Cardiovascular Physiology 20 Flashcards
Through what nerves does the heart receive sympathetic innervation?
Through the Thoracic spinal nerves
Through what nerve does the heart receive Parasympathetic innervation?
Through Vagus nerve
Which parts of the heart do Sympathetic postganglionic fibers innervate?
- Atria
- Ventricles
- SA node
- AV node
Which neurotransmitter do Sympathetic postganglionic fibers release?
Norepinephrine
Which parts of the heart do Sympathetic nerves innervate?
- Atria
- Ventricles
- SA node
- AV node
Which part of the heart do Parasympathetic nerves innervate?
- Atria
- SA node
- AV node
Which neurotransmitter do Parasympathetic nerves release?
Acetylcholine
Why is the ventricular myocardium not affected by Parasympathetic activity?
Because it does not have parasympathetic innervation
How does the Sympathetic nervous system affect the adrenal medulla?
It causes the releases of epinephrine from the adrenal medulla
What kind of receptors are there for Norepinephrine and Epinephrine?
Beta adrenergic receptors
What kind of receptors bind to acetylcholine?
Muscarinic receptors
How does Parasympathetic stimulation affect the SA node?
It decreases the rate of depolarization to threshold, decreasing the heart rate
How does the Parasympathetic system affect the AV node?
It decreases the conduction of the AV node increasing the AV nodal delay
How does the Parasympathetic system affect Atrial muscle?
Decreases contractability
How does the Parasympathetic system affect Ventricular muscle?
No significant innervation
How does Sympathetic stimulation affect the SA node?
Increases the rate of depolarization to threshold, increasing heart rate
How does Sympathetic innervation affect the AV node?
Increases conduction, decreasing the AV nodal delay
How does Sympathetic innervation affect the Atrial muscle?
Increases contractability
How does Sympathetic innervation affect Ventricular Muscle?
Increases contractility
What is Cardiac Output?
The amount of blood pumped by each ventricle in one minute
What does Cardiac Output provide insight on?
An indication of ventricular efficiency overtime
What is the formula for Cardiac Output?
CO = HR * SV
What is Stroke Volume?
The amount of blood pumped out of each ventricle during systole
What are the two ways to alter cardiac output?
- Altering the heart rate
* Altering the stroke volume
How can HR be altered?
By altering the activity of the SA node
How can stroke volume be altered?
By altering the contractility of the ventricular myocardium
