B1

Physical Fitness- the ability to do physical activity

Measure fitness by:

• Stamina
• Agilty
• Speed
• Flexibility
• Cadiovascular efficiency ( efficient heart/normal blood pressure) 

Good health- Being free from disease

Risk of developing heart disease increases

• High Blood Pressure
• Eat to much saturated fat
• Smoking
• Eat to much salt

When the heart beats, its muscle contracts. This pushes blood out to the arteries at the correct pressure so it reaches all parts of the body

Pressure in the arteries when the heart contracts- Systolic pressure

Pressure in the arteries when the heart relaxes- Diastolic pressure

Blood pressure increases from:

• Smoking
• Eating to much salt
• being overweight
• stress
• drinkin go tmuch alcohol
• eating a lot of saturated fat

Exercise+eating a balanced died help to lower blood pressure to normal. 

High blood pressure can cause:

• Heart attacks
• Strokes
• Kidney Damage

Smoking increases blood pressure:

• Carbon monoxide combines with haemoglobin in red blood cells and prevents them from carrying as much oxygen
• Heart beats faster to compensate- puts strain on the heart
• Nicotine increases heart rate

Saturated fat increases blood pressure:

• Liver makes cholesterol from saturated fat
• Cholesterol is carried in the blood and may be deposited in the artery walls
• These deposits narrow the arteries-restrict blood flow
• Blood pressure increases to force blood through the narrow gap

Carbohydrates- Energy- Stored in the liver as glycogen or converted to fats

Fats- Energy- Stored under the skin and around organs as adipose tissue

Proteins- Growth and Repair

Iron- To make haemoglobin

Vitamin C- Prevent Scurvy

Fibre- Prevent constipation

Water- Prevent dehydratopn, replacing water lost from the body

Infectious diseases:

• Caused by microorganisms called Parasites.
• Body is the host for parasites
• They realease chemicals called toxins
• Spread by Vectors

Antibodies are proteins. Each type of antibody can destroy a particular type of bacterium or virus, this is because:

• Each type of pathogen has particular antigens with a specific shape on its suprface.
• Each tpe of antibody has a particular shape and can lock onto a particular antigen.
• Your immune system makes the right sort of anyiboddoes to lock onto the antigens of the particular pathogen that is in your body.
• Once the pathogen is coated with antibodies, white blood cells can ingest and kill the pathogens.

Immunisation

• Small amount of dead pathogen is introduced into your body- this is called being vaccinated.
• Dead pathogens still have antigens on their surfaces
• Some white blood cells recognise these and respond to them by making antibodies,
• If activated pathogens were to get into the body, the white blood cells quickly make the right sort of antibodies to destroy the pathogens before they harm you.

Both eyes facing forwards- binocular vision

Eye on each side of the head(some animals)- Monocular vision

Humans can focus on near or distant objects, but not at the same time, so to do so, the lense must change shape, this is called accomondation. ( See table in book) 

Red-green colour blindness is an inherited condition. Means they do not have certain specialied cells in the retina.

Long sight- Can see things in the distance clearly

Short Sight- Can see things close up clearly. 

( See diagrams) 

• Cornea- Refracts light
• Iris- Coloured part made of muscle- controls amount of light going in
• Lens- Focuses light n the retina
• Optic Nerve- Carries impluses to the brain

Changes in the environment- Stimuli.

Receptor cells- special cells adapted to detect stimuli

Information from receptors passes as electricall impulses. Travels along neurones

Neurones:

• Nerve cells
• Make up the brain+spinal chord

Motor Neurones

Sensory Neurones                   ( See diagram)

Relay Neurones

Small gaps between adjacent neurones

An impulse in the first neurone, triggers the release of a chemical transmitter subsstace ( Neurotransmitter) 

Transmitter substance crosses the gap by diffusion

On the far side, molecules of the transmitter bind with receptor molecules in the membrane of the next neurone, this causes the impulse to continue.

See diagram

Response is coordinated by the spinal chord. 

Each Reflex action follows a pathway:

Stimulus --> Receptor --> Sensory Neurone --> Relay Neurone --> Motor Neurone --> Effector --> Response

Effectors: Glands or muscles that carry out a response