Cardiovascular System (Paper 1) (Miss J Kieser) Flashcards
What is the cardiac conduction system ?
neurones send electrical impulses in order to allow for the heart to contract
Define the term myogenic.
the capacity of the heart to generate its own heart beat
What is the role of the sinoatrial node (SAN) in the cardiac conduction system?
generates own heart beat ; acts as a pacemaker
What is the role of the atrioventricular node (AVN) in the cardiac conduction system ?
carries the impulse between the upper and lower sections of the heart
What is the role of the bundle of his in the cardiac conduction system?
a group of heart muscles that transmit electrical impulses from the AVN via the bundle branches to the ventricles.
What is the role of the purkinje fibres in the cardiac conduction system ?
muscle fibres that send impulses along the walls of the ventricles
Factors which affect heart rate
Chemoreceptors:CO2
Baroreceptors: Blood pressure
Propioreceptors: positioning, movement
What does the term sympathetic mean?
leads to an increase in heart rate
What does the term parasympathetic mean?
leads to a decrease in heart rate
What is the role of the chemoreceptor?
detect an increase or decrease in CO2 levels in the body.
What is the role of the Baroreceptor?
responds to the stretching of the arterial wall caused by changes in blood pressure.
increase in blood pressure=heart rate decreases
decrease in blood pressure=heart rate increases
What is the role of the proprioreceptor?
provides information about movement
What does the word anticipatory rise mean?
when you expect to do a physical activity, this results in the release of adrenaline which leads to the increase in heart rate
What does the word stroke volume mean?
volume of blood pumped out of the heart per contraction
What are the two factors which affect stroke volume?
- Venous return: this the amount of blood returning to the heart, an increase in venous return leads to the increase in stroke volume
- elasticity of cardiac fibres
What are the 3 mechanisms which help with venous return?
- Skeletal muscle pump
- Respiratory muscle pump
- Pocket Valve
How does the respiratory pump work as a mechanism?
whenever you exhale and inhale your muscles contract in your thorax and stomach. This cause pressure. Whenever there is pressure change your muscles in the thorax and stomach squeeze the blood back to the heart
How does the skeletal pump work as a mechanism ?
when your muscles contract they change shape. This then leads to your muscles compressing and squeezing the blood to the lungs