Biology Chapter 5: Homeostasis
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Questions and Answers

What is the primary function of insulin in the body?

  • To cause cells to take up glucose (correct)
  • To enhance amino acid absorption
  • To regulate blood pressure
  • To increase fat utilization as energy

When there is excess water in the body, ADH secretion is increased.

False (B)

What hormone is released by the juxtaglomerular cells when blood pressure decreases?

renin

Angiotensin II causes the adrenal gland to secrete __________.

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

Match the following components of the renin-angiotensin system with their roles:

<p>Renin = Converts angiotensinogen into angiotensin I Angiotensin I = Converted into angiotensin II Angiotensin II = Causes aldosterone release Aldosterone = Increases blood pressure and fluid retention</p> Signup and view all the answers

What is the main purpose of a thermostat in a negative feedback system?

<p>To activate mechanisms that restore conditions to their original state (C)</p> Signup and view all the answers

Negative feedback systems are designed to enhance changes in the body.

<p>False (B)</p> Signup and view all the answers

Which part of the control system interprets data and sends messages out?

<p>Control Center</p> Signup and view all the answers

The process by which a mechanism is activated to restore conditions to their original state is known as __________.

<p>negative feedback</p> Signup and view all the answers

Match the components of the feedback control system to their functions:

<p>Sensors = Gather data and sense changes Control Center = Receives and interprets data Communication System = Delivers messages to targets Targets = Respond to changes</p> Signup and view all the answers

What happens when CO2 levels rise in the body during homeostasis?

<p>The control system forces exhale and inhale (D)</p> Signup and view all the answers

Positive feedback systems are used to maintain steady states in the body.

<p>False (B)</p> Signup and view all the answers

What is the term for the systems that deliver messages to target organs?

<p>Communication System</p> Signup and view all the answers

Sweat glands are an example of __________ that help maintain homeostasis.

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

Which of the following describes a characteristic of negative feedback?

<p>Both B and C (C)</p> Signup and view all the answers

What is the normal body temperature range for humans?

<p>36.2 to 37.2 degrees Celsius (C)</p> Signup and view all the answers

Homeostasis refers to the body's attempt to maintain stable conditions within an acceptable range.

<p>True (A)</p> Signup and view all the answers

What condition indicates a body temperature that falls below the normal range?

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

Homeostasis is often referred to as a __________ equilibrium.

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

Match the components of homeostatic control systems with their functions:

<p>Monitor = Sends signals about changes in conditions Coordinating centre = Processes signals and initiates responses Regulator = Acts to restore normal balance Change = Indicates a deviation from normal levels</p> Signup and view all the answers

What happens to body temperature during an infection?

<p>It increases to help fight off the infection (C)</p> Signup and view all the answers

The thermostat in a household is an example of a homeostatic control system.

<p>True (A)</p> Signup and view all the answers

What could happen if hypothermia is left untreated?

<p>cell damage and possibly death</p> Signup and view all the answers

What stimulates the release of insulin?

<p>High blood glucose levels (B)</p> Signup and view all the answers

Glucagon decreases blood glucose levels by promoting glucose uptake into cells.

<p>False (B)</p> Signup and view all the answers

What is the primary function of insulin?

<p>To decrease blood glucose levels.</p> Signup and view all the answers

The process of maintaining a stable body temperature is known as ________.

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

Match the hormones with their primary function:

<p>Insulin = Facilitates glucose uptake and storage Glucagon = Stimulates glycogen breakdown Oxytocin = Stimulates mammary gland delivery Epinephrine = Prepares the body for 'fight or flight'</p> Signup and view all the answers

Which hormone is primarily responsible for promoting glycolysis?

<p>Insulin (A)</p> Signup and view all the answers

The hypothalamus is involved in thermoregulation.

<p>True (A)</p> Signup and view all the answers

What is glycogenesis?

<p>The conversion of glucose into glycogen for storage.</p> Signup and view all the answers

When blood glucose levels are low, glucagon triggers the process of ________ to increase glucose levels.

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

Which of the following systems is NOT involved in thermoregulation?

<p>Digestive (D)</p> Signup and view all the answers

Flashcards

Homeostasis

The body's ability to maintain a stable internal environment.

Normal Range

The set of values that the body tries to maintain, like temperature, blood sugar, and pH.

Monitoring

The process of detecting changes in the internal environment.

Coordinating Center

The control center that receives information from the monitor and sends instructions to the regulator.

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Regulator

The component that carries out the instructions from the coordinating center to restore the balance.

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Dynamic Equilibrium

The condition when the body's internal environment is stable and functioning within its normal range.

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Hypothermia

A condition where the body's temperature drops below the normal range.

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Human Body Temperature

The normal body temperature for humans is between 36.2 to 37.2 degrees Celsius.

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Blood Glucose Regulation

The process of regulating blood glucose levels to maintain energy balance.

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Insulin

A hormone produced by beta cells in the pancreas, responsible for lowering blood glucose levels.

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Glucagon

A hormone produced by alpha cells in the pancreas, responsible for raising blood glucose levels.

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Glycogenesis

Insulin's role in converting glucose into glycogen for storage.

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Glycogenolysis

Glucagon's role in breaking down stored glycogen into glucose.

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Inhibit Glycogenolysis

Insulin's role in preventing the breakdown of glycogen into glucose.

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Gluconeogenesis

Glucagon's role in producing glucose from non-carbohydrate sources in the liver.

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Lipogenesis

Insulin's role in converting excess glucose into fatty acids and promoting fat storage.

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Decrease Blood Glucose

Insulin's primary function in regulating blood glucose.

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Increase Blood Glucose

Glucagon's primary function in regulating blood glucose.

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What is insulin?

The hormone that regulates blood glucose levels by promoting the uptake and storage of glucose in cells, lowering blood sugar.

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What happens when insulin is absent?

When insulin levels are low or absent, cells don't absorb glucose, and the body turns to fat as an energy source. This leads to the breakdown of fat stores.

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What is homeostasis?

The process of maintaining a stable internal environment despite external changes, like body temperature or blood sugar.

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What is aldosterone?

The hormone secreted by the adrenal glands, which regulates blood pressure by constricting blood vessels and increasing fluid retention.

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What is the renin-angiotensin system?

This complex system involves several hormones like renin and angiotensin, which work together to regulate blood pressure in response to changes in blood volume.

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Negative Feedback

A type of feedback loop where a change in a variable triggers a response that opposes the initial change, bringing the variable back to its set point.

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Sensor

A mechanism that detects changes in the internal environment of the body, like a thermometer detecting temperature.

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Control Center

The control center that receives information from sensors, interprets it, and sends instructions to effectors.

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Effector

A mechanism that carries out the instructions from the control center to restore balance, like muscles contracting or glands releasing hormones.

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Communication System

The network that delivers messages from the control center to the effectors, like nerves and hormones.

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Set Range

The range of acceptable values for a variable in the body, like temperature or blood sugar levels.

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Feedback

The process of comparing current conditions to the set range to determine if adjustments are needed.

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Positive Feedback

A feedback loop that amplifies the initial change, leading to a rapid and significant change in the variable.

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Positive Feedback Loop

A process where a change in a variable triggers a response that reinforces the initial change, leading to a cyclical effect.

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Study Notes

Chapter 5: Homeostasis

  • Homeostasis is the body's attempt to maintain "normal" levels within the body.
  • It is often referred to as dynamic equilibrium.
  • This is a mechanism to ensure that all body systems function within an acceptable range to sustain life.
  • Homeostasis involves keeping the internal environment within set ranges.

Core Temperature

  • Humans have a normal temperature of around 36.2 to 37.2 degrees Celsius.
  • Body temperature above normal likely indicates an infection.
  • Body increases temperature to fight infection.
  • Body temperature below this range indicates hypothermia which can lead to cell damage and possibly death if left untreated.

Homeostatic Control Systems

  • Homeostatic control systems have 3 components:

    • Monitor: monitors changes
    • Coordinating centre: receives signals from the monitor to respond
    • Regulator: acts on the signal from the coordinating centre to restore normal balance

  • The monitor sends a signal to the coordinating centre about changes in normal levels.

  • The coordinating centre then sends messages to the regulator to restore homeostasis.

Example: Household Thermostat

  • A thermostat is a negative feedback system.
  • The thermostat is set to 22 degrees Celsius.
  • When the temperature falls below 22 degrees, the thermostat switches on the furnace.
  • When the temperature rises above normal the thermostat switches off the heating.

Negative Feedback Loops

  • Negative feedback loops ensure that small changes don't become too large.
  • The process by which a mechanism is activated to restore conditions to their original state.
  • This is how homeostasis is maintained

Components of Control Systems

  • Sensors: Gather data (senses).
  • Control Center: Receives data, interprets information, and sends messages (e.g., brain).
  • Communication System: Delivers messages to target organs/tissues (e.g., PNS - motor neurons).
  • Targets: Respond to change (e.g., muscles, glands).

Negative Feedback Loops are Necessary for Homeostasis

  • Feedback compares current conditions to the body's comfort levels (set ranges).
  • Negative feedback counteracts changes and brings the body back to homeostasis.

Homeostasis and Temperature Control

  • The nervous system signals dermal blood vessels to dilate/constrict and sweat glands to secrete.
  • If body temperature continues to drop, nervous system signals muscles to contract involuntarily.
  • Body heat is conserved/generated by increased muscle activity.
  • Body heat is lost to surroundings.

Positive Feedback

  • Positive feedback increases change away from the set points, needed for rapid change in the body.
  • Example 1: Torn blood vessels stimulate the release of clotting factors to stop blood flow.
  • Example 2: Delivery process and stimulation of mammary gland by oxytocin.

Homeostasis and Water Balance

  • All living things need water.

  • The body maintains the balance between water intake (drinking, food, metabolic processes) and water loss (urine, sweat, breathing, feces).

  • Kidneys regulate the amount of water lost in urine.

  • Concentrated urine during dehydration & diluted urine when excess water is present.

    • Hypothalamus detects water levels and signals pituitary gland.

  • Homeostasis is affected by water intake and excess water intake.

Renin-Angiotensin-Aldosterone System (RAAS)

  • RAAS regulates blood pressure by acting on the kidneys.
  • Low blood pressure triggers the release of Renin.
  • A chain of reactions results in the secretion of Aldosterone, a hormone that holds onto sodium resulting in an increase in blood volume and thus blood pressure.

Insulin & Glucagon

  • Purpose: To regulate blood glucose levels and ensure energy supply/metabolic balance.
  • Two major players: Insulin and glucagon.
    • Insulin: lowers blood glucose.
    • Glucagon: raises blood glucose.
    • Regulation and interaction are dependent on the postprandial (after eating) or fasting state.

Body Processes

  • Thermoregulation: Maintaining a steady body temperature.
  • Components of thermoregulation: muscular, integument (skin), respiratory, circulatory, nervous (hypothalamus in brain), endocrine (hormones, feedback).
  • Homeostasis in action: excess water intake, dehydration
  • Thermoregulation In Hot and cold conditions: Skin, heart, lungs, nervous system, muscular system

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Homeostasis: Biology Notes PDF

Description

This quiz covers Chapter 5 on homeostasis, the body's mechanism to maintain stable internal conditions essential for life. It discusses core temperature regulation, homeostatic control systems, and their components for monitoring and maintaining balance. Test your understanding of these vital biological processes.

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