Topic 1 - Lifestyle, Health and Risk Flashcards
(23 cards)
Why do some animals have circulatory systems?
They do not have a high enough surface area to volume ratio to diffuse necessary substances in and out of cells efficiently enough.
Why is water a useful solvent?
It is a polar molecule which means it can dissolve all other polar substances. This includes essential substances for living organisms which can be easily transported as solutes in water.
Why does water have a high specific heat capacity and why is it useful?
Hydrogen bonds between molecules of water are very strong so it requires a great deal of energy to warm water.
It is useful as it helps living organisms maintain a constant temperature which is essential for many vital processes.
What is the first stage of the cardiac cycle?
Atrial systole
- Atria contract
- Blood moves into ventricles
- Blood pressure in atria decreases
What is the second stage of the cardiac cycle?
Ventricular systole
- Pressure in ventricles increases
- Closing of atrioventricular valves causes first ‘lubb’ sound
- Semilunar valves open and blood enters arteries
What is the third stage of the cardiac cycle?
Ventricular diastole
- Pressure in ventricles decreases
- Semilunar valves close (second sound ‘dupp’
- Blood slowly fills in atria then a-v valves reopen when atria pressure>ventricular
How does the structure of capillaries link to their function?
- Function: supply cells with requirements and remove waste
- Very thin walls and narrow lumen brings blood in close contact with body tissue to allow efficient diffusion
How does the structure of arteries relate to their function?
-Function: carry blood away frim heart at high pressure
- Thick & strong walls to withstand the pulsing of blood
- Narrow lumen helps to maintain high blood pressure
- Elastic fibres in the walls help to recoil behind blood and provide a pulse to keep blood moving quickly to prevent backflow
How does the structure of veins relate to their function?
-Function: Return blood to the heart
- Valves prevent backflow of blood as the pressure is too low for blood to want to flow one way
- Thin walls as there is low blood pressure
- Wide lumen offers less resistance to blood flow
What is the course of events that leads to atherosclerosis?
Endothelial dysfunction - risk factors cause tear in artery wall
Inflammatory response - white blood cells move into artery wall and cholesterol begins to accumulate (atheroma)
Plaque formation - calcium salts and fibrous tissue build up at atheroma and form a solid plaque
Raised blood pressure - plaque makes it difficult for heart to pump blood around as it narrows the lumen of the artery, causing raised blood pressure
What is the blood clotting process?
Thromboplastin release - platelets in contact with damaged artery wall release thromboplastin
Conversion of soluble prothrombin to thrombin via thromboplastin
Conversion of fibrinogen into fibrin via thrombin enzyme
Fibrin strands form a tangled mesh which trap a bundle of blood cells (clot)
What is a monosaccharide?
Simplest units of carbohydrates and simplest form of sugar
Glucose, fructose and galactose
What is a disaccharide?
A sugar formed when two monosaccharides are joined by a glycosidic bond.
Maltose, sucrose and lactose
What is a polysaccharide?
A long chain of monosaccharides joined together by glycosidic bonds
Starch (amylose and amylopectin), glycogen
How do monosaccharides join to form disaccharides or polysaccharides?
Through condensation reactions forming glycosidic bonds. They can be split again using hydrolysis reactions
How is a triglyceride formed?
Ester bonds form during condensation reactions between glycerol and three fatty acids
What is the use, benefits and risks of antihypertensives?
Use: reduce high blood pressure, diuretics, vasodilators
Benefits: effects can be monitored at home, can be given in combinations
Risks: lots of side effects eg. drowsiness, headaches, can cause kidney problems
What is the use, benefits and risks of statins?
Use: reduce cholesterol in blood and how much is absorbed from gut
Benefits: reduce CVD risk
Risks: reduce some vitamin absorption from gut
What is the use, benefits and risks of anticoagulants?
Use: reduce formation of blood clots, less chance of blood vessel blockage
Benefits: prevent clot growth as well as new clot formations
Risks: reduces healing rate
What is the use, benefits and risks of platelet inhibitory drugs?
Use: reduce formation of blood clots by preventing platelets clumping together
Benefits: can be used to treat those with existing CVD not just a prevention
Risks: reduces healing rate, lots of side effects eg liver problems
What are LDLs?
Low density lipoproteins which can raise risk of CVD.
LDL can build up along walls of arteries as plaques and encourage atherosclerosis by increasing blood pressure
What are HDLs?
High density lipoproteins collect fat from cells and tissues and return it to the liver
Why do lipoproteins form?
Lipids are insoluble and therefore in order to be transported in the blood, they form complexes with proteins
