T1 Lifestyle and Risk Flashcards
How is the dipole nature of water essential for living organisms?
-water can form hydrogen bonds
therefore
-water is a solvent / ions/polar molecules can be transported in water
-water is used as a thermal buffer meaning it needs a lot of energy to change its temperature
- hydrogen bonds hold water together as a liquid so it can move together in a mass flow systems
Why do many small animals have a heart?
-diffusion isn’t efficient enough
- allows for mass flow/transport
- allows for the transportation of certain substances i.e., oxygen
- fast movement of blood to cells/ increases blood pressure
Why is a mass transport system necessary?
- larger animals have a smaller surface area to volume ratio and a higher metabolic rate
- diffusion isn’t efficient enough
Explain the differences between the atria and the ventricles.
- atria are thin walled and elastic as they only need to pump blood to the lungs and so that they can stretch when filled with blood
- ventricles have thick muscular walls that pump blood under high pressure, left ventricle is thicker than the right as it has to pump blood to the whole body
How does the structure of the arteries allow it to carry out its functions?
- thick muscular walls to withstand high pressure
- elastic tissue to allow recoil
- folded endothelium to allow artery to expand to cope with high pressure
- narrow lumen to maintain high pressure
How does the structure of the veins allow it to carry out its functions?
- thin walls with little elastic or muscle tissue due to low blood pressure
- contains valves to prevent backflow of blood
- blood flow through veins is helped by contraction of muscles surrounding them as the vein has very little muscle tissue
How does the structure of the capillaries allow it to carry out its functions?
- one cell thick endothelium to allow for a shorter space thus speeds up diffusion
- comes in large amounts and branched to increase surface area
- very narrow so can permeate tissues and red blood cells can lie flat on the walls so oxygen can be delivered sufficiently
What happens during ventricular diastole and atrial systole?
- ventricles are relaxed
- blood flows into both atria under low pressure via the pulmonary vein and the vena cava
- atria contract, causing the chambers’ volume to decrease and increasing the pressure of the chambers, increasing blood pressure. This increase in blood pressure pushes open the AV valves, leaking blood into the ventricles.
- there is a slight increase in ventricular pressure and chamber volume as ventricles receive blood from contracting atria
What happens during ventricular systole and atrial diastole?
- atria are relaxed
- ventricles contract from the base of the heart upwards, causing ventricles’ pressure to be higher than atria, forcing AV valves shut to prevent the backflow of blood.
- the pressure in the ventricles are higher than the pressure in the pulmonary artery and aorta, forcing the semilunar valves open
- this causes blood to flow from ventricles into the pulmonary artery and aorta
What happens during cardiac diastole?
- ventricles and atria both relax
- elastic recoil of relaxing heart walls lowers pressure in atria and ventricles
- higher pressure in pulmonary artery and aorta forces semilunar valves shut to prevent backflow of blood into ventricles
- low blood pressure in the atria and high pressure in the pulmonary vein and vena cava causes atria to fill again
- the whole process is repeated again: atrial systole, ventricular systole, and cardiac diastole.
Describe the ethical issues involved with using invertebrates in experiments.
- unethical as they can’t give consent and they may be subject to painful procedures
- some believe it’s more acceptable to perform experiments on invertebrates (i.e., daphnia, spiders and insects) than on vertebrates (i.e., dogs and monkeys)
- this is due to them being considered simpler organisms than vertebrates as they have less sophisticated nervous system which could mean they feel less/no pain
- some believe it’s unethical to cause distress or suffering to any living organism
How does atherosclerosis happen?
-High blood pressure causes damage to the endothelial cells
Describe the stages of thrombosis.
- Thromboplastin released by damaged blood vessel
- calcium + vitamin k and thromboplastin triggers conversion of prothrombin (soluble protein) into thrombin (enzyme)
- thrombin causes conversion of fibrinogen (soluble protein) into fibrin (insoluble protein)
- fibrin fibres mesh together, trapping platelets and red blood cells. Blood clot is formed
Explain how atheroma increase the risk of thrombosis.
- Thermos cause the narrowing of blood vessels thus increasing BP. Raised BP makes blood vessels more susceptible to damage.
How can blood clots cause heart attacks?
Blood clots can block arteries thus blocking blood flow to the heart so the arteries are are ischaemic (without blood).
If muscle cells are started of oxygen for a long time, they will be permanently damaged.
This is what a heart attack/ myocardial infarction is
What is a stroke?
A stroke is a sudden loss of brain function in a localised area due to disruption to blood flow to the brain.
Strokes caused by blood clots are called is ischemic strokes..
