Factors that affect the Cardiac conduction system Flashcards
1
Q
The cardiac control centre
A
- The cardiac control centre is located in the medulla oblongata.
- Here, HR is controlled by 2 systems:
1. Sympathetic nervous system:- Sympathetic nerve impulses increase HR.
- More impulses= increased HR.
- Parasympathetic nervous system:
- Parasympathetic nerve impulses decrease HR.
- Less impulses= decreased HR.
2
Q
What receptors stimulate the cardiac control centre?
A
- The cardiac control centre is stimulated by 3 main receptors.
- Chemoreceptors
- Baroreceptors
- Proprioceptors
3
Q
Chemoreceptors (chemical)
A
- Exercise begins
- Chemoreceptors detect a rise in carbon dioxide in the blood (increased acidity).
- During exercise more CO2 is produced as a result of more O2 being consumed and utilised. - This info is sent to the medulla oblongata.
- As a result the sympathetic nervous system is stimulated.
- Increased impulses are sent to the SAN.
- Heart rate increases to match the demands of exercise.
4
Q
Baroreceptors (neural)
A
- Baroreceptors detect changes in blood pressure (the stretching of arterial walls).
- The baroreceptors detect a drop in blood pressure.
- This info is sent to the medulla oblongata.
- The sympathetic nervous system is stimulated.
- Increase signals are sent to the SAN.
- HR increases to increase blood pressure.
5
Q
Baroreceptors pt.2
A
- The opposite happens if the baroreceptors detect an increase in blood pressure (parasympathetic NS stimulation/ decreased signals to the SAN/ decrease HR/ decreased blood pressure).
6
Q
Baroreceptors and exercise
A
7
Q
A