Co-ordination and response

Question 1

What is a stimulus?

Answer 1

A stimulus is a change in an animal’s surrondings.

Question 2

What is a response?

Answer 2

A reaction to the change in surrondings.

Question 3

What is a receptor?

Answer 3

An organ that detects the change in surrondings or stimulus for examples eyes.

Question 4

What are effectors?

Answer 4

The response was brought about by a contraction of muscles, which are a type of effector organ in response to the stimulus

Question 5

What is the coordination system diagram?

Answer 5

stimulus > receptor > coordination > effector> response

Question 6

What is the role of the receptors?

Answer 6

The role of a receptor is to detect the stimulus, by changing its energy into the electrical energy of the nerve impulses

Question 7

What are different type of receptors and what they convert their energy into?

Answer 7

Eye- light
Ear-sound
Ear-mechanical
Tongue-chemical
Nose-chemical
Skin-mechanical
Skin-heat-
Muscle-mechanical

Question 8

What is the biological name for a nerve cell?

Answer 8

Neurone.

Question 9

How do neurones work?

Answer 9

The impulses that travel along a neurone are caused by the movement of charged particles (ions) in and out of the neurone. Impulses travel at enough speed to produce rapid responses.

Question 10

What do impulses go?

Answer 10

impulses from a receptor pass along nerves containing sensory neurones until they reach the brain and spinal cord. These two organs are known as the central nervous system.

Question 11

What are motor neurones?

Answer 11

Other nerves contain motor neurones, transmitting impulses to the muscle and glands. Some nerves contain only sensory or motor cells, while others contain both. A typical nerve contains thousands of individual neurones

Question 12

What are the structure of sensory and motor neurones?

Answer 12

Both very long. Motor neurones leading from the CNS to the muscle in the finger has a fibre about a metre in legnth.

Question 13

What is the outer coat of the eye called?

Answer 13

Sclera

Question 14

What is the front of the eye called?

Answer 14

Cornea

Question 15

What is the coloured ring of tissue behind the cornea?

Answer 15

Iris

Question 16

What is the hole in the middle of the iris?

Answer 16

pupil lets light through the eye not light escapes from it

Question 17

What is the dark layer underneath the sclera?

Answer 17

Choroid it is dark as it contains many pigment cells as well as blood vessels. The pigment stop light being reflected around the inside of the eye.

Question 18

What is the innermost layer at the back of the eye?

Answer 18

retina, light sensitive layer where light energy is converted into the electrical energy of nerve impulses. It contains rods and cones.

Question 19

What are cones and rods?

Answer 19

These cells react to light, producing impulses in sensory neurones. they then pass the impulses to the brain through the optical nerve. Rod cells work well in dim light, but they can’t distinguish different colours so the brain sees it produced in black and white. Why cant see colours well in dim lights. Cones only work well in bright light both rods and cones are found in the retina.

Question 20

How does the eye form an image?

Answer 20

To form an image on the retina, light needs to be bent or refracted. Refraction takes place when light passes from one medium to another of a different density. in the eye this happens first at the cornea boundary and then at the lens and the cornea acts as the first lens of the eye.

Question 21

What is the role of the iris?

Answer 21

The roe of the iris is to control the amount of light entering the eye by changing the size of the pupil. The iris contains two types of muscles. Circular muscle contracts and the radial muscle relax in darkness and in light opposite happens

Question 22

What is accommodation?

Answer 22

The changes that take place in the eye which allow the eye to see objects at different distances.

Question 23

What happens when the eye focuses nearby object?

Answer 23

When the eye focuses on a nearby object the light rays from the object are spreading out when they enter the eye. In this situation the lens has to be more convex in order to refract the rays enough to focus them on the retina. the ciliary muscles now contract.

Question 24

What happens when the eye focuses on a distant object?

Answer 24

When the eye is focused on a distant object the rays of light from the object are almost parallel when they reach the cornea cornea refracts the rays, but the lens does not need to refract them much to focus on the light.

Question 25

How is the stimulus detected?

Answer 25

By tempreture or pain receptors in the skin.

Question 26

What does the stimulus generate?

Answer 26

The stimulus generates impulses in sensory neurones. The impulses enter the CNS through part of the spinal nerve called the dorsal root. In the spinal cord the sensory neurones connect by synapses with short relay neurones which connect with motor neurones and send impulses back out of the muscle the muscle then contracts,

Question 27

What is a reflex arc?

Answer 27

A reflex action is a rapid involuntary response to a stimulus.

Question 28

What makes the reflex quick?

Answer 28

Impulses travel through the reflex arc in a fraction of a second so that the reflex action is quick and does not need to be started by impulses from the brain. The brain is slightly aware of what’s going on because in the spinal cord the reflex arc neurones also form connections called synapses with nerve cells leading to and from the brain. brain receives information about the stimulus how we feel pain

Question 29

What are synapses?

Answer 29

A synapse is a gap between two nerve cells. The gap is not crossed by the electrical impulses passing through the neurones Impulses arriving at a synapse cause the end of the fine branches of the axon to secrete a chemical called a neurotransmitter. This chemical diffuses across the gap and attaches to the membrane of the second neurone. it then starts off impulses in the second cell.

Question 30

What is a gland?

Answer 30

A gland is an organ that releases a secretes or a substance this means that the cell in the gland make a chemical which leaves the cells through the cell membrane. The chemical then travels somewhere in the body the carry its function out.

Question 31

What is a hormone?

Answer 31

A hormone is a chemical substance produced by a gland and carried by the blood which alters the activity from one or more specific target organs

Question 32

What are some important hormones?

Answer 32

Adrenaline, insulin, testosterone, progesterone.

Question 33

What is adrenaline?

Answer 33

When you a person is frightened excited or angry their adrenal glands secrete the hormone adrenaline it prepares the different organs for action, Adrenaline produces several changes to the body.
-breathing rate increases and breaths become deeper taking more oxygen in
-Heat beats faster sending more blood to the muscles so that they receive more glucose and oxygen for respiration blood diverted to the muscles
-Mental awareness
increases reactions faster
-

Question 34

What is insulin?

Answer 34

When the body is short of glucose glycogen can be broken down into glucose then passing into the blood stream. Many hormones keep the glucose level constant the main one being insulin made by special cells in the pancreas. stimulates the liver cells to take up glucose and convert into glycogen lowering the levels of glucose in the body.

Question 35

How does the concentration of glucose go up?

Answer 35

After a meal.

Question 36

What causes diabetes?

Answer 36

pancreas cannot make enough insulin to keep their blood glucose level constant, rises to very high concentrations. normally people that dont have diabetes have no glucose on their urine

Question 37

What is homeostasis?

Answer 37

When conditions are kept relatively constant this this is called homeostasis kidneys and organs remove waste products filter the blood removing substances controlling the conditions of the body. It is the controlling of internal conditions.

Question 38

What happens when your body is too hot?

Answer 38

increased sweat productions from sweat glands evaporates to the skin and removes heat.
arterioles at the skin dilate increasing blood flow to the surface and then increasing the heat lose to the surrondings.
hairs lie flat to remove insulation

Question 39

What happens when your body is too cold muscles contract to shiver increasing respiration which releases heat from the body cells to war the body.
Arterioles at the skins surface constrict decreasing blood flow to the surface decreasing the heat that is lost.
Hairs on skin stand on end to trap air insulate the body.

Question 40

What is reflex arc?

Answer 40

1) The pin(stimulus) is detected by pain receptors in the skin on a persons foot.
2) A sensory neurone sends electrical impulses to the CNS
3) An electrical impulse is passed to a relay neurone in the spinal cord
4) A relay neurone synapses with a motor neurone.
5) A motor neurone carries an impulse to a muscle in the leg.
6)When stimulated by the motor neurone, the muscle will contract and pull the foot up and away from the sharp object the response will happen in a fraction of a second