cardiovascular system Flashcards
why is the cardiovascular system important?
- It is the body’s transport system. it includes the heart and blood vessels.
The heart pumps blood through the blood vessels to deliver oxygen to the working muscles and gather waste products - It also transports heat(a by-product of exercise) to the skin so the performer can cool down.
what are the chambers of the heart?
Atrium- are smaller than ventricles. they push blood down into ventricles which does not require much force.
Ventricles- have thicker muscular walls because they use more force to contract to push blood out of the heart.
what are the blood vessels of the heart?
Vena cava- brings deoxygenated blood back to the right atrium.
Pulmonary vein- delivers oxygenated blood to the left atrium.
Pulmonary artery- leaves the right ventricle with deoxygenated blood to go to the lungs.
Aorta- leaves the left ventricle with oxygenated blood leading to the body.
what are the valves of the heart?
Tricuspid valve- located between the right atrium and right ventricle.
Bicuspid valve- located between the left atrium and left ventricle.
Aortic semilunar valve- located between the left ventricle and the aorta.
Pulmonary semilunar valve- located between the right ventricle and the pulmonary artery.
what is the cardiac conduction system?
A group of specialised cells located in the wall of the heart which send electrical impulses to the cardiac muscle causing it to contract.
what is the order of the cardiac conduction system?
Contractions in the heart start when electrical impulses are sent from the SA node which is located in the right atrium.
These impulses cause a wave of excitation and the electrical impulse spreads through the walls of the atria causing them to contract and force blood into the ventricles.
The impulse then passes through AV node found in the atrioventricular septum. the AVN delays the transmission of the cardiac impulse so that the atria can fully contract before ventricular systole begins.
The electrical impulse then passes through the Bundle of His which is located in the septum. The bundle of His branches out into two bundle branches and then moves into smaller bundles called purkinje fibres. this causes the ventricles to contract. the left contracts slightly before the right.
myogenic
The capacity of the heart to generate its own impulses.
sinoatrial node
A small mass of cardiac muscle found in the wall of the right atrium that generates the heartbeat.
atrioventricular node
This node relays the impulse between the upper and lower sections of the heart.
what is systole
When the heart contracts
what is the bundle of His
A collection of heart muscle cells that transmit electrical impulses from the AVN via the bundle branches to the ventricles.
what are the purkinje fibres
muscle fibres that conduct impulses in the walls of the ventricles.
what is the neural control mechanism?
It is made up of two parts.
-The ventral nervous system consists of the brain and spinal cord
-The peripheral nervous system consists of nerve cells that transmit information too and from the CNS.
The two systems are coordinated by the cardiac control centre located in the medulla oblongata.
what are chemoreceptors?
They detect a change in blood acidity which would be caused by an increase/decrease in carbon dioxide
why is blood carbon dioxide important?
it is important in controlling heart rate. An increased concentration in carbon dioxide in the blood will have the effect of stimulating the sympathetic nervous system which means the heart will beat faster.
