Week 6

Question 1

Define spontaneous rhythmicity

Answer 1

contracts without external stimulation

Question 2

4 components to the conduction of cardiac impulse

Answer 2

1. Sinoatrial (SA) node
   
   2. Atrioventricular (AV) node
   3. AV bundle (Bundle of His)
      Purkinje fibres

Question 3

What does the P - Wave represent

Answer 3

• Activation of the atria

Atrial depolarization

Question 4

what does QRS represent

Answer 4

• Activation of the ventricles

- Ventricular depolarization

Question 5

What does T-wave represent

Answer 5

• Recovery of the ventricles

- Ventricular repolarization

Question 6

where do the impulses that modulate medullary activity come from

Answer 6

Somatomotor central command center

Question 7

what has greatest control over HR during exericse

Answer 7

Central command center

Question 8

what are the 3 effects of the sympathetic nervous system on regulation of HR

Answer 8

• Sympathetic cardioaccelerator nerves releases epinephrine and norepinephrine
  
  • Causes vasoconstriction except in coronary arteries
  • Highers HR

Question 9

what are the 3 effects of the parasympathetic nervous system on regulation of HR

Answer 9

• Acetylcholine release delays rate if sinus discharge
  
  • Inhibition of parasympathetic stimulation during exercise
  • Lowers HR

Question 10

what 2 types of receptors monitor chemical and physical state

Answer 10

Chemoreceptors

mechanoreceptors

Question 11

What 3 mechanisms monitor exercise and mass of muscle activated

Answer 11

• 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

Question 12

Define nitric oxide and its cause

Answer 12

• Serves as a signal molecule that dilates blood vessels and decreases vascular resistance
  
  • Causes vasodilation