Organisation

• Tissue definition 


  A group of cells with a similar structure and function
• Organ definition 


  A group of tissues working together for a function (eg stomach)
• Organ systems definition 


  groups formed together to form a living organisms
• Digestion definition 


  Large food molecules broken down by enzymes.

  Molecules can now be absorbed into the bloodstream
• ORDER OF DIGESTIVE SYSTEM

  Mouth

  oesophagus

  stomach

  small intestine (chemicals released from liver and pancreas)

  large intestine

  waste released from the body
• Mouth (digestive system)


  Food chewed

  Enzymes in saliva begin to digest starch into small sugar molecules
• Oesophagus (digestive system)


  Where food travels from mouth into the stomach
• Stomach (digestive system)


  Enzymes in the stomach begin the digestion of proteins

  Also contains hydrochloric acid which helps digestion

  Spends several hours here, food turns into fluid increasing SA for enzymes to digest
• Small intestine (digestive system)


  Panreas releases enzymes to digest starch, protein and lipids

  Liver releases bile to speed up lipid digestion and to neutralise stomach acid
• Large intestine


  Water is absorbed into the bloodstream
• Enzymes definition 


  Catalyse chemical reactions (speed up)

  Their surface contains an active site, which the molecule they break down attaches to
• Substrate definition


  The thing which enzymes break down

  Attach themselves to an enzymes active site, if it fits

  (lock and key theory)
• Enzyme types in the digestive system

  Protease- break down proteins, found in stomach, pancreas, small intestine

  Carbohydrases- break down carbs, found in saliva, pancreas fluid

  Lipase- breaks down lipids, found in pancreas fluid, small intestine
• Bile


  Made in liver

  Stored in gall bladder

  NOT an enzyme

  Alkaline acid
• Effect of PH and temperature on enzymes

  Increased temperature, faster reaction due to more collisions

  Optimum temperature (fastest collision rate) 37°c in humans

  Enzyme stops working when it changes shape, becomes denatured

  If PH is more acidic/alkaline the enzyme stops working (denatures)
• Villi


  Found inside the small intestine

  Good blood supply

  Thin membrane, short diffusion, active transport

  Increases surface area for absorption of molecules

  MICROvilli on surface of Villi increase SA
• Circulatory system order


  Heart - lungs- oxygenated blood- heart- organs- body cells- heart
• The heart


  Vena cava brings deoxygenated blood in

  Blood goes through pulmonary artery to lungs

  Blood goes from lungs to heart through pulmonary vein

  Blood is pumped from heart to body through the aorta

  Coronary arteries branch out of aorta and into muscle(provide oxygen to heart muscles)

  Blood enters the left and right atrium

  Atriums contract forcing blood into ventricles

  Ventricles contract and force blood out of the heart

  Valves stop blood from flowing backwards

  
• Arteries


  Carry high pressure blood from heart to organs

  Thick muscular walls

  Blood travels here every time heart beats

  Elastic fibres stretch and recoil
• Capillaries 


  Glucose and oxygen diffuse from blood into cells

  Carbon dioxide diffuses from the cells back into blood

  Very thin walls (can diffuse rapidly)
• Veins


  Blood travels slow and low pressure (can stop or revers)

  Thin wall

  Contain valves to stop blood flowing backwards
• Blood plasma

  Liquid part

  Transports digested products around the body

  Transports carbon dioxide

  Transports urea
• Red blood cells


  Transport oxygen from the lungs to body cells

  Contain haemoglobin

  No nucleus

  Biconcave disc shape- greater SA, oxygen diffuses quicker
• White blood cells


  Make antibodies

  Contain nucleus, has instructions
• Platelets


  Tiny cell fragments

  Helps the blood clot together
• Donated blood


  Replace blood loss

  Proteins and antibodies can be given

  Has to have same blood types

  Risks of infection
• Cardiovascular disease definition 


  Diseases in heart/blood vessels

  Non communicable
• Coronary heart disease


  Layers of fatty material build up inside coronary arteries

  Causes arteries to narrow, blood flow is reduce,lack of oxygen in heart and muscles

  TREATMENTS- Statins, stents (tubes)
• Lungs adaptations 


  Air passes into lungs through trachea

  Splits into bronchi, tube into each lung

  Bronchi branches into bronchioles, then into air sacks called alveoli

  in alveoli gases diffuse in and out of bloodstream
• Alveoli adaptations 


  Loads of alveoli in lungs means huge SA

  Thin walls for diffusion

  Good blood supply, high concentration gradient
• Tumour production 


  Uncontrolled growth of cells and mitosis
• Benign tumours


  Growths of abnormal cells found in one area

  Usually contained within a membrane

  Do not invade other parts of the body
• Malignant tumours


  Malignant cells invade surrounding tissues and move into the blood stream

  Spreads over the body and form new tumours (secondary tumour)
• Cancer causes


  Linked to genetics (breast, prostate, large intestine)

  Linked to lifestyle (smoking, UV, alcohol)

  Radon (radioactive gas in our environment, lung cancer)
• Communicable diseases


  Spread from person to person (measles)

  Spread by bacteria and viruses (pathogen)
• Non communicable diseases


  Cannot be passed from person to person
• Health definition


  Someone’s state of physical and mental well-being
• Tuberculosis TB


  Communicable lung disease

  TB can be fatal

  People with weak immune system are more likely to suffer from this
• HPV


  Extremely common

  In most people it’s nearly harmless

  Can cause cervical cancer
• Allergies formation


  A disease can be triggered by the immune system (asthma, dermatitis)

  The body is infected with a pathogen which the immune system fights off, but the person is left with an allergy