73. Introduction to the Autonomic Nervous System

Question 1

The nervous system can be divided into 2

Answer 1

Central and Peripheral (CNS and PNS)

Question 2

what do we say when a signal is going towards the CNS

Answer 2

afferent

Question 3

what do we say when a signal is going away from the CNS

Answer 3

efferent

Question 3

PNS is split into 3 sections

Answer 3

Somatic efferent
Autonomic
Somatic afferent

Question 4

the autonomic nervous system is split into 3

Answer 4

Sympathetic
Parasympathetic
Enteric

Question 5

what is the overall function of the autonomic nervous system

Answer 5

mediates output from the CNS to the whole of the body, with the exception of skeletal (voluntary) muscle
Output is modulated by external and internal sensory input, often via reflexes involving negative feedback loops within PNS and the CNS

Question 6

ANS regulates functions which are…

Answer 6

essential
do not require conscious effort
largely involuntary
examples - heart beat, metabolism, exo/endocrine secretions

Question 7

Two neurons in series are described

Answer 7

preganglionic and postganglionic

Question 8

why do the Sympathetic and parasympathetic divisions of the ANS often work simultaneously

Answer 8

to maintain homeostasis

Question 9

Sympathetic is what kind of response

Answer 9

fight or flight and energy consuming

Question 10

Parasympathetic is what kind of response

Answer 10

rest and digest
restorative
energy conserving

Question 11

The transmitter of the preganglionic neurons, sympathetic and parasympathetic, is always what

Answer 11

acetylcholine (ACh)

Question 12

what does acetylcholine (ACh) act on

Answer 12

excitatory nicotinic cholinoceptors

Question 13

describe the chemical transmission of the ANS sympathetic division

Answer 13

1. Action potential originates from the CNS
2. Travels to the presynaptic terminal of the preganglionic neuron
3. Triggering Ca2+ entry through voltage-gated, calcium selective, ion channels and the release of Ach by exocytosis.
4. ACh binds to and opens ligand-gated ion channels (nicotinic ACh receptors) in the postganglionic neuron
5. Causing depolarization and the initiation of action potentials that propagate to the postsynaptic presynaptic terminal of the neuron
6. Triggering Ca2+ entry and the release, usually, of noradrenaline.
7. Noradrenaline activates G-protein-coupled adrenoceptors in the effector cell membrane to cause a cellular response

Question 14

SNS where does the action potential travel to on the neuron

Answer 14

presynaptic terminal on the preganglionic neuron

Question 15

SNS when the action potential travels to the presynaptic terminal on the preganglionic neuron, what does this cause?

Answer 15

Ca2+ entry through voltage-gated, calcium selective, ion channels

Question 16

SNS when Ca2+ enters through voltage-gated, calcium selective, ion channels what does this cause

Answer 16

the release of ACh by endocytosis

Question 17

SNS after the release of ACh by endocytosis from the preganglionic neuron what happens and where?

Answer 17

ACh binds to and opens ligand-gated ion channels (nicotinic ACh receptors) in the postganglionic neuron

Question 18

SNS when ACh binds to and opens ligand-gated ion channels (nicotinic ACh receptors) in the postganglionic neuron. what does this cause?

Answer 18

depolarization and the action potential to continue

Question 19

SNS once depolarization and the action potential continuing occurs in the postganglionic neuron it travels down to the presynaptic terminal to do what which releases what

Answer 19

to trigger the entry of Ca2+ which causes the release of Noradrenaline

Question 20

SNS Once Noradrenaline is released it activates…..

Answer 20

G protein coupled adrenoreceptors in the effector cells causing a cellular response

Question 21

This is the same process for parasympathetic except what is released from the postganglionic neuron

Answer 21

Acetylcholine ACh

Question 22

and in the parasympathetic system what does the postganglionic acetylcholine activate

Answer 22

G protein coupled muscarinic acetylcholine receptors

Question 23

what is the transmission called when neither NA or ACh are used

Answer 23

NANC - Non-Adrenic Non-cholineric transmission

Question 24

In NANC - Non-Adrenic Non-cholineric transmission. Which neurotransmittors are used instead for parasympathetic and sympathetic

Answer 24

Parasympathetic - NO & VIP
sympathetic - ATP & NPY

Question 25

ACh - Classical Receptor Classes of the Ganglia and Effector Cells (Cholinoceptors). Name the 2 types

Answer 25

Nicotinic and Muscarinic

Question 26

describe Nicotinic ACh receptors

Answer 26

Ligand-gated ion channels (LGICs),
Structurally and pharmacologically distinct from nicotinic receptors at the skeletal neuromuscular junction, or in the CNS

Question 27

describe muscarinic ACh receptors

Answer 27

G-protein-coupled receptors (GPCRs)

Question 28

describe muscarinic ACh receptors in their 5 subtypes

Answer 28

five subtypes: M1, M2, M3, M4 and M5 that are differentially expressed across tissues/organs

Question 29

out of the five muscarnic ACh receptor subtypes. why are the most important

Answer 29

M1-M3

Question 30

NA and adrenaline (A) are the endogenous agonists all bind to

Answer 30

G protein coupled receptors