Neurohistology

Question 1

Where are the location of neuronal cell bodies in the CNS? PNS?

Answer 1

CNS - Gray matter, deep nuclei

PNS - ganglia

Question 2

Where are the locations of axons in the CNS? PNS?

Answer 2

CNS - white matter

PNS - nerves

Question 3

What is the are dendritic spines?

Answer 3

Transient membrane protrusions that increase the surface area for synapses on dendrites

Important in neural plasticity

Question 4

What are the features of the neuronal soma?

Answer 4

Large nucleus with prominent nucleolus

Presence of Nissl bodies

Typical organelles

Lipofuscin

Question 5

What are Nissl bodies?

Answer 5

RER and polyribosomes

grainy apprearance

Question 6

What is the axon hillock?

Answer 6

Location of action potential initiation

Question 7

Describe anterograde transport

Answer 7

Movement forward from the soma to the axon terminal

Uses kinesin

Transport of cytoskeletal proteins occurs more slowly

Question 8

Describe retrograde transport

Answer 8

Movement backward from the axon terminal to the soma

Uses dynein

Question 9

Describe multipolar neurons

Answer 9

Multiple dendritic processes

Characteristic of motor neurons and interneurons

Question 10

Describe bipolar neurons

Answer 10

One main dendrite and one axon

Characteristic of special sensory neurons (e.g. vision, olfaction, hearing)

Question 11

Describe pseudounipolar neurons

Answer 11

Single bidirectional axon-peripheral process and a central process

Characteristic of sensory neurons in the dorsal root ganglia

Question 12

What are the four glial cells of the CNS?

Answer 12

Astrocyte

Oligodendrocyte

Ependymal cell

Microglia

Question 13

What are the functions of astrocytes?

Answer 13

Formation of the Blood-brain barrier

Nutritional support

Uptake of neurotransmitters

Regulation of extracellular ionic concentrations

Question 14

What is the function of ependymal cells?

Answer 14

Line the ventricles of brain and central canal of spinal cord

Produce cerebrospinal fluid

Apical ends have cilia and microvilli

Question 15

What are microglial cells?

Answer 15

Small cells with mobile processes that sense the environment

Change shape when activated and begin to phagocytose damaged/foreign cells

Derived from monocytes

Important for immune surveillance

Question 16

What is the function of oligodendrocytes?

Answer 16

Myelinates axons in the CNS

One cell can myelinate multiple internodes of one or more neurons

Question 17

What are the supportive cells of the PNS?

Answer 17

Schwann cells

Satellite cells

Question 18

What is the function of Schwann cells?

Answer 18

Meylinates internodes in the PNS

One schwann cell wraps one internode of one neuron

Also envelop small diameter neurons and provide support, but don’t myelinate them

Question 19

How is gray and white matter oriented in the brain?

Answer 19

Gray matter on the outside (cerebral cortex)

White matter on the inside

Question 20

How is gray and white matter oriented in the spinal cord?

Answer 20

Gray matter on the inside

White matter on the outside

Question 21

What are meninges?

Answer 21

Connective tissue membranes that wrap the brain and spinal cord

Question 22

What is the Dura mater and what two layers make it up?

Answer 22

The outermost and toughest CT membrane

Periosteal layer

Meningeal layer

Question 23

What is the periosteal layer?

Answer 23

Layer of the dura mater attached to the bone of the sull

Trauma may cause bleeding between bone and dura
–epidural hematoma

Question 24

What is the meningeal layer?

Answer 24

Will separate to form the walls of a dural sinus and rejoin to form a dural fold

Question 25

What is the arachnoid mater?

Answer 25

Layer between the dura mater and pia mater Contains spider web-like extensions that cross the subarachnoid space

Question 26

Where is the subarachnoid space and what does it contain?

Answer 26

Located between the arachnoid and pia mater Contains cerebrospinal fluid

Question 27

What is the Pia mater?

Answer 27

A delicate, highly vascularized layer that is intimately applied to the surface of the brain and spinal cord

Question 28

Describe the cerebral cortex

Answer 28

Gray matter in the cerebrum that is organized into 6 layers Pyramidal cells are located here, major output comes from layer V

Question 29

What are the layers of the cerebellum?

Answer 29

Molecular layer Granular layer Medulla (white matter)

Question 30

What are the layers of the cerebellar cortex?

Answer 30

Molecular layer Purkinje cell layer Granular layer

Question 31

What does the dorsal horn contain?

Answer 31

Terminal portion of somatosensory neurons

Question 32

What does the ventral horn contain?

Answer 32

Somatomotor neurons

Question 33

What connective tissue layers cover nerves in the PNS?

Answer 33

Epineurium - surrounds entire nerve Perineurium - surrounds nerve fibers bundled in fascicles Endoneurium - surrounds individual axon

Question 34

What are tactile (Meissner's) corpuscles?

Answer 34

Encapsulated sensory receptor located in the dermal papillae of thick skin Modality - light touch, texture

Question 35

What are Lamellar (Pacinian) corpuscles?

Answer 35

Encapsulated sensory receptor located deep in the dermis Modality - deep pressure, vibration, stretch

Question 36

What sensory receptors are responsible for propioception?

Answer 36

Muscle spindles Tendon organ

Question 37

What are the two unencapsulated sensory receptors?

Answer 37

Free nerve endings - pain, heat, cold Hair receptors - light touch, movement of hair

Question 38

Describe filiform papillae of the tongue

Answer 38

Smallest and most numerous Keratinized tips Sense texture of food No taste buds

Question 39

Describe fungiform papillae

Answer 39

Mushroom shaped Scattered widely over the tongue Taste buds

Question 40

Describe circumvallate papillae

Answer 40

Located towards the back of the tongue Taste buds are embedded on the lateral aspects

Question 41

Describe folaite papillae

Answer 41

Located on the posterolateral aspect of the tonuge Associated with taste buds, but not well developed in humans

Question 42

What three types of cells do taste buds contain?

Answer 42

Taste receptor cells Supporting cells (sustentacular cells) Basal cells

Question 43

Where is the olfactory epithelium located?

Answer 43

Upper 1/3 of the nasal cavity

Question 44

What type of neurons are located in the olfactory epithelium?

Answer 44

Bipolar neurons

Question 45

How do the olfactory sensory neurons synapse with the olfactory bulb?

Answer 45

The travel through the holes in the cribriform plate of the ethmoid bone