Foundation: B5 - Homeostasis

Question 1

What is homeostasis?

Answer 1

The maintenence of internal conditions

Question 2

What three things are maintained in the human body?

Answer 2

blood glucose concentration
body temperature
water levels

Question 3

What do all control systems include:

Answer 3

receptors, coordination centres, effectors

Question 4

What is the importance of the nervous system in humans?

Answer 4

It allows humans to react to their surroundings and to coordinate their behaviour

Question 5

What is the central nervous system (CNS) made up of?

Answer 5

Brain and spinal cord

Question 6

What is a stimulus?

Answer 6

A change in the environment, eg. temperature change

Question 7

Why are reflex actions important?

Answer 7

They are automatic and rapid, they do not involve the consious part of the brain. They help to keep us safe from harm.

Question 8

What is the endocrine system made of?

Answer 8

Glands, hormones, bloodstream, target organs

Question 9

What are hormones?

Answer 9

Chemical messengers

Question 10

Which gland is considered to be the ‘master gland’?

Answer 10

The pituitary gland

Question 11

Compare the action of the nervous system to the action of the endorcrine system.

Answer 11

Nervous system: messages travel as electrical impluses, faster response, shorter effect on the body.
Endocrine system: messages travel as chemical messengers, slower response, longer effect on the body.

Question 12

How do messages travel in the nervous system?

Answer 12

As electrical impluses through neurons.

Question 13

Which hormone reduces the concentration of glucose in the blood?

Answer 13

Insulin

Question 14

Which organ releases insulin?

Answer 14

The pancreas

Question 15

When is insulin released from the pancreas?

Answer 15

When the blood glucose concentration is too high.

Question 16

What effect does insulin have on blood glucose?

Answer 16

It causes glucose to be converted into glycogen to be stored in the liver or muscles.

Question 17

What is type 1 diabetes?

Answer 17

A disorder which a person is born with. The pancreas does not produce insulin and is treated with insulin injections.

Question 18

What is type 2 diabetes?

Answer 18

A disorder which a person develops due to poor diet. The body stops responding to insulin. It is treated with a carbohydrate-controlled diet & exercise plan.

Question 19

What are the main male & female reproductive hormones?

Answer 19

Males: testosterone
Females: oestrogen

Question 20

What are the three main hormones involved in the menstrual cycle?

Answer 20

Oestrogen, FSH, LH

Question 21

What is the role of FSH?

Answer 21

Causes an egg to mature, stimulates the release of oestrogen

Question 22

What is the role of oestrogen?

Answer 22

Repairs & thickens the uterus lining, inhibits the release of FSH, stimulates the release of LH

Question 23

What is the role of LH?

Answer 23

Causes a mature egg to be released.

Question 24

List three non-hormonal methods of contraception, and state how they work.

Answer 24

1. Condom - prevents sperm from reaching the egg
2. Spermicial jelly - kills sperm before it reaches the egg
3. Intrauterine device - prevents a fertilised egg from implanting on the uterus wall

Question 25

How do hormonal methods of birth control reduce the risk of pregnancy?

Answer 25

They contain oestrogen, which inhibits the release of FSH, so no egg matures.

Question 26

Outline the process of a nervous system response.

Answer 26

Stimulus --> receptor --> coordinator --> effector --> receptor

Question 27

Outline the process of a reflex action.

Answer 27

Stimulus --> receptor --> sensory neuron --> relay neuron --> motor neuron --> effector --> response

Question 28

What is a synapse?

Answer 28

A small gap between two neurons.

Question 29

How do messages travel across a synpase?

Answer 29

When the electrical impluse reaches the end of a neuron, it stimulates the neuron to release a chemical messenger. The chemical messenger travels across the synapse and attaches to receptors on the second neuron. This stimulates the neuron to generate another electrical impluse.

Question 30

What are the sense organs and what stimuli do they detect?

Answer 30

``` Skin - touch, temperature, pain Tongue - chemicals in food and drink Nose - chemicals in the air Eye - light Ear - sound ```

Question 31

List some effectors and the response they could cause.

Answer 31

A muscle contracting to move an arm | A gland releasing a hormone into the blood

Question 32

HT What hormone is released when blood sugar is too low?

Answer 32

Glucagon

Question 33

HT Where is glucagon released from in the body?

Answer 33

The pancreas

Question 34

HT What effect does glucagon have on blood glucose levels?

Answer 34

It causes glycogen from the liver and muscles to be converted back into glucose to be released into the blood, to increase blood glucose levels.

Question 35

HT What hormones are given to a woman to increase the chance of becoming pregnant?

Answer 35

FSH and LH

Question 36

HT What is infertility?

Answer 36

Not being able to get pregnant through sexual intercourse.

Question 37

HT How can infertility be treated?

Answer 37

Fertility drugs to promote ovulation or through IVF

Question 38

HT What are the steps in IVF?

Answer 38

1. The woman is given fertility drugs to promote ovulation 2. Eggs are collected and fertilised with a sperm sample in a lab 3. The fertilised eggs develop into embryos 4. The embryos are implanted into the mother's uterus

Question 39

HT What are some possible negative effects of IVF?

Answer 39

It can be emotionally and physically stressful, it does not have high success rates, it can lead to multiple births which can be a risk to the babies and mother

Question 40

HT What is the role of thyroxine in the body?

Answer 40

It stiumulates the basal metabolic rate, and plays an important role in growth and development.

Question 41

HT What is the role of adrenaline in the body?

Answer 41

Is increases heart rate and boosts oxygen and glucose delivery to the brain and muscles in times of fear or stress - it prepares the body for fight or flight.