HOMEOSTATSIS

Question 1

What is homeostasis

Answer 1

The process by which the body maintains a constant internal environment

Question 2

How do temperature and pH changes impact enzyme activity?

Answer 2

• Enzyme activity is sensitive to changes to temperature and pH levels
• Variations can affect rate of enzyme activity

Question 3

What is a set point?

Answer 3

the ideal value or range that a specific variable within the body should be maintained at to ensure proper function and stability.

Question 4

What role does the hypothalamus play in homeostasis?

Answer 4

• crucial control centre
• contains receptors that detect variations from the set point and sends signals to effectors to intiate responses to restore levels back towards set point

Question 5

Role of effectors in maintaining homeostasis

Answer 5

• • organs that carry out responses to restore deviations from the set point
• counteracts the original stimulus
• maintaining internal balance

Question 6

What is a stimulus?

Answer 6

Changes in the level of a variable in the internal environment

Question 7

Define negative feed back loop

Answer 7

• Negative feedback aims to bring a variable back to set point
• eg. temperature

Question 8

What is the internal environment

Answer 8

• Fluid surrounding a cell

Question 9

What happens in the stimulus response model?

Answer 9

• A change or stimulus in the level of a variable occurs that triggers response in the organism
• receptors detect the stimulus
• receptor communicates to the control centre
• control centre (hypothalamus) sends signals to effectors to carry out response
  *

Question 10

How does the body initiate cooling mechanisms when it detects an increase in body temperature?

Answer 10

Receptors detect elevated body temperature, sending messages to the anterior area of the hypothalamus (heat-loss control centre), which then activate processes to lose heat.

Question 11

What is the role of thermoreceptors in temperature regulation?

Answer 11

Thermoreceptors detect changes in temperature (stimulus), some in the skin and others in the hypothalamus.

Question 12

What are the processes involved in cooling the body to return it to its set point temperature?

Answer 12

Cooling processes include vasodilation (dilation of blood vessels), activation of sweat glands, and the reduction of thyroxine hormone production by the thyroid gland.

Question 13

Describe how vasodilation contributes to cooling the body.

Answer 13

Vasodilation involves blood vessels dilating, bringing blood closer to the skin, allowing heat to escape and aiding in cooling.

Question 14

How does the activation of sweat glands help with cooling?

Answer 14

sweat glands secrete sweat, which removes heat from the body through evaporation, turning liquid to gas and aiding in cooling.

Question 15

Explain the role of the thyroid gland in cooling the body.

Answer 15

The thyroid gland reduces thyroxine hormone production, lowering the rate of metabolism and helping to decrease body temperature.
hen less energy is being used, there is less heat generated as a byproduct of metabolic processes.

Question 16

How does the body initiate** warming proceses** in response to a decrease in body temperature?

Answer 16

When a decrease in body temperature is detected, messages are sent to the posterior area of the hypothalamus (heat gain control centre) to activate processes for heat conservation and warming.

Question 17

What processes are involved in warming the body to maintain its set point temperature?

Answer 17

Warming processes include
* vasoconstriction (constriction of blood vessels)
* contraction of hair erector cells,
* release of thyroid stimulating hormone (TSH),
* shivering.

Question 18

Explain vasoconstriction’s role in warming the body.

Answer 18

Vasoconstriction involves blood vessels constricting, reducing blood flow to the skin surface, conserving heat and aiding in warming.

Question 19

How does the release of thyroid stimulating hormone contribute to warming the body?

Answer 19

Pituitary gland stimulates the thyroid gland to increase thyroxine hormone production, raising the rate of metabolism and heat production.

Question 20

How does shivering help warm the body?

Answer 20

muscle contractions generate heat through friction

Question 21

What is role of contraction of hair errector cells to warm the body?

Answer 21

• causes fur/hair to stand on end ‘‘goosebumps’’
• traps are warm layer of air around the body helping to reduce heat loss

Question 22

: What are the two hormones secreted by the pancreas that regulate glucose levels and target the liver and skeletal muscles? What are their roles?

Answer 22

• insulin: Stimulates liver to absorb glucose from the blood and store it as glycogen, reducing blood glucose concentration.
• Glucagon: Stimulates liver to convert stored glycogen to glucose and release it into the blood, increasing blood glucose concentration.

Question 23

How is glucose regulation achieved through a negative feedback mechanism?

Answer 23

1. Increased Blood Glucose after intake of carbohydrates
2. Beta cells in the pancreas detect the rise in blood glucose levels.
3. Release of Insulin:
   Elevated blood glucose triggers beta cells to release insulin into the bloodstream.
4. Insulin binds to receptors in cells and instructs cells to take in glucose. This glucose can be utilised for energy or stored as glycogen in the liver and muscles.
5. Stored glucose as glycogen decreases blood glucose concentration.
6. Insulin actions restore blood glucose levels to the optimal set point.

Question 24

How is low blood glucose restored during fasting or intense exercise?

Answer 24

• Alpha cells in the pancreas release glucagon.
  Glucagon prompts the liver to convert stored glycogen into glucose, increasing blood glucose concentration levels.

Question 25

What are endotherms, and why do they need adaptations?

Answer 25

• Endotherms are organisms that can maintain a constant body temperature regardless of temperature variations.
  They require adaptations to reduce heat exposure and enhance heat loss to regulate their temperature effectively.

Question 26

Provide an example of a structural adaptation in endotherms for heat regulation.

Answer 26

Insulating fur or feathers provide a layer of insulation, reducing heat loss from the body to the environment.

Question 27

Give an example of a behavioral adaptation in endotherms for temperature regulation.

Answer 27

• huddling- reduces surface area exposed to the cold
• basking in the sun allowsendotherms to absorb external heat

Question 28

How does the surface area to volume ratio contribute to temperature regulation in endotherms?

Answer 28

• Animals like polar bears have a larger body size and smaller surface area to volume ratio, allowing them to conserve heat effectively.
• Smaller animals like possums have reduced ear size to minimize heat loss through their ears.

Question 29

Name a structural adaptation seen in marine mammals like the Australian fur seal.

Answer 29

A layer of blubber serves as an insulating adaptation in Australian fur seals, helping them conserve heat in cold water environments.

Question 30

What is the purpose of behavioral adaptations like migration and nocturnal activity in endotherms?

Answer 30

Migration allows endotherms to move to warmer climates during colder seasons.
Nocturnal activity helps them avoid hotter daytime temperatures by being more active at night.