Nervous System Flashcards
1
Q
cells of nervous tissue
A
Neuron
Neuroglial cells / Neuroglia / Glial Cells / Gliocytes
2
Q
DEVELOPMENT OF NERVOUS TISSUE
A
ectoderm
CNS: brain and spinal cord
PNS: cranial, spinal,
peripheral nerves
3
Q
Neuron 3 main parts
A
Cell body
Dendrites
Axon
4
Q
what do you call the cell membrane of the neuronner
A
neurolemma
5
Q
Main part from which axon & dendrites arise. it is also called perikaryon or soma.
A
cell body
6
Q
clumps of basophilic
substance (aggregates of RER and free
polyribosomes)
A
Nissl bodies
7
Q
nissl substance is present in axon hillock and axon
A
false
8
Q
pale staining area of cell body
A
Axon hillock
9
Q
▪ Relatively long, cylindrical process
▪ Arises from axon hillock & ends on effector organ or ganglia
A
Axon
10
Q
Axon Gives off terminal branches called ____ with expanded _____ ______ ______
A
telodendron
terminal synaptic bulb
11
Q
plasma membrane of axon?
what do you call the cytoplasm of axon?
A
axolemma
axoplasm
12
Q
what are the processes of neurons?
A
axon
dendrites
13
Q
also called nerve fiber
A
axon
14
Q
2 types of axon
A
unmyelinated
myelinated
15
Q
Surrounded by Schwann cells/oligodendrocytes wrapped
several times forming a _____
A
myelin sheath
16
Q
Lipid-rich, insulating sheath
Extends from the initial segments of the axon to the
terminal branches
A
myelin sheath
17
Q
Gaps in myelin sheath between the myelinating cells
Myelin sheath is absent
A
nodes of ranvier
18
Q
▪ Typically short, small processes radiating from the cell body
▪ May branch and re-branch with each branch tapering at its end
▪ All organelles are present
A
dendrites
19
Q
Small dendritic branches have tiny projections called _____
A
dendritic spine/gemmules
20
Q
CLASSIFICATION OF NERUONS (4)
A
unipolar
bipolar
multipolar
pseudounipolar
21
Q
One cell body, one axon
Found in sensory ganglia located in roots of cranial and spinal nerves
A
unipolar
22
Q
One dendrite and one axon; purely sensory
Sensory neurons of the retina, the olfactory epithelium, the inner
A
bipolar
23
Q
Cell body gives rise to multiple branches, several dendrites, and an
axon
Most common
A
multipolar
24
Q
CLASSIFICATION OF NEURONS BASED ON FUNCTION (3)
A
sensory neurons
interneurons
motoneurons
25
Afferent
Receive stimuli from receptor
Sensory neurons
26
Act as connectors between neurons in a chain or typically between sensory and motor
neurons within the CNS
Interneurons
27
Efferent
Send impulses from the CNS to the targets organs (e.g. muscles, glands)
Motoneurons
28
4 TYPES OF NEUROGLIAL CELLS IN CNS
1. Oligodendrocytes
2. Astrocytes
3. Ependymal cells
4. Microglial cells / microgliocytes
29
Smaller than astrocytes with fewer
cytoplasmic processes
Predominant glial cells in _____
A single oligodendrocyte can surround and
myelinate several axons
oligodendrocytes
white mater
30
Functions:
Myelinates and insulates CNS axons
Allows faster action potential propagation
along axons in the CNS
oligodendrocytes
31
Most numerous glial cells of the brain
Most abundant glial cells in _____ matter
Most diverse structurally and functionally
astrocytes
gray matter
32
Functions:
Provide structural support to CNS
Helps form the blood-brain barrier
Regulates interstitial fluid composition
Assists with neuronal development
Replicates to occupy space of dying neurons
Astrocytes
33
2 types of Astrocytes
Fibrous astrocytes
Protoplasmic astrocytes
34
type of astrocyte With long, slender, and moderately branched processes
Abundant in white matter
Fibrous astrocytes
35
type of astrocyte With many shorter and highly branched processes
Abundant in gray matter
Protoplasmic astrocytes
36
Simple cuboidal or low columnar epithelial cells
In some locations of the CNS, apical surface contain cilia
and microvilli
Ependymal cells
37
Functions:
Lines ventricles of brain and central canal of spinal cord
Assists in production and circulation of cerebrospinal fluid
(CSF)
Ependymal cells
38
Smallest glial cells
With actively mobile processes evenly distributed
throughout gray and white matter
Microglial cells / microgliocytes
39
Functions:
Phagocytic cells that move through the CNS
Constitute the major mechanism of immune
defense in the CNS
Protects the CNS by engulfing infectious agents and other potential harmful substances
Microglial cells / microgliocytes
40
2 TYPES OF NEUROGLIAL CELLS IN PNS
Amphicytes
Schwann cells (aka Neurolemmocytes)
41
Derived from the embryonic neural crest
Surround the neurons of PNS ganglia
Satellite glial cells (aka Amphicytes)
42
Functions:
Electrically insulates PNS cell bodies
Regulates nutrient and waste exchange for
cell bodies in ganglia
Satellite glial cells (aka Amphicytes)
43
Derived from the embryonic neural crest
Surround peripheral nerve fibers
Schwann cells (aka Neurolemmocytes)
44
Functions:
Surround and insulate PNS axons and
myelinate those having large diameters
or enclose unmyelinated axons
Allows for faster action potential
propagation along an axon in the PNS
Schwann cells (aka Neurolemmocytes)
45
Associated structures of CNS (3)
Meninges
Choroid plexus
Cerebrospinal fluid
46
BRAIN
Abundant neuronal cell bodies, dendrites,
astrocytes, microglial cells
Contain a meshwork of axonal, dendritic, and glial
processes (neuropil)
Unmyelinated axons
Where most synapses occur
Outer: Gray matter
47
Main component: mostly myelinated nerve fibers
Some unmyelinated axons
Oligodendrocytes
Inner: White matter
48
Gray matter folded into gyri and
sulci
Gyri = ridge
Sulci = fissures
Composed of 6 layers
cerebrum Cortex
49
layers of cerebral cortex (6)
1. Molecular layer
2. External granular layer
3. External pyramidal layer
4. Internal granular layer
5. Internal pyramidal layer
6. Multiform layer
50
Horizontal cells of Cajal, cell processes, neuroglia
1. Molecular layer
51
Mostly tightly packed granule (stellate) cells,
neuroglial cells
External granular layer
52
Large pyramidal cells
Increasingly larger from external to internal
border
Granule (stellate) cells, neuroglial cells
External pyramidal layer
53
Thin layer; closely arranged small granule cells,
some pyramidal cells, and neuroglia
Greatest cell density of the cerebral cortex
Internal granular layer
54
Medium and large pyramidal cells, neuroglia
Lowest cell density
Internal pyramidal layer
55
Cells of various shapes (many are fusiform),
Martinotti cells, neuroglia
Multiform layer
56
CEREBELLUM 3 layers
1. Molecular layer
2. Purkinje cell layer
3. Granular layer
57
Directly below the pia mater
Predominantly composed of neuropil
Dendrites of Purkinje cells
Scattered neuronal cell bodies
Stellate cells, basket cells
cerebellum molecular layer
58
Single layer
Large, flask-shaped
Purkinje cell layer
59
Deepest layer
Various very small, densely packed neurons (including granule cells)
Little neuropil
_______ (cerebellar islands)
Mainly represent areas of synapses on granule cell dendrites
Granular layer
Glomeruli
60
Primarily ascending and descending tracts of myelinated nerve fibers
Outer: White matter of SPINAL CORD
61
Interneuron
Projection neuron
Efferent neuron
Inner: Gray matter of spinal cord
62
Gray matter of spinal cord has 2 parts called
Dorsal horn - posterior gray horn/column
Ventral horn - anterior gray horn/column
63
Spinal cord parts (3)
outer white matter
inner white matter
central canal
64
Lined by ependymal cells
Represents the lumen of original neural tube
Central canal
65
Connective tissue coverings of the brain
and spinal cord
MENINGES
66
meninges 3 layers
Dura mater
Arachnoid
Pia mater
67
Outermost
Dense irregular CT
Closely apposed in adult
DURA MATER
68
does not adhere
to the walls of the vertebral canal
Spinal dura mater
69
2 layers of dura mater
Periosteal dura mater (outer)
Meningeal dura mater (inner)
70
Between dura mater and bony walls of vertebral canal
Epidural space
71
Between dura and arachnoid
Considered “potential space”
Appear only as aftermath of injury
Subdural space
72
Intermediate layer
Avascular but the blood vessels course
through it
ARACHNOID
73
2 regions of arachnoid
Flat, sheet-like membrane
Deeper, gossamer-like region
(Arachnoid trabeculae)
74
region of arachnoid in contact with dura
Flat, sheet-like membrane
75
region of arachnoid with Modified fibroblasts
Deeper, gossamer-like region
(Arachnoid trabeculae)
76
Innermost layer of meninges
PIA MATER
77
Intimately associated with the brain,
following closely all of its contour
Consists of flattened, mesenchymally-derived cells
Separated from neural tissue by
neuroglial cells
pia mater
78
Highly vascular tissue
Elaborately folded and projecting into the large ventricles of the brain
Found in lateral, third, and fourth ventricles of the brain
Produces CSF
CHOROID PLEXUS
79
Clear, colorless fluid
Protect the brain and spinal cord
Brings nutrients to nourish brain cells
Removes metabolites that enter the ____ from the brain cells
Provides an optimal chemical environment for neuronal functions and impulse
conduction
CEREBROSPINAL FLUID
80
Set of neurons and fibers outside the CNS
PERIPHERAL NERVOUS SYSTEM (PNS)
81
Functions:
Detect changes and cause actions
Very limited capacity to process information
PERIPHERAL NERVOUS SYSTEM (PNS)
82
PERIPHERAL NERVOUS SYSTEM (PNS) in anatomically divided into
Cranial nerves
Spinal nerves
83
PNS is functionally divided into
Sensory (afferent)
Motor (efferent)
84
Receives and transmits impulses to the CNS for processing
Sensory (afferent)
85
Originates in the CNS and transmits impulses to effector organs throughout
the body
Motor (efferent)
86
Motor component of PNS is subdivided into
Somatic
Autonomic
87
Impulses originating in the CNS are transmitted directly
Via single neuron to skeletal muscles
Somatic
88
Impulses from CNS → autonomic ganglion, via one neuron
A second neuron: originating in the autonomic ganglion then transmits the
impulses to smooth muscles, cardiac muscles, or glands
Autonomic
89
Two divisions of the autonomic nervous system:
1. Sympathetic
2. Parasympathetic
90
Also called the thoracolumbar division
Efferent fibers originate from the neurons in the gray column of the thoracic
and lumbar segments of the spinal cord
1. Sympathetic
91
Craniosacral
Nerve fibers originate from neurons in the brain stem (nuclei of cranial
nerves III, VII, IX, X an XI) and the sacral segment of the spinal cord
2. Parasympathetic
92
Enlargement formed by enlargement formed by a group of nerve cell bodies outside CNS
GANGLION
93
Ganglion is divided into
1. Sensory ganglia
2. Motor ganglia
94
Formed by cell bodies of afferent neurons
Contain cell bodies of pseudounipolar neurons
1. Sensory ganglia
95
ganglion Associated with autonomic NS
Motor ganglia
96
motor ganglia is divided into
a. Sympathetic ganglia
b. Parasympathetic ganglia
97
lie parallel to spinal cord
Smaller than sensory ganglia
Mainly multipolar neurons
Sympathetic ganglia
98
Extramural or intramural ganglia of visceral organs
Parasympathetic ganglia
99
nerve plexus of visceral organs (e.g. Auerbach’s plexus in T. muscularis of intestine)
*Intramural ganglia
100
Dendritic zones of afferent neurons; receive sensations
AFFERENT NERVE ENDINGS
101
AFFERENT NERVE ENDINGS are divided into
1. Nonencapsulated
2. Encapsulated
102
Free nerve endings
Hair follicle terminals
Nonencapsulated tactile corpuscles
. Nonencapsulated afferent nerve endings
103
Encapsulated afferent nerve ending have 3 structures. what are they
Meissner’s corpuscle
Pacinian corpuscle
Neurotendinous spindles
104
largest encapsulated
nerve ending
Pacinian corpuscle
105
– located at muscle–
tendon junctions and are activated by tension
neurotendinous spindle
106
dermal papillae of hairless skin
Meissner’s corpuscle
107
explain the regeneration of nervous cells
The complexity and distances of the neuronal and glial interconnections with
the CNS make regeneration and restoration of function within this tissue after
major injury very difficult
