7. Chapter 11- Efferent Division

Question 1

What is the difference between parasympathetic and sympathetic?

Answer 1

Parasympathetic is rest and digest
Sympathetic is fight or flight

These are divisions of the autonomic nervous system

Graph on slide 3 Oct 12
Main difference is sympathetic has the sympathetic chain

Go through slide 11 oct 12

Question 2

Why are autonomic reflexes important for homeostasis?

Answer 2

The autonomic nervous system works closely with the endocrine system and behavioural systems to maintain homeostasis
Chart of input-responses on slide 11 oct 10

Question 3

What are examples of parasympathetic and sympathetic responses?

Answer 3

SLIDE 12 oct 10
Symp- dilated pupils, increase heart rate, ejaculation, fat breakdown
Parasmyp- constricts pupils, shows heart rate, erection

Question 4

What are the two efferent neurons in autonomic pathways?

Answer 4

The two neurons synapse in an autonomic ganglion
Preganglionic neuron
Postganglionic neuron

1 preganglionic will synapse with 8 or 9 postganglionic neurons

Picture on slide 13 oct 10

Question 5

Where do the sympathetic branches originate? (Ganglia, preganglion, long/short)

Answer 5

Ganglia are mainly found in two ganglion chains running along the vertebral column
Preganglionic Neurons originate in thoracic and lumbar regions
Short preganglionic, long post ganglionic neurons
Picture on slide 14 oct 10

Question 6

Where do the parasympathetic branches originate? (Ganglia, preganglion, long/short)

Answer 6

Ganglia are mainly located on or near their target organs
Preganglionic neuroms originate in the brainstem and exit via cranial nerves or from the sacral region of the spinal cord
Long preganglionic, short postganglionic neurons
Picture on slide 15

Question 7

What are the chemical signals parasympathetic and sympathetic pathways use?

Answer 7

Sympathetic- use acetylcholine and norepinephrine
Parasympathetic- use acetylcholine
Picture on slide 16 oct 10

Some autonomic neurons are non adrenergic and non-cholinergic (use substance P, ATP, NO)

Question 8

What is the adrenal medulla?

Answer 8

Specialized neuroendocrine structure associated with the sympathetic nervous system
Often described as a modified sympathetic ganglion, contain chromaffin cells which are modified postganglionic neurons
Pictures on slide 17 oct 10

Question 9

What are autonomic pathways?

Answer 9

Target smooth and cardiac muscle, many exocrine glands, a few endocrine glands, and some adipose tissue
Picture on slide 18 oct 10

Question 10

What are the stages of the synthesizing of the primary neurotransmitter Norepinephrine (NE)? (8 steps)

Answer 10

1. AP arrived at varicosity
2. Depolarization opens Ca2+ channel
3. Ca2+ entry triggers exocytosis of synaptic vesicles
4. NE binds to adrenergic receptor on target
5. Receptor activation ceases when NE diffuses away from synapse
6. NE is removed from synapse
7. NE can be taken back into synaptic vesicles for re release
8. NE is metabolized by monoamine oxidase (MAO)
   Picture on slide 19 oct 10

Question 11

What are the stages of the synthesizing of the primary neurotransmitter acetylcholine? (4 steps)

Answer 11

1. Acetylcholine (ACh) is made from choline and acetyl CoA
2. In the synaptic cleft, ACh is rapidly broken down by the enzyme acetylcholinesterase
3. Choline is transported back into the axon terminal by cotransport with Na+
4. Recycled choline is used to make more ACh
   Picture on slide 20 oct 10

Question 12

What are sympathetic adrenergic (NE and E) receptors?

Answer 12

G protein coupled receptors (metabotropic receptors)
Contains alpha and beat categories with multiple subtypes
Alpha most common
Table on slide 7 oct 12 don’t need to know

Question 13

What are parasympathetic cholinergic (ACh) receptors?

Answer 13

G protein coupled receptors

5 subtypes M1-M5

Question 14

How does the neuromuscular junction work?

Answer 14

Contains axon terminals, motor end plates on muscle membrane and Schwann cell sheaths
Motor neuron vesicles contain acetylcholine
AP arrives at axon terminal cause voltage gated Ca2+ channels to open and Ca cause synaptic vesicles to fuse with presynaptic membrane and release ACh into synaptic cleft
Slide 14 oct 19

Question 15

What is the nicotinic acetylcholine receptor?

Answer 15

Binds two ACh molecules which opens cation channel which allows for Na+ and K+ to pass
Slide 15 oct 19
Na+ entry through aACh generates excitatory end plate potential that spreads to adjacent voltage gated Na channels on sarcolemma and initiated an action potential
Slide 16 oct 19

Question 16

What is neural transmission ceased?

Answer 16

Once APs stop firing the alpha motor neuron ACh diffuses away or broke down to acetate
Choline is transported back into motor neuron and combined with acetyl CoA