1. BIOLOGY

3. Nerves and hormones
• Information being sent to the brain is by • The body contain lots of organs.
nerves. • These organs work together to be able to
• These are fast moving electrical communicate with one another.
impulses.
• The brain then send more impulses •Hormones also convey messages
around the body. between organs.
•Hormones are chemicals made by the
glands.
•Nerves carry information to and from the
•A gland is an organ that makes and
brain and spinal cord. These make up the
releases useful substances. This is called
central nervous system.
secretion.
•Nerves contain special cells called nerve
•The gland secrete the hormones into the
cells and carry information as electrical
blood and carry throughout the
impulses.
bloodstream around the body.

4. Nerves and behaviour: Hormones and target organs:
• Whilst making a simple movement • In the nervous system, nerves carry
huge amount of information are being information between one organ and
another.
passed along nerves.
• Hormones also move around the
• These are between the eye, brain body by blood vessels.
and muscles. • Most hormones affect a few organs
• Tiny adjustment are being made and these are called target organs.
constantly. • The hormone adrenaline has more
• All the information used then target organs than most hormones.
produces a perfectly coordinated • Adrenaline affects the heart,
piece of behaviour. breathing muscles, eyes and
digestive system.

5. Receptors
Vision- eyes
Receptors are special cells that (light)
detect stimuli.
Stimulus is a change in the Smell-
environment. nose
(chemicals)
Receptors send electrical impulses
along nerves to your brain.
Taste-
tongue
Your brain then sends impulses Hearing – ears
(chemicals)
speeding along other nerves to Touch- skin (sound and
a muscle e.g. in the hand or leg. (temperature movement)
All your muscles are effectors. and
pressure) •eyes to see
An effector is an organ that does
•ears to hear
something to respond to a
•nose to smell
stimulus.
•tongue to taste
As well as muscles being effectors, our •skin to touch and
gland are also effectors. feel

6. Neurones
•It carries information from the nervous system as electrical impulses.
•These cell that carry this information are called nerve cells or neurones.
•This is a sensory neurone.
•It carries information from the receptor to the CNS.
•This is a motor neurone.
•It carries information from the CNS to the effector.

7. Transducers
• Receptor are transducers
• A transducer is a devise that
converts one form of energy into
another kind of energy, when one
is chemical energy.
• Receptors transfer energy from a
stimulus to electrical energy in
neurones.
For example:
•In the eyes are receptors called rod cell
•When light energy hits this rod cell, it
starts up an electrical impulse that
travels in a neurone along an optic
nerve to the brain.
•The rod cell is a transducer because it
transferred light energy into electrical
energy.

8. In a reflex action:
Reflex actions A receptor detects a stimulus.
The receptor sends an electrical
• The tap on the knee in the knee jerk
impulse along a sensory
test is a stimulus.
neurone
• Its detected by receptors in the thigh These impulses are sent to the
muscle connected to your knees. CNS.
• The receptor sends signals to your
The CNS sends an electrical
spinal cord.
impulse along a motor neurone
• The spinal cord sends nerve impulses to an effector.
to your leg muscles.
• The leg muscles respond by The effector responds to the
contracting which pulls your lower leg stimulus.
upwards.
A reflex action is a fast, automatic
A reflex action is a fast, automatic
response to aastimulus.
response to stimulus.

9. Reflex arc Synapses
•The tiny gap between the end of one neurone
•A reflex arc is pathway and the start of the next is a synapse.
taken by nerve impulses as
it passes from receptor. •Electrical impulses cannot jump across these
gaps.
•It then goes to the central
nervous system and then to •Instead when the impulse get to the end of
an effector. the neurone, it causes a chemical to be
secreted.
•This diffuses across the gap but at a slower
rate than an electrical impulse travelling the
same distance.
•The chemical diffuses across the gap and
arrives at the beginning of the next neurone.
•This starts off an electrical impulse that
whizzes along that neurone.

11. Water Controlling water and ions:
• Cells in your body are always •The blood had many dissolved substances
working. in it.
•Some are ions such as sodium and
• Chemical reaction take place
chloride, both in salt.
inside them.
•To much salt and not enough water in the
• These need to happen at the right blood can lead to high blood pressure.
time and speed. •People who eat to much salt can increase
• The conditions need to be perfect risks of a heart attack.
and constant. •The kidney helps keep balance of water
and ions.
•They do this by varying the amount of water
These conditions include: and water from the body in urine.
•The water content
•The ion (salt) content
•The temperature
•The concentration of sugar in blood
Your body can lose water:
•From the lungs when you breathe.
•From your skin when you sweat.
•From the kidneys when you
urinate.

12. Sweating
•Sweating keeps us cool.
•It is made by glands in the skin.
•The gland take water and ions out of
Insulin the blood to make sweat.
• sugar content in the body is controlled •The sweat travels through a sweat
by a hormone called insulin. duct and lies on the surface of the skin.
•A meal with starch or sugar, a sugar •It is a mixture of water, ions and small
called glucose is absorbed into the amounts of urea.
blood. •When you sweat you lose these.
•The blood carries this all over the body. •The water in sweat evaporates.
•Cells need glucose for energy. •As it changes from liquid water to
•If a meals contains to much sugar or water vapour, it takes out from the skin.
starch then the blood glucose level rises
and the pancreas detects this.
•It responds by excreting the hormone
insulin.
•This is carried to the liver in the blood.
•The liver takes out glucose from the
blood and stores it.
•If your glucose levels fall then the liver
stores this glucose back into the blood.

13. Reproductive hormones
Menstrual cycle • The menstrual cycle is controlled by
• The cycle, is when an egg is hormones:
released from a woman's • FSH- secreted by the pituitary gland.
ovaries every 28 days. • LH- secreted by the pituitary gland.
• Oestrogen- secreted by the ovaries.
• Before the egg is released, the
lining of the womb thickens.
• If the egg is fertilised the womb In the pituitary In the ovary
is ready to conceive the tiny gland
FSH causes
embryo. FSH is
secreted and egg to
• If not the lining breaks down. mature
• This passes through and is
FSH cause
called menstruation. Oestrogen the ovary to
stops the secrete
pituitary oestrogen
secreting FSH
oestrogen LH causes the
cause the mature egg to
pituitary to be released
from the ovary

14. Hormones and menstrual cycle
•Concentration of FSH,
LH and Oestrogen change
during the cycle.
•As oestrogen levels rise
they cause the thickness
of the uterus lining.
•As oestrogen levels fall,
the lining breaks down.
1. On the first day of the 2. One week into the cycle, the
cycle, menstruation begins. lining build up. An egg is ripening
The thick lining of the uterus in the ovary.
breaks down and is lost
through the vagina.
Two weeks into the cycle,
an egg is released from
the ovary. The lining is soft
4. Three weeks into the cycle, the egg and thick and ready to
has almost reached the uterus. If it hasn’t receive if egg is fertilised.
been fertilised, it will die.

15. Controlling fertility
• When a women doesn’t produce
IVF- In Vitro Fertilisation
eggs, then she can be given
fertility treatment.
The women is given fertility drugs in
The women is given fertility drugs in
• The hormones used are called her ovaries to mature the eggs.
her ovaries to mature the eggs.
fertility drugs.
These eggs are then removed and
These eggs are then removed and
• The hormone FSH, can used. This
some are placed inside a Petri dish
some are placed inside a Petri dish
stimulates the women eggs to
containing a special solution.
containing a special solution.
mature in the ovaries.
• This egg is then released into the Then some of the mans sperm cells
Then some of the mans sperm cells
oviduct and conceive normally. are added to this mixture.
are added to this mixture.
These eggs can then fertilise, then
These eggs can then fertilise, then
Oral contraceptives when they form into tiny balls, the
when they form into tiny balls, the
•The contraceptive pill contains chosen embryos are then placed back
chosen embryos are then placed back
hormones such as oestrogen. into the women’s uterus.
into the women’s uterus.
•This hormone stops the production of Then ififthe process is successful a
Then the process is successful a
FSH, and then the eggs don’t mature in baby can develop.
baby can develop.
the ovaries.
•So no egg in released into the ovaries
and she cannot get pregnant.

17. Diet and Energy • Different people require different energy
needs.
A balanced diet • Exercise takes up lots of energy.
• The amount of energy you need also
Carbohydrates- for Energy depends on the type of job you do .
Fats – for stored energy and •Another reason that affects the amount of food you eat
making cell membranes is our metabolic rates.
Proteins- for growth and •All our metabolic rates are different.
repair and energy •Metabolic rate is the rate at which chemical reactions
happen in the cells.
Vitamins and Minerals- for •Men tend to have faster metabolic rates then women.
keeping healthy and not •Young people have faster metabolic rates than older
developing deficiency people.
diseases •The greater the proportion of muscle to fat in you body
the higher your metabolic rate is.
Fibre- to help the •It can also be affected by genes.
digestive system •In winter people tend to have higher metabolic rates
water than in summer due to the less amount of food we
need.
BMI – Body Mass Index
= weight (kg)
height (m)²

18. FAT • Babies have brown fat
• 5% of babies weight in brown fat
• Brown fat cells have a very high
• We have fat in our bodies metabolic rate.
• Most is white fat • It is used to generate heat
• It the baby is cold, then the brown
• It is found beneath the skin fat cells generate the heat fast.
around the organs, e.g. Kidneys
• It is an energy store
• It helps to insulate our bodies
and keep heat in
• It can protect internal organs
from bruising

19. Obesity
• The more food you eat each day,
can lead to excess store of fat in
the body
• You need fat but to much is bad.
•People who are overweight are
called obese.
•Being obese can lead to a high risk
of being ill.
Problems include:
•Arthritis
•Diabetes
•High blood pressure
•Heart disease

20. Illnesses by obesity
Diabetes
Arthritis • An illness where a person cannot
• This is ‘inflammation of the joints’ control their blood glucose level.
• Anyone can get it but its common in • In Type 1 diabetes, the pancreas
obese people doesn't make enough insulin.
• Arthritis in the knee joint is common • In Type 2 the body cells don’t respond
in UK and many need to get their to the insulin.
joint replaced. • Type 2 is mostly suffered by obese
• A major and expensive operation. people.
• This is dangerous because you have to
much glucose in the blood which can
damage cells as it draws water out of
High blood pressure them.
•Blood pressure is the pressure of the blood in
the arteries.
•The pressure is highest just after the heart
beats. The pressure falls between heartbeats.
•The average blood pressure is 130 over 85.
•High blood pressure is when it is too high.
•This is bad because it puts strain on the heart
and their is an increases chance of blood
vessels damaging.

21. Starvation
Malnutrition- diet is in adequate
When a person doesn’t have enough
••Insome countries, some people live
In some countries, some people live to eat:
by growing their own crops.
by growing their own crops. • their resistance to diseases is
lowered.
Sometimes they can be affected by:
Sometimes they can be affected by: • They can die from diseases such
••Droughtsor floods, so crops can’t
Droughts or floods, so crops can’t as, cholera, tuberculosis.
grow properly.
grow properly. • Women’s periods become
••Awar, so people can’t visit their
A war, so people can’t visit their irregular or stop.
fields or look after their kids.
fields or look after their kids.
••Peopleare to poor to buy food.
People are to poor to buy food.
•Shortage of food affects little kids.
•This is because they’re still growing.
•They need protein for cells.
•Without protein they can't grown and become
weak and even die.
•They may receive energy from some foods but
no enough protein.

22. Cholesterol and Salt
Fast food contains lots of fat and salt.
Salt
Salt
Cholesterol ••Weneed some salt but
We need some salt but
• Too much cholesterol in the blood can not too much
not too much
form blockage in blood vessels and ••Tomuch can increase
To much can increase
increased risk of heart disease. blood pressure
blood pressure
• Saturated fats are found in animal ••Processedfoods
Processed foods
products e.g. Eggs, meat and dairy
products. contains lots of salt
contains lots of salt
• Some fats lower your cholesterol levels. ••Likecrisps and nuts
Like crisps and nuts
These are unsaturated fats, e.g. Plant
oils ex sunflower oil.
• Cholesterol can be used to make cell
membranes e.g. Your liver makes
cholesterol.
• If you eat a diet with less saturated fats
then your cell will have enough.
• If you have too much then the liver
makes less.
• The amount of cholesterol you have
depends on your genes and how much
fat you eat.

23. Cholesterol and heart disease
• Cholesterol can’t dissolve in water,
therefore it can’t dissolve into watery
blood plasma.
• Instead it is carried around in tiny ball
mixed up with proteins called
lipoproteins.
•The plaque reduces the space that
blood can flow through. • High density lipoproteins (HDLs)- is a
•It slows down the blood, so it clots. good cholesterol and keeps you
•If clots break away, they get carried healthy.
along in the blood and get stuck in • Low density lipoproteins (LDLs)- is a
smaller blood vessels, blocking blood bad cholesterol and can lead to heart
flow. disease.
•Sometimes a clot block one of the arteries
that oxygenate blood to the heart muscle. • High levels of LDLs in the blood can
•The muscle cant work, and the heart can’t increase the risk of developing plaques
beat properly. in the wall of the arteries and can lead
•This can cause a heart attack. to heart problems
• HDLs can protect us against heart
disease. They help remove cholesterol
from the walls of blood vessels.

24. Different fats
Saturated fats- raise blood cholesterol Mono un-saturated fats- they reduce
levels overall blood cholesterol levels
Found in foods such as meat, butter and improve balance between
and cheese. LDLs and HDLs in the blood
Found in foods such as olive oil,
olives, peanuts and many
margarines
Polyunsaturated fats- these are better
at reducing blood cholesterol levels
and balances HDLs and LDLs more
that mono unsaturated.
Found in foods such as corn oil,
sunflower oil, oily fish and many
margarines.

25. Statins
• If a person’s liver seems to have
their cholesterol making is
permanently at high, then it is
difficult fro them to keep
cholesterol levels down.
• They then have to take drugs
called statins.
• These affect the enzymes that
control cholesterol synthesis in the
liver and inhibits cholesterol
production.

27. Drugs Dangers of drugs
 Alcohol
• A drug is something that changes  Cannabis
the chemical processes in the  Cocaine and heroin
body.  Tobacco
• Recreational drugs are taken for
pleasurable reasons. • Alcohol and tobacco are legal drugs.
• Cannabis, cocaine and heroine are illegal.
• People can become addicted to a drug.
• They feel dependent on it.
• Drug addiction can have long term affects.
• They can affect the brain and liver.
• The liver is damaged as its job is
destroying harmful chemicals within the
body.
• Legal drugs can be misused and become
a danger.

28. Trialling drugs
1. Is it safe? • This process can take years and
may not be successful
The drug is tested in a lab to see if it is
toxic. • Even if a drug gets through the
stages, it is 5 years before it is
2. Is it safe for humans?
sold in chemists
The drug is given the volunteers. They • When people use it, it may not be
are given different doses to
the miracle cure
determine the maximum dose.
Any side effects are recorded. E.g.
3. Does it work? • Thalidomide.
The drug is tested on the ill people who • This was originally developed as a
the drug was made for. If it makes sleeping pill.
them feel better it is sold • It was never tested on pregnant
commercially. women.
• It is now being used to treat
leprosy.
• But no pregnant women is allowed
it.

29. Illegal drugs Cocaine and heroine
Cannabis • They come from opium poppies which
are grown in Afghanistan and Columbia.
• Drug made from dried leave.
• They make people feel happy and
• It can be smoked like tobacco and causes
relaxed.
bronchitis and lung cancer.
• Heroine and cocaine are dangerous and
• It makes you feel relaxed and happy.
known as hard drugs.
• People who suffer from multiple sclerosis
• Cocaine is addictive and you can get
say it makes them feel better.
addicted after taking it once.
• It is likely to cause the illness
schizophrenia.

30. Alcohol
• Is commonly used drug.
• It can be misused. • The liver gets damaged because
Alcohol affects the nervous system. It its job is to break down alcohol.
causes:
 Reactions to slow down • Its changes it to harmless
 Loss of self control substances.
 Unconsciousness, coma and even • Too much can kill the livers cells.
death, when a lot is drunk
•People drink to relax and enjoy
• Alcohol damages the brain and liver
• Brain cells are affected quickly themselves.
•If to much is drunk they get aggressive
• The cells shrink
and violent
• People can get permanent brain
damage
Alcohol dependency
•People can become dependent on alcohol
•They can’t manage without out
•They spend so much they can't support their families or themselves.
•They can lose jobs and families

31. Alcohol is
swallowed
The cortex(the wrinkled surface layer of the
and then
absorbed into
Blood carries brain) which is responsible for conscious
the body alcohol the thought and actions
through the brain
stomach
The cerebellum
which controls
movement and
posture
Blood The medulla
stomach carries the which controls
alcohol to
the liver breathing and
heart rate
Depressants
•Alcohol is a depressant.
•These are drugs that slow down brain activity
•A part of the brain called the cortex allows a person to think clearly and make
decisions.
•Alcohol affects this ability
•It also affects the cerebellum, which helps with coordination.
•If to much is drunk, it can kill and cause a person to fall into a come or die due to
the inhibit of breathing.

32. Lung diseases
Tobacco • A smoker get lung infections.
• In the bronchitis, the smokers
Cigarette poisons bronchi inflames.
• Tobacco contains many different • Lots of mucus is produced.
substances including nicotine, tar
• This can cause excessive
and carbon monoxide.
coughing.
Nicotine- affects the brain. It is addictive. • The air sacs lose stretchiness.
• It is difficult to get oxygen into the
Tar – is a poison that causes cancer. Its a blood.
carcinogen.
Cigarette smoke often causes lung cancer, but
• This is called emphysema.
can risk development of other cancers. • Someone with this condition may
have to breathe oxygen from a
Carbon monoxide- takes the place of cylinder.
oxygen in red blood cells, so the blood carries
less oxygen. This can harm body cells.
In pregnant women this can be dangerous as
the baby will get less oxygen, it may not grow
properly and have a low birth weight. A person
who smokes is likely to have heart disease.

33. Pathogens
Microorganisms Microorganisms and disease
• These are living things that we • Some bacteria and viruses can
cannot see. cause disease.
• They include bacteria and viruses • A microorganism that causes
disease is called a pathogen.
• Humans are visible organisms,
which are made up of tiny cells. • If bacteria can get into the body, it
reproduces rapidly.
• Each bacterium is made up of one
cell. • They produce toxins that make
you feel ill.
• Their cells are smaller than ours.
• They are carried in the blood.
• You can’t see bacteria clearly.
• A virus can get into a cell and
• Viruses are even smaller. reproduce there.
• There are some viruses that can • When to much is produced they
get into bacteria, so bacteria can can burst out of the cell and
also get ill. destroy it.

34. Body defences
White blood cells Epidemic and pandemics
• These are our defence forces. • Sometimes people get a flu.
• They attack and destroy • When lots of people have an
pathogens in the body. infectious disease at the same
• They are part of our immune time, this is an epidemic.
system. • When an epidemic spreads
• Some white blood cells surround worldwide, its known as a
bacteria and take them into its pandemic.
cytoplasm.
• They kill them and make
antibodies, that destroy bacteria.
• Or antitoxins, that neutralise the
poisons that the bacteria makes.

35. Antibodies
Phagocytosis • Other white blood cells, called
lymphocytes, that attack pathogens in a
different way.
• They produce chemicals called
antibodies.
• This is an anti body molecule.
•This shows how a white blood cell, called • The end bits fit onto molecules of the
phagocytes. pathogen.
•They surround and ingest bacteria. This • Each shape fits one kind of pathogen.
activity is called phagocytosis. • So we have millions of lymphocytes.
• The antibodies group around and stick to
•This is what happens when you have an infected the pathogen.
wound. • They can kill it directly or stick to it in
•Some of the cells around the wound produce clumps, so phagocytes can gather and
chemicals that tells the phagocytes they’re destroy them more easily.
needed. • Some of the chemical that the
•Extra blood flows to the infected site, bringing lymphocytes make can stick to the
more phagocytes with it. dangerous toxins made and given off by
bacteria, can destroy them
•The would becomes inflamed and red.
• These chemicals are called antitoxins.
•But under the skin, they are dong their best to kill
the pathogens.

36. Drugs against disease
Painkillers Sources of antibiotics
• A drug used to get rid of pain. • Penicillin is made from a fungus.
• You can buy these, e.g. Aspirin, • The drug companies are always on
paracetamol and ibuprofen. the look out for new antibiotics.
• They reduce symptoms of whatever • Nowadays, most antibiotics are
is wrong with you. made chemically.
• This is better then extracting them
Antibiotics from fungi or other organisms
•These are drugs that kill bacteria inside your because you know hat you're
body. getting.
•They don’t kill viruses. • If you take it from fungus, you don’t
•Antibiotics include penicillin and know the strength of it.
streptomycin. • Making it chemically means you
know its pure
•We different ones as they don't all work
equally well against all kind of bacteria.
Antiviral
•Viruses are more difficult to kill.
•If they go inside a cell they are impossible to kill it
without killing the cell.
• Antivirals are used to kill viruses.

37. Resistance to antibiotics
MRSA
Resistance to antibiotics
•Methicillin Resistant
• This is a population of bacteria in
Staphylococcus aureus.
a person’s body. One of them is
different. •Staphylococcus aureus is a
common bacterium.
•It doesn’t normally harm
someone except a weak, very
• The person takes antibiotics to young or very old person.
kill the bacteria. It works but of •MRSA infection is in
them is resistant to the antibiotic.
hospitals.
•It can’t be killed with usual
• The bacterium has now divided antibiotics.
and made copies of itself. There •It is difficult to kill once
is now a population of bacteria
someone is infected.
that the antibiotic cannot kill.

38. Vaccination
Immunisation • They can even make antibodies.
• Means making immune • These stick to bits of the surface of
• You can be immunised against the virus or bacteria and attack it.
mumps, measles and rubella, polio They are called antigens.
and diphtheria • The white blood cells make different
• You have a small amount of dead or antibodies for each antigen.
inactive viruses or bacteria jabbed • If you get infected by the real, live
into you blood. pathogen, your white blood cells are
• Your white blood cells don’t know ready to make the right sort of
they’re harmless and attack them antibodies.
like pathogens. • They will then destroy the pathogen
before it makes you ill.
The MMR jab
•This is given to children to protect them against Measles,
Mumps and Rubella.
•These disease are caused by viruses.
•In 1988 it was told MMR jab caused autism.
•However scientist had no evidence that it was.