Central and Autonomic Regulation of Cardiac Function

Question 1

Which of the following areas in the brain are involved in the central control of cardiac function?

A. Substantia nigra
B. Rostral ventrolateral medulla
C. Hypothalamus
D. Limbic system

Answer 1

All except A.

Question 2

Regarding cardiac intrinsic autorhythmicity (true or false):

The SAN is said to have dominance

Answer 2

True

Question 3

Regarding cardiac intrinsic autorhythmicity (true or false):

The intrinsic rate of the SAN is 40–60 bpm

Answer 3

False. This is the intrinsic rate of the AVN.

Question 4

Regarding cardiac intrinsic autorhythmicity (true or false):

The rate of decay of the pacemaker potential determines HR

Answer 4

True

Question 5

Regarding cardiac intrinsic autorhythmicity (true or false):

Sodium is the principal ion responsible for Phase 4 of the SAN action potential

Answer 5

False. Whilst sodium permeability increases in Phase 4 of the SAN action potential it is actually the fall in potassium permeability and increase in calcium permeability that is most important.

Question 6

Regarding cardiac intrinsic autorhythmicity (true or false):

Activation of L-type voltage gated calcium channels and calcium flux occurs in Phase 0 of the SAN action potential

Answer 6

True

Question 7

Regarding baroreceptors (true or false):

They are mechanoreceptors

Answer 7

True

Question 8

Regarding baroreceptors (true or false):

The carotid sinus baroreceptors are high pressure baroreceptors

Answer 8

True

Question 9

Regarding baroreceptors (true or false):

The glossopharyngeal nerve relays afferent impulses from the aortic arch baroreceptors

Answer 9

False. The glossopharngeal nerve relays afferent impulses from the carotid sinus baroreceptors.

Question 10

Regarding baroreceptors (true or false):

The vagus nerve relays afferent impulses from the aortic arch baroreceptors

Answer 10

True

Question 11

Regarding baroreceptors (true or false):

The Bainbridge Reflex describes a paradoxical increase in heart rate seen with increased preload

Answer 11

True

Question 12

Regarding CNS control of cardiac function (true of false):

The NTS is the main relay centre

Answer 12

True

Question 13

Regarding CNS control of cardiac function (true of false):

The RVLM is the main group of central sympathetic premotor cells

Answer 13

True

Question 14

Regarding CNS control of cardiac function (true of false):

The Nucleus Ambiguus increases parasympathetic output to the heart in periods of high blood pressur

Answer 14

True

Question 15

Regarding CNS control of cardiac function (true of false):

The NTS receives modulation for higher cortical structures

Answer 15

True

Question 16

Regarding CNS control of cardiac function (true of false):

The PAG is important in the flight and fight response

Answer 16

True

Question 17

Regarding to autonomic regulation of cardiac function (true or false):

The SNS predominates at rest

Answer 17

False. PNS inhibition of intrinsic cardiac pacemaker activity predominates.

Question 18

Regarding to autonomic regulation of cardiac function (true or false):

The PNS has a more rapid onset and offset action than the SNS

Answer 18

True. The PNS has is faster in onset and offset than the SNS because Ach is the principle post ganglionic neurotransmitter and is broken down by the widely available and rapid acting enzyme acetylcholinesterase.

Question 19

Regarding to autonomic regulation of cardiac function (true or false):

The SNS originates from the intermediolateral columns of the upper thoracic spinal cord T1-T7

Answer 19

False. It originates from T1 – T5.

Question 20

Regarding to autonomic regulation of cardiac function (true or false):

SNS stimulation increases cardiac lusitropy

Answer 20

True

Question 21

Regarding to autonomic regulation of cardiac function (true or false):

Ach is the principle preganglionic neurotransmitter in the SNS and PNS

Answer 21

True