of urea in the renal medulla?

    <p>Urea creates a hyperosmotic environment gradient found in the medulla of the kidney, allowing for water conservation.</p> Signup and view all the answers

    The ____________________ system prevents the production of liters of diluted urine every day.

    <p>countercurrent multiplier</p> Signup and view all the answers

    What is the primary function of the kidneys in terms of water conservation?

    <p>To conserve water by reabsorbing it into the bloodstream</p> Signup and view all the answers

    What is the primary function of the stomach?

    <p>To degrade food both physically and chemically</p> Signup and view all the answers

    What is the function of the pancreas in the digestive system?

    <p>To secrete enzymes that break down carbohydrates, fats, proteins, and acids</p> Signup and view all the answers

    What is the liver's function during the postabsorptive period?

    <p>To convert glycogen to glucose, fatty acids, and amino acids</p> Signup and view all the answers

    What is the primary function of the small intestine?

    <p>To absorb nutrients into the bloodstream</p> Signup and view all the answers

    What is the function of the duodenum in the small intestine?

    <p>To synthesize and secrete CCK and secretin</p> Signup and view all the answers

    What is the function of the jejunum in the small intestine?

    <p>To mix food with bile, enzymes, and mucus</p> Signup and view all the answers

    What is the function of the large intestine?

    <p>To remove waste products from the body</p> Signup and view all the answers

    What is the role of the liver in clotting functions?

    <p>To produce several essential clotting factors</p> Signup and view all the answers

    What is the primary function of pancreatic juice?

    <p>To provide a mixture of enzymes and buffers to facilitate digestion</p> Signup and view all the answers

    What happens when the body temperature is too high?

    <p>Blood vessels dilate to increase heat loss</p> Signup and view all the answers

    What is the effect of glucocorticoids on the body?

    <p>Increase blood sugar levels by breaking down proteins and fats</p> Signup and view all the answers

    What is the function of calcitonin?

    <p>Increase bone density by reducing calcium uptake in the kidneys</p> Signup and view all the answers

    What is the role of the parasympathetic nervous system during digestion?

    <p>Promote digestion and peristalsis</p> Signup and view all the answers

    What is the function of estrogen during bone remodeling?

    <p>Decrease osteoclast activity</p> Signup and view all the answers

    What is the primary function of flat bones?

    <p>Protect internal organs</p> Signup and view all the answers

    What stimulates the release of secretin?

    <p>Presence of acid in the duodenum</p> Signup and view all the answers

    What is the primary function of long bones in the human body?

    <p>To facilitate movement and weight support</p> Signup and view all the answers

    During meiosis, what is the result of nondisjunction in Meiosis I?

    <p>Failure of homologous chromosomes to separate, resulting in abnormal gametes</p> Signup and view all the answers

    What is the primary function of Sertoli cells in the human body?

    <p>To produce inhibin and androgen-binding protein, and support spermatogenesis</p> Signup and view all the answers

    What hormone is responsible for regulating follicle growth in the human body?

    <p>FSH, which affects Sertoli cells</p> Signup and view all the answers

    What is the result of cytokinesis during cell division?

    <p>Division of cytoplasm, resulting in 2 complete daughter cells</p> Signup and view all the answers

    What is the primary function of the corpus luteum in the human body?

    <p>To secrete progesterone and estradiol, and regulate menstruation</p> Signup and view all the answers

    What is the result of meiosis II during gamete production?

    <p>Separation of sister chromatids, resulting in 4 haploid daughter cells</p> Signup and view all the answers

    What hormone surge directly causes ovulation in the human body?

    <p>LH, which causes ovulation and regulates menstruation</p> Signup and view all the answers

    What is the primary function of the ileum in the small intestine?

    <p>Absorbs water, minerals, and salts</p> Signup and view all the answers

    Which phase of gastric secretion is directed by the CNS and prepares the stomach to receive food?

    <p>Cephalic phase</p> Signup and view all the answers

    What is the function of insulin in the body?

    <p>Stimulates the liver and most other body cells to absorb glucose</p> Signup and view all the answers

    Which hormone is released when there is too little glucose in the blood?

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

    What is the primary function of the large intestine?

    <p>Absorbs water, bile salts, and electrolytes</p> Signup and view all the answers

    Which hormone stimulates the pancreas and gallbladder, but also suppresses gastric secretion and motility?

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

    What is the primary function of the jejunum in the small intestine?

    <p>Absorbs carbohydrates, proteins, and vitamins</p> Signup and view all the answers

    Which phase of gastric secretion involves the control of the stomach by the small intestine?

    <p>Intestinal phase</p> Signup and view all the answers

    What is the function of glucagon in the body?

    <p>Stimulates the liver to release glucose</p> Signup and view all the answers

    Which hormone is released from the pancreas when there is too much glucose in the blood?

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

    Study Notes

    Nephron Function

    • Filtration of blood and removal of waste via urine, retaining essential substances for biochemical processes
    • Regulation of blood pH, blood pressure, and blood fluid maintenance

    Types of Nephrons

    • Two types: Juxtamedullary and Cortical
    • Juxtamedullary nephrons:
      • Glomeruli located near the cortical-medullary border
      • Extended loop of Henle in renal pyramids
      • 20% of total nephrons
    • Cortical nephrons:
      • Glomeruli located in outer cortex
      • Shorter loops of Henle
      • 80% of total nephrons

    Regulation and Function

    • Both types of nephrons regulate solutes, water, and blood
    • Concentrate and dilute urine
    • Mainly perform excretory and regulatory functions

    Nephron Structure

    • Each nephron has two sets of arterioles and capillaries forming a portal system
    • Afferent arterioles bring blood to the glomerulus
    • Efferent arterioles take blood away from the glomerulus
    • Glomerulus capillaries are located between the afferent and efferent arterioles
    • Leaky capillaries forcing plasma into the nephron

    Blood Flow and Tubules

    • Blood flows from afferent arteriole to glomerulus to efferent arterioles to peritubular or vasa recta capillaries
    • Filtered fluid flows from Bowman's capsule to proximal tubule, then to Loop of Henle, and finally to distal tubule and collecting duct

    Regulation of Micturition

    • The process of emptying urine into the urethra is regulated by nervous signals from both the somatic and autonomic nervous systems.
    • The internal sphincter and detrusor muscle are under autonomic control, while the external sphincter is a voluntary muscle under the control of voluntary nerves.

    Glomerular Filtration Rate (GFR)

    • GFR is regulated by three main pressures: glomerular blood hydrostatic pressure (55mmHg), capsular hydrostatic pressure (15mmHg), and blood colloid osmotic pressure (30mmHg).
    • Glomerular filtration rate is influenced by four mechanisms: myogenic response, tubuloglomerular feedback, neural regulation, and hormonal regulation.

    Mechanisms Regulating GFR

    • Myogenic response:
      • When renal blood flow increases, hydrostatic pressure against the walls of the afferent arteriole increases.
      • Stretch receptors in vascular smooth muscle cells initiate vasoconstriction, decreasing renal blood flow and GFR.
    • Tubuloglomerular feedback:
      • Macula densa cells in the distal convoluted tubule act as sodium sensor receptors.
      • When sodium levels are too high, signaling molecules constrict the afferent arteriole, reducing GFR.
    • Neural regulation:
      • Sympathetic nervous system activation constricts afferent arterioles, reducing GFR.
      • Also acts on the endocrine system, releasing angiotensin II, which constricts both afferent and efferent arterioles, further decreasing GFR.
    • Hormonal regulation:
      • Angiotensin II, produced in the glomerulus, constricts or dilates afferent arterioles, affecting GFR.

    Renal Medulla and Urine Concentration

    • The salinity gradient of the renal medulla concentrates or dilutes urine.
    • Urea creates a hyperosmotic environment in the medulla, which allows water conservation.
    • The countercurrent multiplier system in the loop of Henle establishes the hyperosmotic renal medulla.
    • Active transport of NaCl and passive transport of urea drive the countercurrent multiplier.

    Filtrate Contents and Nephron Function

    • The filtrate contains water, urea, NaCl, KCl, phosphates, and other waste products.
    • The nephron filters out waste and excess substances, reabsorbs water and salts, and secretes additional unwanted substances.

    Vasopressin and Aldosterone

    • Vasopressin (ADH):
      • Regulates water reabsorption in the collecting duct.
      • In the presence of vasopressin, the collecting duct is permeable to water, allowing reabsorption and water conservation.
    • Aldosterone:
      • Directly regulates blood levels of electrolytes and indirectly regulates water levels.
      • Acts on the distal convoluted tubule, increasing sodium reabsorption and indirectly increasing water reabsorption, which increases blood volume and blood pressure.

    pH Balance and Regulation

    • The body controls pH through three systems: the carbonic acid-bicarbonate buffer system, ventilation, and renal regulation.
    • The major sources of hydrogen ions in the body are metabolism, breaking down glucose, fatty acids, amino acids, and nucleic acids.

    Digestive System

    • Mechanical digestion: physical breakdown of solid foods
    • Chemical digestion: chemical breakdown of food by enzymes into smaller compounds
    • Absorption: movement of small organic molecules, electrolytes, vitamins, and water across the digestive epithelium and into the blood
    • Defecation: removal of waste products

    Organs and Their Functions

    • Stomach:
      • Holds ingested food
      • Degrades food both physically and chemically
      • Delivers chyme to the small intestine
      • Enzymatically digests proteins with pepsin
      • Secretes intrinsic factor required for absorption of vitamin B12
    • Pancreas:
      • Enzymes secreted help break down carbohydrates, fats, proteins, and acids in the duodenum
      • Secretes bicarbonate to neutralize stomach acid in the duodenum
      • Hormones secreted regulate glucose levels in the blood (insulin and glucagon)
    • Liver:
      • Postabsorptive period: produces glucose from glycogen and fatty acids and amino acids
      • Clotting functions: produces essential clotting factors
      • Exocrine functions: synthesizes bile salts
    • Small Intestine:
      • Duodenum: receives roughly digested and mixed food from the stomach, neutralizes stomach acid, and synthesizes and secretes CCK and secretin
      • Jejunum: absorbs nutrients such as carbohydrates, proteins, and vitamins
      • Ileum: absorbs water, minerals, and salts, and remaining nutrients
    • Large Intestine:
      • Absorbs water, bile salts, and electrolytes
      • Absorbs vitamins liberated by bacterial action
      • Forms and stores feces
      • Carries out defecation

    Regulation of Gastric Secretion

    • Happens in three phases:
      1. Cephalic phase: directed by the CNS, prepares the stomach to receive food
      2. Gastric phase: begins with arrival of food in the stomach, stomach controls itself
      3. Intestinal phase: controls the rate of gastric emptying, ensuring secretory, digestive, and absorptive functions of the small intestine

    Hormones

    • Insulin:
      • "Storage hormone"
      • Released from pancreas when there is too much glucagon in blood stream
      • Stimulates liver and most body cells to absorb glucose
      • Negative feedback
    • Glucagon:
      • Released when there is too little glucose
      • Stimulates liver to release glucose
      • Negative feedback
    • Other hormones:
      • CCK: stimulates pancreas and gallbladder, suppresses gastric secretion and motility
      • Secretin: stimulates pancreas and gallbladder, suppresses gastric secretion and motility
      • Gastrin: stimulates gastric secretion and motility
      • Somatostatin: inhibits gastric secretion and motility
      • Motilin: stimulates gastric secretion and motility

    Pancreatic Juice

    • Mixture of enzymes and buffers (sodium bicarbonate) secreted by acinar cells into pancreatic duct and released into duodenum
    • 5 major components:
      1. Pancreatic amylase
      2. Lipase
      3. Proteases
      4. Nucleases
      5. Sodium bicarbonate

    Bone Remodeling

    • Hormones involved:
      • Calcitonin: increases bone density by reducing Ca uptake in kidneys
      • Parathyroid hormone: decreases bone density, increases Ca uptake in intestines
      • Calcitriol (Vitamin D): increases Ca intake in intestines
      • Testosterone: increases osteoblast activity, osteoblast deposit Ca to bones
      • Estrogen: decreases osteoclast activity, osteoclast break down bone

    Bone Types

    • Long bones: support weight, facilitate movement
    • Short bones: provide stability, some movement
    • Flat bones: protect internal organs, provide large surface for muscle attachment
    • Irregular bones: have complex shapes, protect internal organs
    • Sesamoid bones: small, round bones, reinforce tendons

    Cell Division

    • Meiosis: diploid, produces 2 daughter cells, growth and repair
    • Mitosis: gametes, production of gametes, occurs in sex cells, results in 4 haploid, genetically different cells
    • Cytokinesis: cytoplasmic division
    • Nondisjunction: meiosis I, failure of homologous chromosomes to separate; meiosis II, failure of sister chromatids to separate

    Interphase and Anaphase

    • Interphase: G0 stage, normal functions; G1 stage, cell doubles organelles, grows in size; S stage, DNA replication; G2 stage, proteins needed for division are synthesized
    • Metaphase: homologous chromosomes lined up side by side
    • Anaphase: separating sister chromatids

    Gene Regulation

    • Each gene contains information about a certain trait
    • Genes are transcribed and translated by the cell to make proteins
    • Proteins create a visible phenotype
    • Different proteins are produced by different cell types, with different shapes and functions

    Reproductive System

    • Interstitial cells: produce testosterone
    • Sertoli cells: produce inhibin and androgen binding protein
    • LH causes ovulation by releasing egg every 14 days
    • FSH effects Sertoli cells in guys, LH effects interstitial cells
    • GnRH: hormone released from hypothalamus
    • Corpus luteum: secretes progesterone and estradiol
    • Menses start when levels of progesterone and estradiol dip

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    This quiz tests your knowledge of the main functions of the kidneys, including filtration, waste removal, and hormone regulation. Learn about the essential roles of the kidneys in maintaining overall health.

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