D3 - Nervous control of cardiac cycle Flashcards
1
Q
Cardiac cycle is …
A
- the process of the heart filling with blood and then contracting
2
Q
What is the heart controlled by?
A
- electricity
3
Q
What is the hearts electrical system made out of?
A
- sinoatrial node (SAN)
atrioventricular node (AVN) - bundle of his and purkinje fibres
4
Q
Sinoatrial node (SAN) is …
A
- the pacemaker
- found in the walls of the right atrium
- sends electrical impulses from the right atrium through the walls of the atria, causing muscular walls to contract
- contraction forces blood through valves to ventricles
5
Q
Atrioventricular node (AVN) is …
A
- located in the center of the heart between the atria and ventricles
- acts as a buffer to slow down electrical signal from the SA node
- this allows the atria to contract before the ventricles contract (ventricles relaxed and receive blood)
6
Q
Bundle of His and Purkinje fibers are ..,..
A
- specialised heart muscle cells that are responsible for transporting the impulses from the AV node
- found in the walls of ventricles and septum
- ends of these BOH are thin filaments called PF
- these allow the ventricles to contract at a paced interval
- ventricular contraction causes blood to be pushed out through the valves into the arteries
7
Q
Autonomic nervous system is …
A
- regulates body function & involuntary movements (breathing and heart beat)
- can be divided into the sympathetic and parasympathetic nervous system
8
Q
Sympathetic nervous system is …
A
- prepares body for intense physical activity (referred to as ‘fight or flight’ response)
- cause heart to beat faster and lungs to ‘work harder’ (increase in tidal volume) = creates more energy
9
Q
Parasympathetic nervous system is …
A
- relaxes body and slows energy function (known as the ‘rest and recovery’ response)
- after exercise your heart rate will need to slow down to it’s normal resting level, PNS slows heart rate as a result
