Everything

Question 1

Circulation

Answer 1

The function of blood and circulation, is to deliver nutrients and oxygen to all the cells in the body. It consists of the heart and the blood vessels running through the entire body. The arteries carry blood away from the heart and the veins carry it back to the heart.

Question 2

What is double circulation

Answer 2

It is two loops in our body that blood circulates. One is oxygenated and one is deoxygenated. Oxygenated blood is rich in oxygen and deoxygenated has little to no oxygen in it, but a lot of carbon dioxide. It can also define as all the blood flows through the heart twice in each circuit.

Question 3

Do we need carbon dioxide

Answer 3

It is waste and is taken away to be excreted

Question 4

Why are the valves present

Answer 4

The valves are present in the heart to prevent back flow and push the blood in the correct direction

Question 5

Why is the left ventricle thicker

Answer 5

The left ventricle in the heart has thicker walls as it has to push blood all around the body and the right ventricle only has to push to the lungs

Question 6

Arteries

Answer 6

Carry blood away from the heart 
Blood at high pressure 
No valves 
Thick muscular walls 
Pulse created by pumping and contraction of heart muscle 
Strong walls

Question 7

Capillaries

Answer 7

Carry blood through organs and tissues 
Blood at low pressure 
No valves 
Very thin walls (one cell thick)
No pulse 
Delicate and easily broken 
Bruises are broken capillaries

Question 8

Veins

Answer 8

Carry blood towards the heart 
Blood at very low pressure 
Valves to stop blood flowing back 
Thinner walls less muscle 
No pulse 
Flexible and squashed easily so blood pushed further along vessel

Question 9

4 parts of the blood

Answer 9

Red blood cells
White blood cells
Platelets
Plasma

Question 10

Red blood cells

Answer 10

Are very small and have no nucleus
Are biconcave in shape, giving a large surface area ; volume ratio
Contain an iron pigment called haemoglobin which can pick up oxygen
When oxygen combines with haemoglobin forms oxyhemoglobin
When oxygen is released to the tissues it turns purple/red

Question 11

White blood cells

Answer 11

Are slightly larger than red blood cells
Are concerned with protecting the body
They are able to detect bacteria and then destroy them before they harm the body
Phagocytosis is when they engulf the bacteria to destroy them
Produce antibodies, these protect us from infections
They work by making the bacteria cells stick together so that it is easier to kill them and some others release toxins which neutralise the poison released by the bacteria

Question 12

Platelets

Answer 12

Are tiny cell fragments
Are carried around in the blood and usually do nothing
If the blood is exposed to the air in a cut the platelets help to form a network of fibres at the cut called a colt
This prevents blood being lost from the cut and stops bacteria and dirt getting in
The colt hardens to a scab. This keeps the wound clean while new skin grows.

Question 13

Plasma

Answer 13

It is the liquid portion of the blood
It is a yellow coloured liquid
It makes up 55% of the body’s blood volume

Question 14

How are heart attacks or blockages caused

Answer 14

The fitter and healthier you are the better your blood vessels circulate blood.
To keep you heart pumping you heart needs oxygen and food.
If it gets blocked it results in heart disease
Cholesterol or a clot can block arteries so that the blood flow stops
This blockage is called a hormbosios
A heart attack is caused by a blockage in the coronary arteries.
A stroke is caused by a blockage in the blood vessels leading to the brain

Question 15

How are heart attacks and strokes caused part 2.

Answer 15

A heart attack happens if the flow of oxygen rich blood to a section of heart muscle suddenly becomes blocked and the heart can’t get oxygen. Most heart attacks occur as a result of coronary heart disease.
CHD is a condition in which a waxy substance called plaque builds up inside of the coronary arteries

Question 16

How exercise effects your heart

Answer 16

It gives you a sense if highness.
If you are use to exercising regularly than your heart rate is use to beating fast so it adapts and is able to beat slower
Exercise can prevent high blood pressure
An unfit person has a higher heart rate as a fit person is use to exercising
Exercising gets rid of access fat and reduces the risk of heart disease
Not exercising, a bad diet, foods in high fat and sugar, smoking, stress and drinking all can lead to heart disease

Question 17

Microbes and disease :

Bacteria

Answer 17

Bacteria are really important microbes
It has only one cell, shaped like a rod, sphere or spiral.
They have been around for millions of years, they can live on any part of the earth.
Very few bacteria are harmful, bad bacteria make you sick, while bad spoil you food or drink, making it unsafe.
One bad bacterium can make you sick
Probiotics work very well to keep you healthy and have more benefits then nutrients like vitamins and minerals
They fight disease and protect you form bad bacteria. They help digest your food, bacteria some of the best decomposers.
They break down dead, decaying organic matter.

Question 18

Viruses

Answer 18

Viruses are among the smallest microbes on earth, even smaller than bacteria
They cannot survive on they own. They make copies of themselves
They can make you very sick, such as diseases, like cold sores and warts to measles, colds/flus
They can be very contagious, they spread quick in air and in droplets when people sneeze and cough.
Antibiotics don’t work on them
There are not many good viruses, one virus did make a big in cowpox
Cox pox can be vaccinated against lots of nasty diseases scientists are trying to make viruses to fight bacteria instead of antibiotics

Question 19

Fungi

Answer 19

Fungi is a special type of microbe, it doesn’t make its own food from the sun like plants, instead it gets its food from , decaying plants and animals.
Bad fungi are very dangerous, some mushrooms can make you sick and they sometimes look safe to eat
Some fungi can grow on your skin and make it crack and bleed
Lots of crops get damaged by fungi
There are lots of good fungi but they can look a lot like bad fungi
Moulds are fungi it is used to make some cheeses.
Scientists use fungi to make antibiotics. They are made from organic matter

Question 20

Uses, dangers and examples of microbes

Answer 20

Uses: 
Bacteria- making yogurt 
Fungi- yeast to make alcohol and bread
Viruses- weakened viruses for vaccines
Dangers:
Bacteria- typhoid or food poisoning 
Fungi- fungal nail infections or skin infections 
Viruses- flu and many infections 
Examples:
Bacteria- salmonella, meningitis, MRSA, tuberculosis 
Fungi- athletes foot, thrush 
Viruses- measles, HIV leads to aids.

Question 21

Aseptic techniques

For testing with perti dishes

Answer 21

Use sterile equipment, much of equipment must be sterilised in the autoclave
Have a hot flame near work place to kill bacteria around or in the air and on some equipment
In addition scientists must wear a sterile white lab coat to prevent bacteria form the clothes getting on the samples
Having a Bunsen burner helps destroy bacteria that may fall on to the samples
The perti dish must be kept sealed once it has been the incubator as the bacteria inside could be harmful, as it is groat body temperature. It may cause harm and the bacteria may be dangerous
After the investigation is finished the dish must be incinerated as the bacteria may contain to grow and become more dangerous

Question 22

Non specific defences and physical barriers

Answer 22

Mucus, traps dust and germs. Cilla helps move mucus up and out
Tears are antiseptic and kill germs in the eye.
Hair follicles, glands in skin make an antiseptic oil
Stomach acid, kills germs which may make there way into the stomach.
Cuts, when cut the blood clots and hardens to form a scab to prevent bacteria and dirt entering and allowing new skin to form.
Skin, is a natural barrier dead outer layer of skin forms a barrier to germs.

Question 23

What are phagocytes

Answer 23

Phagocytes are the type of white blood cells responsible for ‘mopping up’ infected cells and pathogens that have entered the body, these cells go around investigating and then digesting microbes. They work a bit like a Pac-Man. This process is known as phagocytosis

Question 24

What are lymphocytes

Answer 24

Lymphocytes produce antibodies when a lymphocyte encounters a microbe it will produce antibody molecules
These join onto a specific part of a microbe called the antigen. This can instantly cause the microbe to rupture or it can group them together

Question 25

What are antibodies

Answer 25

For every different microbe you encounter there’s a new antibody produced.
Antibodies are very specific. The production of antibody can take some time
During this period you will feel ill or symptoms of the sickness

Question 26

Memory cells

Answer 26

When you have experienced 1 type of pathogen the immune system produces specialised cells called memory cells. These can remain in your body for life meaning that if you are infected for a second time you immune system can respond much more quickly
So fast that you do not have any symptoms
This is why you can only have chickenpox once- you have become immune to them.

Question 27

Antibiotics

Answer 27

Alexander Fleming discovered antibiotics. He was a Scottish scientist. He noticed that an interesting pattern of growth in one of his unclean bacterial growth plates. This was on an area of the plate that was no longer covered in bacteria.
This observation led him into a series of investigations into how the fluid from mould was capable of killing bacteria.
The first successful use on humans did not come until February 1941- penicillin helped save a 15 year old boy from a serious blood poisoning

Question 28

Superbugs

Answer 28

No new antibiotics have be introduced since 1987, whereas pathogens were emerging every year.
Superbugs are a strain of bacteria that has become resistant to antibiotic drugs.
These bugs can develop while a person is taking a course of antibiotics
One common superbug increasingly seen outside hospitals is methicillin- resistant staphylococcus aureus (MRSA)
These bacteria don’t respond to methicillin and related antibiotics
MRSA can cause skin infections and in more serious cases, pneumonia or bloodstream infections