Chapter 3: Autonomic Nervous System, Rapid Interpretation of EKG's

Question 1

Secretion from terminal ends of sympathetic nervous system + receptor

Answer 1

Norepinephrine activates adrenergic receptors

Question 2

Secretion from terminal ends of parasympathetic nervous system + receptor

Answer 2

Acetylcholine (ACh) activates cholinergic receptors

Question 3

Receptors activated by norepinephrine in the heart + response (4)

Answer 3

activates B1 (adrenergic) receptors, producing excitatory response:

a) Stimulates SA node to pace faster
b) improves AV node conduction an accelerates conduction through atrial an ventricular myocardium
c) increases force of myocardial contraction
d) increases irritability of atrial an junctional automaticy foci and minimally affect ventricular foci

Question 4

Epinephrine - source + effects

Answer 4

Secrete into blood by adrenal glans

Is an even more potent stimulator of the hearts B1 receptors

Question 5

Receptors activated by acetylcholine in the heart + response

Answer 5

Activates cardiac cholinergic receptors (most within atria) to produce a cardiac inhibitory effect:

1) Inhibits the SA node decreased heart hrate
2) Decreases the speed of myocarial conuction and depresses the AV nodes
3) Diminishes the force of myocardial contraction
4) Depresses irritability of automaticity force mainly those in the atria and AV junction

Question 6

Sympathetic stimulation arterial system - receptors + effect

Answer 6

arterial alpha 1 (adrenergic) receptors
Constricts arteries throughout boy
Thereby increasing blood pressure and blood flow

Question 7

Affinity alpha 1 receptors to different adrenergic hormones

Answer 7

More responsive to neuroransmitter nor-epinephrine than to circulating epinephrine

Question 8

Parasympathetic stimulation arterial system - receptors + effect

Answer 8

• activates arterial (cholinergic) receptors

- iltates arteries thereby decreasig blood pressure and reducing blood flow

Question 9

Syncope - meachnism (from severe pain/ seeing ones own blood = merciful reflex)

Answer 9

1) Severe pain/fright
2) Parasympathetic reflex
3) Slows SA node pacing = bradycardia an dilates systemic arteries = hypotension
4) Leads to reduced perfusion of the brain and loss of consciousness (syncope)

Question 10

Vagal maneuvers

Answer 10

Produce reflex parasympathetic response
1) Gastrointestinal stimulation (gag reflex)
2) Carotid sinus massage
both produce parasympathetic response

Question 11

Compensory sympathetic response to standing

Answer 11

Blood gravitates into the lower extremities
Compensatory sympathetic response constrict peripheral arteries to prevent distal blood pooling
Also stimulates sinus pacing (increasing heart ate slightly)
To conserve blood flow to brain

Question 12

Orthostatic hypotension

Answer 12

An abrupt fall in blood pressure caused by failure of compensatory mechanism upon standing
i.e. causes diminish of blood to brain producing syncope

Question 13

Paradoxical parasympathetic response causing syncope

Answer 13

• in older adults
• standing for long period time causes syncope
• standing for lng periods of time = pooling in lower extremeties
• in older adults sinus pacing accelerates but peripheral vasoconstriction is inadequate
• partially filled ventricles contract rigorously stimulating parasympathetic mechanoreceptors in the left ventricle
• initiates an undesirable parasympathetic reflex that slows SA node pacing and reduces blood pressure - so blood flow to the brain is reduced -causes syncope (neuro-cardigenic syncope)

Question 14

Confirmation of neuro-cardiogenic syncope

Answer 14

Head Up Tilt test