B1.2 Nerves and Hormones Flashcards Preview

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Flashcards in B1.2 Nerves and Hormones Deck (45)
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1

What is the purpose of the nervous system?

To enable humans to react to their surroundings and coordinate their behaviour

2

Name the five sense organs and their receptors.

- Eyes : light receptors
- Ears : sound receptors, balance receptors (detecting change in position)
- Nose : smell receptors
- Tongue : taste receptors
- Skin : touch, pressure, pain and temperature change receptors

3

Define 'reflex'?

A fast automatic response of the body to a potentially dangerous stimulus

4

What is the CNS?

A system consisting of the brain and spinal cord where all the information from sense organs is sent and where reflexes and actions are coordinated.

5

Describe the reflex arc.

- Stimulus detected by receptor
- Impulses sent along sensory neurone
- Impulse reaches synapse
- Electric impulse in relay neurone
- Impulse reaches synapse
- Electric impulse in motor neurone
- Impulse reaches effector
- Response

6

What happens at a synapse?

- The nerve signal is transferred by chemicals which diffuse across the gap
- The chemicals set off a new electrical signal in the next neurone

7

Define 'synapse'

A connection between two neurones

8

Define 'hormone'

Chemical messengers which travel in the blood to activate target cells, co-ordinating many processes in the body.

9

Where are hormones produced?

In glands

10

What is the difference between a nerve and a hormone?

- Nerve = fast action vs Hormone = slower action
- Nerve = act for a short time vs Hormone = act for a longer time
- Nerve = act on a precise area vs Hormone = act in a more general way

11

What is the function of LH and where is it produced?

- Pituitary gland
- Stimulates ovulation

12

What is the function of oestrogen and where is it produced?

- Ovaries
- Causes pituitary gland to produce LH
- Inhibits further release of FSH

13

What is the function of FSH and where is it produced?

- Pituitary gland
- Stimulates egg maturation
- Stimulates ovaries to produce oestrogen

14

What is the function of progesterone and where is it produced?

- Ovaries
- Maintains uterus lining

15

Name 2 functions of the uterus

- Feeds foetus
- Protects foetus

16

What period is stage 1 of the menstrual cycle and what happens?

Day 1 - 4
Lining of the uterus breaks down

17

What period is stage 2 of the menstrual cycle and what happens?

Day 4 - 14
Lining of the uterus builds up

18

What period is stage 3 of the menstrual cycle and what happens?

Day 14
An egg is released

19

What period is stage 4 of the menstrual cycle and what happens?

Day 14 -28
The lining of the uterus is maintained

20

Define 'contraception'

A substance preventing conception

21

What do modern pills contain lower doses of oestrogen?

There were concerns about links to dangerous side effects e.g blood clots

22

What two hormones do modern pills contain and why?

- Progesterone: stimulates the production of thick cervical mucus stopping sperm reaching the egg
- Oestrogen: inhibits production of FSH (no more egg maturation)

23

What are the advantages of the pill?

- Over 99% efficient at preventing pregnancy
- Reduces risk of some cancers

24

What are the disadvantages of the pill?

- Isn't 100% efficient
- Side effects e.g headaches, irregular menstrual bleeding
- Doesn't protect against STDs

25

What two hormones are injected as fertility treatment?

- FSH
- LH

26

What are the disadvantages of fertility treatment?

- Expensive
- Doesn't always work
- Too many eggs could be stimulated

27

What is homeostasis?

The maintaining of a constant internal environment

28

What does the body control?

- Ion content
- Water content
- Sugar content
- Temperature

29

Where do ions in the body come from?

Absorbed into the blood from food

30

How are excess ions removed?

By the kidneys in urine and sweat