B1A: Fitness & Health
Physical Fitness- the ability to do physical activity
Measure fitness by:
- 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
- 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:
- Eating to much salt
- being overweight
- 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
- 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
B1B: Health And Diet
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
B1C: Preventing Disease
- Caused by microorganisms called Parasites.
- Body is the host for parasites
- They realease chemicals called toxins
- Spread by Vectors
Immunity and immunisation
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.
- 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
B1D: The Nervous System
Changes in the environment- Stimuli.
Receptor cells- special cells adapted to detect stimuli
Information from receptors passes as electricall impulses. Travels along neurones
- Nerve cells
- Make up the brain+spinal chord
Sensory Neurones ( See diagram)
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.
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