Obj. 7: Cholinergic & Adrenergic Fibers, Neurotransmitters & Receptors

Question 1

What are the two main neurotransmitters of the ANS?

Answer 1

Acetylcholine (ACh)

and

Norepinephrine (NE)

Question 2

Which axons release Acetylcholine (ACh)?

Answer 2

**All preganglionic axons **

& ALL parasympathetic postganglionic axons

Question 3

Which neurotransmitter is released by cholinergic fibers?

Answer 3

Acetylcholine (ACh)

Question 4

Which neurotransmitter is released by Adrenergic fibers?

Answer 4

Adrenergic fibers are a type of sympathetic postganglionic axons that release

**NE (and Epinephrine) **

Question 5

What are the effects of neurotransmitters?

Answer 5

excitatory or inhibitory depending upon the receptor type

Question 6

What are the two types of Cholinergic receptors that bind ACh?

Answer 6

**nicotinic **

&

muscarinic

Question 7

Where did the names for muscarinic and nicotinic receptors come from?

Answer 7

The names came from drugs that bind to them and mimic ACh effects.

Question 8

Where are Nicotinic Receptors found?

Answer 8

• Motor end plates (skeletal muscle)
• All ganglionic neurons of both sympathetic and parasympathetic divisions
  
  • (site of synapse of preganglionic fibers)
• The hormone-producing cells of the adrenal medulla (NE & Epi)

Question 9

What is the effect of ACh binding to nicotinic receptors?

Answer 9

ACh binding to nicotonic receptors is always stimulatory as it directly opens ion channels,

depolarizing the postsynaptic cell

Question 10

Where are Muscarinic Receptors found?

Answer 10

Muscarinic Receptors occur on all effector cells stimulated by postganglionic cholinergic fibers (all parasympathetic and some sympathetic)

Question 11

What is the effect of ACh binding to Muscarinic Receptors?

Answer 11

Can either be inhibitory or excitatory

depends on the receptor type of the target organ

Question 12

What are the two types of Adrenergic Receptors (sympathetic postganglionic only) ?

Answer 12

Alpha and Beta

Question 13

What are the subclasses for each of the alpha and beta adrenergic receptors?

Answer 13

alpha1

alpha2

beta1

beta2

beta3

Question 14

What are the effects of NE binding to alpha adrenergic receptors?

Answer 14

generally stimulatory

Question 15

What are the effects of NE binding to beta adrenergic receptors?

Answer 15

generally inhibitory

exception: NE binding to beta receptors of the heart is stimulatory

Question 16

True or false?

In the Somatic Nervous system, all receptors are cholinergic (ACh) - nicotinic at skeletal muscle

Answer 16

TRUE

Question 17

In the Parasympathetic Nervous System,

preganglionic terminals release __?__, so ganglion receptors are ________?_____

Answer 17

In the Parasympathetic Nervous System,

Preganglionic terminals release ACh, so ganglion receptors are cholinergic-nicotinic

Question 18

In the Parasympathetic Nervous System,

Postganglionic terminals release ____, so effector organ receptors are ______?_____

Answer 18

In the Parasympathetic Nervous System,

Postganglionic terminals release ACh, so effector organ receptors are cholinergic - muscarinic

Question 19

In the Sympathetic Nervous System,

preganglionic terminals release __?___, so ganglion receptors are ____?____

Answer 19

In the Sympathetic Nervous System,

Preganglionic terminals release ACh, so ganglion receptors are cholinergic - nicotinic

Question 20

In the Sympathetic Nervous System,

Post ganglionic terminals release _?__, at a few effectors (eccrine sweat glands & some skeletal muscle blood vessels), so these are ___?______

Answer 20

In the Sympathetic Nervous System,

Post ganglionic terminals release ACh at at few effectors (eccrine sweat glands & some skeletal muscle blood vessels), so these are cholinergic - muscarinic

Question 21

In the Sympathetic Nervous System,

Most postganglionic terminals release ____?___, so ganglion receptors are either

_________ or ____________, depending on receptor type (alpha or beta)

Answer 21

In the Sympathetic Nervous System,

Most postganglionic terminals release NE, so ganglion receptors are either alpha-adrenergic or beta-adrenergic, depending on the receptor type (alpha or beta)