Peripheral Nervous System

Question 1

What is the function of the PNS?

Answer 1

Transmission of signals between the CNS and receptors/effectors

Question 2

What are Nerves?

Answer 2

bundled groups of axons

Question 3

How many pairs of Nerves are in the PNS?

Answer 3

43 pairs of nerves in the PNS

• Cranial (12)
• Spinal: cervical (8), thoracic (12), lumbar (5), sacral (5) and coccygeal (1)

All spinal nerves have both afferent and efferent neurons

dont need to know numbers or names

Question 4

What is The function of the Somatic Nervous System?

division of the PNS

Answer 4

• Skeletal muscle innervation
• Cell bodies found in brainstem / ventral horn (spinal cord)
• Large diameter, myelinated axons travel from the CNS to skeletal muscle without additional synapses
• Excitatory-only – no somatic neurons inhibit skeletal muscle contraction

Question 5

A division of the PNS

What is The Autonomic Nervous System?

Innervates non-skeletal muscle

Answer 5

• regulates involuntary bodily functions
• Can be excitatory or inhibitory

Two neurons in series that connect the CNS to the effector

• 1st neuron has cell body in CNS
• Synapse between two neurons is outside the CNS, in the autonomic ganglion

Question 6

What are divisions of the ANS?
(Autonomic Nervous System)

Answer 6

The Sympathetic Nervous System
The Parasympathetic Nervous Systems

Question 7

ANS

What is the Sympathetic Nervous System?
What major neurotransmitters does it release?

Answer 7

The Sympathetic Nervous System

• “Fight or flight”
• Typical for response to be “body-wide”
• Neurons leave spinal cord at thoracic & lumbar regions
• Major NT released between pre- and postganglionic neurons -> ACh
• Major NT released between postganglionic neuron and receptor cells -> NorEpinephrine

Question 8

What does The Adrenal Medulla release?

Answer 8

Sympathetic innervation

• Activation by preganglionic sympathetic neurons causes the release of epi and NE into the blood (80: 20)
• Hormones travel in the blood to effector cells

Question 9

What are The Parasympathetic Nervous Systems?

Answer 9

“Rest and digest”

• Typical for response to be “tailored”
• Neurons leave the spinal cord at brainstem and the sacral region of the spinal cord

Question 10

What are the Major NT of The Parasympathetic Nervous Systems?

Answer 10

Major NT released between
pre- and postganglionic neurons -> ACh

Major NT released between
postganglionic neuron and receptor cells -> ACh

Question 11

Summary image

Answer 11

Question 12

What is Dual Innervation?

Answer 12

many effector cells are innervated by both the parasympathetic and sympathetic nervous system.

Question 13

Effects of Sympathetic and Parasympathetic

Answer 13