The Cardiovascular System Flashcards
What does the right and left side of the heart do?
Right side: receives deoxygenated blood from body and pumps to the lungs
Left side: receives oxygenated blood from lungs and pumps to the body
What are the 3 main blood vessels in the heart? And what do they do?
- Arteries: transport blood from Away from the heart
- Veins: transport blood to the heart
- Capillaries: act as sites of substance exchange
What are the 2 major valves called?
- Atrioventricular valve
- Semilunar valve
What are the 2 main circuits? And what do they do?
- Pulmonary circuit: movement of blood/fluid through lungs
- Systemic circuit: movement of blood/fluid through body
What is the tip of the heart called?
The apex
How may layers comprise the heart wall? And what are they called?
3
1. Epicardium
2. Myocardium
3. Endocardium
What are the 2 components of cardiac muscle? And what do they do?
- Desmosomes: mechanical junctions between cells that prevent cardiomyocytes from being pulled apart
- Electrical junctions: gap junctions that allow ions to flow between cells -> spreading action potential
How many valves are there? And what are they called?
4
1. Tricuspid valve (AV)
2. Mitral valve (AV)
3. Aortic valve (SL)
4. Pulmonic valve (SL)
What do AV valves do?
Open and allow blood flow from atria -> ventricles (diastole)
Close to prevent backflow (systole)
What do SL valves do?
Open to allow blood flow into pulmonary trunk
Close to prevent backflow
What are the 4 structures of the heart? And what are they called?
- Sinoatrial Node (SA)
- Atrioventricular Node (AV)
- Bundle of His
- Purkinje Fibres
What does the SA Node do?
Acts as a pacemaker to generate electrical impulses that spread to both atria and AV node
What does the AV Node do?
Transmits electrical signals after slight delay to bundle of His
What does the Bundle of His do?
Divides into right and left bundle branches for each ventricle
What does the Purkinje Fibres do?
Large diameter myofibres (specialised muscle cells) that conduct signals quickly to ventricular muscle
Explain the Conduction System of the Heart.
- Spread of depolarisation from SA node stimulates two atria to contract simultaneously and push blood into the ventricles
- Electrical signal goes through AV node which allows the ventricles to fill
- Depolarisation wave travels very quickly through Bundle of His and Purkinje fibres
- Entire ventricular myocardium depolarises and contracts in unison, results in blood being pushed from both ventricles at same time
What are the 3 waves/complexes represented in an ECG? And what do they represent?
- P Wave: depolarisation of the atria
- QRS Complex: depolarisation of the ventricles and repolarisation of the atria
- T Wave: repolarisation of the ventricles
What are the 2 broad areas of the Cardiac Cycle? And what do they do?
- Ventricular Diastole (filling): blood flows from atria at the end of atrial contraction
- Ventricular Systole (contraction): ejection of blood through semilunar valves
What is the formula of Cardiac Output?
CO = HR x SV
HR: Heart rate
SV: Stroke volume
What is the formula of Stroke Volume?
SV = EDV - ESV
EDV: End-diastolic volume
ESV: End-systolic volume
What are the 3 factors that affect stroke volume?
- Venous Return/Preload
- Contractility
- Afterload
What are the 6 factors that affect cardiac output?
- Chronotropic Agents
- Venous Return
- Inotropic Agents
- Afterload
- Heart Rate
- Stroke Volume
What are the 3 layers of blood vessels? And what do they do?
- Tunica Intima (Interna): innermost layer of endothelium
- Tunica Media: middle layer, made of smooth muscle cells and supported by elastic fibres
- Tunica Externa: outer layer of areolar tissue (loose connective tissue), contains elastic and collagen fibres
What are the 3 types of arteries?
- Elastic Arteries (largest)
- Muscular Arteries (middle)
- Arterioles (smallest)
