Pns

What is a ganglion

Collection of neuron cell bodies outside CNS

What does motor innervation do?

Sends instructions from the CNS to the muscles and glands

What does sensory innervation do?

What neuron is this

Motor

What neuron is this

Sensory

What is a neuron

Entire nerve cell

What is a nerve

Bundle of axons that have left the CNS to join the PNS

What is yellow

Sensory neuron

What is pink

Motor neuron

What does somatic innervation concern?

Body wall (skeletal muscle and skin)

What does visceral innervation concern?

Internal organs (heart)

How many neurons connect the CNS to the target muscle

1

How many neurons connects the site of stimulus to CNS for somatic sensory innervation?

One

1

Prechordal mesoderm

2

Lateral plate mesoderm

3

Intermediate mesoderm

4

Paraxial mesoderm

5

Notochord

What does the paraxial mesoderm give rise to?

Bone, skeletal muscle of the trunk, and overlaying dermis

1

Somites

2

Paraxial mesoderm

3

Prechordal mesoderm

What is the prechordal mesoderm limited to?

Head and neck

How many pairs of somites are there

37

How many pairs of somites are occipital

4

How many pairs of somites are cervical

8

How many pairs of somites are thoracic

12

How many pairs of somites are lumbar

5

How many pairs of somites are sacral

5

How many pairs of somites are coccygeal

3

What does the somite turn into first

Dermanmyotome and sclerotome

What does somite turn into second

Expaxial dermamytome, hypaxial dermamyotome, sclerotome

What gives rise to Expaxial dermamytome and hypaxial dermamyotome,

Dermamyotome

What kind of muscles does the epaxial dermamyotome give rise to?

Deep back muscles and the dermis that covers them

What does the hypaxial dermamyotome give rise to?

All other skeltal myscle and dermis below the neck

Why do epaxial and hypaxial dermamyotomes have seperate supplies?

Thoracolumbar fascia

How many cervical

8

How many thoracic

12

How many lumbar

12

How many sacral

5

How many coccygeal

1

What vertbrae are dermatome only?

Co1 and S5

What spinal nerves have parasympathetic axons?

S2-S4

1

Epaxial Dermatome

2

Dorsal ramus

3

Dorsal root ganglion

4

Dorsal horn

5

Dorsal horn

6

Spinal cord gray matter

7

Ventral horn

8

Ventral root

9

Ventral ramus

Blank yellow box

Hypaxial dermamyotome

Which root do motor pathways go through?

Ventral root

Which root does sensory go through

Dorsal

What are roots made up of?

Either sensory or motor

What are rami made up of?

Mixture of sensory and motor

Where are cell bodies located?

Ventral horn of spinal cord gray matter

How many neurons connect the CNS to the target tissue for visceral motor innervation

Two

What are visceral structures in the body wall?

Sweat glands, arrector pili, smooth muscle in skin and vessel walls

What are the the components of visceral innervation

Sympathetic, parasympathetic, enteric innervation

What are the exceptions to the rule that nearly all the of the visceral r=structures on the body receieve sympathetic innervation only

External genitalia

Where are preganglionic cell bodies for sympathetics?

T1-L2 only

Where is the location for preganglionic cell bodies for parasympathetics?

Brain or in the S2-S4 levels of the spinal cord

Where are preganglionic cell bodies?

Lateral horn of spinal cord gray matter

Where do preganglionic axons exit the spinal cord?

Ventral root

Where are postganglionic cell bodies found?

Paravertebral ganglia

How do the preganglionic axons reach the postganglionic?

White rami communicantes

Where does the synapse between pre and post ganglionic occur?

Paravertebral ganglion

How do post ganglionic axons return to the ventral ramus?

Gray rami communicantes

What are gray rami only used for?

To return to the body wall

How are 14 spinal cord levels (T1-L2) able to supply sweat glands for 31

dermatomes?

The sympathetic trunk is used as a pathway that lets levels T1-L2 share their preganglionic axons with somites at every level.