Biology Chapter: Homeostasis

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Questions and Answers

What does the term 'homeostasis' literally mean?

Stable movement

Same state (correct)

Dynamic balance

Constant change

Which of the following is NOT a component involved in maintaining homeostasis?

CO2 levels

External temperature (correct)

Glucose levels

Neurological signals

What percentage of water in humans is typically found inside the cells?

60% (correct)

80%

20%

40%

How are the needs of most cells in large animals met?

Internal bodily fluids Signup and view all the answers

Which of the following best describes homeostatic fluctuations?

They are regulated within specific parameters Signup and view all the answers

What type of fluids make up extracellular fluid in humans?

Interstitial fluid and plasma Signup and view all the answers

Why is the internal environment crucial for large animal cells?

It enables survival in hostile habitats. Signup and view all the answers

Which of the following statements about homeostasis is accurate?

It is a dynamic process involving auto-regulatory mechanisms. Signup and view all the answers

What is the primary mechanism for maintaining blood glucose levels?

Hormonal regulation Signup and view all the answers

What happens to glucose from the small intestine once it enters the bloodstream?

It can be utilized for cell respiration or stored. Signup and view all the answers

Which of the following statements is true regarding temperature sensitivity in cells?

Physiological processes are temperature sensitive within a limited range. Signup and view all the answers

How do warm-blooded animals primarily obtain heat?

Through chemical energy from cell respiration Signup and view all the answers

Which term describes animals that cannot regulate their body temperature internally?

Poikilothermic Signup and view all the answers

Insulin and glucagon primarily function through which type of feedback mechanism?

Negative feedback Signup and view all the answers

Which of the following best describes the primary role of the liver in blood glucose regulation?

It is involved in releasing, storing, and converting glucose. Signup and view all the answers

What is the significance of maintaining blood glucose levels within a specific range?

To ensure efficient physiological function and energy balance Signup and view all the answers

What happens to the metabolic rate of endotherms within the thermoneutral zone?

It remains low and independent of temperature. Signup and view all the answers

Which of the following is a physiological response to cooling in endotherms?

Shivering Signup and view all the answers

What method do ectothermic animals primarily use to control their body temperatures?

Behavioural means Signup and view all the answers

Which of the following correctly describes the metabolic rate of ectothermic animals?

Lower than endothermic animals Signup and view all the answers

What is the role of the hypothalamus in temperature regulation?

It detects changes in body temperature. Signup and view all the answers

What is a significant characteristic of endothermic animals regarding their food requirements?

Require large quantities of food Signup and view all the answers

Which statement best describes vasoconstriction?

It directs blood flow away from the skin surface. Signup and view all the answers

What is the basal metabolic rate (BMR) of an endotherm?

The metabolic rate when the animal is resting in the thermoneutral zone. Signup and view all the answers

Which statement about ectothermic animals' activity levels is correct?

They may become inactive when temperatures drop. Signup and view all the answers

What happens to the body's metabolic rate during warming?

It increases to generate more heat. Signup and view all the answers

Endothermic animals have which of the following adaptations?

High metabolic rate and heat conservation mechanisms Signup and view all the answers

How does the body typically respond to cooling through behavioral means?

By huddling together. Signup and view all the answers

Aquatic ectothermic animals generally maintain what characteristic concerning their body temperature?

It remains the same as the water temperature. Signup and view all the answers

Which of the following behaviors is NOT associated with ectothermic animals for temperature regulation?

Using internal metabolic processes Signup and view all the answers

Which of the following describes an effect of the autonomic nervous system on body temperature regulation?

It triggers actions like sweating and vasodilation. Signup and view all the answers

In what environment do ectothermic land animals have the advantage of being more active?

In environments with variable air temperatures Signup and view all the answers

Study Notes

Homeostasis Overview

Homeostasis is the maintenance of a stable internal physiological state, despite external fluctuations
This state is maintained by auto-regulatory processes within the body
The body must remain within a narrow range of physical & biochemical conditions for optimal functioning
This includes maintaining homeostasis of glucose, ion levels, osmotic pressure, CO2 levels and temperature

Internal Environment

The internal environment of large animals provides a stable fluid medium for cells to function
The fluid surrounds cells and contains nutrients, absorbs waste & maintains cellular health
Approximately 60% of the human body is water
About 60% of that water is found within cells
The remaining 40% is extracellular fluid, consisting of 20% plasma and 80% interstitial fluid

Homeostatic Control

A corrective mechanism exists, within the body, for maintaining homeostasis
The corrective mechanism responds to:
- Excess
- Deficiency
It uses a negative feedback loop to return the body to ideal conditions

Blood Glucose Control

Blood glucose levels must be maintained at a constant level
The liver plays a key role in glucose homeostasis, carrying out several different functions (e.g., glycogen storage and conversion to fat)
Blood glucose level changes can affect which bodily reactions occur within the liver
These processes are governed by hormones

Temperature Sensitivity

Cells function optimally within a narrow range of temperatures (~0°C to ~40°C)
Biochemical reactions are temperature sensitive, differing in their rates at various temperatures
Most biochemical reactions triple with every 10°C increase in temperature

Control of Body Temperature

Animals obtain heat from the sun (solar energy) and through cell respiration (chemical energy)
Animals may be endothermic or ectothermic
- Endotherms generate their own heat (e.g., birds and mammals)
- Ectotherms gain heat from the environment (e.g., most reptiles and fish)

Aquatic Animals

Aquatic ectothermic animals have body temperatures that are similar to the water temperature.
The water temperature is fairly constant thus these animals do not need to work as hard to regulate their body temperature
Exceptions exist, 'hot' fish for example, are able to regulate their body temperature

Land Animals

Ectothermic land animals regulate their body temperature via behavioral means
- Basking in the sun to warm up
- Seeking shade to cool down
Behavior is used to increase or decrease the amount of heat they absorb from their environment.

Invertebrates

Not all invertebrates are ectothermic
Insects for example, both social insects and flying insects, exhibit some degree of homeothermy

Heat Exchange in Ectotherms

Heat exchange occurs through conduction, convection, radiation, and evaporation.

Endotherms

Endotherms can alter their metabolic rate to regulate their temperature
In the thermoneutral zone, the metabolic rate is low, as the body temperature is not significantly affected by the external environment
The basal metabolic rate (BMR) assesses metabolic rate at rest.

Outside the Thermoneutral Zone

Endotherms employ various behavioral and physiological mechanisms to remain within the thermoneutral zone
E.g. shivering, seeking shelter, and sweating to cool down

Negative Feedback Loop

Negative feedback mechanisms help to return the body temperature to an appropriate range
Examples of negative feedback: sweating to cool down, constricting blood vessels to retain heat, or behavioral changes.

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Description

Test your knowledge on homeostasis in biology with this quiz. Explore the mechanisms and factors that maintain internal balance in living organisms, particularly in large animals. Understand various concepts related to fluids, temperature regulation, and feedback mechanisms essential for life.