ANS control

Question 1

what does the ANS exert control over

Answer 1

smooth muscle, exocrine secretion and rate and force of contraction in the heart

Question 2

what are the 2 divisions of the ANS

Answer 2

sympathetic and parasympathetic

Question 3

where do the preganglionic nerve in the sympathetic originate from

Answer 3

thoracic and lumbar regions of the spinal cord

Question 4

where do the preganglionic nerve in the parasympathetic originate from

Answer 4

medulla region and sacrel outflow

Question 5

what increases sympathetic activity

Answer 5

stress

Question 6

what increases parasympathetic activity

Answer 6

basal conditions

Question 7

where are alpha 1 receptors found

Answer 7

pupil of the eye, sweat glands and smooth muscle

Question 8

where are beta 2 receptors found

Answer 8

airways and lungs

Question 9

where are beta 1 receptors found

Answer 9

HEART

Question 10

where are M2 receptors found

Answer 10

heart

Question 11

where are M3 receptors found

Answer 11

pupil, airways, lungs

Question 12

true or false: sympathetic activity to the heart can only be increased if other systems are also activated

Answer 12

false

Question 13

true or false: the ANS initiates electrical activity of the heart

Answer 13

false - it only increases speed and force

Question 14

by which subsystem of the ANS is the heart predominantly controlled by

Answer 14

parasympathetic

Question 15

which nerve supplies the parasympathetic input to the heart

Answer 15

vagus nerve

Question 16

where are the post ganglionic cells on the heart for parasympathetic input

Answer 16

SA - for decreased heart rate

AVN - decreased conduction velocity

Question 17

what does a negative chronotropic effect mean

Answer 17

decreased heart rate

Question 18

what is released from postganglionic neurones in the parasympathetic NS

Answer 18

ACh

Question 19

what nerve produces the sympathetic input to the heart

Answer 19

sympathetic trunk

Question 20

where are the post ganglionic cells on the heart for sympathetic input

Answer 20

SAN - increase heart rate
AVN
Myocardium - increase force of contraction

Question 21

what does a positive ionotropic effect mean

Answer 21

increase in force of contraction

Question 22

what type of receptors are acted on in the heart by the sympathetic NS

Answer 22

beta 1

Question 23

true or false: there are only beta 1 receptors found on the heart

Answer 23

false - there are also beta 2 and beta 3

Question 24

where are baroreceptors found

Answer 24

carotid sinus

arch of the aorta

Question 25

where in the brain controls the ANS output of the heart

Answer 25

cardiovascular centre in the medulla oblongata

Question 26

how does the sympathetic NS change the action potentials of the SAN myocytes

Answer 26

increases the depolarising slope speeding up action potentials

Question 27

how does the parasympathetic NS change the action potentials of the SAN myocytes

Answer 27

decreases the depolarising slope, slowing down action potentials

Question 28

what does activation of the beta 1 receptors in the heart do

Answer 28

- increase cAMP which can cause a direct effect on the HCN - also activates PKA which phosphorylates Ca channels increasing Ca entry during plateau - increase uptake of Ca in stores - increased sensitivity of contractile machinery to Ca - increases force of contraction

Question 29

what does activation of the M2 receptors in the heart do

Answer 29

- increase potassium conductance through the beta gamma subunit - decrease cAMP

Question 30

what receptors are found in most arteries and veins

Answer 30

alpha 1 adrenoreceptors (although skeletal and coronary muscle have beta 2)

Question 31

what is vasomotor tone

Answer 31

the amount of tension in the smooth muscle of vessel walls

Question 32

what increases vasomotor tone of arteries

Answer 32

increased sympathetic output

Question 33

what decreases vasomotor tone of arteries

Answer 33

decreased sympathetic output

Question 34

true or false: alpha 1 receptors are the only receptors found in the blood vessels

Answer 34

false - beta 2 receptors are as well

Question 35

which receptor in smooth muscle of blood vessels has a higher affinity for circulating adrenaline

Answer 35

beta 2

Question 36

what do activated beta 2 receptors in smooth muscle of blood vessels cause

Answer 36

- increase in cAMP - activation of PKA which phosphorylates and inactivates MLCK - opening of potassium channels - relaxation of smooth muscle (vasodilation)

Question 37

what do activated alpha 1 receptors in smooth muscle of blood vessels cause

Answer 37

- stimulates IP3 production - increases Ca release from store - increase of Ca causes contraction of smooth muscle

Question 38

true or false: activated beta 2 receptors are the main method of vasodilation

Answer 38

false - its the increase in metabolites (adenosine, potassium, hydrogen ions and CO2) from active tissues in coronary and skeletal muscle

Question 39

how does high pressure change baroreceptors

Answer 39

it causes them to stretch which increases the firing of action potentials

Question 40

which nerve endings are found in the carotid sinus

Answer 40

glossopharyngeal nerve

Question 41

which nerve ending are found in the arch of the aorta

Answer 41

vagus nerve

Question 42

what happens to baroreceptors if there is maintained high blood pressure

Answer 42

they re-set to higher levels so will only respond to changes of BP at higher values

Question 43

what are sympathomimetics

Answer 43

alpha and beta agonists

Question 44

what are uses of sympathomimetics

Answer 44

- adrenaline causes vasoconstriction on alpha 1 go restore function in cardiac arrest and is also administered for anaphylactic shock - beta 1 agonists e.g. dobutamine is given in cardiogenic shock and salbutamol for asthma

Question 45

what are alpha antagonists used for

Answer 45

anti-hypertension agent as it inhibits NA to cause vasodilation

Question 46

give an example of an alpha antagonists

Answer 46

prazosin

Question 47

give an example of a selective beta antagonist

Answer 47

atenolol

Question 48

give an example of a nonselective beta antagonist

Answer 48

propranolol - this slows heart rate and reduces force of contraction but also causes bronchoconstriction

Question 49

give an example of a muscarinic agonist

Answer 49

pilocarpine - used to treat glaucoma

Question 50

give an example of a muscarinic antagonist

Answer 50

atropine - increases heart rate and bronchial dilation. also dilates eyes