Mrs H bio 4 The Heart Flashcards
what type of tissue is the heart made from?
cardiac muscle
what happens to the size of the four chambers when the heart ‘beats’?
decreases
what is the name of the blood vessel that supplies the heart with its own blood supply?
coronary artery
what is pulmonary ventilation?
the blood passes the heart and is pumped t the lungs, returning back to the heart
what is systemic circulation?
the blood passes through the heart a second time (the blood is re-pressurised) and pumped round the body organs before returning to the heart.
which side of the heart is thickest and what does this mean?
left side meaning stronger contractions
what and where does the vena cava transport?
deoxygenated blood returns from the body in the vena cava and enters the right atrium
what are the 4 steps of blood flow through the heart?
1.deox blood vena cava and into right atrium
2.passes via atrio-ventricular valve into the right ventricle and out via the semi-lunar valve into the pulmonary artery
3. the blood passes through the lungs and returns to the left atrium via the pulmonary vein
4.the blood passes through 2nd atrio-ventricular valve into left ventricle and then through semi-lunar valve into aorta and then onto body tissues
why is the left ventricle thicker?
right ventricle only pushes blood through pulmonary arteries, the left ventricle is pushing blood through a much larger no. of capillaries around body so requires more pressure so a thicker wall and more muscle fibres allow for a greater contraction force
which blood vessel enters the right atrium and what does it do?
vena cava brings blood from the body
which blood vessel is leaving the right ventricle and what does it do?
pulmonary artery and takes blood to the lungs
which blood vessel enters the left atrium and what does it do?
pulmonary vein and brings blood from the lungs
which blood vessel is leaving the left ventricle and what does it do?
aorta takes blood to the body
what does systole mean?
contraction of the heart muscle
what does diastole mean?
heart muscle relaxed
why do valves open and close?
pressure changes on either side
when do the atrio-ventricular valves open?
when the pressure in the atria increases above that in the ventricles
when do the semi-lunar valves open?
when the pressure in the ventricle increases above that of the aorta
how and why can valves only open on way?
due to tendons that anchor the valve to prevent back flow
what is the equation for cardiac output?
stroke volume x heart rate
what is stroke volume?
volume of blood expelled from the left ventricle in on heart beat
draw a diagram of a heart
https://www.google.com/url?sa=i&url=https%3A%2F%2Fcommons.wikimedia.org%2Fwiki%2FFile%3ADiagram_of_the_human_heart.svg&psig=AOvVaw1wA-9SfyIGRzS1XtQkXRI7&ust=1702026580068000&source=images&cd=vfe&ved=0CBMQjhxqFwoTCLjojaD9_IIDFQAAAAAdAAAAABAE
what is coronary heart disease?
any interference with the coronary arteries which supply blood to the heart muscle itself
describe the process of an atheroma forming (atherosclerosis)
- lumen of artery narrowed due to build up of fatty deposits and cholesterol underneath artery endothelium
- muscle fibres and calcium salts accumulate + form uneven patches called plaque which bulges into artery lumen
3.partial blockage= deprived muscle cells during exercise so lactic acid and pain. - if completely blocked then muscle cells= no O2 and die causing heart attack
when does atherosclerosis usually occur?
damage occurred to the artery wall for some reason like high BP or bacterial toxins
how does an atheroma increase the chances of an aneurysm?
when artery is blocked, blood flow restricted. BP builds up in front of blockage and presses on artery wall causing wall to weaken and bulge out known as an aneurysm
how does an atheroma increase the chances of thrombosis?
the plaque may rupture and trigger blood clotting over the damaged area which builds up rapidly causing further blockage of artery known as a thrombus
what could happen if a thrombus breaks up?
travel in the blood stream and cause blockage elsewhere (e.g. stroke)
name the risk factors for CHD (6)
age, gender, genetic factors, smoking, stress, high lipid/cholesterol diet
describe how blood cholesterol can lead to an atheroma
cholesterol is transported in the blood connected to LDL so a higher conc of LDL means Higher risk of CHD
how can high blood LDL be treated?
statins
describe how cigarette smoking can lead to an atheroma
- Nicotine increases blood pressure and damage to endothelium
-increases cholesterol levels
-chemicals increase chance of thrombosis
describe how a student could investigate wether their heart rate when sitting down was similar to other people their age?
- obtain pulse rated for a large number of students
2.belonging to a variety of different groups like sex and ethnicity
3.calculate mean and standard deviation
4.see if their mean lies within the standard deviation
explain 4 ways in which the aorta is adapted for its function
elastic tissue stretches and recoils maintaining pressure
elastic tissue stretches when ventricles contract and recoil when ventricles relax
muscle for contraction
thick wall withstands pressure
smooth endothelium reduces friction
aortic valve prevents backflow
describe how blood is moved from the left ventricle of the heart to the body and back to the heart
- left ventricle contracts
2.increasing pressure so semi-lunar valve opens
3.increased pressure shuts AV valves so no backflow
4.blood leaves heart via aorta to body
5.blood travels in arteries to capillaries to veins
6.valves in veins prevent back flow
7.blood drains into vena cava
8.enters right atrium
