Coordination and Control

Question 1

What are the three types of neuron?

Answer 1

Sensory neurones, Relay neurones, Motor neurones

Question 2

What is a stimulus?

Answer 2

Change in the animal’s surroundings.

Question 3

What is the receptor?

Answer 3

Is the organ which detects the change.

Question 4

What is the effector?

Answer 4

Muscles are the effectors and they contract as you catch the ball

Question 5

Describe the reflex that occurs when we touch a hot object?

Answer 5

1. The receptors detect the stimulus (change in temperature) and send an impulse along the sensory neurone.
2. The sensory neurone passes the impulse to the spinal cord to a relay neurone. The gap between neurones is called a synapse. The relay neurone then passes the impulse through the spinal cord
   to a motor neurone.
3. The motor neurone causes the
   effector (in this case arm muscle) to
   contract and move the arm away
   from the stimulus (hot object).

Question 6

What is a synapse/

Answer 6

The gap between two neurons.

Question 7

Describe how impulses travel across synapses.

Answer 7

1. An electrical impulse travels along an axon.
2. This triggers the nerve-ending of a neuron to release chemical
   messengers - neurotransmitters.
3. These chemicals diffuse across the synapse and bind with receptor
   molecules on the membrane of the next neuron.
4. The receptor molecules on the second neuron bind only to the specific chemicals released from the first neuron. This stimulates the second neuron to transmit the electrical impulse.

Question 8

What is the cornea and what’s it role?

Answer 8

A curved transparent disc at the front of the eye that focuses on objects.

Question 9

What is the pupil and what’s it role?

Answer 9

A circular opening whose size is controlled by the iris.

Question 10

What is the iris and what’s it role?

Answer 10

A ring of muscles with a hole in the middle - it controls the amount of light that enters the eye.

Question 11

What is the lens and what’s it role?

Answer 11

It is flexible and transparent - it changes shape to focus light on the retina.

Question 12

What are the ciliary muscles and what’s their role?

Answer 12

A ring of muscles at the edge of the eye which circles the lens - it controls the shape of the lens.

Question 13

What happens to the lens when the ciliary muscles contract?

Answer 13

the lens gets fatter

Question 14

What happens to the lens when the ciliary muscles relax?

Answer 14

the lens gets thinner

Question 15

What are the suspensory ligaments?

Answer 15

Strong fibres which attach the lens to the ciliary muscle.

Question 17

What is the retina

Answer 17

The back part of the eye that contains light sensitive cells called rods and cones.

Question 18

What is the optic nerve and what’s it role?

Answer 18

Consists of many neurons which carry impulses from the retina to the brain.

Question 19

What is the fovea?

Answer 19

The region of the retina with the most cones.

Question 20

What is the conjunctiva and what’s its role?

Answer 20

A mucous membrane that covers the eye preventing inflection.

Question 21

What happens to the eye in dim light?

Answer 21

In dim light the radial muscles contract and the circular muscles relax. This makes the iris narrower and the pupil dilates.

Question 22

What happens to the eye in bright light?

Answer 22

In bright light the circular muscles contract and the radial muscles relax. This makes the iris wider and the pupil constricts.

Question 23

What happens when we want to focus on an object far away?

Answer 23

• Relaxing ciliary muscles
• Meaning suspensory ligaments are therefore pulled tight.
• Lens is pulled thin and has a less convex shape.
• Therefore there is less refraction of light.

Question 24

Differences in speed of endocrine to nervous system?

Answer 24

Endocrine: slow
Nervous: fast

Question 25

What happens when we want to focus on an object close up?

Answer 25

- Contracting the ciliary muscles - Meaning suspensory ligaments are therefore slack. - Lens is not stretched out so becomes thicker with more is more convex shape - Therefore there is more refraction of light.

Question 26

Differences in responses to the message in endocrine and nervous system?

Answer 26

Endocrine: only target cells respond Nervous: message sent to target muscle or gland.

Question 27

Differences in way message is sent in endocrine and nervous system?

Answer 27

Endocrine: via the blood (in plasma) Nervous: along neurons

Question 28

What is the role of the endocrine system in the body?

Answer 28

Controls long term processes such as reproduction and growth

Question 29

What is the role of the nervous system in the body?

Answer 29

Used when a fast response is needed

Question 30

Key glands in the body?

Answer 30

- thyroid - brain - pancreas - adrenal - testis -ovaries

Question 31

What is the role of insulin and where is it produced?

Answer 31

ROLE: Causes liver and muscles to take up glucose and convert it to glycogen for storage. PRODUCED IN: Pancreas

Question 32

What is the role of ADH and where is it produced?

Answer 32

ROLE: Reduces the amount of water lost in urine PRODUCED IN: Pituitary gland

Question 33

What is the role of adrenaline and where is it produced?

Answer 33

ROLE: Increases heart and breathing rate for fight, fright or flight. PRODUCED IN: Adrenal gland

Question 34

What happens when too many glucose are detected?

Answer 34

- Too much glucose in blood - pancreas produces insulin which enters blood - Insulin allows glucose to be absorbed by body cells. - Blood glucose restored.

Question 35

What happens when too few glucose are detected?

Answer 35

- normal levels of glucose in blood - insulin not produced by pancreas - less glucose absorbed by cells. - blood glucose remains the same.

Question 36

What is homeostasis?

Answer 36

The maintenance of a constant internal environment

Question 37

How does the body control temperature?

Answer 37

1. sweating 2. shivering 3. controlling heat loss by controlling the amount of blood which flows near the surface of the skin

Question 38

What happens when we are cold?

Answer 38

- Vasoconstriction - Hairs stand on end (this traps hair which acts as an insulator) - Less sweat produced

Question 39

What is vasoconstriction?

Answer 39

Arterioles supplying the capillaries near the surface of the skin constrict. Less blood will flow through capillaries near the surface of the skin, therefore less heat will be lost by radiation.

Question 40

What happens when we are hot?

Answer 40

- Vasodialation - More sweat released - Hair lie flat

Question 41

What is vasodilation?

Answer 41

Arterioles supplying the capillaries near the surface of the skin dilate. More blood will flow through capillaries near the surface of the skin, therefore more heat will be lost by radiation.

Question 42

Why do we sweat when we are hot?

Answer 42

When the sweat evaporates, heat energy is taken away from the skin as evaporation of water requires energy, this cools us down.

Question 43

What happens when there is too much water in the blood?

Answer 43

1. High levels of water detected by hypothalamus. 2. Less ADH secreted by the pituitary gland 3. Collecting duct in kidneys made less permeable to water. 4. Less water absorbed back into blood. 5. More dilute urine produces 6. Blood water level back to normal

Question 44

What happens when there is too little water in the blood?

Answer 44

1. Low levels of water detected by hypothalamus. 2. More ADH secreted by the pituitary gland 3. Collecting duct in kidneys made more permeable to water. 4. More water absorbed back into blood. 5. Less urine produced 6. Blood water level back to normal

Question 45

What is a tropism?

Answer 45

The growth of a plant towards a directional stimulus.

Question 46

What is phototropism?

Answer 46

Phototropism - the growth response to light from one direction. Growth towards the light it is called a positive phototropism

Question 47

What is geotropism?

Answer 47

Geotropism - the growth response to gravity. Growth towards gravity it is called a positive geotropism

Question 48

What happens when light is detected by the tip of a shoot?

Answer 48

- Light is detected by shoot tip - Auxin is produced - Auxin diffuses down shaded side of shoot because light kills auxin - Auxin causes cells to elongate. - This causes shoot to bend towards the light source.