6)Coordination and Response

Question 1

How does responding to the environment help organisms survive?

Answer 1

• Animals can increase their chance of survival by responding to changes in their external environment
• They can also control their internal environment

Question 2

What is a change in the internal or external environment called?

Answer 2

A stimulus (plural stimuli)

Question 3

What do receptors detect?

Answer 3

A receptor detects stimuli

Question 4

What do receptors in the sense organs detect?

Answer 4

They are group of cells that detect external stimuli

Question 5

What are the sense organs?

Answer 5

The eyes, ears, nose, tongue and skin

Question 6

What are effector cells?

Answer 6

Bring a response to stimuli

Question 7

How do receptors communicate with effectors?

Answer 7

Via the nervous system, the hormonal system but sometimes both

Question 8

What is the CNS?

Answer 8

Central Nervous System

Question 9

What are the main type of neurons?

Answer 9

• Sensory
• Relay
• Motor

Question 10

What does the CNS consist of?

Answer 10

Brain and spinal cord

Question 11

What happens when receptors in a sense organ detect a stimulus?

Answer 11

They send electrical impulses along the sensory neurons to the CNS. Then the CNS sends electrical impulses to an effector along a motor neuron.

Question 12

What is the main job of the CNS?

Answer 12

Its to coordinate the response

Question 13

What do coordinated responses always need?

Answer 13

A stimulus, a receptor and an effector

Question 14

Why can the nervous system bring about very rapid responses?

Answer 14

Because neurons transmit information using high speed electrical impulses

Question 15

What are reflexes?

Answer 15

Reflexes are automatic responses to certain stimuli, they can reduce the chances of being injured

Question 16

What happens if someone shines a bright light in your eyes?

Answer 16

Your pupils automatically get smaller so that less light gets into the eye - this stops it getting damaged

Question 17

What is the conjunctiva?

Answer 17

Lubricates and protects the surface of the eye

Question 18

What is the cornea?

Answer 18

The cornea refracts light into the eye. The cornea is transparent and has no blood vessels to supply it with oxygen, so oxygen diffuses in from the outer surface

Question 19

What is the iris?

Answer 19

Controls the diameter of the pupil and therefore how much light enters the eye

Question 20

What do the lens do?

Answer 20

The lens focusses the light onto the retina

Question 21

What does the optic nerve do?`

Answer 21

Carries impulses from the receptors to the brain

Question 22

What is the iris reflex?

Answer 22

Adjusting for bright light

Question 23

How do you look at distant objects?

Answer 23

1) The ciliary muscles relax

2) This makes the lens go thin

Question 24

How can you look at near objects?

Answer 24

1) The ciliary muscles contract

2) The lens become more fat (more curved)

Question 25

What is the difference between long sighted people and short sighted people?

Answer 25

- Long sighted people are unable to focus on near objects | - Short sighted people are unable to focus on distant objects

Question 26

What is ADH? (Give the source, role and effect)

Answer 26

- Source: Pituitary gland - Role: Controls water content - Effects: Increases the permeability of the kidney tubes to water

Question 27

What is adrenaline? (Give the source, role and effect)

Answer 27

- Source: Adrenal glands - Role: Readies the body for a 'fight or flight' response - Effect: Increases heart rate, blood flow to muscles and blood sugar level

Question 28

What is insulin? (Give the source, role and effect)

Answer 28

-Source: Pancreas -Role: Helps control blood sugar level Effect: Stimulates the liver to turn glucose into glycogen for storage

Question 29

What is testosterone? (Give the source, role and effect)

Answer 29

- Source:Testes - Role: Main male sex hormone - Effect: Promotes male secondary characteristics

Question 30

What is progesterone? (Give the source, role and effect)

Answer 30

- Source: Ovaries - Role: Supports pregnancy - Maintains the lining of the uterus

Question 31

What is oestrogen? (Give the source, role and effect)

Answer 31

- Source: Ovaries - Role: Main female sex hormone - Effect: Controls the menstrual cycle and promotes secondary sexual characteristics

Question 32

What are the three things that nerves do?

Answer 32

1) Send a very fast message 2) Act for a short time 3) Act on a precise area

Question 33

What are the three things that hormones do?

Answer 33

1) Send a slower message 2) Act for a longer time 3) Act in a more general way

Question 34

What does it mean if a response is really quick?

Answer 34

Its nervous

Question 35

What is homeostasis?

Answer 35

Homeostasis is the maintenance of a constant internal environment

Question 36

Give two examples of homeostasis

Answer 36

1) Water content | 2) Body temperature

Question 37

Name three ways of how water is lost through the body

Answer 37

1) Through the skin as sweat 2) Via the lungs in breath 3) Via the kidneys as urine

Question 38

What is the optimum body temperature and why?

Answer 38

- 37°C | - Enzymes work best at this temperature

Question 39

What does the skin do when you're too hot?

Answer 39

- When sweat is produced it evaporates which transfers heat, which cools the body down - Blood vessels close to the skin widen - Hair lies flat

Question 40

What is it called when blood vessels widen?

Answer 40

Vasodilation

Question 41

What does the skin do when you're too cold?

Answer 41

- Very little sweat is produced - Blood vessels near the surface constrict - You shiver, which generates heat in the muscles - Hairs stand up on end

Question 42

How does a plant increase their chances of survival?

Answer 42

By responding to their environment

Question 43

Give twoexamples of how a plant responds to their environment

Answer 43

1) They sense the direction of light and grow towards it to maximize light absorption for photosynthesis 2) They sense gravity

Question 44

What are auxins?

Answer 44

Auxins are plant hormones that control growth at the tips of shoots and roots

Question 45

Where is auxin produced?

Answer 45

Auxin is produced in the tips and diffuses backwards to stimulate the cell elongation process, which occurs in the cells just behind the tips

Question 46

What is the response to light called?

Answer 46

Phototropism

Question 47

What is the response to gravity called?

Answer 47

Geotropism

Question 48

What does it mean if a shoot is positively phototrophic?

Answer 48

It grows towards light. The shoot will bend towards the light

Question 49

What does it mean if a shoot is negatively geotrophic?

Answer 49

It grows away from gravity

Question 50

What does it mean if a root is positively geotrophic?

Answer 50

It grows towards gravity