Organisation

• Tissue

  One type of cell carrying out one function
• Organ

  Made up from lots of different types of cells carrying out a joint function
• Organ system

  A group of organs that work together to carry out a function
• Digestive system

  • Mouth - mechanically breaks down food
  • Salivary gland - produces amylase
  • Liver - produces bile to emulsify fat and neutralize stomach acid
  • Gall bladder - stores bile
  • Small intestine - moves glucose, ions and other things into the blood and has a very large surface area
  • Stomach - churns out food, produces hydrochloric acid to kill bacteria and provide an environment for proteases
  • Pancreas - produces enzymes
  • Large intestine - removes excess water
  • Rectum and anus - gets rid of waste food
• Enzymes in the digestive system

  • Lipase - breaks down fats into fatty acids and glycerol, made in the pancreas and small intestine, works in the small intestine
  • Protease - breaks down proteins into amino acids, made in the stomach, pancreas and small intestine, works in the stomach and small intestine
  • Amylase - breaks down starch into sugars, made in the salivary glands, pancreas and small intestine, works in the mouth and small intestine
• Enzyme mechanism

  • Enzyme has a specifically-shaped active site that only certain substrates can fit into
  • Enzyme-substrate complex forms
  • Enzyme breaks apart or joins together things
  • Enzyme is then released unchanged and can be used again
• Temperature affects enzyme activity

  • Low temperatures - not enough energy
  • Optimal temperature - peak activity
  • High temperatures - enzymes get denatured (links between them holding everything together are being destroyed)
• pH affects enzyme activity

  • Optimal pH
  • Too high or too low pH - bonds break down, active site of the enzyme denatures
• Respiratory system


  • Air goes in through the mouth or the nose down into the trachea, then into the bronchus, then into the bronchiole, and into the alveoli - where gas exchange happens
  • Diaphragm moves up and down to bring air in and out
  • Heart pumps blood around the body
  • Intercostal muscles allow the ribcage to expand
  • Ribs protect the lungs
• Cardiovascular system


  • Double system - blood gets pumped from the heart to the lungs, goes back to the heart and then gets pumped around the rest of the body
  • Right side - pumps blood to the lungs
  • Left side - pumps blood to the rest of the body
• Veins carry deoxygenated blood apart from the pulmonary vein which carries oxygenated blood back into the heart, and arteries carry oxygenated blood apart from the pulmonary artery which carries deoxygenated blood from the heart to the lungs.
• Pacemakers


  Artificial pacemakers can be introduced to help the heart keep time if it isn't functioning properly
• Arteries


  Have very thick walls and a thin lumen because they are carrying blood under high pressure
• Capillaries


  Are very small, only one cell thick, to allow for diffusion, in a mesh network around things like the gut and lungs to have a large surface area
• Veins


  Carry deoxygenated blood back to the heart, have valves, thin walls and a thick lumen because they are carrying blood under low pressure
• Components of blood


  • Serum - the liquid component
  • Red blood cells - give blood its color, have no nuclei to carry more oxygen
  • White blood cells - part of the immune system
  • Platelets - fragments of cells, important for clotting
• Cardiovascular disease


  Fatty deposits build up in the coronary arteries, leading to blood clots that can block arteries, restricting oxygen to cells which then die, potentially causing a heart attack if too many cells die
• Risk factors for cardiovascular disease are smoking, high blood pressure, or having too much salts or fat in your diet.
• Blood


  Liquid component of the blood, cells give it its actual color
• Red blood cells


  • Have no nuclei so they have more space to carry oxygen, which is their main function
• White blood cells


  Part of the immune system
• Platelets


  Fragments of cells, important for clotting
• Cardiovascular disease


  Fatty deposits build up in coronary arteries around the heart, can lead to blood clots
• Blood clot blocking an artery

  Restricts oxygen to cells, causing them to die
• Many cells dying


  Can lead to heart attack if heart can't function or pump blood properly
• Risk factors for cardiovascular disease

  • Smoking
  • High blood pressure
  • Too much salt or fat in diet
• Health


  Overall state of physical and mental wellbeing, affected by diet, exercise, community, loneliness, friends, and genes
• Cancer


  Cells begin to divide uncontrollably, leading to lumps (benign or malignant tumors)
• Risk factors for cancer


  • Smoking
  • Poor diet
  • Sun exposure
  • Unprotected sex
• Tobacco mosaic virus


  Reduces chlorophyll in plants, leading to reduced photosynthesis and lower yields
• Salmonella


  Bacteria spread by eating infected foods, causes diarrhea, vomiting, fever
• Gonorrhea


  Bacteria spread through sexual contact, causes unpleasant symptoms like discharge and pain
• Rose black spots


  Fungus spread by spores, causes discoloration and loss of vigor in plants
• Malaria


  Parasite spread by female mosquitoes, causes fever, sweats, chills, headache, vomiting
• Vaccinations


  Contain small amounts of dead or inactive pathogens to allow immune system to develop antibodies
• Advantages of vaccinations


  • Wiped out many diseases
  • Provide herd immunity
• Disadvantages of vaccinations


  • Don't always work
  • Can be painful with side effects
• Antibiotic resistance


  Bacteria can quickly develop resistance through random mutations, leading to antibiotics becoming ineffective
• Antibiotics are overused, driving antibiotic resistance
• New drugs need to be tested for toxicity, efficacy and dosage