Homeostasis

Question 1

What is homeostasis?

Answer 1

• the maintenance of stable conditions in the internal environment by keeping internal factors within a very narrow range

Question 2

What does homeostasis require?

Answer 2

• requires control and regulation in response to both external and internal changes
• regulatory systems: the nervous system and endocrine system

Question 3

what is the difference between positive and negative feedback?

Answer 3

• positive: tells regulatory system to amplify or increase the response, Beyond the set-point
• negative: tells regulatory system to reduce the response

Question 4

What is a set-point?

Answer 4

It is the value at which certain factors (like proteins and cholesterol) need to be maintained.

Question 5

Define endotherm

Answer 5

Regulate body temperature by producing heat or active mechanisms of heat loss.
- eg. human, mouse

Maintain temperature regardless of the temperature of the external environment.

Question 6

Define ectotherm

Answer 6

Animals whose body temperatures are determined mainly by external sources of heat
- e.g. lizard

Question 7

What are processes in which heat is lost or gained?

Answer 7

Metabolism: generates heat in the body. All reactions in the body are inefficient and releases heat as a by-product.

Evaporation: helps to release heat from the body. evaporation of water from the body surfaces or breathing passages cool the body. OR
Blood flows to the skin - heat from the body via blood is lost to the environment.

Question 8

What is the basal metabolic rate (BMR)?

Answer 8

Minimal amount of energy expenditure in an awake bird or mammal at rest

Question 9

What part of the brain is in charge of regulating the body’s temperature?

Answer 9

hypothalamus

Question 10

What responses occur when the body temperature is too high or too low?

Answer 10

Body temp too low:

• blood vessels constrict
• skeletal muscles contract
• shivering

Body temperature too high:

• blood vessels dilate
• skeletal muscles relax
• panting and sweating

Question 11

What is hyperthermia and what are its effects?

Answer 11

Forms of hyperthermia result (when body temp is too high)

• heat cramps: loss of sodium via sweating
• heat exhaustion: nausea, vomiting, weakness
• heat stroke: failure of major organs.

Hyperthermia leads to improper function of proteins and cell membranes and can lead to cell death.

Question 12

What are the factors that could lead to heat stress?

Answer 12

High environment temperature (>37C) 
and
- exercise or strenuous work
- insufficient hydration
- impaired heat dissipation

Question 13

what is a fever

Answer 13

When there is an increase in temperature which can help fight infections

Question 14

What is Hypothermia and its causes?

Answer 14

When the body temperature is below normal due to exposure to extreme cold, serious illness.
- drop in temperature is unregulated

Question 15

Hibernation

Answer 15

A regulated drop in temperature which is .an adaptation in animals to scarce food or periods of cold.

Question 16

Heterotherm

Answer 16

An animal that regulates body temperature at a constant level sometimes, but not other time such as during hibernation