Autonomic Nervous System

Question 1

Devision of the nervous system

Answer 1

Question 2

Structure of neuron

Answer 2

Question 3

ganglion

Answer 3

collection of cell body bundled together

Question 4

Describe:

Efferent

Answer 4

-from brain to effector

Question 5

Describe:

Afferent

Answer 5

-from effector to brain

Question 6

Innervates definition

Answer 6

• supply an organ with nerves
• To stimulate a nerve (or other part of the body) into action

Question 7

Overview:

Autonomic Nervous System

Answer 7

• conveys information from the CNS to the rest of the body (except the skeletal muscles–> somatic afferent system)
• innervates internal (visceral) organs- basic processes needed for normal bodily functions
• not under voluntary control

Question 8

What does ANS regulates?

Answer 8

ANS regulates:

• contraction and relaxation of smooth muscle
• all exocrine glands eg. sweat gland
• some endocrine glands eg, pancreas, adrenal gland
• heartbeat
• certain intermediary metabolism

Question 9

Autonomic Nervous System neuron structure

Answer 9

2 neuron system, serially connected -preganglionic neuron and postganglionic neuron connected by autonomic ganglion (synaptic cleft)

Question 10

Autonomic Nervous System division

Answer 10

• sympathetic nervous system (fight or flight)
• parasympathetic nervous system (rest and digest)
• enteric nervous system (gut)–>sometimes considered part of the autonomic nervous system and sometimes considered an independent system.

Question 11

Parasympathetic Nervous System

Answer 11

• rest & digest response
• branches off the cranial and sacral section of spinal cord
• both preganglionic and postganglionic neurons releases acetylcholine (Ach) as neurotransmitter

Question 12

structure of parasympathetic neuron

Answer 12

• Preganglionic fibers of the parasympathetic branch are longer than those of the sympathetic branch.
• The ganglia of the parasympathetic system are generally situated close to, or within the tissue to be affected.

Question 13

Sympathetic Nervous System

Answer 13

• flight or fight response
• branches off thoracic and lumbar section of spinal cord.
• preganglionic neurons releases acetylcholine (Ach) as neurotransmitter
• postganglinic neurons releases noradrenaline (NA) as neurotransmitter, -except postganglionic neurons of sweat gland –> Ach

Question 14

structure of sympathetic neuron

Answer 14

• Sympathetic ganglia are usually situated near the central nervous system.
• The postganglionic fibers then extend a longer distance to the intended organ.

Question 15

Other exception in sympathetic nervous system: Adrenal gland system

Answer 15

• branch off sympathetic nervous system
• preganglionic neurons do not synapse in the paraverterbral sympathetic ganglion (no postganglionic neurons
• Preganglionic neurons synapse directly on the adrenal gland in the adrenal medulla, release acetylcholine

Question 16

How do drugs influence ANS?

Answer 16

Direct acting:

• parasympathomimetic
• sympathomimetic
• parasympatholytic
• sympatholytic

Question 17

Parasympathomimetic

Answer 17

• drugs that mimics Ach (agonist)
• therfore, it’s cholingenic
• acts primarily on muscarinic receptor (M)
• limited clinical use

Question 18

Sympathomimetic

Answer 18

• drugs that mimics NA & A (agonist)
• therefore, it’s adrenergic
• acts on adrenergic receptors alpha & beta receptor

Question 19

Parasympatholytic

Answer 19

-drugs that inhibits/antagonise the action of Ach (antagonist)

Question 20

Sympatholytic

Answer 20

-drugs that inhibits/antagonise the action of NA & A (antagonist)

Question 21

Parasympathetic and Sympathetic branches

Answer 21

Question 22

comparison of motor route of somatic nervous system and autonomic nervous system

Answer 22

Question 23

Anatomy of the spinal cord and the relex arc

Answer 23

• The spinal cord consists of highly organized regions of gray matter and white matter.
• Gray matter contains the cell bodies of a variety of association and motor neurons -
• the white matter consists of tracts of myelinated nerve fibers.

Question 24

Travelling of nerve impulse/action potential

Answer 24

• Incomming sensory fibers connect through the dorsal roots of spinal nerves.
• Outgoing motor fibers leave through the ventral roots of spinal nerves.

Question 25

Preganglionic aka.

Answer 25

Presynaptic

Question 26

Postganglionic aka.

Answer 26

Postsynaptic

Question 27

Ganglion aka.

Answer 27

synaptic cleft

Question 28

What happens when Na⁺enters cell?

Answer 28

- It causes the membrane to depolarize slightly (becomes more positive) - Raising the membrane potential from -70mV closer to the action potential threshold

Question 29

What happens when Cl^- enters cell?

Answer 29

- makes the membrane potential slightly more negative than -70mV, known as hyperpolarization. - the membrane potential is now even further away from the threshold potential, making it harderr for an action potential to be initiated

Question 30

Neurotransmitter removal

Answer 30

-After neurotransmitter have been released during synaptic transmission, there must be a fast mechanism in place to remove the neurotransmitter ready for the next signal.

Question 31

What happen to acetycholine in synapse

Answer 31

- acetycholine is enzymically degraded by *acetylcholinesterase* into acetate and choline - therse products may be uptakes into the presynaptic nerve terminal and resynthesized into new acetylcholine for reuse.

Question 32

Ways of halting neurotransmitter action

Answer 32

- Fast enzymic degradation - Uptake into presynaptic cells or neighbouring cells - Diffusion out of the synapse before further uptake or enzymatic degradation

Question 33

Why do we need to remove neurotransmitter from the synapse after an action potential is generated

Answer 33

- Neurotransmitter must act to transmit each action potential separately. - The delay between action potentials may be very short in rapidly firing nerves, ie motor neurons - The neurotransmitter must be removed quickly before the next action potential reached the nerve terminal If not, depolarizing block may occur.

Question 34

Acetylcholine

Answer 34

- formed in presynaptic terminal by *choline O-acetyltransferase* - this enzyme removes an acetyl group from acetyl coenzyme A and links it to choline - released via exocytosis in response to an increased in Ca²⁺concentration

Question 35

Formation of Acetycholine diagram

Answer 35

The neuron is presynaptic At postsynaptic cell, - if it's a nerve cell, can cause action potential - if it's a muscle cell, can cause a response

Question 36

Terminatin of ACh action

Answer 36

- unused ACh rapidly remoced - results in BRIEF and LOCALISED action of neurotransmitter

Question 37

Two ways of ACh removal in the synapse

Answer 37

- acetycholine is enzymically degraded by *acetylcholinesterase* into acetate and choline - therse products may be uptakes (via ion gated membrane channel) into the presynaptic nerve terminal and resynthesized into new acetylcholine for reuse.

Question 38

Noradrenaline (NA)

Answer 38

- synthesised at the postganglionic sympathetic nerve endings - in adrenal medulla, NA & A is secreted as hormone

Question 39

Termination of NA/A action

Answer 39

- Enzymatic degradation free NA/A--\>slow * -Monoamine oxidase (MAO)*-associated with mitochondria - *Catechol-o-methyl transferase(COMT)*-present in cardiac and smooth muscle - Reuptake by surrounding cells - uptake 1-high affinity/low rate - uptake 2-low affinigy/high rate

Question 40

Autonomic Receptors

Answer 40

Question 41

Types of neuron system

Answer 41

Question 42

Cholingernic receptors and its endogenous agonist

Answer 42

Question 43

Adrenergic receptors and its engodenous agonist

Answer 43