Autonomic nervous system

Question 1

What are the three components of the efferent pathway in the autonomic nervous system?

Answer 1

1. Preganglionic neuron (myelinated)
2. Autonomic ganglion (collection of cell bodies)
3. Postganglionic neuron (unmyelinaed)

Question 2

What are the two possibilities for the postganglionic neuron ?

Answer 2

Excitatory or inhibitory (in general, but not always associated with sympathetic and parasympathetic)

Question 3

What is the sympathetic response ?

Answer 3

The fight, flight or freeze response. It is a fast response.

Question 4

What is the parasympathetic response?

Answer 4

The rest and digest response. It is a slower response.

Question 5

What are the two types of autonomic neurons?

Answer 5

Cholinergic and adrenergic

Question 6

What are cholinergic neurons and how would you describe their effects?

Answer 6

Neurons that release acetylcholine, the effects are localized and short lived.

Question 7

What are adrenergic neurons and how would you describe their effects?

Answer 7

Neurons that release norepineprhine. Their effects are widespread and long lasting.

Question 8

What is the structural difference in the efferent pathways in the sympathetic and parasympathetic systems?

Answer 8

In sympathetic systems, the preganglionic neurons are short, and go to ganglia close to the spinal cord. The post ganglionic neurons are long and go to the effectors. In parasympathetic pathways, the preganglionic neurons are long and go to ganglia close, or in the effectors and the post ganglionic are short.

Question 9

Describe the neurotransmitters and receptors involved in the efferent pathway of sympathetic NS.

Answer 9

Preganglionic neurons are cholinergic. The postsynaptic neurons have nicotinic receptors. The post ganglionic are mostly adregenic, except sweat glands and blood vessels associated with skeletal muscles). The effectors have alpha and beta adregenic receptors, except the ones that receive Ach, that have muscarinic receptors.

Question 10

Describe the neurotransmitters and receptors involved in the efferent pathway of parasympathetic NS.

Answer 10

Preganglionic neurons are cholinergic. The postsynaptic neurons have nicotinic receptors. Post ganglionic neurons are also cholinergic, and the receptors have muscarinic receptors.

Question 11

What is a nicotinic receptor?

Answer 11

a ligand-gated ion channel, causes depolarization of the membrane (excitatory)

Question 12

What is a muscarinic receptor?

Answer 12

A G-protein coupled receptor. It can cause excitatory or inhibitory responses.

Question 13

What are alpha and beta adregenic receptors?

Answer 13

G-protein coupled receptors. It can cause excitatory or inhibitory responses.

Question 14

What type of response do somatic neurons elicit ?

Answer 14

Excitatory

Question 15

What general tone does the body have in terms of autonomic nervous system?

Answer 15

Parasympathetic tone

Question 16

Describe the differences between somatic and autonomic nervous systems

Answer 16

• Motor neurons in both, and sensory neurons from the skeletal muscles and special somatic senses, and sensory neurons from the visceral organs or other autonomic sensory receptors
• Sensory input consciously perceived in SNS and not in ANS
• Somatic motor neurons innervate skeletal muscles to produce conscious movement and AMN regulate visceral activity by activating or inhibiting ongoing activity of smooth muscle, cardiac muscle and glands. Most responses cannot be consciously altered or suppressed
• Structures of efferent pathways differ

Question 17

What are called organs that have both sympathetic and parasympathetic neuron impulses?

Answer 17

Dually inervated