CH 11: efferent division - autonomic and somatic motor control Flashcards

1
Q

What type of neuron carries out commands from the CNS to the muscles and glands of the body? How can it be further divided?

A
  • Efferent neurons
  • Further divided into:
  • Somatic motor neurons: control skeletal muscles, mostly voluntary
  • Autonomic neurons: control smooth muscle, cardiac muscle, glands, and some adipose tissue, mostly involuntary
    ***Diaphragm controlled by both!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does the sympathetic branch of the autonomic system do?

A

fight or flight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does the parasympathetic branch of the autonomic division do?

A

rest and digest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What type of control is primarily used in the autonomic division? (agonist, antagonist, mixed, etc)?

A
  • antagonistic
  • one branch is (sympathetic) excitatory and the other one (parasympathetic) is inhibitory
  • some exceptions (sweat glands & BV only by sympathetic & rely on tonic [up regulation] control)
  • sometimes they can work together and have different functions
  • neurotransmitter receptor often determines response in the target tissue
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a ganglion?

A
  • a cluster of neuronal cell bodies outside the CNS
  • equivilant in CNS is nucleus
  • act as mini-integration centers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Is the autonomic ganglion closer to the CNS or the target tissue in parasympathetic?

A

target tissue (or more in the middle)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What neurotransmitter does the preganglionic neuron release in the parasympathetic division and what receptor on the ganglion does it bind to?

A
  • acetylcholine
  • binds to nicotinic receptors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Is the autonomic ganglion closer to the CNS or the target tissue in sympathetic?

A

CNS (close to preganglioninc neuron)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What neurotransmitter does the preganglionic neuron release in the sympathetic division and what receptor on the ganglion does it bind to?

A
  • acetylcholine
  • binds to nicotinic receptors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where are the ganglions in the sympathetic and parasympathetic pathways (CNS or PNS)?

A

PNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What neurotransmitter does the postganglionic neuron release in the parasympathetic division and what receptor on the target cell does it bind to?

A
  • acetylcholine
  • binds to muscarinic receptor (GPCRs —> second messenger changes)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What neurotransmitter does the postganglionic neuron release in the sympathetic division and what receptor on the target cell does it bind to?

A
  • norepinephrine
  • adenergic receptors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the preganglionic neuron?

A
  • first neuron in chain with cell body in CNS
  • projects from CNS to an autonomic ganglion outside the CNS
  • synapses with postganglionic neuron
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what is the postganglionic neuron?

A
  • second neuron in the chain with cell body located in the autonomic ganglion
  • projects from an autonomic ganglion to the target tissue
  • synapses with target cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Look at slide 13 & 14

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the neuroeffector junction?

A

synapse between postganglionic autonomic neuron and target cell

17
Q

What is varicosity?

A
  • swelling in regions of axon – represents end of postganglionic neuron (looks like beading)
  • have neurotransmitters and APs cause cause them to be released (throuhg large area, not just 1 small)
18
Q

Can the release of autonomic neurotransmitters be modulated?

A

Yes

19
Q

Where are autonomic neurons synthesized?

A

in the axon

20
Q

What is the neuromuscular junction?

A

the synapse between somatic motor neuron and skeletal muscle

21
Q

What is the adreanal medulla (type of tissue, neurotransmitters released, pre & post synaptic ganglion, etc)?

A
  • has modified nerve cells
  • secreats norepinephrine and epinephrine neurohormones
  • neuron doctrine tissue
  • Innervated by sympathetic pregangionic fibers
  • post-ganglionic neuron lacks axon (chromaffin cells)
  • PG neuron secretes epinephrine (neurohormone) into blood
22
Q

How does norepinephrine get released and removed at the varicosity?

A
  1. AP arrives at varicosity
  2. Depolarization opens voltage gated Ca2+ channels
  3. Ca2+ entry triggers exocytosis of synaptic vesicles
  4. NE binds to andrenergic receptor on target
  5. Receptor activation ceases when NE diffuses away from the synapse
  6. NE is removed from the synapse
  7. NE can be taken back into synaptic vesicles for re-release
  8. NE is metabolized by monoamine oxidase (MAO)
22
Q

Where are autonomic neurotransmitters synthesized?

A

in the axon

23
Q

Does every autonomic receptor have the same affinity for neurotransmitters?

A

No! some prefer NE, 1 prefers E (b2), and 1 is equal (b1)

24
Q

What is a catecholamine?

A

a hormone released from the adrenal medulla

25
Q

Where does the somatic motor pathways originate & facts about?

A
  • In the CNS (brain or ventral horn of spinal cord)
  • myelinated, very long, always excitatory
  • terminal branches close to target
  • each terminal innervated single target
26
Q

What kind of receptors are in the neuromuscular junction?

A

nicotinic

27
Q

What is a motor end plate?

A
  • a series of folds that look like shallow gutters to increase surface receptors
  • on postsynaptic side of neuromuscular junction
  • on skeletal muscle cell membrane
  • have SEVERAL ACh receptors
28
Q

What enzyme is in the neuromuscular junction to break down neurotransmitters?

A

achetylcholinesterase (AChE)

29
Q

What channels are on skeletal muscles?

A
  • nAChR channels of skeletal muscle (NM subtype)
  • similar to NN ACh receptors
  • Chemically-gated channels with 2 binding sites for ACh
  • Always excitatory (muscle contraction)
30
Q

What receptors are on neurons?

A
  • NN ACh receptors
31
Q

What are the components of the neuromuscular junction?

A

axon terminals, motor end plates on muscle membrane, and schwann cell sheaths

32
Q

Look at figure 11.10 ©-(e)

A