Topic 1 ~ Lifestyle Health Risk Flashcards
Definition of Diffusion
The movement of molecules or ions from a region of high concentration to a region of low concentration by random movement of molecules
Why do only small animals have an open circulatory system
Movement of oxygen, carbon dioxide, and other products carried by blood relies on diffusion in animals with an open circulatory system. Diffusion is only fast enough for small organisms.
What are the advantages of having a double circulatory system
Blood can pass slowly through region where gaseous exchange takes place maximising transfer of oxygen and CO2 and then be pumped around the rest of the body enabling organism to be active
Definition of a polar molecule
A molecule with unevenly distributed electrical charge (H2O)
What are the properties of water
- it’s a dipole so slightly positive end is attracted to the negative end with hydrogen bonding resulting in cohesion
- can act as a solvent as many chemicals easily dissolve in it except non polar hydrophobic substances
- high specific heat capacity so warms and cools slowly
Describe the structure of arteries
- narrow lumen
- thicker walls
- more collagen, smooth muscle and elastic fibres
- no valves
(High pressure blood from heart)
Describe the structure of veins
- wide lumen
- thinner walls
- less collagen, smooth muscles and elastic fibres
- has valves
(Low pressure blood to the heart)
Describe atrial systole
The atria contact, opening the atrioventricular valves, forcing blood into the ventricles
Describe ventricular systole
Ventricles contract, opening the semilunar valves, forcing blood out the pulmonary arteries and aorta
Describe diastole
Elastic recoil as the heart relaxes causes low pressure in the heart, helping refill the chambers with blood
Process of atherosclerosis
- the endothelium becomes damaged
- inflammatory response where white blood cells move into the artery wall accumulating chemicals and cholesterol from blood creating atheroma
- calcium salts build up causing plaque formation, artery becomes less elastic
- lumen becomes narrow causing higher blood pressure
- positive feedback occurs
Why do arteries get atherosclerosis
Because they contain fast flowing blood under high pressure
Definition of thrombosis
Blood clotting
Definition of myocardial infarction
Heart attack
Process of thrombosis (clotting cascade)
- platelets stick to damaged wall and to each other, forming platelet plug
- thromboplastin is released from damaged vessel with calcium and vitamin K
- activates an enzyme to convert prothrombin into thrombin
- catalyses conversion of soluble fibrinogen into insoluble fibrin
- mesh of fibrin forms, trapping blood cells, forming a clot
How could atherosclerosis cause heart attack
- narrowing of coronary arteries limits blood flow
- limiting oxygen to the heart muscles
- muscles forced to respire anaerobically producing lactic acid
- muscle cells will become damaged/die
Definition of risk
The probability of occurrence of some unwanted event or outcome
What are cohort studies
Studies that follow a large group of people over time to see who develops the disease and who does not.
What are case-control studies
Studies that compare histories of a group of people with a disease with a control group who do not have the disease.
What are the risk factors of CVD
- diet
- high blood pressure
- smoking
- inactivity
- genetics
- gender
- age
How does your diet increase risk of CVD
Eating too many saturated fats increases levels of cholesterol in the blood, leading to atheroma formation, blood clotting and heat attacks
How does high blood pressure increase risk of CVD
High blood pressure can damage the arterial wall increasing atheroma formation
How does smoking increase risk of CVD
Carbon monoxide in cigarette smoke has a high affinity for haemoglobin, reducing the amount of oxygen in tissues, leading to heart attack or stroke
Definition of oedema
Fluid building up in tissues and causing swelling
