Chapter 12 Peripherial Nervous System

Question 1

Peripheral nervous system (PNS)

Answer 1

Includes all nervous tissue outside CNS and ENS
Delivers sensory information to the CNS
Carries motor commands to peripheral tissues

Question 2

Nerves (peripheral nerves)

Answer 2

Bundles of axons with connective tissues and blood vessels
Carry sensory information and motor commands
Cranial nerves connect to brain
Spinal nerves attach to spinal cord

Question 3

Functional divisions of the PNS

Answer 3

Afferent division
Carries sensory information
From receptors in peripheral tissues and organs to CNS
Efferent division
Carries motor commands
From CNS to muscles, glands, and adipose tissue
Receptors
Detect changes or respond to stimuli
May be neurons or specialized cells
May be single cells or complex sensory organs (e.g., eyes, ears)
Effectors
Target organs that respond to motor commands

Question 4

Efferent division of PNS

Answer 4

Somatic nervous system (SNS)
Controls skeletal muscle contractions
Both voluntary and involuntary (reflexes)
Autonomic nervous system (ANS)
Controls subconscious actions, contractions of smooth and cardiac
muscle, and glandular secretions
Sympathetic division has a stimulating effect
Parasympathetic division has a relaxing effect

Question 5

From the Brain and Spinal cord, to the PNS Motor Commands of the Efferent system, to the Somatic Nervous system, to the Skeletal muscles

Answer 5

From the Brain to the PNS Motor Commands of the Efferent system, to the Autonomic Nervous Syst, to the Parasympathetic Division, to the Smooth muscle, Cardiac muscle and glands.
Or the Sympathetic Division, then to Smooth muscle, Cardiac muscle, glands and or Adipose Tissue.

Question 6

Neuroglia of the PNS

Answer 6

Insulate neuronal cell bodies and most axons
Two types
Satellite cells
Surround ganglia (clusters of neuronal cell bodies)
Regulate interstitial fluid around neurons
Schwann cells
Form myelin sheath or indented folds of plasma membrane
around axons
Neurolemma—outer surface of Schwann cell
A myelinating Schwann cell sheaths only one axon
Many Schwann cells sheath entire axon

Question 7

Neuroglia are found in

Answer 7

The PNS
Satellite Cells - Surround the neuron cell body in Ganglia: regulate O2, CO2, neutrients, and neurotransmitter levels around neurons in Ganglia.
Schwann Cells - Surrounds all axons in the PNS, responsible for Mylin of peripheral axons; participates in repair process after injury.