Communication and Homeostasis

Question 1

Name 3 features of a good communication system

Answer 1

• Cover the whole body
• Enable SPECIFIC communication
• Enable RAPID communication
• Enable short and long-term responses

Question 2

Name at least 3 conditions in the body controlled by homeostasis

Answer 2

1. Blood pressure
2. Body temperature
3. Blood glucose concentration
4. Carbon dioxide concentration
5. Water potential of the blood

Question 3

For negative feedback to work, what processes must occur?

Answer 3

1. A change to the internal environment must be detected
2. The change must be signalled to other cells
3. There must be an effective response that reverse the change in conditions

Question 4

Name a time when positive feedback is beneficial (used to stimulate an increase in a change)

Answer 4

During birth/labour to bring about the dilation of the cervix

Question 5

What is an Ectotherm?

Answer 5

An organism that relies on external sources of heat to maintain body temperature

Question 6

What is an Endotherm?

Answer 6

An organism that uses heat from metabolic reactions to maintain body temperature

Question 7

Give the 4 identifying features of an Endotherm

Answer 7

○ Maintain constant body temperature
○ Internal sources of heat
○ Activity possible in cool temperatures
○ Higher caloric requirements

Question 8

Name 3 adaptations of Endotherms

Answer 8

– Sweat glands on skin
– Capillaries near skin surface
– Hairs on skin

Question 9

Name three characteristics of Ectotherms

Answer 9

○ External environment controls body temp
○ Less food required
○ More energy available for growth
○ Relies heavily on behaviour to help maintain body temp

Question 10

Give 3 advantages of ectothermy

Answer 10

• Less of their food is used in respiration
• Need to find less food
• Can survive for long periods without food

Question 11

Give 3 advantages of Endothermy

Answer 11

1. Maintain fairly constant body temp, whatever the external temp
2. Remain active even when external temps are low so can escape from predators
3. Inhabit colder parts of the planet

Question 12

Give 3 disadvantages of Endothermy

Answer 12

1. Need more food
2. Use lots of their energy intake keeping warm in the cold
3. Can overheat in hot weather

Question 13

What changes will the hypothalamus bring about if the core temperature is too low?

Answer 13

• Changes in skin to reduce heat loss
• release of heat through extra muscular contraction
• Increased metabolism in order to release more heat from exergonic reactions

Question 14

What part of the hypothalamus monitors blood temp and detects change in the core body temp?

Answer 14

The thermoregulatory centre