Cardiovascular System Flashcards
What does the cardiovascular system provide? (3)
- O2
- Nutrients
- Water
What does the cardiovascular system move? (6)
- Immune cells
- Antibodies
- Clotting proteins
- Hormones
- Bodily wastes
- Red blood cells (CO2)
What are the 3 components of the CVS (cardiovascular system)? (3)
- Heart as pumps
- Blood vessels
- Blood circulation in CVS
What does the inferior vena cava carry?
deoxygenated blood from body to heart
What does the superior vena cava carry?
deoxygenated blood from brain to heart
What does the pulmonary artery carry?
deoxygenated blood from heart to lungs
What does the pulmonary vein carry?
oxygenated blood from the lungs to the heart
what does the aorta carry?
oxygenated blood from the heart to the body (systemic circuit)
what is the circuit involving the heart and lungs?
pulmonary circuit
what is the circuit involving the heart and the rest of the body?
systemic circuit
what % of cardiac muscle cells are autorythmic cells?
1%
what is the node thats responsible for initiating a heartbeat (autorythmic cells)
sino-atrial node
What is the node responsible for connecting the electrical systems of the atrium and ventricle?
atrio-ventricular node
what are the specialised nerve cells that transmit electrical signals to the heart’s ventricles, causing them to contract and pump blood throughout the body.
purkinje fibres
Describe the stages of the conducting system (5)
- SA node activated (depolarises)
- Electrical activity goes rapidly to AV node via inter-nodal pathways
- Activation signal (depolarisation) spreads more slowly across atria
- Signal (depolarisation) moves rapidly through purkinje fibres to apex of heart
- Signal (depolarisation) wave spreads upward from apex
Describe the trace of a human electrocardiogram (3)
- P wave - trace starts
- QRS wave - middle sharp and relatively large peak
- T wave - final gentle bump
What does the P wave represent on the human electrocardiogram?
SA node activation
What does the QRS wave represent on the human electrocardiogram?
Activation of AV node and purkinje fibres
What does the T wave represent on the human electrocardiogram?
Ventricle diastole
What represents a cardiac cycle on the human electrocardiogram?
From the peak of one P wave to the next P wave
Describe the blood flow system (5)
- Diastole - all chambers relaxed, ventricles fill passively
- Atrial systole - contraction forces small amount of additional blood into ventricle via AV valves
- Ventricular depolarisation (purkinje fibres) - 1st phase contraction, AV valves closed, not enough pressure to open semilunar valves
- Ventricular ejection - ventricle pressure rises enough, semilunar valves open, blood ejected
- Ventricular diastole - pressure falls and blood flows back into cusps of semilunar valves, closing them
What is the equation for cardiac output?
HR x SV = CO (l/m)
Heart rate x systolic volume = cardiac output (litres/minute)
What is the equation for stroke volume?
EDV - ESV = SV
End diastolic volume - end systolic volume = stroke volume
(volume of blood pumped per contraction)
What is the cardiac output % of the digestive tract and liver at rest?
27%
