Cardiovascular System - Cardiac cycle, sounds and rhythms Flashcards
1
Q
Systole
A
- Heart contaction
2
Q
Diastole
A
Relaxation of heart
3
Q
Atria contraction
A
- Diastole initial when the atrium is filling with blood
- then Atrium in systole when contracting and pushing blood to ventricle
4
Q
Ventrical contraction
A
- Initially diastole when the ventricle is being filled with blood from atrium
- Systole when ventricle contracts until all blood enters either aorta or pulmonary vein then returns to diastole
5
Q
Sino Atrial node
A
- Specialised electrically active Myocardial tissue of atrium
- Intrinsic unstable spontaneous depolarisation
- Generates electrical activity-Impulse
6
Q
Atria ventricular node
A
- Specialised electrically active Myocardial tissue ventricular midline
- Intrinsic unstable spontaneous depolarisation
- Generates electrical activity-Impulse
7
Q
Inter nodal tracks
A
- Conduction pathways (Anterior, Middle & Posterior)
- Carry pulse, depolarise and contract atria (right and left)
- Converge at AV node
8
Q
Fibrous mid-line
A
No electical conductivity
9
Q
Bundle of HIS (AV bundle)
A
- Collect and carry to higher and lower part of the ventricles
10
Q
Purkinge Fibres
A
Specialised myocardium for electrical conduction towards contractile myocytes
11
Q
Vagus innervation
A
Suppress the heart rate
12
Q
Sympathetic Innervention
A
-Stimulates the AV and SA node this increases the heart rate
13
Q
Cardiac muscle
A
- Striated branched muscle fibre containing single nucleus with many mitochondria
- Gap junctions so depolarisation between cells
- Desmosomes hold the fibres close together in contractions
14
Q
Properties of Cardiac muscle
Auto-rhythmicity
A
Ability to initiate heart rate consistent and continuous at regular pace without any external stimuli (autonomic)
15
Q
Properties of Cardiac muscle
Excitability
A
- Ability to respond to stimuli of adequate strength and duration (threshold or more)
- Ability to generate and process action potential
