Nerve

Question 1

Identify

Answer 1

Node of Ranvier: between two Schwann cells. Covered by interdigitating cytoplasmic processes

Question 2

Identify

Answer 2

1 myelinated axon in longitudinal section showing 5 Schmidt-Lanterman clefts and the Axon

Question 3

Identify

Answer 3

4 myelinated axons in cross section

Question 4

Epineurium

Answer 4

• Outermost layer
• Binds bundles or fascicles together into nerves
• Dense irregular or loose connective tissue

Question 5

Perineurium

Answer 5

• Prominent layer of modified fibroblasts (epitheloid myofibroblasts - form tight junctions with each other) and collagen fibers
• Groups nerve fibers into bundles or fascicles
• Acts as a selective diffusion (blood-nerve) bundle that protects nerve from macromolecules

Question 6

Endoneurium

Answer 6

Delicate layer of reticular fibers produced by Schwann cells

Surround axons (wrapped in Schwann cells)

Question 7

Identify

Answer 7

1. Epineurium
2. Perineurium
3. Endoneurium

Question 8

Identify

Answer 8

Sensory Ganglia

1. Contain cell bodies of pseudounipolar neurons (single process)
2. No synapses within ganglion
3. Numerous myelinated fibers
4. Central nucleus
5. Regular ring of satellite cells, for protection

Question 9

Identify

Answer 9

Autonomic ganglion

1. Contain cell bodies of multipolar neurons (many processes, appear disordered)
2. Synapses in ganglion
3. Numerous unmyelinated fibers
4. Neurons have an acentric nucleus and smaller cell bodies

Question 10

Identify

Answer 10

Meissner’s corpuscles: encasulated endings found in dermal papillae of hairless skin

• Touch receptors
• Respond to low frequency stimuli

Question 11

Identify

Answer 11

Pacinian Corpuscles: Large (1 mm) encapsulated ending in dermis/hypodermis of skin from flattened layers of concentric Schwann cells

-Mechanoreceptors: respond to pressure and vibration (capsule lamellae displaced)

Question 12

Identify

Answer 12

Muscle spindle: encapsulated receptors in skeletal muscle

• Important for proprioception (maintaining posture and walking)
• Contain intrafusal fibers in fluid-filled space (gray arrow)

Question 13

Identify

Answer 13

Auerbach’s Plexus: parasympathetic ganglion between outer longitudinal and inner circular layers of smooth muscle in intestines

Question 14

Identify

Answer 14

1. Unmyelinated fibers
2. Myelinated fibers (stain with osmic acid to see lipid portion)