SNAB Biology AS Unit 1 Topic 1

A mindmap primarily for the synoptic element of the A2 paper. A broad overview of topic 1 of unit 1; lifestyle, health, and risk

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  • Created on: 30-05-13 18:39
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  • AS TOPIC 1 - LIFESTYLE, HEALTH, AND RISK
    • Transport and Circulation
      • Water
        • Good solvent
        • Polar
        • Hydrogen bonding
          • Creates cohesion
      • Why do we need transport?
        • Need substances to enter and leave the body
        • Small organisms: diffusion is good enough
        • Big organisms: smaller SA/V ration
          • Mass transport system overcomes limitations of diffusion
        • Arteries, veins and capilarries
          • Arteries
            • Relatively thick wall
              • Withstands high blood pressure
            • Smooth muscle
              • Alters diameter of lumen to vary blood flow
            • Elastic fibres
              • Allows stretching of walls
            • Smooth layer of endothelial cells
              • Low friction
            • Narrow lumen
          • Veins
            • Relatively thin wall
              • Blood under low pressure
            • Very little smooth muscle/elastic fibres
              • No pusle of blood so no stretching
            • Wide lumen
              • Large volume acts as blood resevoir
            • Valves
              • Prevents back flow
          • Capillaries
            • Very thin walls
              • Allow rapid exchange between blood and tissues
    • Cardiac Cycle and Heart Rate
      • Atria and ventricles contract during systole and relax during diastole
      • Elastic recoil of heart muscles lowers pressure in atria and ventricles
    • CVD
      • Blood clotting
        • Minimises blood loss
        • Helps prevent entry of pathogens
        • Provides a framework for repair
        • Damage exposes collagen fibres, to which platelets attach
          • Platelets release thromboplastin
            • In presence of calcium ions and vit K, thromboplastin converts prothrombin into thrombin
              • Thrombin converts soluble fibrinogen into insoluble fibrin
                • Fibrin traps cells and debris --> clot
        • Fibrin traps cells and debris --> clot
      • Atherosclerosis
        • Positive feedback
        • Damage to lining
          • Inflammatory response
            • Atheroma forms
              • Plaque formation
                • Raised blood pressure
                  • Damage to lining
                    • Inflammatory response
                      • Atheroma forms
                        • Plaque formation
                          • Raised blood pressure
        • Stroke
        • Angina
        • Heart attack
        • Treatment
          • Antihypertensives
            • Diuretics
              • Lowers blood volume and pressure
              • Dizziness, nausea, muscle cramps
            • Beta Blockers
              • Block response of heart hormones, making contractions less frequent and less powerful
              • Possible link to diabetes
            • ACE Inhibitors
              • Block production of angiotensin, which causes arterial constriction and a rise in blood pressure
              • Cough, dizziness, arrhythmia, impaired kidney function
          • Statins
            • Lower cholesterol level in blood by blocking liver enzyme
            • Muscle aches, nausea, constipation, diarrhoea, inflammation, liver failure, people stop eating healthy diet
          • Anticoagulants
            • Reduce risk of clot formation
            • Uncontrolled bleeding, dosage control essential
          • Platelet Inhibitory Drugs
            • Platelets become less sticky
            • Irritation of stomach lining, stomach bleeding
      • Structure and Function of Carbohydrates
        • Monosaccharides
          • E.g. glucose
        • Disaccharides
          • E.g. lactose
        • Polysaccharides
          • Unbranched
            • E.g. amylose
              • Found in starch
              • Alpha glucose molecules
              • Tight spirals
              • No osmotic effect
              • Insoluble
          • Branched
            • E.g. glycogen
              • Energy storage molecule
              • Compact
              • No osmotic effect
              • Insoluble
        • Glycosidic bonds
          • Formed in an condensation reaction
      • Structure and Function of Lipids
        • Insoluble in water
        • Soluble in organic solvents
        • Triglycerides = 3x fatty acids + 1 glycerol
        • Formed in condensation reactions
        • Variation in Triglycerides
          • Length of hydrocarbon chain
          • Absence/presence and number of double bonds
          • Mix of fatty acids
          • Saturated Fats
            • Strong intermolecular bonds
            • Solid at RTP
            • Straight
          • Monounsaturated
            • Weaker intermolecular bonds due to kink(s)
              • Polyunsaturated
                • Liquid at room temperature
            • Liquid at room temperature
          • Polyunsaturated
        • Risk Factors for CVD
          • Genetic
            • Tendency for high BP and poor cholesterol metabolism
            • Mutations in genes affect HDL:LDL levels
          • Gender
            • Oestrogen = protection (before menopause)
          • Ageing
            • Elasticity and width of arteries decrease with age
          • Diet
            • Correlations between dietary habits and level of CVD
          • High Blood Pressure
          • Smoking
            • CHemicals in smoke physically damage artery linings
            • Causes arterial constriction
          • Inactivity
            • Exercise reduces blood pressure and raises HDLs
          • Obesity
          • Energy Balance
            • BMI = Body mass in kg / (height in m) squared
        • Correlation/ Causation
          • Correlation suggests there MIGHT be a causal link
          • To show causality, a mechanism by which one factor causes the other needs to be proved
        • What makes a good study?
          • Valid and reliable data
            • Valid = accurately measure what it's supposed to
            • Reliable = data that accurately measures what they are supposed to every time
          • Sample representative of whole population
          • Variables controlled as far as possible
          • Good sample size

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