Topic E - cardiovascular system, cardiovascular diseases and the eye Flashcards
what is the cardiovascular system?
- a closed system of the heart, blood and blood vessels
- made up of :
1. systemic circulation
2. pulmonary circulation - responsible for :
1. delivery of oxygen and nutrients
2. removal of carbon dioxide and other waste products
review diagrams in part 1 slide 9,10
okey
what are the 9 important components ( in order of blood flow )
- superior vena cava
- inferior vena cava
( both brings deoxygenated blood into 3 ) - right atrium
- right ventricle
- left atrium
- pulmonary artery
- pulmonary vein
- left ventricle
- aorta
** very important
how does blood flow through the heart? (9)
- OXYGEN-POOR blood enters the RIGHT ATRIUM[ through the superior VENA CAVA and the inferior VENA CAVA
- blood passes through the TRICUSPID VALVE to the RIGHT ventricle
- blood is forced through the PULMONARY VALVE to the pulmonary trunk and enters the PULMONARY ARTERIES
- blood travels to the lungs, where carbon dioxide is unloaded and oxygen is loaded
- OXYGEN-RICH blood returns to the heart from lung through the FOUR PULMONARY VEINS to enter the LEFT ATRIUM
- blood passes through the BICUSPID (MITRAL) VALVE to the LEFT VENTRICLE
- blood is forced through the AORTIC VALVE to the AORTA
- blood travels from the aorta to the rest of the body
- blood returns to the heart through the superior and inferior VENAE CAVAE
what is the direction that O2 poor blood takes?
superior and inferior venae cavae -> right atrium -> right ventricle -> pulmonary artery -> lung
what is the direction of O2 rich blood?
pulmonary vein -> left atrium -> left ventricle -> aorta -> body parts
what are the blood vessels of the heart? (5)
- superior vena cava
- inferior vena cava
both transports
- deoxygenated blood
- from other parts of body
- to right atrium
6. pulmonary artery transports - deoxygenated blood - from right ventricle - to lungs
7. pulmonary vein transports - oxygenated blood - from lungs - to left atrium
9. aorta transports - oxygenated blood - from left ventricle - to other parts of the body
what is the atirum systole and ventricle systole?
part 2 slide 4
what is the cardiac conduction system?
- stimulates the heart to contract
- also known as the nodal system
- sets the basic rhythm of heartbeat
- cardiac muscle is auto-rhythmic
~ this means that it does not need to be stimulated by the brain to contract - the cardiac muscle cells initiate and carry the electrical impulses as part of the conduction system that stimulates heart contraction
- nerve impulses are not needed to initiate a heart conduction
~ heart pumping -> controlled by electrical impulses -> the cardiac conduction system -> measured by ECG
what are the components of the cardiac conduction system?
- SA node
- AV node
- bundle branches
- purkinje fibers
- AV bundle/bundle of His
- purkinje fibers
what is the pathway of signals?
- a heartbeat/contraction started by SA node (sinoatrial node), located in the right atrium near the entrance of the superior vena cava.
- this is the natural pacemaker of the heart.
- it initiates all heartbeats and determines heart rate.
- electrical impulses from the SA node spread throughout both atrium and stimulate them to contract and depolarize.
- the impulses are then passed on to the AV node (atrioventricular node), located on the other side of the right atrium, near the AV valve.
- The AV node serves as an electrical gateway to the ventricles.
- it delays the passage of the electrical gateway to the ventricles.
- this delay is to ensure that the atrium have ejected al the blood into the ventricles before the ventricles contract.
- the impulse then goes to AV bundle (atrioventricular bundle/bundle of His.
- this bundle is then divided into right and left bundle branches which conduct the impulses toward the apex of the heart.
- the signals are then passed onto Purkinje fibres, turning upward and spreading throughout the ventricular myocardium to contract and depolarize.
** important
what is the ECG (electrocardiogram)?
- it is a means of looking at cardiac rhythm
- a graph showing the electrical activity in the heart
- the five waves per cycle represents three electrical events :
1. P wave ( first small wave ) - shows atrium depolarization ( contract)
- Q,R,S waves/complex ( sharp, high wave )
- represents ventricular depolarising (contract) - T wave ( same as p wave but after Q,R,S wave )
- represents ventricular repolarising (relax)
~ atrium repolarizing (relax) = same time as ventricles depolarizing
when atirum contract, ventricle relax and vice versa
contract,deploarize = discharge
relax, reploarize = recharge
what is the basic concept of the cardiac cycle?
- is a complete contraction and relaxation of the heart ( the heartbeat)
- can be repeated 70-80x/min ( average ~75x/min )
- systole: contraction
- diastole: relaxation
- the right/left atrium go through systole and diastole together at the same time, same for the ventricles and the valves
*** important
what are the four phrases of the cardiac cycle?
- atrial systole
- atrium contracts and depolarize, blood is pushed into the ventricles - ventricular diastole
- ventricle relax and repolarize, blood flow from the atrium to the ventricle passively - atrial diastole
- relax and repolarize, blood flow back to atrium - ventricular systole
- contract and depolarize. blood is pumped out and pushed through the pulmonary and aortic valves into the pulmonary trunk and aorta
what is the cardiac cycle?
- the event of one comlete heartbeat
- average heart beats/rate is around 75 beats per minute
- one cardiac cycle is around 0.8 second
female ~72-80 beats
male ~64-72
athletes ~ 40-60