GCSE OCR Gateway Science - B1 A-D

Systolic pressure - is the maximum pressure the heart produces

Diastolic pressure- is the blood pressure between heart beats

systolic/diastolic = ___mmHg = blood pressure

Blood pressure is produced when muscles contract.

High blood pressure causes strokes, brain damage, parylsis and loss of speech.

Cuases of high blood pressure - fatty foods, lack of exercise, salt, stress, smoking

Low blood presure causes poor circulation, dizziness and fainting.

Health - being free from disease

Fitness measured in strenght, flexibility, stamina, agility, speed, heartrate, breathing rate, blood pressure, cardio-vascular efficiency.

Pulse rate - surge in the artery wall, corresponding with a heartbeat.

Respiration provides the body with energy.

Aerobic Respiration glucose+oxygen ^ carbon dioxide+water+ENERGY

This meets energy demands most of the time. The gas oxygen releases energy from glucose.

Anaerobic Respiration glucose ^ lactic acid+ENERGY

This is used in strenuous exercise when there is not enough oxygen or glucose getting to the cells fast enough to supply the energy demands.

Oxygen Debt - when muscles cannot get enough oxygen quick enough. The cells start using anaerobic respiration but release less energy as the glucose is only partly broken down.

Aerobic - involves oxygen, releases more energy, produces carbon dioxide and water which is brethed out, glucose completely broken down.

Anaerobic - doens't involve oxygen, releases less energy, produces lactic acid which is poison causing muscles to cramp, ache and pain, glucose partly broken down.

Basic Food Types -

carbohydrates - a source of immediate energy - potatoes

Protein - growth and repair - fish

Fat - energy store and insulation - crisps, margarine

Vitamins - required in very small concentrations, a variety of functions - limes, carrots

Minerals - required in very small concentrations, a variety of functions - spinach

Fibre - adds bulk to food and absorbs poisons - All-Bran, brown rice/bread

Water - a variety of functions, including cell solvent, transport, etc

Problems with obesity - risk of arthritis, heart disease, diabetes, breat cancer

Balanced diet

Proteins are needed for growth and repair. They are made from amino acids that are essential, as the body can't make these so they need to be obtained from the diet. Non-essential amino acids can be made from other amino acids.

BMI - Body Mass Index - mass(kg)/height (m)2

Protein deficiency - Kwashiorkor is caused from starcation. Without protein, their bodies cannot absorb excess water so their bellies swell.

Meat and Fish contain first-class proteins

RDA - Recommended Daily Allowance - 0.75 * mass(kg) = __g

Types of Diet - Muslim, Jewish, Vegan, Vegetarian, Allergies

People choose their diets due to religion, choice or allergy.

Muslims will only eat Halal meat, which is blessed.

Jews don't eat pork as they believe pigs are dirty animals.

Vegetarians and Vegans do not eat anything killed, but Vegans do not eat anything from animals.

When you are allergic to a certain food, you have to make sure you don't eat it.

Digestion - to break down large molecules of food to small molecules, insoluble to soluble.

Mechanical digestion - chewing

Peristalsis and chemical digestion - using enzymes

Carbohydrates, proteins and lipids need to be digested.

Carbohydrates ^ Carbohydrase ^ simple sugar

Proteins ^ Protease ^ amino acids

Lipids ^ Lipase ^ Fatty acids and glycerol

The gall bladder stores the bile, which is used in digestion.

Pathogens - disease-causing organisms. There are four types -

Fungi - athlete's foot Viruses - flu

Bacteria - cholera Protozoa - malaria

Preventing Diseases - Body's Defences

Skin stops entry of pathogens

Hydrochloric acid in stomach kills pathogens

Sticky mucus lines membranes in breathing system trapping pathogens

Blood clots to heal wounds

Diseases and Disorders

Some pathogens are non-contagious and some diseases are caused by

Diet deficiences, Genetic Causes, Poor unhealthy lifestyle

VITAMIN NAME - WHAT WE NEED IT FOR - DEFICIENCY SYMPTOMS

A night vision night blindness

C healthy skin and gums scurvy

MINERAL NAME - WHAT WE NEED IT FOR - DEFICIENCY SYMPTOMS

Iron blood cells anaemic

Calcium strong bones and teeth rickets, bow-legged, tooth decay

GENETIC DISORDER - PROBLEMS ASSOCIATED WITH THE DISEASE

Cystic fibrosis can't breath properly

Haemophilia blood doesn't clot

BODY DISORDER - SYMPTOMS

Diabetes faulty pancreas

Eczema itchy, dry skin

CANCER - POSSIBLE CAUSE

Skin ultraviolet rays

Lung smoking

Breast heredity, obesity, smoking

Liver too much alcohol

Bowel lack of fibre

Benign tumours - are slow to divide but harmless

Malignant tumours - divide out of control but spread through body

Malaria

Vector - an animal that carries a disease

Parasite - an organism that feeds off another living organism and causes damage

Host - the organism the parasite feeds off

Malaria is spread by the vector. It carries a protozoa called plasmodium which brings about the malaria. The parasite is injected into the human host, which then gets symptoms of the disease.

Preventing Malaria - spraying insecticide, draining stagnant water, using malaria nets, taking malaria tablets (Larium)

Immunity and Vaccinations

Immunity - where a person is infected by a pathogen but does not develop symptoms of the disease.

Passive Immunity - being injected by the antibodies

Active Immunity - when the body makes its own antibodies as a result of pathogens entering the body

Placebo - a harmless pill used in drug testing

Blind Trial - when volunteers don't know whter they are taking treatment or not.

Double Blind Trial - when the dooctors don't know whther the volunteers are taking the treatment either.

ADVANTAGE DISADVANTAGE

Passive Immunity safer and quicker doesn't last as long

Active Immunity lasts longer takes time to start working safely

The Eye

Cornea - transparent, refracts light rays

Conjunctiva - protective membrane

Sclera - tough, white outer layer

The Eye (continued)

Iris - controls the amount of light enetering the eye

Pupil - allows light rays to enter eye

Lens - refracts rays

Ciliary Muscle - controls suspensory ligaments

Suspensory Ligaments - alter shape of lens to focus

Retina - light sensitive and image forms on it

Optic Nerve - carries nerve impulses to the brain

Binocular vision - where an area is seen by both eyes, so is more accurate and acute

Monocular vision - two eyes but area of vision doesn't overlap so is not as accurate

Controlling Light Entering the Eye

Dim light - circular muscle relaxes, radial muscle contracts, pupil dilates

Bright light - circular muscle contracts, radial muscle relaxes, pupil constricts

Eye Defects

Short-sighted people wear concave lens.

Long-sighted people wear convex lens.

Colour blindness is genetic.

Nerves - make us aware of our environment.

Motor Neurones - How they adapt :

long and thin (like a wire), branching dendrites to make connections, sheath to stop impulse disapating (leaking)

Spinal Reflex Actions Hot plate (Stimulus) ^ Pain receptor in skin ^ Sensory neurone ^ C.N.S. (spinal cord) ^ Relay Neurone ^ Motor neurone ^ Biceps (muscle effector) ^ Hand moves (response)

Synapse

- a gap between two neurones. The impulse travels across the synapse by chemicals called neurotransmitters, an example being acetycholine. This chemical triggers the start of an electrical impulse in the next neurone.