1.2 Nerves and Hormones

Question 1

What are sense organs?

Answer 1

Organs which contain receptors

Question 2

What are receptors?

Answer 2

Cells that detect stimuli (changes in the environment)

Question 3

Give examples of sense organs and the receptors (5)

Answer 3

• Eyes - light receptors
• Ears - sound receptors, “balance” receptors
• Nose - smell (chemical) receptors
• Tongue - taste (chemical) receptors
• Skin - touch, pressure, pain and temperature receptors

Question 4

How is information transferred from receptors?

Answer 4

Nerve impulses that are passed along in neurones

Question 5

What are the different types of neurones? (3)

Answer 5

Sensory neurones, relay neurones, motor neurones

Question 6

Where do sensory neurones carry nerve impulses to and from?

Answer 6

Receptors to the Central Nervous System

Question 7

Where do relay neurones carry nerve impulses to and from?

Answer 7

Sensory neurones to motor neurones

Question 8

Where do motor neurones carry nerve impulses to and from?

Answer 8

The Central Nervous System to the effector

Question 9

What does the Central Nervous System consist of?

Answer 9

The brain and spinal cord

Question 10

What are effectors?

Answer 10

Muscles and glands that do something as a result of a neeve impulse

Question 11

How are neurones connected together?

Answer 11

Synapses

Question 12

How do synapses work?

Answer 12

The nerve impulse causes chemicals to be released which diffuse across the synapse and trigger another nerve impulse to be sent in the next neurone

Question 13

What are reflexes?

Answer 13

Automatic respones to a specific stimulus. They help prevent injury

Question 14

What are the stages in the reflex arc?

Answer 14

• Stimulus
• Receptor
• Sensory neurone
• Relay neurone
• Motor neurone
• Effector
• Response

Question 15

Why is the reflex arc quicker than the normal thing?

Answer 15

The reflex arc doesn’t use the brain so we don’t have to spend time thinking about it

Question 16

What are the internal conditions of the body that need to be controlled?

Answer 16

• Water content
• Ion content
• Temperature
• Blood sugar levels

Question 17

How are hormones transported?

Answer 17

Bloodstream

Question 18

Where are hormones released from?

Answer 18

Glands

Question 19

What hormones are involved in the menstrual cycle?

Answer 19

• FSH
• LH
• Oestrogen

Question 20

What releases FSH and what does it do?

Answer 20

The pituitary gland. It causes eggs to mature in the ovaries. Stimulates the production of oestrogen

Question 21

What releases LH and what does it do?

Answer 21

Pituitary gland. It stimulates the release of an egg

Question 22

What releases oestrogen and what does it do?

Answer 22

Ovaries. Causes production of LH. Inhibits production of FSH

Question 23

What is stage 1 of the menstrual cycle?

Answer 23

Lining of the uterus breaks down for about 4 days

Question 24

What is stage 2 of the menstrual cycle?

Answer 24

Lining of the uterus builds up from day 4 until day 14

Question 25

What is **stage 3** of the menstrual cycle?

Answer 25

An egg is released (day 14)

Question 26

What is **stage 4** of the menstrual cycle?

Answer 26

The wall is maintained for 14 days until day 28. If the egg isn't fertilised, the cycle starts again

Question 27

What hormones can be used to **reduce** fertility?

Answer 27

* Oestrogen - inhibits production of FSH therefore eggs aren't produced * Progesterone - Stimulates production of thick cervical mucus which blocks sperm

Question 28

What hormones can be used to **increase** fertility?

Answer 28

Some women have low levels of FSH so eggs can't mature. FSH and LH can be injected into these women to make eggs mature.

Question 29

What is in *the pill* and what are the advantages/disadvantes?

Answer 29

It contains oestrogen and progesterone. Advantages: * Over 99% effective * Reduces the risk of some cancers Disadvantages: * Not 100% effective * Side-effects * Doesn't protect against STDs

Question 30

What does IVF stand for?

Answer 30

In vitro fertilisation

Question 31

What happens in IVF?

Answer 31

A woman's eggs and a man's sperm is collected. They are artifically ferilised and grown into embryos. 1 or 2 embryos are transferred into the woman's uterus so she is likely to get pregnant.

Question 32

What are the advantages and disadvantages of IVF?

Answer 32

Advantages: * Allows an infertile couple to have a child Disadvantages: * Some women have a strong reaction to the hormones * Possible increased risk of cancer * Multiple births are more common which make it more dangerous for the woman and the babies

Question 33

What are plants sensitive to?

Answer 33

Light, moisture and gravity

Question 34

How do plant's shoots/roots grow in terms of light/gravity/moisture?

Answer 34

Shoots: * Towards light * Against gravity Roots: * Towards moisture * With gravity

Question 35

What is the **plant hormone** that contols **growth**?

Answer 35

Auxin

Question 36

How do auxins make a plant grow **towards light**?

Answer 36

They move to the side of the shoot that is in the shade so that the cells grow faster on the shaded side and elongate towards the light

Question 37

What agricultural uses do plant hormones have? (2)

Answer 37

* Selective weed killers * Rooting powder which makes plant cuttings' roots to grow faster