PBL 1- Heart murmur Flashcards
What are the functions of the CV system?
Transport of nutrients, oxygen, waste products around the body
Transfer of heat (generally core to skin)
Buffers body pH
Transport of hormones (e.g. adrenaline from adrenals)
Assists in response to infection
Assists in formation of urine-filtration and circulation
What are the atrioventricular valves?
Tricuspid valve
Bicuspid/ Mitral valve
What are the semilunar valves?
Pulmonary Valve
Aortic Valve
What are the associated structure and function of atrioventricular valves?
Chordae tendinae connect the valves to the papillary muscles.
when relaxed- chordae tendinae are loose
when contracts- chordae tendinae tenses and prevents regurgitation of blood back into the atria.
What are the associated structure and function of semilunar valves?
The semilunar valves prevent the backflow of blood into the right and left ventricles.
They do NOT have Chordae Tendinae.
What is the structure of the Serous Pericardium.
Serous Pericardium is a sac of fluid that has 2 walls:
- Outer Parietal layer: made of connective tissue and holds heart in place.
- Inner Visceral layer- forms the epicardium (outer layer of heart)
Pericardial fluid-fills the space between the 2 layers and allows lubrication of heart/ prevents friction.
What is the structure of the myocardium?
it is the muscular middle layer.
has cardiac myocytes
has coronary vessels
What is the structure of the endocardium?
it is the innermost layer of the heart
- made of endothelium
- lines the heart chambers and valves
Define the cardiac cycle.
The cardiac events that occur from the beginning of one heartbeat to the beginning of the next.
What is an action potential in the heart?
AP is spontaneously generated by the SA node. The AP travels from SA node intro the atria, through the AV valves into the ventricles.
What is the SA node?
Sino atrial node.
Cluster of cells located in the R atrium of the heart.
It is the heart’s natural pacemaker.
Functions to spontaneously generate APs that travels through the heart via the electrical conduction system.
Describe the cardiac cycle.
Ventricular filling (diastole):
- large amounts of blood in the right and left atria because AV valves are closed.
- AV valves open because atrial pressure > ventricular pressure
- Blood flows from atria into ventricles
- -> rapid filling of the ventricles.
Isovolumetric Contraction (systole)
- The ventricular pressure increases abruptly causing the AV valves to close.
- The ventricles begin to contract in this closed chamber.
Ejection (systole)
- ventricular pressure > atrial pressure
- semilunar valves open
- blood is ejected at a high pressure from the ventricles into the arteries
Isovolumteric relaxation (diastole)
- the ventricles relax
- intraventricular pressure drops
- blood flows back against the cusps of the semilunar valves and forces them to close
What is End-Diastolic Volume (EDV)?
The amount of blood remaining in each ventricle at the end of ventricular diastole.
What is End-Systolic Volume (ESV)?
The amount of blood remaining in each ventricle at the end of ventricular systole.
What are Cardiac Myocytes?
Cardiac myocytes are cardiac muscle cells. Each myocardial cell contains myofibrils.