Coordination and response

Question 1

What is excretion?

Answer 1

The removal of toxic materials, waste products and excess materials in both plants and animals

Question 2

What does homeostasis do?

Answer 2

Maintains a constant internal environment

Question 3

What internal conditions have to be controlled?

Answer 3

Skin - Core body temperature
Kidney - Water and ion content
Lungs - CO2 content in the blood
Pancreas & Liver - Blood glucose level

Question 4

What is normal body temperature?

Answer 4

37 degrees

Question 5

Why must the body remain at around 37.5 degrees?

Answer 5

So that enzymes working in the body work at their optimum temperature and don’t denature

Question 6

What happens if the body gets too cold?

Answer 6

• Blood vessels narrow
  (vasoconstriction)
• Less blood flows near skins
• Hairs stand to trap insulating air
• Shivering = rapid muscle
  contractions which creates heat

Question 7

What happens if the body gets too hot?

Answer 7

• Blood vessels widen (vasodilation)
• More blood flows near skins surface
• More heat is lost by radiation
• More sweat produced and released

Question 8

What does the nervous system do?

Answer 8

Detects changes in the environment (stimuli) and co-ordinate a response

Question 9

What coordinates a response to
a stimulus in an animal?

Answer 9

They have receptors in their sense organs

Question 10

What does a receptor do?

Answer 10

It’s a special type of cell that detects changes in the environment

Question 11

What is a sense organ made up of?

Answer 11

lots of receptor cells

Question 12

What is a stimulus?

Answer 12

change in the environment

Question 13

What is a response?

Answer 13

A change in an organism triggered by a stimulus

Question 14

Give 5 examples of sense organs and what they do.

Answer 14

• Mouth/tongue - detects food chemicals
• Eyes - detects light
• Ears - detects vibrations (sound)
• Nose - detects scent
• Skin- Detects pressure, heat + pain

Question 15

What is the central nervous system made up of?

Answer 15

The brain and spinal cord which is protected by your skeleton

Question 16

What do receptors do?

Answer 16

Sends an electrical impulse along nerve cells (neurones) to your central nervous system

Question 16

What is the pathway of nerve impulses?

Answer 16

Stimulus, receptors, sensory neurone, relay neurone, CNS, motor neurone, effector, response

Question 17

What job does the long axon have in a nerve cell?

Answer 17

It carries messages over large distances quickly

Question 17

What job does the Myelin Sheath have in a nerve cell?

Answer 17

increases the speed electrical impulses can travel

Question 18

What job do dendrites have in a nerve cell?

Answer 18

connects to many other neurones

Question 19

Name the 3 types of neurones

Answer 19

Sensory, motor and relay

Question 20

What is a synapse?

Answer 20

A tiny gap between two neurones

Question 21

What is the electrical impulse converted to?

Answer 21

A chemical signal that is passed across the synapse

Question 22

How do nervous impulses travel?

Answer 22

In one direction

Question 23

Why do reflexes not require you to think about the response and are said to be involuntary/automatic?

Answer 23

To help protect the body from harm

Question 24

Why does a reflex action bypass the brain?

Answer 24

To instead pass through a relay neurone in the spinal cord to make the action faster

Question 25

What is the eye?

Answer 25

A sense organ containing receptors that detect change in light

Question 26

What is the stimulus converted into in an eye?

Answer 26

Electrical impulses that are sent to the brain to form an image

Question 27

What is the sclera?

Answer 27

The visible, white part of the eye that provides a tough and protective outer coating

Question 28

What is the Iris?

Answer 28

The coloured ring of muscular tissue that controls the size of the pupil and the amount of light hitting the retina

Question 28

What is the Cornea?

Answer 28

Curved, transparent section of the sclera in front of the eye that allows light to enter and refract it

Question 29

What is the Pupil?

Answer 29

A hole in the middle of the iris that allows light to enter

Question 30

What is the Lens?

Answer 30

A transparent disc that refracts light as it enters the eye and is able to change shape to focus on the retina

Question 30

What are Ciliary muscles and suspensory ligaments?

Answer 30

A ring of muscle attached to ligaments that are connected to the lens that contract and allow us to focus on objects at different distances

Question 31

What is the Retina?

Answer 31

Light sensitive layer containing the photoreceptors which initiate the nerve impulse that travels down the optic nerve to the visual centre in the brain

Question 32

What is the Optic Nerve?

Answer 32

A nerve made of bundles of sensory neurones that connects the eye to the visual centre of the brain. Electrical impulses travel along it

Question 33

What are the two types of photoreceptors?

Answer 33

Rods and cones

Question 34

What do cones do?

Answer 34

Detect colour

Question 35

What do rods do?

Answer 35

Detect dim light

Question 36

What is a hormone?

Answer 36

Chemical release from a gland

Question 37

What does homeostasis do?

Answer 37

Maintains a constant internal environment