B1 OCR gateway science
- Created by: Eleanor200101
- Created on: 13-02-17 20:01
Fitness and blood pressure 1
Being healthy=being free from disease
Being fit=how well you fufil physical tasks
Different ways you can measure fitness:
-Strength
-Speed
-Agility
-Flexibility
-Stamina
Stamina=Good indication of cardiovascular efficency !!!!The ability of the heart to supply the muscles with oxygen
Fitness and blood pressure 2
Blood is pumped around the body under pressure:
-Pumped around by contractions of heart muscles
-Contractions increase pressure so they reach every part of the body
-Blood flows through arteries then back through veins to the heart
-Blood pressure at its highest when it contracts (systolic pressure)
-Lowest when the heart relaxes(diastolic pressure)
Blood pressure mmhg
Increase in blood pressure as a result of:
weight
smoking
alcahol
Stress
Can be decreased by:exercise/diet
High blood pressure and heart disease
Smoking can increase blood pressure and consequently lead to hear disease
1)Contains lots of nasty chemicals such as Nicotene which increases heart rate heart contractions more often lead to increased blood pressure
2)Heart disease any disease that affects the heart and lead to things such as heart attacks
Poor diet
-If diet high in saturated fat or salt at risk of developing heart disease
Saturated fats:
Cholesterol a fatty substance
saturated fat=high levels of choleterol
to much saturated fat builds up arteries
Forms plaque and narrows arteries
Reduces the flow of blood leading to a heart attack
Blood pressure and heart disease continued
High salt levels can increase blood pressure
Some salt as a balanced diet however too much can cause high blood pressure
Increases the risk of damaged arteries
Build up of plaque can lead to a heart attack
EATING HEALTHY
A balanced diet keeps you healthy!!!!!!
contains all nutrients you need
Carbohydrates-energy
Fats-energy
Proteins-growth and repair of tissues
Vitamins-many functions eg vitamin c prevents scurvy
Minerals- many functions eg iron needed to make haemoglobin for healthy blood
Water-prevents dehydration
Also need fibre to prevent constapation
Carbohydrates simple sugars like glucose
Fats fatty acids glycerol
Proteins amino acids
EATING HEALTHY
Balanced diet is according to different people
Age = children/teenagers=proteinf for growth and repair
Gender= females =iron for loss of blood during periods
Physical activity=Active people craboyhdrates=energy
Diet problems
Eating to little can cause problems:
little protein=kwashikor(swollen stomach)
Developing countries to low in protein
overpopulation protein=rich food
not a lot of money for agriculture therefore difficult to produce foods high in protein
Amount of protein you consume each day=Estimated average daily allowance Ear(g)=0.6xbm(kg)
Eating disorders =poor diet
Caused by low self esteem and desire to be perfect
poor diet can lead to ilnesses such as liver failiure death heart attacks
Eating to much can lead to obesity
20%more over your recomended body weight
eating to much=not enough exercise
Risk of Diabeties heart disease and breast cancer
Infectious diseases
Infectious diseases are caused by pathogens
Infectious diseases are caused by micro organisms called pathogens four main types:
-Fungi-athletes foot
-Bacteria-cholera
-Protozoa-malaria
-Viruses-flu
Symptoms include=
Cell damage by toxins produced by pathogens
Ginetic disorders faulty genes (non infectious)
Infectious diseases continued
Malaria for example is caused by a protozoa carried by mosquitoes
Protozoa is a parasite that lives of ,another organism called a host
Vectors carry without getting it themselves
Mosquitos pick up when they feed on infected animals it passes paraites on every time it feeds of another animal
These diseases often occur in hotter places such as africa as pathogens reproduce faster
poorer countries they dont have the money to treat diseases or educate people
Four main ways of keeping pathogens out
Skin-stops entering
The blood-blood clots seal cuts
The stomach-hydrochloric acid kills pathogens in food and drink
The airways-sticky mucus traps bacteria
Preventing and treating infectious diseases
Immune system:
if pathogens enter body the immune system kills them (white blood cells)
White blood cells constantly travel around the body looking for pathogens
Two lines of attack:
Consuming them white blood cells engulf and digest pathogens
Producing antibodies molecules on the surface of pathogens called antigens
when comes into contact with white blood cell lock onto and kill it
immunisation
New pathogens can take white blood cells a longer time to produce antibodies for and in time can make you very ill
To avoid this you can be immunised(vacinated)against some diseases such as polio and measels
Active immunity immune sytem makes own antibodies
Passive immunity antibodies made by other organisms
Antibiotics and Antivirals
Antibiotics kill bacteria
They can get rid of bacterial infections
Antibiotics dont kill viruses
Antivirals stop viruses from reproducing
They can treat viral imfections no effect against bacteria
DRUGS
Drugs are substances which change the way the body works
Some are useful eg antibiotics however can be harmful if misused
Some are addictive drugs where you have a physical need for them if not then will have withdrawal symptoms
Tolerance develops with some drugs = get used to it
Depressants=alcahol solvents and temazepam slow down brains activitys
Stimulants eg nicotene ecstasy and caffine increase brains activity
Painkillers such as aspirin and paracetamol block nerve impulses
Perfomance enhancers anabolic steriods build muscles and help speed
Hallucanogenics eg LSD distrort whats seen/heard
Alcohol-depressant drug
Depressant that decreases the activity of the brain
slows down the nervous system
when youre drunk it can have impacts such as:
Impaired judgement
Slurred speech Blured vision
Drowsiness
Reaction time is slower therefor you cant drive after drinking
Longterm effects include - Brain and liver damage
Doctors reccomend no more than 21 units of alcahol
Smoking/cigarettes
Smoking cigarettes:
Carbon minoxide reduces oxygen in blood
Nicotene-addictive chemical
Tar-covers the cillia irritation can cause cancer
Particulates-Small particles build up and cause irritation
Smoking can cause many illnesses such as heart disease cancer as well as a smokers cough and bronchitus/emphyesema
The eye
Eyes jobs
Cornea = refracts light
Iris=contols how much light enters the pupil
Lens=refracts light focusing it into the retina
Retina=light sensitive part covered in receptors sensitive to light of colours
Optic nerve=carries impulses from receptors to the brain
Blind spot=no recepters cant detect light
Eye details
Light travelling into the eye:
Light from object is refracted into the eye by the cornea
The lens then refracts light a bit more to focus it on your retina
Long sighted=cant focus on nearby objects lens maybe the wrong shape
eyeball maybe to short
Short sighted=cant focus on distant objects lens maybe wrong shape eyeball to long
Binocular vision=see with both eyes eg humans
They have narrow field of vision
Monocular vision=See with one eye wide field of vision but cant judge distances easily
Neurones and reflexes
Neurones are nerve cells that send information around the body as nerve impulses
Nerve impulse is an electrical signal passed among the axon of the neurone
Three types of neurone=sensory/relay/motor
Central nervous system consists of the brain and spinal chord which ultimately organises information
All neurones outside cns make up peripheral nervous system
A change in envrionment is called a stimulus
Detecting of a stimulus recpetors generate a nerve impulse which travels along sensory neurones
REFLEX ACTIONS
Reflex actions stop you injuring yourself and are sutomatic so very fast
Conscious brain isnt involved in a reflex arc the sensory neurone connects the relay neurone in the spinal chord
Relay neurone links to correct motor neurone
Reflex actions have a protective role like pulling your hand back when you tough a burning hot plate
Homeostasis
Maintains a constant internal envrionment
keeps conditions steady by automatic control systems
Cells can function at their optimum
Involves balancing imputs with outputs
Water content and body tempretures are all maintained by homeostasis
Controlling blood sugar
Insulin controls blood sugar levels
Insulin is a hormone that controls the sugar quantity in the blood
Respiration causes the amount of sugar in the blood to decrease
insulin is produced by an organ called the pancreas
Insulin is carried in the blood to ther parts of the body
But only affect particular organs called target organs
Travelling by blood is slow and so hormones react more slowly
Diabetes
Type 1)prancreas cant produce enough insulin
if blood sugar rises could kill them
controlled carefully by diet
They also need insulin therapy involving an injection of insulin several times a day
Type 2)Cant respond to insulin
limiting sugary foods
Plant hormones and growth
Auxins are plant growth hormones
plant growth is controlled by hormones
They control the groth of the shoot and roots and are called Auxins
Auxins are involved in the responses of plants to light and gravity
Auxins why they are needed????
-Plants need light to make food through photsythesis otherwise they die
Plant shoots grow towards and light increasing their survival rate
Also plants require water which is why roots grow downwards
Commercial use of plant hormones
selective weedkillers:
plant growth hormones only affects weeds (kills them)
Growing from cuttings with rooting powder
They wont grow but add rooting powder they will produce roots and new plants
lets growers produce lots of clones
Controlling the ripening of fruit
Delays the ripening (plant hormones)
Ripening hormones can be added which will ripen fruit for supermarket purposes
Controlling dormacy:
Seeds wont germinate through certain conditions called dormacy so plant hormones will break dormacy
Genes and chromosomes
Most cells in the body have a neucleus this contains ginetic info in the form of chromosomes
Most animal chromosomes come in pairs depending on species as to the pairs human body cell has 23 chromosomes
Chromosomes carry genes different genes control the development of different characteristics eg eye colour
A gene is a short length of a chromosome
Quite a long length of DNA
Genes and the environment
Characteristics such as eye colour depend on your genes
There can be different versions of the same gene called alleles
Everybody has different combinations called ginetic variations
Characteristics can be dominant or recessive
Some inherited from parents eg eye colour
Dominant are eg brown eyes over blue eyes
Blue eyes are a reccesive characteristic
recesive are only seen where no dominant characteristics to inherit
Is your environment responsible for some characteristics????
environment controls some such as scars
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