Everything Flashcards
Circulation
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.
What is double circulation
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.
Do we need carbon dioxide
It is waste and is taken away to be excreted
Why are the valves present
The valves are present in the heart to prevent back flow and push the blood in the correct direction
Why is the left ventricle thicker
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
Arteries
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
Capillaries
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
Veins
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
4 parts of the blood
Red blood cells
White blood cells
Platelets
Plasma
Red blood cells
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
White blood cells
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
Platelets
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.
Plasma
It is the liquid portion of the blood
It is a yellow coloured liquid
It makes up 55% of the body’s blood volume
How are heart attacks or blockages caused
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
How are heart attacks and strokes caused part 2.
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
How exercise effects your heart
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
Microbes and disease :
Bacteria
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.
Viruses
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
Fungi
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
Uses, dangers and examples of microbes
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.
Aseptic techniques
For testing with perti dishes
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
Non specific defences and physical barriers
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.
What are phagocytes
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
What are lymphocytes
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
