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Veterinary Histology
Nervous system
79
Histology
Graduate
09/22/2012

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Cards

Term
Perikaryon
Definition
Neuronal cell body
Term
Soma
Definition
Neuronal cell body
Term
Nissl material
Definition
basophilic regions if cytoplasm of neuronal cell bodies
Term
lipofuscin granules
Definition
secondary lysosomes located in cytoplasm of neuronal cell body
Term
Nissl material
Definition
basophilic regions if cytoplasm of neuronal cell bodies
Term
Axon hillock
Definition
region of cell body from which axon projects
Contains neurofilaments and microtubules
Term
neurofilaments
Definition
type of intermediate filament located in axon hillock of nerve cells
Term
Why is axon hillock less basophilic than other parts of cytoplasm?
Definition
Few organelles here (less ER)
Term
2 sections that form peripheral nervous system
Definition
1. Somatic (skeletal muscle control)
2. Visceral nervous system
Autonomic efferent = sympathetic and parasympathetic
Term
Somatic nervous system
Definition
Portion of PNS;
Afferent sensory fibers
Efferent fibers innervate skeletal muscle
Term
Visceral nervous system
Definition
Afferent sensory fibers
Efferent fibers form autonomic nervous system - innervate heart sm. muscle, glands
Term
Autonomic nervous system
Definition
Efferent version of visceral nervous system of PNS
parasympathetic and sympathetic fibers
innervate heart, smooth muscle, glands
Term
Purpose of dendrites
Definition
increase cell surface available for cell-to-cell contact
Term
Multipolar neurons
Definition
one axon, many dendrites
Term
Bipolar neurons
Definition
one axon, one dendrite
Term
Pseudo-unipolar neurons
Definition
a single cytoplasmic stalk projects from the cell body and then bifurcates into axon and dendrite
Term
Pseudo-unipolar neurons located
Definition
sensory neuron in peripheral nervous system
Term
Types of glial cells in PNS
Definition
1. Schwann cells
2. Satellite cells
Term
Schwann cells
Definition
Schwann cells wrap around PNS nerve fibers many times creating a myelin sheath
Single myelenated axon is covered by many Schwann cells in tandem
Term
Myelinated fibers
Definition
Nerve fibers wrapped many times by Schwann cells in the PNS
Term
Unmyelinated fibers
Definition
Nerve fibers that lie in simple invaginations of schwann cells
Term
Nerve fiber
Definition
nerve cell process with its associated cellular coating
Term
Nerve cell body in PNS is covered by:
Definition
satellite cells
Term
Schwann cells provide what kind of insulation
Definition
Electrical - as it is lipid rich, ions do not pass through easily
Term
Node of Ranvier
Definition
Where the edges of adjacent Schwann cells meet - a single myelinated axon is covered by many Schwann cells
Term
Epineurium
Location and composition
Definition
Location: Outermost layer of a peripheral nerve
Composition: Connective tissue containing collagen fibers and some adipose cells
Term
Perineurium
Location and composition
Definition
Location: Layer surrounding eachfascicle (group of nerve fibers) within a nerve
Composition: Cellular layer
Term
Endoneurium:
Location and composition
Definition
Location: between individual nerve fibers within a fascicle
Composition: Collagen and (often) reticular fibers, fibroblasts
Term
Collection of nerve cell bodies located outside the central nervous system
Definition
Ganglion
Term
What surrounds cell bodies in a ganglia?
Definition
Satellite cells (glial cells), and a fibrous capsule that is continuous with the epineurium
Term
Where are cell bodies of motor neurons located
Definition
CNS
Term
What is a motor neuron?
Definition
Somatic efferent neuron that innervates skeletal muscle cells
Term
Where are cell bodies of sensory (afferent) neurons located?
Definition
Ganglia in the dorsal roots of spinal nerves (dorsal root ganglia)
Term
Dorsal root ganglia
Definition
Sensory neuron afferent cell bodies located in ganglia in the dorsal roots of spinal nerves
Term
What nerves have pseudo-unipolar axons?
Definition
Sensory (afferent) neurons
Term
Morphology of neuron cell bodies
Definition
Round and many have prominent nuclei - small satellite glial cells surround each neuron cell body
Term
What are the 2 neurons of the autonomic efferent pathway?
Definition
1. preganglionic neuron with cell body in CNS and axon that extend out of the CNS to a ganglion
2. postganglionic neuron who's axon extends to the effector organs
Term
Autonomic postganglionic neurons are: unipolar, multipolar, or pseudo-unipolar?
Definition
multipolar
Term
Where are sympathetic postganglionic nerve cell bodies located?
Definition
Ganglia lying along the vertebral column (sympathetic trunk) or at some distance from it (collateral or pre vertebral ganglia)
Term
What group of nerve cell bodies are "collateral ganglia"?
Definition
Sympathetic postganglionic cell bodies that lie some distance from vertebral column
Term
What group of nerve cell bodies are "pre vertebral ganglia"?
Definition
Sympathetic postganglionic cell bodies that lie some distance from vertebral column
Term
What is the sympathetic trunk?
Definition
Sympathetic postganglionic nerve cell bodies in sympathetic ganglia lying along the vertebral column
Term
Where are parasympathetic postganglionic nerve cell bodies located?
Definition
Ganglia (terminal ganglia) that are in or near effector organ
Term
What are terminal ganglia?
Definition
Nerve cell bodies of parasympathetic postganglionic neurons (efferent) that are located in or near effector organs
Term
Axons of motor neurons: myelinated or unmyelinated?
Definition
Myelinated
Term
Axons of autonomic preganglionic fibers: myelinated or unmyelinated?
Definition
Mostly myelinated
Term
Axons of autonomic postganglionic fibers: myelinated or unmyelinated?
Definition
Mostly unmyelinated
Term
Axons of afferent neurons: myelinated or unmyelinated?
Definition
can be myelinated or unmyelinated
Term
Synapse can occur between a nerve and:
Definition

Dendrite

Cell body

Axon

Term
Neuromuscular junction
Definition
Contact of efferent motor neurons with skeletal muscle cells
Term
Varicosities occur on what type of nerve fibers?
Definition
Autonomic post-ganglionic (efferent) fibers who synapse with smooth and cardiac tissue
Term
What is the purpose of varicosities
Definition
Allow efferent autonomic neurons to release NTs some distance from the muscle and affect larger surface area
Term
Unencapsulated sensory nerve endings
Definition
Afferent sensory nerve endings unmyelinated, free Receptors for pain and temperature
Term
Encapsulated sensory nerve endings
Definition
Afferent nerve endings urrounded by a connective tissue capsule
Term
Meissner's corpuscle
Definition

Afferent encapsulated nerve ending

Mechanoreceptor in skin

Sensitive to fine/light touch

Term
Pacinian corpuscle
Definition

Encapsulated afferent nerve ending

Mechanoreceptor in skin, sensitive to pressure

Term
Neuromuscular spindle
Definition
Encapsulated afferent nerve ending signals the rate and extent muscle is stretched
Term
Neurotendon spindle
Definition

Encapsulated sensory nerve ending located at junction of muscle and tendon

Stimulated when tension increases

Term
Golgi tendon organ
Definition
Neurotendon spindle
Term
What lies within the epidural space?
Definition
Anastomosing venous plexuses lying in luse connective tissue
Term
What lines inner surface of dura mater?
Definition
Mesothelium
Term
Subdural space
Definition
Potential space, filled with very small amt of fluid
Term
What are trabeculae made up of?
Definition
Collagenous and elastic fibers covered with mesothilium
Term
What makes up pia mater?
Definition
Collagen fibers and fibroblasts
Term
White matter
Definition

Tracts of myelinated fibers and glial cells

No nerve cell bodies

Term
Grey matter
Definition

Nerve cell bodies, dendrites, and initial portions of axons

Glial cells

Background = neuropil

Term
Neuropil
Definition

Background of gray matter

Meshwork of dendritic, axonal, and glial processes

Term
2 Paths of axons extending from nerve cell bodies in CNS
Definition

1. Leave grey matter --> transverse white matter --> terminate in grey matter a distance away

2. Leave CNS and end in periphery

Term
What lines and fills central canal of spinal cord?
Definition
Ependymal cells and filled with CSF
Term
Ventral column of gray matter
Definition
Site of nerve cell bodies of motor neurons that innervate skeletal muscles
Term
Purpose of cerebellum
Definition
Control movements of skeletal mm - coordination, posture, equilibrium
Term
Order of grey and white matter in brain
Definition
Grey is on outside, white on inside
Term
Layers of cerebellum
Definition

1. Molecular

2. Purkinje cell

3. Granular

Term
Medulla of cerebellum
Definition
White matter
Term

[image]

pink arrows

Definition
Purkinje cells
Term
Cerebellar nuclei
Definition
Collection of nerve cell bodies that occurs in the white matter
Term
Molecular layer of grey matter in cerebellum
Definition
Few small nerve cell bodies and many unmylenated fibers; glial cells
Term
Granular layer of gray matter in cerebellum
Definition

Glial cells

Many neuron cell bodies

Unmyelinated fibers

Term
 Purkinje cell layer
Definition

Purkinje cell nuclei lie between molecular and granular cell layers in grey matter of cerebellum

Extensive dendritic tree in molecular layer and axon in the granular layer

Action potentials that enter the cortex exit via Purkinje cells

Integrating locus of cerebellum - can have as many as 100,000 synapses with other neurons

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