Homeostasis (PPT 1) [U2/ T1]

Question 1

What do cells need to survive?

Answer 1

• Energy
• Oxygen
• Nutrients
• Removal of wastes
• Water
• Warmth

Question 2

Why do cells require energy & oxygen?

Answer 2

To drive respiration and photosynthesis

Question 3

Why do cells require nutrients?

Answer 3

To drive chemical reactions

Question 4

Why do cells require the removal of wastes?

Answer 4

The wastes are toxic to the cell

Question 5

Why do cells require water?

Answer 5

Most chemical reactions occur within a solution

Question 6

Why do cells require warmth?

Answer 6

Enzyme reaction rate

Question 7

What does cellular respiration mean?

Answer 7

All chemical reactions that occur inside a living cell.

Question 8

What is homeostasis?

Answer 8

The maintenance of a stable internal environment in the face of changes in either the external or internal environment.

Question 9

What is a negtive feedback system?

Answer 9

• A stimulus response mechanism that acts to restore the original state.
• The response produced reduces the effect of the original stimulus. Therefore, having a negative effect on the stimulus.

Question 10

What is a postive feedback system?

Answer 10

• Not as common in homeostatis because they lack a regulatory role.
• Invole those in which a stimulus causes a change that increases the effect of the initial stimulus (positive effect).

Question 11

What are receptors?

Answer 11

Specilaised structures capable of responding to specific stimuli by initiating specific signals.

Question 12

Interoreceptors detect…?

Answer 12

Internal stimuli

Question 13

Exteroreceptors detect…?

Answer 13

External stimuli

Question 14

Receptors recieve specialised sensory information that relates to what?

Answer 14

• Photo (light)
• Mechano (touch/ pressure)
• Chemo (chemicals)
• Thermos (temperature)
• Noci (pain)

Question 15

State 2 facts about photo receptors.

Answer 15

• Common in animals
• Vary in complexity
• Light sensitive cells to complex eyes

Question 16

State 2 facts about mechano receptors.

Answer 16

• Stimulus is anything that changes their shape

- Different types control all sorts of bodily functions

Question 17

State 2 facts about chemoreceptors.

Answer 17

• Recieve specific chemicals in an internal & external environment
• Chemicals detected through taste and smell

Question 18

State 2 facts about thermo receptors.

Answer 18

• Temperature is detected by thermoreceptors

- All animals have a optimum temperature

Question 19

State 2 facts about pain receptors.

Answer 19

• Everywhere except the brain
• Have large receptive fields
• Detect chemicals released by damaged cells

Question 20

What does an effector do?

Answer 20

Responde to the signal and brings the system back to a set point.

Question 21

Name the 2 types of effectors and what they do

Answer 21

Muscles - contract or relax in response to neural stimuli

Glands - produce or don’t produce secreations (hormones)