1.1 Cardiovascular disease Flashcards
What is positive feedback?
The enhancing or amplification of an effect by its own influence on the process which gives rise to it.
What is atherosclerosis?
The disease process that leads to coronary heart disease and strokes where fatty deposits can block and artery or increase the chances of a blood clot.
What is thrombosis?
An artery being blocked by a blood clot.
What are the first two processes in atherosclerosis?
1 - The endothelium becomes damaged
2 - Inflammatory response: white blood cells move into the artery wall and accumulate chemicals from the blood, particularly cholesterol. An atheroma builds up.
What are the last two processes in atherosclerosis?
3 - Calcium salts and fibrous tissue build up, resulting in a hard swelling called a plaque.
4 - Plaques cause the lumen to narrow and causes high blood pressure.
What is an atheroma?
A fatty deposits that build up in atherosclerosis.
What happens first when a blood vessel is damaged?
Platelets come into contact with the damaged vessel wall and change shape into spheres with long thin projections. This sticks them to the exposed collagen and each other to form a temporary platelet plug.
What are the first two processes in the clotting cascade?
1 - platelets and damaged tissue release a protein called thromboplastin.
2 - This activates an enzyme that catalyses the conversion of prothrombin to thrombin. Protein factors, vitamin K and calcium ions must be present for this to happen.
What are the last two processes of the clotting cascade?
3 - Thrombin catalyses the conversion of fibrinogen (soluble) into fibrin (insoluble).
4 - A mesh of fibrin forms that traps more platelets and red blood cells to form a clot.
What do unicellular organisms use to move substances?
diffusion
why do multicellular organisms need a circulatory system?
they rely on a mass transport system to move substances around by mass flow
describe an open circulatory system
a simple heart pumps blood out into cavities surrounding the animals organs, substances can diffuse between the blood and cells
describe a closed circulatory system
blood is enclosed within blood vessels, the blood flowed along arteries then arterioles to capillaries. the blood then returns to the heart through veins and venules
what are the advantages of an open circulatory system?
requires less energy for distribution
suited for slow metabolisms and small bodies
what are the disadvantages of an open circulatory system?
almost impossible to increase blood distribution as the total capacity of the system is achieved with virtually every heart beat
what are the advantages of a closed circulatory system?
large concentration gradients over long distances which allows more complex organisms to evolve
what are the disadvantages of a closed circulatory system?
the pressure that is possible is limited because of damage to the exchange organ
what are the two types of closed circulatory system?
single and double
describe a single circulatory system in a fish
the heart pumps deoxygenated blood to the gills so gaseous exchange takes place in the gills through diffusion then the blood flows around the body back to the heart
describe a double circulatory system
the right ventricle pumps deoxygenated blood to the lungs then the blood returns to the heart to be pumped to the body
what is the advantage of a double circulatory system?
the pressure delivering blood to the body tissues can be higher than that delivering blood to the exchange surface
what are the advantages of higher pressure to the body tissues
faster delivery of nutrients and removal of wastes
maintains concentration gradients
enables higher metabolic rates
enables size of organisms to be larger
why is chemicals dissolving easily important for water in the body
allows vital biochemical reactions to occur in the cytoplasm
why is having a high shc important for water in the body
water can absorb large amounts of heat energy before its temperature raises a significant amount so this helps organisms to avoid rapid changes in their internal temperature even when their surroundings varies
describe the blood flow of the vena cava
deoxygenated blood into the right atrium
describe the blood flow in the aorta
oxygenated blood from the left ventricle to the body
describe the blood flow in the pulmonary veins
oxygenated blood from the lungs into the left atrium
what is the advantage of arteries having thick smooth muscular walls?
maintain higher pressure without damage
what is the advantage of arteries having elastic fibre tissue?
elastic stretch to accommodate higher pressure and recoil to maintain high pressure
what is the advantage of arteries having a folded endothelium?
allows stretching to accommodate high pressure
what is the advantage of arteries having a narrow lumen?
maintains blood pressure
what is the advantage of arteries having smooth lining/endothelium?
reside friction/resistance
what is the advantage of arteries having collagen?
avoids damage
what is the advantage of veins having thinner walls?
allow skeletal muscle movement and low pressure to draw blood back to heart
what is the advantage of veins having the presence of valves?
ensures blood continues to move towards heart
what is the advantage of veins having a large lumen?
blood flows back to heart under low pressure
what is the advantage of capillaries having very thin walls?
reduces diffusion distance/higher rate of diffusion
what is the advantage of capillaries having a large network near all cells of a tissue?
increase surface are/ higher rate of diffusion
what is the advantage of capillaries having a lumen wide enough for one red blood cell?
reduces diffusion distance between RBCs and tissue cells
How is the heart muscles supplied with blood?
Through the coronary arteries, a network of capillaries and two coronary veins
What are phase 1,2 and 3 of of the cardiac cycle?
atrial systole, ventricular systole and cardiac diastole
what happens during the atrial systole?
blood flows into the atria causing the atrioventricular valves to push open and leak blood into the ventricles.
the atria walls contract forcing more blood into the ventricles.
what happens during the ventricular systole?
the ventricles contract from the base of the heart upwards which pushes the semilunar valves open causing blood to move up through the pulmonary arteries and aorta. the pressure of the blood closes the atrioventricular valves.
what happens during cardiac diastole?
the atria and ventricles relax me recoil of the heart walls lower the pressure. the semi lunar valves close.
what is coronary heart disease?
narrowing of coronary arteries increasing risk of myocardial infarction
