Define spontaneous rhythmicity
contracts without external stimulation
4 components to the conduction of cardiac impulse
- Sinoatrial (SA) node
- Atrioventricular (AV) node
- AV bundle (Bundle of His)
Purkinje fibres
What does the P - Wave represent
- Activation of the atria
Atrial depolarization
what does QRS represent
- Activation of the ventricles
- Ventricular depolarization
What does T-wave represent
- Recovery of the ventricles
- Ventricular repolarization
where do the impulses that modulate medullary activity come from
Somatomotor central command center
what has greatest control over HR during exericse
Central command center
what are the 3 effects of the sympathetic nervous system on regulation of HR
- Sympathetic cardioaccelerator nerves releases epinephrine and norepinephrine
- Causes vasoconstriction except in coronary arteries
- Highers HR
what are the 3 effects of the parasympathetic nervous system on regulation of HR
- Acetylcholine release delays rate if sinus discharge
- Inhibition of parasympathetic stimulation during exercise
- Lowers HR
what 2 types of receptors monitor chemical and physical state
Chemoreceptors
mechanoreceptors
What 3 mechanisms monitor exercise and mass of muscle activated
- Reflex neural input from afferents within active muscles
- Chemical stimulation of afferents within active muscles
- Feed-forward outflow from the motor areas of the central command
Define nitric oxide and its cause
- Serves as a signal molecule that dilates blood vessels and decreases vascular resistance
- Causes vasodilation
