2. Homeostasis Pt3

Question 1

How would you make you experiment about does practice improve reaction speed a fair test? (7)

Answer 1

• use the same arm
• the same person dropping and catching
• same seating position
• same ruler
• ruler held at the same position relative to hand
• fingers same distance apart
• no prior practise

Question 2

What do the brain and spinal chord do?

Answer 2

Receive impulses and then coordinate an effective response

Question 3

What’s the function of the nervous system in humans?

Answer 3

It enables the body to respond to the stimulus and trigger their reaction

Question 4

What’s the spinal cord in the nervous system?

Answer 4

A coordinator

Question 5

A bright light is a …………

Answer 5

Stimulus

Question 6

Blinking is a ……….

Answer 6

Response

Question 7

Name 2 types of effectors and what do they do?

Answer 7

Glands-secret hormones

Muscles-contracts and relaxes

Question 8

What does the lens (in the eye) do?

Answer 8

Focus light on the retina

Question 9

What does the iris do?

Answer 9

It controls the amount of light entering the eye

Question 10

If a person cut off there are how would it affect them physically and why?

Answer 10

Loss of movement as impulses would be unable to reach the muscle

Question 11

Reflexes can be coordinated by the brain or spinal cord. The reflexes from sense organs in the head or co-ordinated by the brain. What 2 sense organs are involved with reflexes co-ordinated by the spinal cord?

Answer 11

Joints

Skin

Question 12

Which type of eyesight gets worse with age?and why?

Answer 12

Long-sightedness

Ciliary muscles become weaker

Question 13

What are plant growth hormones used for?

Answer 13

Agriculture & horticulture

Question 14

Explain why plants produce hormones?

Answer 14

• to coordinate and control growth and responses to light (phototropism) and gravity (gravitropism or geotropism)
• unequal distributions of auxin cause unequal growth rates in plant roots and shoots

Question 15

What does gibberellins do in plants?

Answer 15

It’s Important in the initiating seed germination

Question 16

What does ethene do in plants?

Answer 16

It controls cell division and ripening fruits

Question 17

What 2 types of responses can the homeostasis produce?

Answer 17

Nervous responses

Chemical responses

Question 18

What happens to your eye when there’s a very bright light?

Answer 18

• bright light can damage your retina so you have a reflex to protect it
• when light receptors detect very bright light a reflex is triggered to make the pupil smaller
• the circular muscles in the iris contract & the radial muscles relax.
• reducing the light entering the eye

Question 19

What happens to your eye when there’s a very dim light?

Answer 19

• the radial muscles contract & the circular muscles relax, which makes the pupil wider
• letting in more light

Question 20

What’s an eye?

Answer 20

It’s a sense organ contains receptors sensitive to light intensity & colour

Question 21

What do ciliary muscle & suspensory ligaments do?

Answer 21

They control the shape of the lens

Question 22

What does the nervous system do?

Answer 22

Allows human to react to their surroundings & coordinate there behaviour

Question 23

What does the endocrine system do and how?

Answer 23

• it’s made up of glands which secret chemicals (hormones) into the blood stream
• the bloodstream carries the hormone to a target organ where it produces an effect
• the effects it’s slower than the nervous system but act for longer

Question 24

Why are reflex arcs important?

Answer 24

It helps prevent injuries

Question 25

Define a reflex?

Answer 25

A rapid, automatic responses to certain stimuli that don’t involve the conscious part of the brain - reducing the chance of you getting injured

Question 26

What’s are the steps in a reflex arc?

Answer 26

Sensory neurone > synapse > relay neurone > motor neurone

Question 27

What makes up the central nervous system?

Answer 27

The spinal chord & the brain

Question 28

What do all control systems include?

Answer 28

• receptor cells, which detect stimuli (changes in the environment)
• coordination centres (eg. Brain, spinal chord and pancreas) that receive & process information from receptors
• effectors, muscles or glands which bring about responses which restore optimum levels

Question 29

What are the 2 types of effectors?

Answer 29

• muscles

- glands

Question 30

What does the pituitary gland do in the endocrine system?

Answer 30

• it’s in the brain aka ‘master gland’
• it secrets several hormones into the blood in response to the body conditions
• these hormones act on other glands to stimulate other hormones to be released to bring about effects

Question 31

What makes up your endocrine system?

Answer 31

Pituitary gland
Pancreas 
-thyroid
-adrenaline gland 
-ovary 
-testes