Homeostasis Part 1
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Questions and Answers

What condition is characterized by an excessively high amount of glucose in the blood?

  • Hypoglycaemia
  • Adrenal insufficiency
  • Hyperglycaemia (correct)
  • Diabetes insipidus

    • Which hormone is responsible for promoting the conversion of glucose into glycogen?

  • Epinephrine
  • Glucagon
  • Insulin (correct)
  • Cortisol

    • In what situation does the pancreas secrete more glucagon?

  • When blood glucose levels decrease (correct)
  • When blood glucose levels increase
  • When blood glucose levels are normal
  • When glycogen stores are full

    • What role does the liver play in glucose regulation?

    <p>It stores glycogen for glucose conversion</p> Signup and view all the answers

    What can severe cases of hypoglycaemia lead to?

    <p>Seizures or loss of consciousness</p> Signup and view all the answers

    What is homeostasis generally defined as?

    <p>The maintenance of a constant internal environment</p> Signup and view all the answers

    Which physiological mechanism is primarily responsible for regulating body temperature?

    <p>Vasoconstriction and vasodilation</p> Signup and view all the answers

    Who was the French physiologist that contributed to the understanding of homeostasis?

    <p>Claude Bernard</p> Signup and view all the answers

    How does the liver contribute to maintaining homeostasis regarding blood glucose levels?

    <p>By secreting glucose into the blood as needed</p> Signup and view all the answers

    What is the Greek origin of the term 'homeostasis'?

    <p>Homeo means 'same' and stasis means 'standing still'</p> Signup and view all the answers

    Why is homeostasis important for the human body?

    <p>To maintain a constant internal environment despite external changes</p> Signup and view all the answers

    Which of the following is NOT a function of homeostasis?

    <p>Controlling emotional responses</p> Signup and view all the answers

    Which of the following best describes the role of cruise control as an analogy for homeostasis?

    <p>It maintains a constant speed despite changes in terrain</p> Signup and view all the answers

    What is the primary role of the skin in terms of body temperature regulation?

    <p>Regulating blood flow through arterioles</p> Signup and view all the answers

    Which method of heat loss accounts for the largest percentage?

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

    What triggers the hypothalamus to send signals for temperature regulation?

    <p>Deviation from the body's normal temperature of 37°C</p> Signup and view all the answers

    Which component of the skin is primarily responsible for detecting changes in temperature?

    <p>Nerve endings/thermoreceptors</p> Signup and view all the answers

    How does the body primarily gain extra heat?

    <p>Through metabolic activities in the liver and muscles</p> Signup and view all the answers

    What role do arterioles play in body temperature regulation?

    <p>They regulate blood flow to the skin</p> Signup and view all the answers

    What percentage of body heat loss occurs through conduction?

    <p>2%</p> Signup and view all the answers

    Which of the following options is NOT a function of the skin?

    <p>Heat production</p> Signup and view all the answers

    What insulating role does hairy skin play?

    <p>It traps air to insulate the body</p> Signup and view all the answers

    What is the main method through which body heat is lost during exercise?

    <p>Evaporation via sweat</p> Signup and view all the answers

    What is the primary reason enzymes must be kept from inactivation or denaturation?

    <p>They can only work within a certain temperature range.</p> Signup and view all the answers

    What is one consequence of a change in pH levels within the cells?

    <p>Altered enzyme reactions.</p> Signup and view all the answers

    Which of the following is NOT an example of a condition that needs to be maintained for homeostasis?

    <p>Oxygen levels in the atmosphere</p> Signup and view all the answers

    What role does negative feedback play in homeostasis?

    <p>It restores conditions to their original state.</p> Signup and view all the answers

    What happens when the water potential of blood increases above normal levels?

    <p>The osmoreceptors detect the increase.</p> Signup and view all the answers

    What defines a homeostatic process?

    <p>A self-regulatory mechanism that aims to maintain constant internal conditions.</p> Signup and view all the answers

    Why is it beneficial for organisms to maintain homeostasis?

    <p>It enables a wider variety of habitats for survival.</p> Signup and view all the answers

    Which of the following statements best describes homeostasis in biological systems?

    <p>It requires the collaboration of multiple systems and organs.</p> Signup and view all the answers

    How are stimuli detected in the process of homeostasis?

    <p>By specialized receptors in the body.</p> Signup and view all the answers

    Which condition is directly influenced by osmoregulation?

    <p>Water balance in cells</p> Signup and view all the answers

    What is the primary function of the hypothalamus in temperature regulation?

    <p>It monitors and regulates body temperature.</p> Signup and view all the answers

    What is the normal set point range for body temperature that the hypothalamus aims to maintain?

    <p>37.5 ± 0.5 °C</p> Signup and view all the answers

    Which mechanism is NOT a way the body regulates temperature?

    <p>Somatic: adjusting breathing rate.</p> Signup and view all the answers

    What thermoregulatory response occurs when body temperature exceeds the set point?

    <p>Vasodilation of blood vessels.</p> Signup and view all the answers

    What physiological response occurs primarily during hypothermia?

    <p>Core body temperature drops below 35 °C.</p> Signup and view all the answers

    Which hormone is least likely associated with thermoregulation?

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

    What behavioral change might someone make to regulate their body temperature on a hot day?

    <p>Sitting in a shaded area.</p> Signup and view all the answers

    Which of the following describes shivering in relation to temperature regulation?

    <p>An autonomic response to cold conditions.</p> Signup and view all the answers

    Which physiological change happens during vasodilation?

    <p>Widening of blood vessels.</p> Signup and view all the answers

    Which action does NOT contribute to cooling the body on a hot day?

    <p>Wearing multiple layers of clothing.</p> Signup and view all the answers

    Study Notes

    Homeostasis Part 1

    • Homeostasis is the maintenance of a constant internal environment.
    • It's a physiological process, characteristically stable, in higher vertebrates.
    • Claude Bernard (1850s) was a French physiologist who established that multicellular organisms have an internal environment that can constantly be changed to maintain cellular function.
    • An organ can adjust blood composition to maintain "milieu interieur".
    • The body must maintain constant conditions, like pH and temperature, inside, despite outer conditions changing.
    • Enzymes only function within specific temperature ranges.
    • pH changes in tissues affect enzyme reactions within those cells.
    • Changes in water potential can damage or burst cells.
    • Homeostasis allows organisms to live in diverse habitats, better control metabolic needs, and make metabolism more efficient and economical.
    • Essential body parts that need to be regulated: body temperature, blood pressure, blood pH, oxygen/carbon dioxide concentration, osmoregulation (water balance), and blood glucose.

    How Homeostasis Works

    • Homeostasis is maintained through stimuli, receptors, regulatory mechanisms, and effectors/response.
    • A stimulus is a change in the internal environment.
    • Receptors identify the stimulus.
    • An automatic, self-regulatory system corrects the change in the environment.
    • Effectors/organs/tissues react to bring about the correction.
    • Response: Negative feedback. The body does the opposite to bring back to normal function.

    Negative Feedback Example: Water Potential

    • An increase in blood water potential (a stimulus) is detected by osmoreceptors (receptors).
    • Your body responds by return the water osmolality to the normal condition.

    Negative Feedback

    • The body reverses the change.
    • This is common in biological systems.
    • Multiple systems are required for homeostasis.
    • The body's organs and systems provide cells with their basic needs.

    Regulation of Body Temperature

    • The main organ involved in body temperature regulation is the skin.
    • The skin acts as a: protective covering, excretory organ, and regulator of body temperature.
    • Changes in environmental temperature can be detected by the skin.

    Skin

    • The skin has Hair, Sebaceous Glands, Sensory Nerve Endings, Sweat Glands, Muscle, Epidermis, Dermis, Subcutaneous Tissue, Capillaries and Arterioles, Fat, Collagen and Fibroblasts.
    • Blood vessels bring oxygen to cells in the skin.
    • Blood vessels can dilate or constrict to regulate blood flow through the skin, maintaining temperature.
    • Sweat glands produce sweat to cool the body.
    • Hair traps air to insulate the body.
    • Nerve endings (thermoreceptors) detect changes in external temperature.
    • Fatty/adipose tissue insulates the body, preventing heat loss.

    Heat Production and Loss

    • Metabolic activities (e.g., tissue respiration) produce body heat.
    • Liver and muscles are major heat-producing organs.
    • Heat can be gained by eating hot food, from the sun, warm air, and exercise.
    • Heat loss occurs in two steps: conduction of heat from deeper organs to the skin then transferring heat from skin to surroundings via Radiation, Conduction, Evaporation (27%), Convection (2%), Urination and Defecation (1%).

    How Body Temperature is Controlled (Homeostasis).

    • Body temperatures are monitored and controlled by temperature receptors in the skin and brain.
    • Receptors detect changes in blood temperature flowing through the areas.
    • The thermoregulatory centre in the brain is the hypothalamus.
    • If the body temperature deviates from 37°C, the hypothalamus and skin receptors send signals, causing actions to raise or lower temperature.

    Regulation of Body Temperature – Hypothalamus

    • Hypothalamus monitors and regulates body temperature.
    • It receives temperature changes from the external environment by receptors in the skin.
    • The hypothalamus has a set point at 37.5 ± 0.5°C.
    • It monitors blood temperature that passes through it.

    Temperature Regulation Mechanisms (Homeostasis).

    • Autonomic: vasodilation and vasoconstriction of blood vessels.
    • Somatic: shivering.
    • Endocrine: hormones like thyroxine and adrenaline.
    • Behavioral: clothing, movement.

    Regulating Body Temperature - On a Hot Day

    • Stimulus: Blood and skin temperatures rise. Receptor: Temperature receptors detect changes and send nerve impulses to the brain.
    • Blood vessels dilate, increasing blood flow to the skin, increasing heat loss.
    • Sweat production increases, which evaporates, increasing heat loss.
    • Hair erector muscles relax, lowering insulation.

    Regulating Body Temperature - On a Cold Day

    • Stimulus: Blood and skin temperatures fall. Receptor: Temperature receptors detect changes and send nerve impulses to the brain.
    • Blood vessels constrict, reducing blood flow to the skin, reducing heat loss.
    • Sweat production decreases, decreasing heat loss.
    • Hair erector muscles contract, increasing insulation.

    Failure of Temperature Regulation

    • Hypothermia: core body temperature below 35°C.
    • Hyperthermia: abnormally high body temperature due to temperature regulation failure.

    Regulation of Blood Glucose

    • Liver and pancreas are involved.
    • Liver is a storehouse for glycogen.
    • Two hormones (glucagon and insulin) control blood glucose levels, secreted from islet cells in the pancreas (islets of Langerhans).
    • Glucagon is released by alpha cells.
    • Insulin is released by beta cells.

    Glucose Homeostasis - Hormone Action

    • Insulin converts glucose into glycogen (glycogenesis), storing excess glucose in the liver.
    • Glucagon converts glycogen back into glucose (glycogenolysis) when needed.

    Glucose Homeostasis

    • If glucose levels rise, less glucagon and more insulin is released to convert glucose into glycogen.
    • If glucose levels decrease, less insulin and more glucagon is released back into the system to increase blood glucose levels.

    What Happens When Glucose Concentration Rises

    • Stimulus: Blood glucose concentration increases. Receptor: Islets of Langerhans in pancreas get stimulated.
    • The corrective mechanism is to release more insulin, which carries itself in the blood to liver/muscle cells and converts the increased glucose into glycogen (glycogen storage).

    What Happens When Glucose Concentration Falls

    • Stimulus: Blood glucose concentration decreases. Receptor: Islets of Langerhans in pancreas get stimulated.
    • The corrective mechanism is to release more glucagon, which travels in the blood to liver/muscle cells and converts glycogen back into glucose.

    Failure of Blood Glucose Regulation

    • High blood sugar (hyperglycemia): excessive glucose in the blood, often leading to diabetes mellitus.
    • Low blood sugar (hypoglycemia): causes serious issues (seizures, loss of consciousness, coma, or death).

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    Related Documents

    Homeostasis Part 1 Lecture Notes PDF

    Description

    Explore the concept of homeostasis and its crucial role in maintaining a constant internal environment in higher vertebrates. Learn about the physiological processes involved, the historical perspective provided by Claude Bernard, and how various body functions stabilize conditions like temperature, pH, and blood composition.

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