B5 - Homeostasis and Response

Question 1

What is homeostasis?

Answer 1

Maintaining stable internal conditions despite changes in the environment

Question 2

Why does the body need to maintain optimal conditions?

Answer 2

For optimal enzyme action and cell function

Question 3

What is the role of the receptor?

Answer 3

Detect changes in the internal or external environment

Question 4

What is the role of a coordination centre?

Answer 4

Interpret changes and organise a response

Question 5

Name two coordination centres in the body

Answer 5

Brain and spinal cord

Question 6

Name the two types of effectors and what they do.

Answer 6

Muscles : contract
Glands : release hormones

Question 7

Which acts faster, the nervous system or endocrine system? Explain why

Answer 7

Nervous system is faster, it relies on electrical impulses that travel very quickly

Question 8

Which acts more generally, the nervous or endocrine system? Explain why

Answer 8

Endocrine, it usually involves releasing hormones into the bloodstream so they spread throughout the body

Question 9

What does homeostasis rely on?

Answer 9

Negative feedback

Question 10

What does negative feedback mean?

Answer 10

When the levels of something are too high, they are brought back down to optimum (and vice versa)

Question 11

How does negative feedback work?

Answer 11

Any change in the system causes an action that reverses the change

Question 12

What passes along nerve cells?

Answer 12

Electrical impulses

Question 13

What is the gap between two neurones called?

Answer 13

Synapse

Question 14

What is released across a synapse?

Answer 14

Chemicals

Question 15

What are two parts of the central nervous system (CNS)?

Answer 15

Brain and spinal cord

Question 16

What does a receptor do in the nervous system?

Answer 16

Detect a stimulus

Question 17

What is the role of a sensory neurone in the nervous system?

Answer 17

Transfer a signal from the receptor to the CNS

Question 18

What is the role of a motor neurone in the nervous system?

Answer 18

Transfer a signal from the CNS to the effector

Question 19

What is the role of a relay neurone in the nervous system?

Answer 19

Transfer a signal from a sensory neurone to a motor neurone

Question 20

What is the pathway of a reflex arc? (7 parts)

Answer 20

Stimulus -> Receptor -> Sensory Neurone -> Relay Neurone -> Motor Neurone -> Effector -> Response

Question 20

What is a reflex?

Answer 20

An automatic response to a stimulus

Question 21

Use two words to describe reflexes, one is about the speed

Answer 21

Fast and automatic

Question 22

Why are reflexes important?

Answer 22

They protect us from harm

Question 23

How many hemispheres is the cerebral cortex split into?

Answer 23

2

Question 24

What are the 3 roles of the cerebral cortex?

Answer 24

1) Consciousness
2) Interpreting senses like hearing & vision
3) Memory

Question 25

What are the 2 roles of the cerebellum?

Answer 25

1) Muscle coordination
2) Balance

Question 26

What does the medulla coordinate? (general)

Answer 26

Unconscious activities

Question 27

Where in the brain is the medulla found?

Answer 27

In the brain stem

Question 28

What are the 2 things the medulla regulates?

Answer 28

1) Breathing rate
2) Heart rate

Question 29

What does the hypothalamus do?

Answer 29

Regulate body temperature

Question 29

What regulates our body temperature?

Answer 29

Hypothalamus

Question 30

Name 3 ways scientists study the brain

Answer 30

1) Study people with brain damage
2) Stimulate different parts of the brain electrically
3) Scanning the brain

Question 31

Name 3 types of scans for the brain

Answer 31

CT scan, PET scan, MRI scan

Question 32

What does the CT scan use?

Answer 32

X-Rays

Question 33

What does the PET scan use?

Answer 33

Radioactive chemicals

Question 34

What does the MRI scan use?

Answer 34

Magnetic fields

Question 35

What are the 3 reasons that the brain is difficult to treat?

Answer 35

1) Poor access - encased within the skull
2) Possibility of negative effects - mental illness to infection
3) Hard to target with medications - very complicated