Nerves And Hormones ~ B1.2

Question 1

What does the nervous system consist of?

Answer 1

~ the brain
~ the spinal cord
~ the neurones
~ the receptors

Question 2

What does the nervous system allow organisms to do?

Answer 2

React to their surroundings and coordinate their behaviour.

Question 3

How is information passes around the body?

Answer 3

Information from receptors passes along neurones (nerve cells) to the brain. The brain co-ordinates the response, which is carried out by an effector. The effector responds by releasing chemicals.

Question 4

What is an effector?

Answer 4

The effector may be a muscle, which responds by contracting, or a gland, which responds by releasing chemicals.

Question 5

What is the order of the nervous system?

Answer 5

~receptors
~sensory neurones 
~relay neuron *
~spinal cord or brain *
~motor neurones
~effector 

• = central nervous system (CNS)

Question 6

What are the three types of neurones and what do they do?

Answer 6

Motor neurone~impulse travels away from the cell body
Relay neurone~impulse travels first towards and then away from the cell body
Sensory neurone~impulse travels towards the cell body

Question 7

What are neurones?

Answer 7

Specially adapted cells that can carry an electrical signal, e.g. A nerve impulse

Question 8

What is the small gap between the neurones called?

Answer 8

A synapse.

Question 9

What is sent across the gap between the neurones?

Answer 9

A chemical neurotransmitter.

Question 10

What are the different receptors?

Answer 10

Light ~ receptors in the eyes.
Sound ~ receptors in the ears.
Change of position ~ receptors in the ears, balance.
Taste ~ receptors on the rounds are sensitive to chemicals.
Smell ~ receptors in the nose are sensitive to chemicals.
Touch, pressure, pain and temperature ~ receptors in the skin

Question 11

What is a reflex action?

Answer 11

Reflex actions speeds up the response time by missing out the brain completely.

Question 12

An example of a reflex action is removing your hand from a hot plate, how does it work?

Answer 12

The hot plate acts as a stimulus.
The receptor is the pain in the finger.
An impulse is sent to the sensory neurone, then to the relay neurone (in the spinal cord), then to the motor neurone, then to the effector (the muscle in the hand)
Then there is a response (the hand withdraws).

Question 13

Humans need to keep their internal environment relatively constant. What things in the body needs to be controlled?

Answer 13

Body temperature, the levels of water, salts (ions) and blood sugar.

Question 14

How are conditions in the body controlled?

Answer 14

Many processes within the body (including control of some internal conditions) are coordinated by hormones.

Question 15

What is a hormone?

Answer 15

Chemicals, produced by glands, which are transported to their target organs by the bloodstream.

Question 16

What do hormones do?

Answer 16

Hormones regulate the functions of many organs and cells.

Question 17

What does FSH stand for?

Answer 17

Follicle stimulating hormone

Question 18

Where is FSH released from and what is its job.

Answer 18

It is released from the pituitary gland. FSH causes eggs to mature in the ovaries and it causes the ovaries to produce oestrogen.

Question 19

Where is oestrogen released and what is its job?

Answer 19

It is produced in the ovaries and inhibits the production of FSH and causes the production of LH. Its job is to thicken the lining of the uterus.

Question 20

Where is LH produced and what is its job?

Answer 20

It is produced from the pituitary gland and stimulates the release of an egg from the ovaries in the middle of the menstrual cycle.

Question 21

What hormones increases fertility?

Answer 21

LH and FSH

Question 22

What does LH stand for?

Answer 22

Luteinising hormone.

Question 23

What hormone reduces fertility?

Answer 23

Oestrogen.

Question 24

What are plants sensitive to?

Answer 24

~Light~their shoots will grow towards light
~Moisture~their roots grow towards moisture
~Gravity~roots grow in the direction of gravity whilst shoots grow against the force of gravity

Question 25

What are auxins?

Answer 25

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

Question 26

What does auxin do?

Answer 26

Auxin promotes the growth of shoots, but inhibits growth in the roots.

Question 27

What happens when a shoot tip is exposed to light?

Answer 27

More auxin is produced on the side of the shoot that is in the shade. This causes the shoot to grow faster on the shaded side and the plant will bend towards the light. This is known as phototropism.

Question 28

What happens if a plant root is growing horizontally?

Answer 28

Gravity will cause more auxin to be produced on the lower side. The extra auxins inhibits growth causing the root to bend downwards, this is called gravitropism or geotropism.

Question 29

Plant hormones can be used in agriculture and horticulture. What can they be used for?

Answer 29

~Encourafe cutting to grow roots~cutting are dipped in rooting compound so they will produce roots quickly.
~Kill weeds~most weeds have broad leaves. Selective weed killers are plant hormones that will disrupt the growth patterns of broad leaved plants whilst by harming the grass or wheat.

Question 30

What are the benefits of IVF?

Answer 30

~Can help a woman become pregnant
~Uses woman’s own eggs and partners own sperm
~Provides an alternative to adoption

Question 31

What are the problems of IVF?

Answer 31

~Only 28% success rate
~Age restrictions
~Uses NHS resources 
~Costly
~Increases expectations for babies on demand

Question 32

What are the benefits of using weed killers?

Answer 32

~Kills weed
~Fast acting
~Many applications

Question 33

What are the problems of using weed killers?

Answer 33

~Harmful to wildlife

~Harmful to humans