Sub 1: Cardiovascular System Flashcards
what are the components of the cardiovascular system?
blood vessels and heart
name 3 types of blood vessel
arteries, capillaries, veins
what materials does the blood transport around the body?
oxygen to respiring cells carbon dioxide away from respiring cells digested food form digestive system to liver for storage urea from liver hormones antibodies heat
what are arteries?
arteries carry blood away from the heart
what features do arteries have and why?
they have thick elastic walls which stretch and recoil in response to the heartbeat, needs to be able to withstand pressure
elastic nature also turns a pulse of blood into a continuous flow
what is a capillary?
capillaries allow the exchange of materials to take place between blood and body cells
what features do capillaries have and why?
walls are one cell thick so materials can diffuse easily to and from the blood
have tiny diameter just wide enough to enable red blood cells to pass through
what are veins?
veins carry blood back to the heart
what features do veins have and why?
thinner less elastic walls, longer lumen than arteries since blood pressure is very low in veins
have valves which prevent the blood flowing backwards
what is blood pressure?
describes the pressure in the aorta
how is blood pressure measured?
using a sphygmomanometer and a stethoscope
what are the units of blood pressure?
mmHg
what is systolic blood pressure?
the pressure in the arteries when the heart contracts
what is diastolic blood pressure?
the pressure in the arteries when the heart relaxes
how is blood pressure written?
systolic/diastolic
what is normal blood pressure?
120/80 mmHG
what is the heart?
muscular pump that keeps blood flowing through the blood vessels
what does the right side of the heart do?
pumps blood to the lungs to be oxygenated
what does the left side of the heart do?
pumps blood around the body
what is the left and the right side of the heart separated by?
septum
what is myocardium?
made up of cardiac muscle. it has small interconnected cells that allow the rapid spread of electrical impulses that cause contractions
what initiates the impulses in the myocardium?
the sinoatrial node high in the right atrium
what is systole?
contraction of the heart muscle
what is diastole?
relaxation of the heart muscle
the bicuspid and tricuspid valve can be known as?
atrio-ventricular valves
During which process are ventricular systole or diastole pressure greater in the ventricles, why?
the pressure is greater during ventricular systole because the ventricle walls have contracted thus putting the blood under increased pressure, forcing blood into arteries
what are heart valves?
stop the blood flowing in the wrong direction
why are the bicuspid and the tricuspid valves also known as atrio-ventricular valves?
goes between atrium and ventricles
why is the left ventricle thicker?
the left ventricle has the thicker muscular wall because it has to pump blood around the body whereas the right ventricle only pumps blood to the lungs
what are coronary arteries?
branches of aorta carrying oxygen and food to the respiring cardiac muscle cells of the heart wall
what do coronary veins do?
returns deoxygenated blood to the vena cava
what is the normal resting heart rate?
72 bpm (60-90)
what is the cardiac output equation?
cardiac output = stroke volume x heart rate
if the person is fit, is their stroke volume and therefore cardiac output high or low?
stroke volume high and cardiac output high
what is the heart rate?
The number of heart contractions a minute out one ventricle
what is stroke volume?
The volume of blood pumped during one systole
what is cardiac output?
The volume of blood pumped out of one ventricle in one minute
what is the normal stroke volume?
0.07 Litres
what is the normal cardiac output?
5 Litres
what are the changes that occur during exercise to the CVS?
cardiac output increases
heart rate increases
stoke volume increases
describe the change to CVS with exercise in more depth
As the heart rate increases, the atria receive more blood back from the body, so the atrial walls are more distended.
Distension causes the force of the atrial contraction to increase, so more blood is pumped into the ventricles.
The increased volume of blood delivered by the atria cause an increase in the distension of the ventricles so the stroke volume is increased.
increased distension of the ventricles increases their force of contraction so the systolic pressure increases. blood flow to skeletal muscle increased, blood flow through coronary artery increased
blood flow to the gut and kidney decreased
blood flow to skin increased
why does the blood supply to the brain stay constant while that of the abdominal organs decrease during exercise?
brain is important but no change in activity of brain which is why there is no change in blood flow
why do you think blood flow to the skin increases during exercise?
for release of heat radiation to cool down the body
muscles work harder during exercise - heat is produced
increase flow to skin means heat can be lost to the air thus cooling body down
what is recovery time?
the period of time it takes for the CVS parameters to return to normal after exercise
