Mechanism for controlling the cardiac cycle and
heart rate
- Hearts electrical system controls the timing of the heartbeat
- Heartbeat commences at sinoatrial (SA) node= specialized muscle cells
(Natural pacemaker)
- Located in the wall of the atrium
Mechanism for controlling the cardiac cycle and
heart rate
- When the SA node stimulates, the atria contracts
- This stimulates the atrioventricular (AV) node = specialized muscle cells
- Located in the septum between atria and ventricles
- AV node transmits electrical signals that makes the ventricles contract –
Heart beats faster and stronger
- Bundle of His = muscle tissue that runs between the ventricles `
- Purkinje fibres= network of fibres coming from the bundle of His
Mechanism for controlling the cardiac cycle and
heart rate
Brain sends signals to heart -> SA node stimulated -> Atrium contracts ->
Purkinje fibres conduct impulse faster-> Bundle of His conduct impulse ->
AV node stimulated -> Ventricles contract
Mechanism for controlling the cardiac cycle and
heart rate
- The nervous system (automatic) controls the heart rate
- It is divided into 2 types of nerves:
, - Sympathetic nerve- send nerve impulses to speed up heart rate –
Adrenalin (fight or flight)
- Parasympathetic nerve – send nerve impulses to return heart rate to normal
(rest and digest)
Electrocardiogram (ECG)
- Electrical change of the heart is traced using an electrocardiogram
- ECG gives doctor information about the efficiency of the heart
Exercise and pulse rate
- During exercise your muscles work harder and therefore release more
energy (ATP)
- Respiration occurs faster -> more CO2 released
- This will lead to an increased heart rate
- It is important to do exercises to increase your heart rate for at least 30 min
- Your heart will become stronger and more efficient- heart rate drops
Blood vessels
- Arteries -> Arterioles
- Capillaries -> Venules
- Veins
Arteries
-Transports blood away from the heart
- Walls comprise 3 parts
- Outer fabrous layer
- Middle layer of elastic and muscular tissue
heart rate
- Hearts electrical system controls the timing of the heartbeat
- Heartbeat commences at sinoatrial (SA) node= specialized muscle cells
(Natural pacemaker)
- Located in the wall of the atrium
Mechanism for controlling the cardiac cycle and
heart rate
- When the SA node stimulates, the atria contracts
- This stimulates the atrioventricular (AV) node = specialized muscle cells
- Located in the septum between atria and ventricles
- AV node transmits electrical signals that makes the ventricles contract –
Heart beats faster and stronger
- Bundle of His = muscle tissue that runs between the ventricles `
- Purkinje fibres= network of fibres coming from the bundle of His
Mechanism for controlling the cardiac cycle and
heart rate
Brain sends signals to heart -> SA node stimulated -> Atrium contracts ->
Purkinje fibres conduct impulse faster-> Bundle of His conduct impulse ->
AV node stimulated -> Ventricles contract
Mechanism for controlling the cardiac cycle and
heart rate
- The nervous system (automatic) controls the heart rate
- It is divided into 2 types of nerves:
, - Sympathetic nerve- send nerve impulses to speed up heart rate –
Adrenalin (fight or flight)
- Parasympathetic nerve – send nerve impulses to return heart rate to normal
(rest and digest)
Electrocardiogram (ECG)
- Electrical change of the heart is traced using an electrocardiogram
- ECG gives doctor information about the efficiency of the heart
Exercise and pulse rate
- During exercise your muscles work harder and therefore release more
energy (ATP)
- Respiration occurs faster -> more CO2 released
- This will lead to an increased heart rate
- It is important to do exercises to increase your heart rate for at least 30 min
- Your heart will become stronger and more efficient- heart rate drops
Blood vessels
- Arteries -> Arterioles
- Capillaries -> Venules
- Veins
Arteries
-Transports blood away from the heart
- Walls comprise 3 parts
- Outer fabrous layer
- Middle layer of elastic and muscular tissue
