Neurohumeral Influences

Question 1

Parasympathetic stimulation (CHOLINERGIC) - control located in

Answer 1

medulla oblongata

carioinhibitory center

Question 2

Parasympathetic stimulation (CHOLINERGIC) - via what

Answer 2

vagus nerve, cardiac plexus
Innervates SA node, AV node and myocardium
Releases Ach

Question 3

Parasympathetic stimulation (CHOLINERGIC) - does what

Answer 3

slows rate and force of myocardial contraction
decreases myocardial metabolism
causes coronary artery VC

Question 4

Sympathetic stimulation (ADRENERGIC) - control located in

Answer 4

medulla oblongata

cardioacceleratory center

Question 5

Sympathetic stimulation (ADRENERGIC) - via what

Answer 5

cord segments T1-T4, upper thoracic to superior cervical chain ganglia
Innervates SA node, AV node, conduction pathways and myocytes
Releases epinephrine and NE

Question 6

Sympathetic stimulation (ADRENERGIC) - does what

Answer 6

Causes increase in rate and force of myocardial metabolism

Causes coronary artery VD

Question 7

Sympathetic stimulation (ADRENERGIC) - the skin and peripheral vasculature receive

Answer 7

ONLY postganglionic sympathetic innervation

Causes VC of cutaneous arteries, sympathetic inhibition must occur for VD

Question 8

Drugs that increase sympathetic function

Answer 8

sympathomimetics

Question 9

Drugs that decrease sympathetic function

Answer 9

sympatholytics

Question 10

Baroreceptors (pressoreceptors)

Answer 10

main mechanism controlling heart rate

Question 11

Baroreceptors (pressoreceptors) located where

Answer 11

in walls of aortic arch and carotid sinus via vasomotor center

Question 12

Baroreceptors (pressoreceptors) - Circulatory reflex: responds to changes in

Answer 12

blood pressure

Question 13

Baroreceptors (pressoreceptors) - Circulatory reflex: Increased BP results in

Answer 13

parasympathetic stimulation
decreased rate and force of cardiac contraction
sympathetic inhibition, decreased peripheral resistance

Question 14

Baroreceptors (pressoreceptors) - Circulatory reflex: Decreased BP results in

Answer 14

sympathetic stimulation

increased HR and BP and VC of peripheral BVs

Question 15

Baroreceptors (pressoreceptors) - Circulatory reflex: Increased right atrial pressure causes

Answer 15

reflex acceleration of HR

Question 16

Chemoreceptors are located

Answer 16

in the carotid body

Question 17

Chemoreceptors are sensitive to

Answer 17

changes in blood chemicals like O2, CO2, lactic acid

Question 18

Chemoreceptors - increased CO2 or decreased O2 or decreased pH (elevated lactic acid) results in

Answer 18

increased HR

Question 19

Chemoreceptors - what leads to decrease in HR

Answer 19

increase in O2 levels

Question 20

Increased body temp leads to

Answer 20

HR increase

Question 21

Decreased body temp leads to

Answer 21

HR decrease

Question 22

Hyperkalemia

Answer 22

Increased K ions

decreases rate and force of contraction

Question 23

Hyperkalemia - ECG changes

Answer 23

widened PR interval and QRS

taller T waves

Question 24

Hypokalemia - ECG changes

Answer 24

Decreased K ions
flat T waves, prolonged PR and QT intervals
May progress to ventricular fibrillation!

Question 25

Hypercalcemia

Answer 25

Inc Ca | Increases heart actions

Question 26

Hypocalcemia

Answer 26

Dec Ca | Depresses heart actions

Question 27

Hypermagnesemia

Answer 27

Inc Mg | Ca blocker - can lead to arryhthmias or cardiac arrest

Question 28

Hypomagnesemia

Answer 28

Dec Mg | causes ventricular arrhythmias, coronary artery vasospasm, and sudden death

Question 29

Peripheral resistance - increased leads to what

Answer 29

increased arterial volume and pressure

Question 30

Peripheral resistance - decreased leads to what

Answer 30

decreased arterial volume and pressure

Question 31

Peripheral resistance - influenced by

Answer 31

arterial blood volume - viscosity of blood and diameter of arterioles and capillaries