11/21/2014 Microscopic Anatomy Nerve Thomas Poole

Question 1

What is another term for a Schwann cell?

Answer 1

Neurolemmocyte

Question 2

T/F: A single Schwann cell can cover many axons.

Answer 2

True

Question 3

What are the progenitors of Schwann cells?

Answer 3

Neural crest cells

Question 4

What creates the Schmidt-Lanterman clefts?

Answer 4

The leftover cytoplasm in the Schwann cell that gets squeezed into this one space, creating an arrowhead like appearance.

Question 5

The lipid component of myelin is not preserved by _____ and standard histological preparation.

Answer 5

Formalin fixation

Question 6

The place where one Schwann cell is adjacent to another is called?

Answer 6

A node of Ranvier

Question 7

What covers a node of Ranvier?

Answer 7

Interdigitating cytoplasmic processes

Question 8

If you want lipid to appear on a histo slide, what chemical should be added to your preparation?

Answer 8

Osmium

Question 9

T/F Nerves may contain both myelinated and unmyelinated fibers.

Answer 9

True

Question 10

What is the epineurium made of?

Answer 10

Dense irregular connective tissue

Loose connective tissue

Question 11

The most prominent and visible coat of a nerve is the ____ that forms a longitudinal bundle (fasicle) of axons.

Answer 11

perineurium

Question 12

How are nerves protected from the outside extracellular environment?

Answer 12

The perineurium is made of several layers of specialized fibroblastic cells (epitheloid myofibroblasts) that form tight junctions with one another. This arrangement provides a barrier to the massage of most macromolecules.

Question 13

The Schwann cell ensheathed axons are surrounded by a delicate layer of _________ called the endoneurium.

Answer 13

Reticular fibers

Question 14

What are ganglia?

Answer 14

Peripheral clusters of nerve cell bodies that are surrounded by satellite cells.

Question 15

T/F: Sensory and autonomic ganglia cannot be distinguished by the light microscope.

Answer 15

False, they can be distinguished at the level of the light microscope

Question 16

Sensory ganglia are also known as:

Answer 16

dorsal root ganglia (DRG)

Question 17

T/F: No synapses take place within the sensory ganglia.

Answer 17

True. DRGs contain the cell bodies of pseudounipolar sensory neurons.

Question 18

How do satellite cells appear around sensory neurons in a sensory ganglion?

Answer 18

Evenly spaced around the neuron, like a chain of pearls.

Question 19

How does the nucleus appear in a sensory ganglion cell?

Answer 19

In the middle.

Also note: many myelinated nerve fibers in these cells.

Question 20

The sensory or dorsal root ganglia contain cell bodies of:

Answer 20

pseudounipolar sensory neurons

Question 21

The autonomic ganglia contain cell bodies of:

Answer 21

multipolar neurons

Question 22

T/F: Synapses do not occur in autonomic ganglia.

Answer 22

FALSE. Synapses do not occur in sensory ganglia, but DO occur in autonomic ganglia.

Question 23

In comparison to sensory ganglia, autonomic ganglia appears more _____.

Answer 23

disordered.

Question 24

What is a main distinguishing feature of autonomic ganglia?

Answer 24

Multiple process coming out of the cell.
Nuclei not in the center.
Smaller neuronal cell bodies than sensory ganglia.
Numerous unmyelinated nerve fibers.

Question 25

Where do motor neurons terminate?

Answer 25

At the motor endplate

Question 26

The postsynaptic membrane of a motor neuron contains two very important features. What are they?

Answer 26

1. Junctional folds

2. Acetylcholine receptors

Question 27

Bare axons (free nerve endings) are important for sensations of what?

Answer 27

Hot and cold from the skin, itching, touch and pain

Question 28

What are the three encapsulated nerve endings?

Answer 28

1. Meissner’s corpuscles
2. Pacinian corpuscles
3. Muscle spindles

Question 29

Where are Meissner’s corpuscles found?

Answer 29

Dermal papillae of hairless skin

Question 30

What kind of touch do Meissner’s corpuscles detect?

Answer 30

low-frequency stimuli

Question 31

Where are Pacinian corpuscles found?

Answer 31

dermis or hypodermis

Question 32

What are Pacinian corpuscles made of?

Answer 32

Concentric layers of flatted Schwann cells

Question 33

What kind of stimuli do Pacinian corpuscles detect?

Answer 33

Pressure, vibration due to displacement of capsule lamellae

Question 34

What is the main function of a muscle spindle?

Answer 34

It is a proprioceptor.

Question 35

Muscle spindles contain specialized muscle fibers called ____ in a fluid-filled space.

Answer 35

Intrafusal fibers

Question 36

How do muscle spindles work?

Answer 36

Sensory nerve fibers exiting the capsule send signals about the extrafusal muscle fiber length and relay this information to the spinal cord where it plays a role in reflexes involved in maintaining posture and coordinating walking.