Neural control of heart rate Flashcards
(9 cards)
What does the autonomic nervous system consist of?
It consists of the sympathetic system and parasympathetic system
What is the sympathetic system?
It stimulates the heart to beat faster
What is the parasympathetic system?
It causes the heart to slow down to its resting value
What is the cardiac control centre?
The CCC coordinates the sympathetic system and parasympathetic system and is located in the medulla oblongata of the brain. The CCC sends an impulse through either the sympathetic or parasympathetic systems to the sinno atrial SA node of the heart.
What is the CCC stimulated by?
The CCC is stimulated by chemoreceptors - which detect chemical change lactic acid and CO2 - and baroreceptors which - detect changes in blood pressure and muscle receptors (which detect movement).
How do hormones control the heart rate?
Adrenalin and noradrenalin stimulate the SA node and increase both the speed and force of contraction
What factors control the heart rate?
The primary factor is the neutral control, then hormonal control and intrinsic control
How does temperature affect the heart rate?
When temperature increases (during exercise), it increases the speed of the nerve impulses, which in turn increases the HR. Temperature decreases (after exercise), decreases the HR.
How does venous return affect the heart rate?
Venous return increases during exercise and this stretches the cardiac muscle, stimulating the SA node and in turn increasing the heart rate and force of contraction. The increase in HR increases the EDV and SV (per Starlings law). After exercise, venous return decreases, which in turn decreases SV.
