Chapter 13 & 14: Peripheral Nervous System and the Autonomic Nervous System

Endoneurium

The delicate areolar connective tissue wrapping around each individual axon

Perineurium

The dense irregular connective tissue wrapping around each nerve fascicle

Epineurium

The dense irregular connective tissue wrapping around the entire spinal nerve

Myelin sheath

The protective layer of fat and protein that wraps around axon; speeds up message transmission

Meninges

Three layers of connective tissue that surrounds the CNS and provides it with protection, cushioning, and support

Pia mater

The innermost meninx layer composed of delicate connective tissue; contains many tiny blood vessels and clings to the CNS like plastic wrap

Arachnoid mater

The middle, web-like meninx layer that forms a loose covering; helps hold the cerebrospinal fluid around the CNS

Subarachnoid space

The space beneath the arachnoid mater that is filled with cerebrospinal fluid; cushions the CNS, absorbs shocks, circulates nutrients, and rids of any wastes

Dura mater

The tough, outermost meninx layer; acts as a strong shield for the CNS

Sensory receptor

Responds to stimulus

Stimulus

Any change in the environment that triggers a response

Sensory neuron

Carries signal through the dorsal root ganglion and into the posterior horn of the spinal cord

Interneuron

The single synapse between the sensory and motor neurons; process information

Motor neuron

Carries response from the anterior horn, through the ventral root, and into the spinal nerve

Effector

The muscle or gland that responds to produce the reflex

List the functions of the autonomic nervous system

1. Controls viscera; smooth/cardiac muscle and glands

2. Unconscious and involuntary

3. Releases either Acetylcholine (ACh) or Norepinephrine (NE)

4. Stimulates/inhibits

Sympathetic division 

“Fight-or-flight” — Heart rate and blood pressure increase

Dilates pupils, airways, vessels to skeletal muscles, hearts, liver, & adipose tissue

Constricts the blood vessels to nonessential organs

Mobilizes nutrients for energy (glucose & fats)

Inhibits hunger

Parasympathetic division (aka craniosacral division)

“Rest-and-digest” — Heart rate and blood pressure decreases/returns to normal

• SLUDD

  • Salivation

  • Lacrimation

  • Urination

  • Digestion

  • Defecation

Collateral ganglia

Ganglia in the sympathetic division; unpaired & anterior to the spinal cord

Terminal ganglia (aka the thoracolumbar division)

Ganglia in the parasympathetic division; nearby/within the walls of the organ it serves

Sympathetic ganglia

Ganglia in the sympathetic division; is unpaired and located besides the spinal cord

Plexus

a network of fibers from different rami; contains fibers from different spinal nerves

Sympathetic nervous system controls what extra organ(s) not found in the parasympathetic nervous system?

The skin, blood vessels, sweat glands, kidneys, and adrenal medulla