Topic 1 Flashcards
What is an open circulatory system?
- Blood is not close in blood vessels
- Substances diffuse between blood and cells
What is a closed circulatory system?
- Blood enclosed in blood vessels
- High blood pressure
What is a single vs double circulatory system?
- Single is where blood flows through once for each complete circuit
- Double is where blood flows through twice for each complete circuit
Why do larger organisms require a mass transport system?
- SA:V ratio is smaller so diffusion cannot be effective
- A transport system facilitates mass flow
What is mass transport?
- Bulk movement of liquids and gases in one direction
What does mass transport help to do?
- Maintain diffusion gradients
- Ensures cell activity
- Movement of substances quickly
What is the properties of water?
- Polar molecule - dipole.
- Hydrogen end negative and oxygen end positive.
- Hydrogen bonds between positive and negative
What is cohesion and adhesion and why is it important?
- Cohesion is attraction between molecules if the same type. Attraction of water molecules to each other
- Adhesion is attraction between non-alike molecules. Water molecules to charged surfaces.
- It is important so water flows easily
How is water a solvent?
- Water surrounds charged particles and causes them to break up
- Water as a solvent is used as a transport medium and a reaction medium
What is the structure of blood vessels?
- Walls contain collagen which makes them strong and durable.
- Elastic fibres which stretch and recoil.
- Smooth muscles allow dilation and constriction.
What are the features of arteries?
- Narrow lumen
- Thick walls
- More collagen, smooth muscle and elastic fibres
How does the structure of arteries relate to their function?
- Lots of elastic fibres recoil to maintain high blood pressure
- Collagen to avoid damage
- Smooth endothelial wall to reduce friction
What are the features of veins?
- Wider lumen
- Thinner walls
- Less collagen, smooth muscle and elastic fibres.
- Valves
What are the features of capillaries?
- One cell thick endothelium for diffusion
- Small lumen
How does the structure of veins relate to their function?
- Less elastic fibres as blood is under lower pressure
- Valves prevent backflow of blood
What is the cardiac cycle?
- Events that take place within one heartbeat
What happens in atrial systole?
- Atria contract and pressure increases
- Atrioventricular valves pushed open forcing blood into ventricles
What happens during ventricular systole?
- Ventricles contract and pressure increases
- AV valves shut, semi-lunar valves open
Blood forces into arteries and out of heart
What happens during diastole?
- Atria and ventricles relax
- SL valve closes so atria fill with blood
Why is there a difference in thickness between the right atrium wall and right ventricle wall?
- The right atrium wall is thinner because of higher blood pressure required in the ventricles.
- The right atrium only pumps blood to the ventricle but the ventricle pumps blood to the lungs
Why is the left ventricle wall thicker than the right ventricle wall?
- It has to pump blood further around the body
- Has to withstand high pressure
What is atherosclerosis?
- The hardening of the arteries due to damage of the endothelium causing fatty deposit to build up
How does atherosclerosis develop?
- Endothelium is damaged.
- Inflammatory response means fatty deposit builds causing an atheroma.
- Plaque builds up and hardens.
- Causes narrowing and loss of elasticity which creates a high blood pressure.
What is the consequence of atherosclerosis?
- Reduces elasticity in the arteries
- Increased blood pressure
- Reduced blood flow
How does the clotting cascade start?
- Platelets come into contact an form long thin projections which triggers the clotting cascade.
What happens in the clotting cascade?
- Platelets form a platelet plug.
- Thromboplastin is released and catalyses protein prothrombin into enzyme thrombin.
- Vitamin K and calcium must be present.
- Thrombin catalyses fibrinogen into insoluble fibrin which causes a mesh to trap red blood cells.
How can atheroma’s increase the risk of blood clotting?
- The plaque deposited rupture the endothelium
- Triggering thrombosis
How does a blood clot lead to heart attacks?
- Atheromas and blood clots restrict blood flow to areas of the heart
- Means less oxygen is received and cells cannot produce ATP or respire making them die
How does a blood clot on the brain cause a stroke?
- Reduced blood flow means oxygen/glucose will not reach cells in the brain.
- no aerobic respiration and no ATP produced. - - The brain needs lots of ATP to function, so lactic acid produced from anaerobic respiration inhibits enzymes and is toxic
What are risk factors?
- Factors leading to an increased chance of disease
What are factors linked to CVD?(5)
- Diet - high salt and high saturated fats
- High blood pressure - damage artery walls
- Smoking - affects haemoglobin
- Genetic - inherit high BP
- Age - build up over time
What are factors that will increase risk of CVD?
- Obesity
- High blood pressure
- High blood cholesterol
- Smoking
- Diet high in fats or salts
What is correlation?
- When a change in one variable is accompanied by a change in another
What is causation?
- When a change in one variable is caused by a change in another
What is a risk?
- The chance/occurrence of an unwanted event
What are the types of medication used to treat CVD?
- Statins
- Anticoagulants
- Platelet inhibitors
- Antihypertensives
How do antihypertensives work?
- Lower blood pressure to reduce risk of arterial damage
- Reduce heart rate and prevent muscles in vessel walls contracting
How do anticoagulants work?
- Reduce the risk of a blood clot forming which inhibits platelet production
How do Statins work?
- Inhibit production of LDL cholesterol to stop atherosclerosis
How do platelet inhibitors work?
- Reduce blood clotting by preventing platelets from becoming activated
What are the benefits and risk of statins?
- Benefits: reduce atheroma development of atheroma, increase HDL’s
- Risks: Taken long term, side effects of tiredness vomiting and muscle weakness
What are the benefits and risks of anti-hypertensives?
- Benefits: Reduce blood pressure, measured at home
- Risks: Headaches, drowsiness, heart palpitations
What are the benefits and risks of anticoagulants?
- Benefits: reduce formation of blood clots and reduce size of any existing blood clots
- Risks: excessive bleeding
What are the benefits and risks of platelet inhibitors?
- Benefits: reduce formation of new blood clots
- Risks: coughing, dizziness, excessive bleeding, liver dysfunction
What are cohort studies?
- Follow the group of people without disease to see who develops it over time
What are case studies?
- Look at the histories of risk factors for those who currently have the disease
What are carbohydrates?
- Biological macromolecules made of C, O and H atoms
What are monosaccharides?
- Single sugar monomers
- Formula = (CH2O)n
- Glucose, fructose, galactose
What is glucose?
- Hexose sugar
- Formula = C6H12O6
- Alpha glucose and beta glucose
What is a glycosidic bond?
- A bond when two hydroxyl (OH) groups on monosaccharides join
- Formed via condensation reaction
What are disaccharides?
- Two monosaccharides joined via condensation reaction
- Glycosidic bonding
- Maltose, sucrose, lactose
What are polysaccharides?
- Chain of monosaccharides joined by glycosidic bonds in a condensation reaction
- Starch, cellulose, glycogen
Why are polysaccharides a good energy store?
- Compact
- Insoluble
- Rapidly hydrolysed
What does starch consist of?
- Amylose
- Amylopectin
What is amylose?
- Alpha glucose
- Joined by 1,4 glycosidic bonds
- Chain coils into helix shape and is compact
What is amylopectin?
- Alpha glucose
- Joined by 1,4 and 1,6 glycosidic bonds
- Branched structure for quick release and rapidly hydrolysed
What is the structure of glycogen?
- Highly branched 1,4 and 1,6 glycosidic bonds
- More terminal glucose molecules which are added or removed by rapid hydrolysis
What are lipids?
- Macromolecules
- Large, complex and non polar molecules
- For energy storage, insulation and hormones
What is a triglyceride?
- Formed of one molecule of glycerol and three fatty acids in condensation reaction
What bond links each fatty acid and the glycerol?
- Ester bond
What do triglycerides form?
- Three molecules of water
- One ester bond
What are the properties of saturated fats?
- Single carbon bonds (C-C) in hydrocarbon chain
- Straight chains with strong intermolecular forces
- Solid at room temp
What are the properties of unsaturated fats?
- Double carbon bonds (C=C) in hydrocarbon chain
- Kinked structure so weaker intermolecular forces
- Liquid at room temp
What are HDL’s?
- High density lipoproteins (good cholesterol)
- Unsaturated fats
- Transports cholesterol from body tissue to liver where it is excreted
- Reduce blood cholesterol when too high
What are LDL’s?
- Low density lipoproteins (bad cholesterol)
- Saturated fats
- Moves cholesterol from liver into bloodstream
How is obesity measured?
- BMI
- Waist to hip ratio
What factors should be taken into consideration when analysing data?
- Sample size
- Individuals
- Control group
- Influence of variables
