12.12 Mass transport in humans Flashcards
The function of the heart..
pump blood around the body
In mammals the heart is part of a
double circulatory system
blood is….
passes through the hear and is pumped to the lungs and is pumped back to the lungs returning back to the heart
what happens when the blood passes around the second time?
blood is re-pressurised and pumped around the body organs before returning to the heart (systematic circulation)
blood moves around due to
pressure difference between pressure in the heart (high) and pressure in the blood vessels (low)
Describe the structure of the heart
- deoxygenated blood returns from the body in the venacava
- blood passes via atrioventicular valve into right ventricle and out via semi lunar valve into pulmonary artery
- blood passes through lungs and returns to left atrium via pulmonary vein
4.blood passes through second atrioventicular calve into left ventricle and the through semi lunar valve into aorta then one body tissues
the activity of the heart i measured as
cardiac output
how to calculate cardiac output (CO)
CO = SV (Stroke vol) x HR (Heart rate)
Stroke volume
Volume of blood expelled from the left ventricle on one cardiac cycle
Heart rate
Number of cardiac cycles per minute
Units
Vol per unit of time (dm^3 min^-1)
Artherosclerosis is…
narrowing or blocking of arteries/ arterioles which normally occurs after damage to the artery wall. This could be due to high blood pressure, high cholesterol, bacterial toxins etc…
Thrombosis is…
The plaque may rapture a blood clotting over damaged area which causes further blocking in the artery . The clot may break up and travel in the blood stream and cause blockage somewhere else which can cause problems like stroke
Aneurism is…
when the artery becomes blocked which causes blood pressure to build in front of the blockage and pressing on the artery wall. This causes the walls to weaken and bulge outwards. This may cause the vessel to rupture and result in internal bleeding
Coronary Heart Disease risks
Age due to gradual deposit over a lifetime
Gender - men are more at risk than women until middle age which risk is similar
Genetic factors
Smoking - nicotine is a vaso-constrictor which increases blood pressure and so damages the endothelium
-Smoking increases cholesterol levels in the blood
Stress increases blood pressure
lipoproteins are made in the… from…
liver
fats, cholesterol and protein
cholesterol transported in blood to…
damaged areas combined with LDL
greater concentration of LDL…
greater risk of CHD
HDL in blood is beneficial because…
they absorb excess cholestrol and return it to the liver where it is removed
high blood LDL may be treated with
statins
in multi-celluar organism all cells need…
a plentiful supply of oxygen
in multi-celluar organism all cells need…
a plentiful supply of oxygen
Pulmonary artery
Blood from right ventricle to lungs
aorta
blood from heart to the organs
venacava
main vein returning blood to right atrium
coronary arteries
branch from aorta and take blood from the muscle of the heart. heat muscle needs its own capillary supple for rapid delivery of oxygen
function of liver
process absorbed food molecules and adjust concentrations in the blood
3 blood vessels associated in the liver
hepatic artery - blood from aorta to the liver
hepatic vein. - blood from the liver to the venacava
hepatic portal vein -blood from the intestines to the liver contains absorbed food molecules
