Homeostasis and Feedback Mechanisms
37 Questions
2 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the set point for blood glucose concentration in humans?

  • 4mmol/dm³
  • 7mmol/dm³
  • 6mmol/dm³
  • 5mmol/dm³ (correct)

    • Positive feedback mechanisms are common in the human body.

    False

    What is the role of alpha cells in the pancreas?

    To secrete glucagon when blood glucose levels fall.

    Diabetes is the condition in which a person has consistently elevated blood glucose levels, leading to the presence of glucose in the ______.

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

    Match the diabetes type with its description:

    <p>Type 1 = Autoimmune disease affecting insulin production Type 2 = Insulin resistance often due to lifestyle factors</p> Signup and view all the answers

    What substance is released by beta cells when blood glucose concentrations rise?

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

    Negative feedback mechanisms work to achieve balance within the body.

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

    What happens to tissues when a person has diabetes?

    <p>They may become damaged.</p> Signup and view all the answers

    Which of the following factors is NOT a main risk factor for Type 2 diabetes?

    <p>High protein diet</p> Signup and view all the answers

    Type 1 diabetes can be treated permanently using stem cells.

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

    What is the human set point for core body temperature?

    <p>37°C</p> Signup and view all the answers

    The hypothalamus initiates responses to regulate body temperature when it detects __________ from thermoreceptors.

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

    Match the following treatments for diabetes with their description:

    <p>Dietary adjustments = Adjusts food intake to manage blood glucose levels Insulin injections = Used to lower blood glucose before meals Exercise = Improves insulin uptake and action Implanted devices = Releases insulin automatically when needed</p> Signup and view all the answers

    Which hormone does the hypothalamus secrete to increase metabolic rate?

    <p>Thyrotropin releasing hormone (TRH)</p> Signup and view all the answers

    What type of thermoreceptors are located in the skin?

    <p>Peripheral thermoreceptors</p> Signup and view all the answers

    Eating small amounts of food frequently helps in managing blood glucose levels in Type 2 diabetes.

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

    What is the primary role of the loop of Henle?

    <p>To maintain the osmotic concentration gradient in the medulla</p> Signup and view all the answers

    The filtrate in the descending limb of the loop of Henle becomes hypotonic as water leaves.

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

    What hormone does the hypothalamus signal the pituitary gland to secrete when osmotic concentration is too high?

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

    If osmotic concentration is too low, the hypothalamus causes the pituitary gland to stop secreting _____, which leads to less water reabsorption.

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

    Match the following sections of the nephron with their function:

    <p>Proximal convoluted tubule = Reabsorption of water, ions, and nutrients Loop of Henle = Establishing osmotic gradient Distal convoluted tubule = Regulation of final water reabsorption Collecting duct = Final urine concentration</p> Signup and view all the answers

    Which of the following is NOT a response of the body to cold temperatures?

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

    Osmoregulation is exclusively the function of the kidneys.

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

    What is the primary function of the nephron?

    <p>To filter blood and produce urine.</p> Signup and view all the answers

    Urea is produced in the liver during a process called __________.

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

    Match the kidney structure with its function:

    <p>Renal artery = Carries blood to the kidney Cortex = Outer region of the kidney Renal vein = Carries filtered blood away from the kidney Ureter = Transport urine from the kidney to the bladder</p> Signup and view all the answers

    What initiates the process of urine formation in the nephron?

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

    The loop of Henle is located in the renal medulla and is involved in concentrating urine.

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

    What is the primary role of vasodilation in thermoregulation?

    <p>To increase blood flow to the skin and enhance heat loss.</p> Signup and view all the answers

    What is the primary function of fenestrations in the capillary walls?

    <p>To allow filtration of small molecules only</p> Signup and view all the answers

    Most of the filtered fluid is returned to the blood capillaries after filtration.

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

    What is the total volume of glomerular filtrate produced per day?

    <p>180 litres</p> Signup and view all the answers

    The filtered fluid that passes through the glomerulus is known as ________.

    <p>glomerular filtrate</p> Signup and view all the answers

    Match the following structures with their functions:

    <p>Afferent arteriole = Wider diameter allows more blood flow Efferent arteriole = Narrower diameter helps maintain pressure Podocytes = Form a network of slits for filtration Proximal convoluted tubule = Main site for reabsorption</p> Signup and view all the answers

    Which of the following is NOT reabsorbed in the proximal convoluted tubule?

    <p>Most proteins</p> Signup and view all the answers

    The volume of urine produced daily is equal to the volume of glomerular filtrate.

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

    What is the concentration gradient in the loop of Henle at the centre of the kidney?

    <p>1200 mOsm</p> Signup and view all the answers

    Study Notes

    Homeostasis

    • Homeostasis is the maintenance of a constant internal body environment
    • Examples of factors maintained include blood glucose concentration, blood osmotic concentration, blood pH, and body temperature
    • Multicellular organisms have an advantage in regulated internal environments between cells

    Feedback Mechanisms

    • Feedback mechanisms use information about the outcome of a process to make decisions
    • Positive feedback increases the difference between the original level and the new level
    • Negative feedback reduces the difference, restoring the original level

    Blood Glucose Regulation

    • The set point for blood glucose concentration is 5mmol/dm³
    • Homeostasis is mediated by insulin and glucagon
    • Pancreas is both exocrine and endocrine
    • Exocrine glands have ducts, while endocrine glands secrete hormones directly into the bloodstream
    • Alpha cells secrete glucagon when blood glucose falls below the set point
    • Beta cells secrete insulin when blood glucose rises above the set point

    Types of Diabetes

    • Type 1 diabetes is an autoimmune disease damaging beta cells in the islets of Langerhans, leading to insufficient insulin production
    • Type 2 diabetes is the inability to process or respond to insulin due to a deficiency in insulin receptors on target cells. Risk factors include sugary/fatty diets, obesity, lack of exercise, and genetic factors

    Thermoregulation

    • Thermoregulation maintains an internal body temperature near 37°C
    • Negative feedback maintains temperature: If body temperature decreases, body generates heat. If body temperature increases, body loses heat
    • Thermoreceptors, located in the skin and the hypothalamus (part of the brain), monitor temperature
    • Responses to cold include vasoconstriction, shivering, and hair erection
    • Responses to heat include vasodilation, sweating, and increased metabolic rate
    • Hypothalamus, the part of the brain that regulates body temperature
    • Metabolic rate is influenced by the hypothalamus and thyroid hormones: hypothalamus' secretion of thyrotropin-releasing hormone (TRH) triggers the pituitary to secrete thyroid-stimulating hormone (TSH), which stimulates the thyroid gland to release thyroxine, increasing metabolic rate.

    Kidney and Osmoregulation

    • Osmoregulation maintains the osmotic concentration of body fluids within normal limits
    • Kidneys control water and salt balance
    • Kidneys remove waste and toxic products, including nitrogen-containing compounds (urea)
    • Kidneys remove extra substances not used by the body, like drugs or pigments from food
    • Kidneys filter substances in blood to produce urine
    • Filtrate is produced by high blood pressure in capillaries & filtered fluid is called glomerular filtrate. Blood cells and proteins are retained

    Nephron Structure and Function

    • Nephrons are the functional units of the kidney
    • Ultrafiltration is the first step of urine production in the Bowman's capsule which filters blood to create filtrate
    • Selective reabsorption is the second step: most water and minerals are reabsorbed into blood capillaries; glucose and amino acids are also reabsorbed. Reabsorption happens in proximal convoluted tubules through active transport, sodium ions, chloride ions, glucose via cotransporters, & water via osmosis
    • Loop of Henle maintains a concentration gradient, essential for water reabsorption
    • In the Loop of Henle, water moves from the filtrate into the blood via the descending limb, while salts leave.

    ADH and Osmoregulation

    • Osmoregulation involves the hypothalamus monitoring blood osmotic concentration

    • If osmotic concentration is too high, the hypothalamus signals pituitary to secrete ADH; ADH increases the permeability of the distal convoluted tubule, increasing water reabsorption, and decreasing the volume of urine.

    • Opposite happens when osmotic concentrations are low (less ADH, less water reabsorption)

    • Urine flows from the collecting duct to the pelvis and then to the urinary bladder

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    D3.3 Homeostasis PDF

    Description

    This quiz explores the concepts of homeostasis, feedback mechanisms, and blood glucose regulation. Understand how multicellular organisms maintain constant internal environments and the roles of insulin and glucagon in glucose management. Test your knowledge on the importance of feedback in biological processes.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser