Chapter 6: Nervous System Flashcards
1
Q
This system provides an animal with sensitivity to environmental energy and thereby awareness of self and surroundings. It is a part of the body where all the activities are being processed. It initiates and controls movement of most secretions, thus, responsible for the all inborn and learned behavior.
A
nervous system
2
Q
This system is unique in the vast complexity of the control actions it can perform. It receives literally millions of bits of information from the different sensory organs and then integrates all these to determine the response to be made by the body. Thus, it is responsible for sending, receiving, and processing nerve impulses. All of the body‟s muscles and organs rely upon these nerve impulses to function.
A
nervous system
3
Q
A highly organized collection of cells known as the ? constitute the nervous system which is found in all higher forms of animals
A
neurons
4
Q
The nerve cells collect information by means of?
A
receptors
5
Q
Receptors coordinate the information with internal activities of the organism in the process known as?
A
integration
6
Q
They also store information in ? of memory and generate adaptive patterns of behavior.
A
7
Q
What system consists of the brain and the spinal cord, is the integrating and communicating center of the body?
A
central nervous system (CNS)
8
Q
The entire CNS is enclosed in a protective membrane called the?
A
meninges
9
Q
What system consists of the spinal and cranial nerves, including associated nerve roots and ganglia?
A
peripheral nervous system (PNS)
10
Q
Nerves and ganglia innervating viscera are designated as what system?
A
autonomic nervous system (ANS)
11
Q
ANS is composed of what two systems?
A
sympathetic nervous system (thoraco-lumbar) and the parasympathetic (cranio-sacral) nervous systems
12
Q
What is a bundle of nerve processes outside the CNS. It is a collection of nerve fibers ensheathed or myelinated by neuroglia and divided into one or more fascicles by connective tissue.
A
Nerve
13
Q
What are bundles of nerve processes within the brain and the spinal cord?
A
Tracts or fasciculi
14
Q
What are group of nerve cell bodies within the brain and the spinal cord.
A
Nuclei
15
Q
Nuclei should not be confused with the central body of the cell that is also called?
A
nucleus
16
Q
What transmit electrochemical impulses?
A
Nerve cells or neurons
17
Q
What are responsible for the structural and nutritional support of neurons, electrical insulation, and enhancement of impulse conduction velocity along axons. It is the connective and supportive tissue of the CNS.
A
Supporting cells or neuroglia (“nerve glue”) or glial cells
18
Q
What is the basic structural and functional unit of the nervous tissue. The primary function of this is to receive stimuli from the internal (interoreceptive) and external (exteroreceptive) environment. The subsequent transmission of information to the effector organs of the body is also an integral part of its function. This form the highly complex intercommunicating network of nerve cells that receive and conduct impulses along their neutral pathways or axons to the CNS for analysis, integration, interpretation, or response. The action of muscles or glands of the body provide the appropriate response to a given stimulus.
A
Neuron
19
Q
Where excitation is initiated(Excitation means “the process of becoming active or stimulated.”)?
A
Dendritic zone
20
Q
What are short, highly branched processes of neurons that collect incoming messages from the synapse and carry them toward the cell body.
A
Dendrites (from Gr. dendron which means tree)
21
Q
Like a bud on a twig, a spine is a short expanded process attached to the dendritic branch by a?
A
narrow stalk
22
Q
Where excitation is transmitted to another cell. It is also branched and has terminal expansions for storage and release of transmitter molecules.
A
Telodendritic zone
23
Q
The plasma membrane of axon is called?
A
axolemma
24
Q
Cytoplasm of axon is called?
A
25
The axon or axis cylinder originates from the ? of the cell body, a conical region devoid of chromatophilic substance.
axon hillock
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Axon of most neurons has a myelin sheath formed by the supporting cells and interrupted by gaps called?
nodes of Ranvier
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What nurtures the nerve cell. It has a nucleus, cytoplasm and plasmalemma surrounding the nucleus.
Cell body (cyton, soma or perikaryon)
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Part of cell body that is large, pale, spherical or slightly ovoid and usually centrally located within the cytoplasm.
nucleus
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Part of cell body that contains filamentous, membranous and granular organelles arranged concentrically around the nucleus.
cytoplasm or perikaryon
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These organelles of the neuronal cell bodies are slender, interlacing threads coursing through the cytoplasm from
one dendrite to another or into the axon.
Neurofibrils
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These organelles of the neuronal cell bodies appear as lumps of basophilic material in the perikaryon. It is composed of blocks of stacked rER and ribosomal aggregations (RNA).
Nissl bodies or chromophillic substances
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These organelles of the neuronal cell bodies is spherical and contains a pair of centrioles. Since neurons do not proliferate, its role in adult nerve cell is unknown.
Centrosome
33
What is a coat of white, fatty tissue that covers nerves of the peripheral nervous system. It is covered by a membrane called neurolemma or Schwann‟s cell. It acts like insulation on a wire and greatly promotes speed and reliability of nerve impulse conduction.
Myelin sheath
34
What are the small-constricted portion of the neuron‟s myelin sheath that separates the axon along the cells length. These narrowing, or gaps, is more permeable to potassium and sodium ions than the rest of the axon body. Consequently, these nodes allow nerve implies to be transmitted from the axon, where otherwise the impulses would be shielded by the insulating myelin sheath.
Nodes of Ranvier
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Myelinated axons between the gaps are called?
internodes
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The internodal transmission that leads to a node is referred to as?
paranode
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What are layers of the cells which cover the myelin sheath segments of some nerve cells, and constrict at the nodes of Ranvier. The neurons of the brain and spinal cord do not have such a cell layer covering their myelin sheaths. It provides a protected immediate environment for PNS neurons. They can become phagocytic in case of nerve damage.
Schwann’s cell (neurolemma, neurolemmocytes)
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What neurons conduct impulses from internal or external receptors to the CNS.
Sensory (afferent) neurons
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What neurons convey impulses from the CNS to the effector muscles or glands?
Motor (efferent) neurons
40
What serve as intermediary cells and are located between sensory and motor neurons in the CNS?
Interneurons (mixed)
41
What type of neurons usually have several dendrites to receive impulses, but only one axon to carry the signal away. It has a cell body within the dendritic zone. They are the most common type in the CNS and include motor neurons and interneurons of the brain and spinal cord.
Multipolar neurons
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What type of multipolar neuron are those with numerous dendrites and very long axon?
Golgi Type I
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What type of multipolar neuron are those with less dendrites and a short axon?
Golgi Type II
44
What type of neuron have a cell body located within the axon. They have one dendrite and one axon that nerve impulses are received and transmitted only in one direction, from one pole of the neuron to the other. They are the receptor cells that are found in the retina of the eye, the organ of hearing in the inner ear, and the olfactory epithelium in the upper region of the nose. Bipolar neurons are not as common and are purely sensory neurons.
Bipolar neurons
45
What type of neuron have a cell body that arise from a single axon and soon bifurcates. Like the bipolar neurons, they convey sensory information to the CNS. They are also sensory and are found numerous in the craniosacral ganglia of the body.
Unipolar neurons (Pseudo-unipolar)
46
What are specialized junctions by which a stimulus is transmitted from a neuron to its target cell?
Synapses
47
What are bulbous enlargement at synapes
Terminal bulbs
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What synapse is the most common, involving a synapse of an axon and dendrite?
Axodendritic synapse
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What synapse involves a synapse of an axon on the cell bod?
Axosomatic synapse
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What synapse involves telodendria (inhibitory effect) or a synapse on the initial segment?
Axoaxonic synapse
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What synapse does not involve telodendria?
Dendrodenritic synapse
52
What membrane is the part of the terminal bouton membrane closest to the target cell. On stimulation, neurosecretory vesicles in the bouton fuse with the synaptic membrane and exocytose their neurotransmitters into the synaptic clef.
Presynaptic membrane
53
What is a fluid-filled space between the pre - and postsynaptic membrane?
Synaptic cleft (Synaptic Gap)
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What membrane is a thickening of a plasma membrane of the next neuron or target cell?
Postsynaptic membrane
55
What is highly branched, supportive, non-neuronal cells in the CNS that are located between the neurons. It comprises well over 90% of the cells that make up the nervous system. These cells do not conduct impulses and are morphologically and functionally different from the neurons
Neuroglia
56
What line the ventricular cavities of the brain and the central canal of the spinal cord?
Ependymal cells
57
What are the largest neuroglial cells and support the neurons, repair the CNS tissue after injury or disease, and form scar tissue after neuronal damage. In addition, the astrocytes may be involved in the energy metabolism and supporting metabolic exchanges between neurons and the capillaries of the CNS.
Astrocytes
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Astrocytes are the largest neuroglial cells and consist of two types:
fibrous astrocytes and protoplasmic astrocytes
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The white matter is said to contain what type of astrocytes?
fibrous astrocytes
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The gray matter is said to contain what type of astrocytes?
protoplasmic astrocytes
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Astrocyte processes terminate in expansions called the end feet?
end feet
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What neuroglia function by forming myelin sheaths around the axon in the CNS?
Oligodendrocytes
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What neuroglia are considered the macrophages of the CNS and are found throughout the CNS. When nervous tissue is injured or damage, microglia proliferates, become phagocytic, and remove dead tissue from the CNS.
Microglial cells
64
What are specialized Schwann‟s cells in craniospinal and autonomic ganglia where they form a one-cell-thick covering over the cell bodies of the neurons (ganglion cells). The nuclei are spheric with mottled chromatin. In sections, the nuclei typically appear as a „string of pearls” surrounding the much larger ganglion cell bodies
Satellite cells
65
Such axons do not have a myelin sheath around them and are considered?
unmyelinated
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Axons that are surrounded by myelin sheath are considered?
myelinated
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axons; the nerve impulse jumps from node to node, resulting in a much more efficient and faster conduction of the impulse. This type of impulse conduction in myelinated axon is called?
saltatory conduction
68
What neurons release adrenaline (epinephrine) and noradrenaline (norepinephirne) respectively?
Adrenergic and noradrenergic neurons
69
What neurons release acetylcholine ?
70
What neurons release dopamine?
Dopaminergic neurons
71
What neurons release GABA, an inhibitory neurotransmitter?
GABAergic neurons
72
What neurons release seratonin (5- hydroxytryptamine)?
Seratonergic neurons
73
What neurons release glycine?
Glycinergic neurons
74
What nerves originate from the spinal cord and exit the vertebral canal?
Spinal nerves
75
What nerves originate from the brain and exit the cranial cavity
Cranial nerves
76
What consists usually of thousands of axons, each sheathed by neurolemmocytes and all enveloped by connective tissue?
Nerve
77
What is the proximal region of the nerve where axons are enveloped by neurolemmocytes and meninges?
Root
78
What fibers are sensory since they conduct excitation to the CNS. These neurons have unipolar cell bodies in craniospinal ganglia. The dendritic zone is composed of receptors, or synaptic contacts on the sensory epithelium of a sense organ.
Afferent fibers
79
What fibers come from axons of multipolar cell bodies located in the CNS or in autonomic ganglia?
Efferent fibers
80
What fibers innervate the skin, skeletal muscles and joints?
Somatic nerve fibers
81
What fibers innervate cardiac and smooth muscles and glands?
Visceral nerve fibers
82
What nerves is composed of one to several nerve fascicles. It contains myelinated and unmyelinated axons, Schwann‟s cells, and fibroblast, but no neuron cell bodies.
peripheral nerve
83
Each peripheral nerve is surrounded by a dense connective tissue or ?, branches of which penetrates the nerve and divides the nerve fibers into bundles or fascicles.
epineurium
84
A nerve is delimited by ?, a sheath surrounding each fascicle.
perineurium
85
Within the nerve fascicle, fibroblast and collagen fibers surrounding neurolemocytes constitute?
endoneurium
86
This perineurium is an outer cell of moderately dense collagenous connective tissue.
Fibrous perineurium This perineurium
87
This perineurium is an inner sleeve of multiple concentric layers of squamos epithelial cell. Collagen fibers are dispersed between the layers of each epithelial cell is enclosed in a basal lamina.
Perineural epithelium
88
What Ganglia are accumulations of peripheral nerve clusters of neuron cell bodies within a nerve fascicle?
89
What are spinal ganglia on dorsal roots and cranial nerve ganglia containing unipolar cell bodies of afferent neurons. The unipolar cell bodies are distributed around the fibers of the nerve, which course through the center of the ganglion. Each unipolar cell body gives rise to a single axon that may coil initially before joining the centrally connected fibers where the axon bifurcates into central and peripheral branches
Sensory ganglia (cranio-spinal)
90
What are produced by multipolar cell bodies accumulated within the autonomic nerve fascicles. Within visceral organs, there are terminal autonomic ganglia composed of only a few cell bodies.
Autonomic ganglia
91
Postganglionic neurons are classified as:
if they synthesize and release acetylcholine
Cholinergic
92
Postganglionic neurons are classified as:
if the neurotransmitter is noradrenaline. This postganglionic neurons can be identified by the presence of dense core synaptic vesicles. Some autonomic ganglia contain numerous large dense-core vesicles and release dopamine.
Adrenergic
93
What neurons innervate skeletal muscle. One such neuron and all of the muscle fibers it innervates is regarded as a motor unit, since the muscle fibers it innervates contract as a unit when the neuron is excited
Somatic efferent neurons
94
What syanpse consist of a presynaptic motor end-plate overlying the postsynaptic sole plate of a muscle fiber?
Neuromuscular synapses
95
Cytoplasm that contains many mitochondria and numerous clear synaptic vesicles?
End-plate cytoplasm
96
End-plate cytoplasm contains many mitochondria and numerous clear synaptic vesicles. The vesicles contain ?, which is released at active sites opposite the junctional folds and then diffuse across the neuromuscular gap and bids to postsynaptic receptor sites.
acetylcholine
97
What is other type of somatic efferent neuron. It innervates small muscle fibers within muscle spindles.
fusimotor or gamma motor neuron
98
synapse on postganglionic neurons in autonomic ganglia. The telodendria form end bulbs typical of interneuronal synapses.
Preganglionic autonomic neurons
99
What neurons have non-myelinated axons that innervate cardiac or smooth muscles or gland?
Postganglionic autonomic neurons
100
What are individual, isolated stimulus detectors widely distributed in the body. It constitute the dendritic zone of an afferent neuron.
Receptors
101
Receptors that are found at the body surfaces?
Exteroreceptors
102
Receptors that are found in musculoskeletal structures?
Propioreceptors
103
Receptors that are found in the viscera?
Enteroreceptors
104
What nonencapsulated receptors are found throughout the body. They detect stimulation described as pain, warmth, cold or touch, as well as consciousness stimuli for reflex activity. They are associated by non-myelinated axons that branch extensively to innervate a wide area. The receptors are simply unsheathed terminal branches, enclosed by basal lamina.
Free nerve endings
105
What nonencapsulated receptors detect body hairs being displaced, are derived from myelinated axons that branch extensively to innervate hundreds of fascicles?
Hair follicle terminals
106
What nonencapsulated receptors are often collected at the base of a slight skin elevation called a tactile pad?
Non-encapsulated tactile corpuscles
107
What encapsulated receptors are touch receptors found in the dermis of glabrous skin?
Encapsulated tactile corpuscles (corpuscles of Meissner)
108
What encapsulated receptors are widely distributed throughout the body, sensitive to transient pressure such as in vibratory stimuli?
Lamellar corpuscles (corpuscles of Vater, corpuscles of Pacini)
109
What encapsulated receptors vary in locations, size and shape. They are mechanoreceptors derived from myelinated axons having highly coiled terminal branches enclosed in a thin capsule of perineural epithelium.
Bulbous corpuscles (corpuscles of Krause, corpuscles of Golgi-Mazzoni, genital corpuscle)
110
What encapsulated receptors are located at muscle-tendon junctions and are activated by tension.
Neurotendinous spindles (Golgi tendon organs)
111
What encapsulated receptors are located in most muscles; consist of an elongate capsule of perineural epithelium containing afferent and efferent innervation and two kinds of intrafusal muscle fibers designated as: nuclear bag and nuclear chain fibers.
Neuromuscular spindles (muscle spindles)
112
What matter is formed by dense accumulations of nerve fibers individually enveloped by a myelin, white lipid-protein insulation. The high lipid content of myelin is responsible for the white appearance. This matter regions are divided functionally into tracts and fasciculi, based on the origin and destination of the nerve fibers.
white matter
113
What matter lacks dense accumulations of myelin and is rich in cell perikarya, neuronal cell bodies, glial cells and neurophil?
gray matter
114
What matter that coats the cerebellum and the cerebrum are called cortex? This matter mass within the spinal cord, brainstem, cerebral
Gray matter
115
Cerebellar white matter are generally called?
nuclei
116
What is composed of paired cerebral hemispheres?
cerebrum
117
What are the ridges called in the surface of each hemisphere?
Gyri
118
What are the grooves called in the surface of each hemisphere?
Sulci
119
In mammals, all the ventral cerebral cortex is designated as ?, since it is phylogenetically recent.
neocortex
120
What layer of neocortex consists of predominantly neurophil oriented tangentially, composed of apical dendrites from pyramidal cells and telodendria from input fibers to the cortex?
Molecular layer
121
What layer of neocortex predominantly small neurons?
External granular layer
122
What layer of neocortex medium and large pyramidal neurons?
External pyramidal layer
123
What layer of neocortex the primary receptive layer for modality (sensory) specific input to the cortex; composed of small stellate neurons that form a thick layer in cortical sensory areas (e.g. visual area).
Internal granular layer
124
What layer of neocortex is medium to very large pyramidal neurons; form a thick layer in the cortical motor area, where electrical stimulation elicits movement.
Internal pyramidal neurons
125
What layer of neocortex many spindle-shaped neurons. Deep to this is cerebral white matter composed of nerve fiber going to and coming from the cortex.
Fusiform (multiform) layer
126
The cerebellar surface, which features the folia (narrow ridges) separated by sulci, is coated by cortex. This regulates muscle tone, posture and movement so that these are expressed in an appropriate, coordinated pattern.
Cerebellum
127
What cerebellar cortex layer is the most superficial and composed predominantly of neurophil?
Molecular layer
128
What cerebellar cortex layer is situated adjacent to white matter, features densely packed granule cells - very small neurons with heterochromatic nuclei?
Granular cell layer
129
What cerebellar cortex layer is a single layer of large cell bodies located at the interface of the molecular and granule cell layer?
Piriform cell layer
130
What cells have elaborate dendritic trees that project into the molecular layer?
Piriform (Purkinje) cells
131
What cells is another neuron found in the cerebellar cortex located at the piriform layer and its dendritic tree extends to the molecular layer?
Basket cell
132
What is divided into segments based on the bilateral emergence of dorsal and ventral roots of spinal nerve?
spinal cord
133
What surrounds by an H-shape profile of gray matter, which is in turn surrounded by white matter?
central canal
134
Bilaterally, the spinal cord is divided by what fissures?
ventral median fissure and a dorsal median septum
135
Column of the gray matter contains somatic efferent neurons that innervate skeletal muscles. The volume of the cell bodies of these neurons is proportional to the volume of its axon and the size of the motor unit being innervated.
ventral gray column (horn)
136
Matter that features a lateral gray column containing visceral efferent neurons that synapse in the autonomic ganglia?
intermediate gray matter
137
What colum contains interneurons and neurons that project axons to distant segments or to the brain via white matter tracts?
dorsal gray column (horn)
138
What matter is composed of fibers that belong to tracts (fasciculi); additionally fibers destined for spinal nerves traverse the white matter?
Spinal white matter
139
What matter may be subdivided into nuclei, which generally are not distinct?
Spinal gray matter
140
Funiculus between the midline and dorsal root attachments?
Dorsal funiculus
141
Funiculus between the midline and ventral root attachments?
Ventral funiculus
142
Funiculus between dorsal and ventral root attachments?
Lateral funiculus
143
What are membranes that envelope the brain, spinal cord and the roots of the peripheral nerves. It also envelop the entire optic nerve, which is actually CNS white matter. It provides a physical and phagocytic barrier and contains cerebrospinal fluid, which attenuates traumatic forces.
Meninges
144
145
What meningeal membrane matter consists of variously oriented space of collagen fibers that forms a thick, strong membrane. Elastic fibers, fibroblasts, nerves, lymph and blood vessel are also present.
Dura matter
146
Spinal dura matter is surrounded by what space? within the vertebral canal.
epidural space
147
What matter is formed by merger of two embryonic membranes?
Cranial dura mater
148
What meningeal membranes consists of a fine net collagen fiber coated both sides by leptomeningeal fibroblasts?
Arachnoid membrane
149
What is the space contains cerebrospinal fluid, separates the arachnoid membrane and the pia matter?
subarachnoid space
150
What are thin strands of the membrane that traverse the subarachnoid space and join pia matter?
Arachnoid trabeculae
151
As the vessels penetrate the CNS, an extension of the subarachnoid space extends around the vessel for a short distance, called a?
perivascular space
152
What are microscopic pockets of arachnoid membrane that penetrates the venous sinus wall?
arachnoid granulations
153
What matter coats the entire CNS surface lining every sulcus and fissure?
Pia matter
154
Bilaterally along the mid-lateral surface of the spinal cord, pial collagen is greatly thickened to form what ligaments? The ligament sends processes to the dura matter and thereby serves to suspend the spinal cord within the pachymeninx.
denticulate ligament
155
Dura matter being thick and strong has been called?
pachymeninx
156
What fluid is produced by choroid plexuses located in brain ventricles. It is produced by active secretion and ultrafiltration.
Cerebrospinal fluid (CSF)
157
What is an expanded villiferous structure from each region of ventricles where its wall is formed only by ependyma and pia matter.
Choroid plexus
158
The plexus consists of dense microvasculature in loose connective tissue coated by modified ependymal cells called?
choroid plexus epithelium
