A&P Lab 11: Nervous System: Histology Flashcards

1
Q

Neurons

A

primary functional units of the nervous system; highly specialized to conduct action potentials along great distances at high speeds

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2
Q

Neuroglia

A

supporting cells of nervous tissue; protect, nourish, and promote the function of neurons

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3
Q

Central cell body

A

AKA soma; part of the neuron containing the nucleus and most of the cell’s organelles (doesn’t have centrioles; rough ER sometimes called Nissl bodies or chromatophilic substances)

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4
Q

Nissl bodies

A

AKA chromatophilic substances; stain differently than the typical rough ER

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5
Q

Neurofibrils

A

cell body contains these; help maintain the cell shape and integrity of the cell; receives action potentials from numerous dendrites

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6
Q

Dendrites

A

appear like branches of a tiny tree extending away from the cell body

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7
Q

Axon

A

usually longer than any of the dendrites; a single process in all neurons

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8
Q

Axon hillock

A

at the junction between the axon and the cell body is this cone-shaped region

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9
Q

Myelin sheath

A

in some neurons, the axon is wrapped with this external coating

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10
Q

Axon collaterals

A

the axon may include these side branches

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11
Q

Axon terminals

A

small processes located at the end of the axon and its axon collaterals; where neurotransmitters are released

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12
Q

Neurotransmitters

A

stimulators of adjacent neurons, muscle cells, or glands

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13
Q

Synaptic cleft

A

neurotransmitters diffuse across this small space

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14
Q

Sensory (afferent) neurons

A

a change in the environment, such as a change in temperature or pressure against the skin, is detected by receptors associated with the dendrites of these neurons, which carry the information of this change in the form of an action potential to the CNS

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15
Q

Interneuron (associated neuron)

A

within the CNS, an impulse is often passed to this neuron, which may carry the impulse to others like it for integration

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16
Q

Motor (efferent) neuron

A

neuron that carries an impulse away from the CNS

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17
Q

Effector

A

a muscle cell or gland that receives an impulse

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18
Q

Multipolar neurons

A

neurons with numerous processes, including a single axon and many dendrites; ex. motor neurons & interneurons

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19
Q

Bipolar neurons

A

a neuron with 2 processes, 1 axon & 1 dendrite on either side of the cell body; ex. organs of special sense ~ the retina of the eye & olfactory cells of the nose

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20
Q

Unipolar neuron

A

a neuron with just 1 process (axon); sensory neurons that form part of peripheral nerves

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21
Q

Astrocytes

A

located throughout the brain and spinal cord, these CNS neuroglia anchor neurons to capillaries, guide neurons during development, & control the chemical composition of cerebrospinal fluid

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22
Q

Oligodendrocyte

A

located throughout the brain and spinal cord, these CNS neuroglia form a protective and insulating covering around axons in the CNS, called a myelin sheath

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23
Q

Microglia

A

mobile cells in the brain and spinal cord that phatocytize invading microorganisms and dead nervous tissue

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24
Q

Ependymal cell

A

lines the ventricles in the brain and the central canal in the spinal cord; forms cerebrospinal fluid and generates a current by their ciliary action

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25
Q

Schwann cell

A

wraps around certain axons of neurons in the PNS; forms the myelin sheath, which increases nerve impulse speed; aids in the regeneration of axons

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26
Q

Satellite cell

A

surrounds neuron cell bodies in PNS ganglia; helps nourish neurons and regulates the chemical environment

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27
Q

Neurolemma

A

most of the cytoplasm and the cell’s nucleus are pushed to the outermost layer of the myelin sheath, forming this small bulge

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28
Q

White matter

A

an area of nervous tissue that is dominated with myelinated axons that is white in color

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29
Q

Gray matter

A

when the area of nervous tissue is dominated with axons lacking the myelin sheath; appears slightly gray in color

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30
Q

Node of Ranvier

A

in peripheral neurons, the Schwann cells form the myelin sheath in segments, one cell per segment; between each segment is this gap, in which the axon is exposed to the extracellular space

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31
Q

Myelinated fibers

A

axons that are covered with the myelin sheath; fastest conductors in the body

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32
Q

Unmyelinated fibers

A

axons that are not covered with the myelin sheath; Schwann cells or oligodendrocytes present, but form a thin, single-layer covering over the axon

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33
Q

Central Nervous System (CNS)

A

brain & spinal cord; receives info from sensory receptors, coordinates & integrates the info, and initiates & transmits a response

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34
Q

Peripheral Nervous System (PNS)

A

nerves/ganglia, which channel impulses to and from the CNS; includes sensory nerves, which carry impulses from sensory receptors to the CNS and motor nerves, which transmit impulses from the CNS to effector organs such as neurons, muscles, and glands

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35
Q

Cerebrum

A

largest part of the brain; integrative center of the brain, receiving and interpreting sensory info, drawing upon memory and learning, and initiating motor responses; conscious thought also resides within the layers of neurons; prominent; fills the superior, anterior, and posterior parts of the cranial cavity

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36
Q

Convolutions

A

cerebrum contains numerous of these wrinkle-like foldings

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37
Q

Gyri

A

upfoldings of the convolutions of the cerebrum

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38
Q

Sulci

A

shallow downfoldings of the convolutions of the cerebrum

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39
Q

Cerebral hemispheres

A

a deep downfold separates the cerebrum into 2 parts, the right & left ___ _____

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40
Q

Longitudinal fissure

A

the separation of the cerebrum into right and left hemispheres

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41
Q

Transverse fissure

A

deep downfolding separating the cerebrum from the cerebellum

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42
Q

Cerebral lobes

A

superficial areas of the cerebrum corresponding to the bones of the cranium (frontal, parietal, temporal, occipital)

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43
Q

Central sulcus

A

downfold that divides the frontal lobe from the parietal lobe

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44
Q

Precentral gyrus

A

upfold anterior to the central sulcus

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45
Q

Postcentral gyrus

A

upfold posterior to the central sulcus

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46
Q

Lateral sulcus

A

downfold that divides the parietal lobe from the temporal lobe

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47
Q

Parieto-occipital sulcus

A

shallow groove (downfold) that divides the parietal and occipital lobes

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48
Q

Cerebral cortex

A

outermost fringe of the cerebrum; roughly 2-3mm thick, consists of several layers of neuron cell bodies that integrate sensory info, participate in intellectual activities/emotions, and generate motor responses; entirely composed of gray matter (neuron cell bodies, dendrites, and unmyelinated fibers)

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49
Q

White matter types of fiber tracts

A

association fibers, commissural fibers, projection fibers

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50
Q

Association fibers

A

fibers which extend to areas within the same hemisphere

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51
Q

Commisural fibers

A

fibers which extend between the 2 hemispheres; includes a prominent tract that connects the 2 hemispheres (corpus callosum)

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52
Q

Projection fibers

A

fibers that ascend or descend through the brain

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53
Q

Corpus callosum

A

prominent tract that connects the 2 hemispheres

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54
Q

Basal ganglia

A

clusters of gray matter embedded within the white matter of each hemisphere; control semiconscious muscle movements and participate in the limbic system (emotional functions of the brain)

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55
Q

Folia

A

upfolds of the cerebellum, closely fitted to resemble the pages of a book

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56
Q

Cerebellar hemispheres

A

right and left portions of the cerebellum

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57
Q

Vermis

A

central area separating the cerebellar hemispheres

58
Q

Cerebellar cortex

A

outer layer of gray matter of the cerebellum

59
Q

Arbor vitae

A

inner area of white matter of the cerebellum that is organized into narrow branches that resemble that of a tree

60
Q

Cerebellar peduncles

A

cerebellum is attached to the rest of the brain by the inferior, middle, and inferior ___ ____

61
Q

Diencephalon

A

located within the center of the brain, inferior to the cerebrum; contains the thalamus, hypothalamus, and epithalamus

62
Q

Thalamus

A

largest part of the diencephalon, forming 80% of its total mass

63
Q

Intermediate mass

A

thalamus includes 2 egg-shaped structures connected by this small bridge of tissue

64
Q

Hypothalamus

A

located inferior to the thalamus; small, roughly triangular region containing important nuclei, which are centers for control for necessary body functions, including temperature regulation, hunger, thirst, emotions/behavior, many hormonal activities, and the autonomic functions (heart rate, blood pressure regulation)

65
Q

Mammillary bodies

A

2 of the nuclei of the hypothalamus appear as small swellings on the ventral side of the brain

66
Q

Pituitary gland

A

pea-shaped gland connected to the hypothalamus

67
Q

Infundibulum

A

narrows stalk that connects the pituitary to the hypothalamus

68
Q

Optic chiasma

A

anterior to the infundibulum is this landmark structure on the ventral side of the brain; where optic nerves from each eyeball meet and cross before continuing to the occipital lobe of the cerebrum

69
Q

Epithalamus

A

located superior to the thalamus; small area dominated by the pineal gland

70
Q

Pineal gland

A

endocrine gland that dominates the epithalamus

71
Q

Brain stem

A

inferior stem-like part of the brain, which connects the higher parts of the brain with the spinal cord; consists of the midbrain, pons, and the medulla oblongata

72
Q

Midbrain

A

superior part of the brain stem; located inferior to the diencephalon; contains the cerebral peduncles

73
Q

Cerebral peduncles

A

bundle of myelinated fibers that connect the upper and lower brain regions

74
Q

Corpora quadrigemina

A

composed of 2 superior colliculi and 2 inferior colliculi

75
Q

Superior colliculi

A

clusters of gray matter that regulate reflexes in eye, head, and trunk movements associated with vision

76
Q

Inferior colliculi

A

house reflexes associated with auditory stimuli

77
Q

Pons

A

expanded portion of the brain stem inferior to the midbrain and anterior to the cerebellum; contains reflex centers that assist the medulla in regulating respiration; also relays info to other parts of the brain by way of connections to the diencephalon and cerebellum

78
Q

Medulla oblongata

A

inferiormost part of the brain, connecting the spinal cord as it exits the cranial cavity through the foramen magnum; contains the respiratory and cardiovascular control centers; also contains reflex centers involved in coughing, sneezing, and vomiting

79
Q

Cranial meninges

A

membranes of the brain, deep to the cranial bones

80
Q

Dura mater

A

outermost meningeal layer; “hard mother”

81
Q

Periosteal layer

A

tough, outer layer of the dura mater, attached to the cranium

82
Q

Meningeal layer

A

inner, thin layer of the dura mater

83
Q

Dural sinuses

A

periosteal and meningeal layers of the dura mater split to form these spaces that collect blood before it drains into the jugular veins for recirculation

84
Q

Superior sagittal sinus

A

larges dural sinus; lies on top of the longitudinal fissure

85
Q

Falx cerebri

A

1 of 2 major extensions of the dura mater; dip down into the longitudinal fissure

86
Q

Tentorium cerebelli

A

1 of 2 major extensions of the dura mater; extends into the transverse fissure

87
Q

Arachnoid

A

deep to the dura mater is this 2nd meningeal layer, which resembles a spider; consists of numerous protein fibers forming a matrix that resembles a spider’s web

88
Q

Subarachnoid space

A

between the arachnoid fibers is this space filled with cerebrospinal fluid

89
Q

Pia mater

A

final meningeal layer; thin, vascular; adheres to the outer surface of the cerebral cortex

90
Q

Cerebrospinal fluid (CSF)

A

in addition to the bones of the cranium and the meninges, the brain receives protection from physical injury by the presence of this liquid, which provides a cushion that absorbs jarring movements of the head; also supports neurons of the brain and spinal cord with a continuous flow of oxygen, nutrients, and other important chemicals; initially formed from blood plasma leadking out of capillary networks

91
Q

Choroid plexus

A

capillary networks form this “pleated membrane”, which is located within 4 cavities within the brain commonly called the brain ventricles

92
Q

Lateral ventricles

A

2 large brain ventricles, 2 in each cerebral hemisphere

93
Q

Septum pellucidum

A

lateral ventricles are separated by this thin partition

94
Q

Third ventricle

A

smaller ventricle located between the 2 masses of the thalamus

95
Q

4th ventricle

A

very small ventricle located between the cerebellum and pons

96
Q

Interventricular foramen

A

channel segment between the lateral ventricles and the 3rd ventricle

97
Q

Cerebral aqueduct

A

segment between the 3rd & 4th ventricle

98
Q

Arachnoid villi

A

CSF is recycled back into the bloodstream by reabsorption through these small, fingerlike projections located in the superior sagittal sinus

99
Q

Spinal nerves

A

31 pairs of nerves extending from the lateral sides of the spinal cord, passing through the intervertebral foramina, and continuing to the body area they innervate

100
Q

Spinal cord gray matter

A

looks like a butterfly or the shape of the letter H in the center of the cord

101
Q

Anterior gray horns

A

part of the gray matter of the spinal cord that contain somatic motor neuron cell bodies

102
Q

Posterior gray horns

A

part of the gray matter of the spinal cord that contain terminal endings of peripheral sensory neurons and their synapses with association neurons

103
Q

Lateral gray horns

A

part of the gray matter of the spinal cord that contain visceral motor neuron cell bodies

104
Q

Gray commissure

A

gray matter of the spinal cord contains this part, which connects the right and left sides of the gray matter

105
Q

Central canal

A

surrounded by the gray commissure; channels CSF

106
Q

Spinal cord white matter

A

surrounds the gray matter of the spinal cord

107
Q

Anterior median fissure

A

deep groove of the white matter of the spinal cord

108
Q

Posterior median sulcus

A

narrow groove of the white matter of the spinal cord

109
Q

White columns (white funiculi)

A

anterior, lateral, and posterior; regions of white matter of the spinal cord

110
Q

Posterior (dorsal) root & anterior (ventral) root

A

external to the spinal cord, the spinal nerves divide into these roots; dorsal contains sensory fibers; ventral contains motor fibers

111
Q

Posterior (dorsal) root ganglion

A

near the division of the spinal nerves into posterior & anterior roots, the posterior root bulges to form this, which is the location of the cell bodies of sensory neurons

112
Q

Plexus

A

in 4 regions of the body, numerous spinal nerves formed a branched network; cervical, brachial, lumbar, and sacral on each side of the vertebral column

113
Q

Cervical plexus

A

formed from the anterior rami of spinal nerves C1-5, innervates muscles of the shoulder and neck

114
Q

Phrenic nerve

A

from the cervical plexus, this nerve arises from spinal nerves C3-5 to pass into the thoracic cavity to innervate the diaphragm for the control of breathing

115
Q

Brachial plexus

A

larger and more complex than the cervical plexus; formed from the anterior rami of C5-T1

116
Q

Axillary nerve

A

from the brachial plexus, this nerve arises to innervate the muscles and skin of the shoulder

117
Q

Radial nerve

A

large nerve that arises to extend down the posterolateral side of the arm and forearm, supplying all of the muscles and skin along its route

118
Q

Median nerve

A

extends parallel to the radial nerve; passes down the anterolateral side of the arm

119
Q

Lumbar plexus

A

located in the lumbar region; arises from the anterior rami of L1-4 (& T12 in some individuals); its nerves supply the lower abdominopelvic region and the anterior thigh

120
Q

Femoral nerve

A

large nerve that arises from the lumbar plexus to innervate the anterior thigh muscles; includes smaller branches that supply the skin and muscles of the anteromedial side of the lower limb

121
Q

Sacral plexus

A

arises from L4-S4; its nerves supply the rear pelvis, posterior side of the thigh, and all sensory and motor functions of the leg and foot

122
Q

Sciatic nerve

A

the largest nerve of the body; arises from the sacral plexus; extends through its notch to continue down the posterior side of the thigh, supplying flexor muscles and skin along its path

123
Q

Common fibular (peroneal) nerve

A

sciatic nerve divides into this and the tibial nerve in the popliteal region; along with the tibial nerve, supplies the remaining muscles and skin of the leg

124
Q

Tibial nerve

A

sciatic nerve divides into this and the common fibular (peroneal) nerve in the popliteal region; along with the common fibular nerve, supplies the remaining muscles and skin of the leg

125
Q

Olfactory nerve

A

carries sensory impulses from the olfactory center to the thalamus; most anterior nerve; = CN I

126
Q

Olfactory bulbs

A

swellings at the base of the frontal lobes where the neurons of the cranial nerves form a synapse with 2nd order neurons

127
Q

Reflex arc

A

simplest form of a reflex; involves a simple pathway with 5 components (sensory receptor & neuron, integration center, motor neuron, and effector)

128
Q

Sensory receptor

A

triggers an action potential if the change in environment, or stimulus, is great enough to generate it

129
Q

Sensory neuron

A

action potential is conducted by this to the CNS, which terminates at a synapse in the spinal cord (in a spinal reflex) or in the brain stem (in a cranial reflex)

130
Q

Integration center

A

action potential is passed to 1 or more neurons in the spinal cord or brain stem by way of synapses to form this center

131
Q

Motor neuron

A

from the integration center, the action potential passes to this, which conducts it to an effector

132
Q

Effector

A

the action potential stimulates the effector to perform work, which may be a skeletal muscle (in a somatic reflex), or a cardiac muscle, smooth muscle, or gland (in a visceral reflex)

133
Q

Patellar reflex

A

when the patellar tendon is stretched, the response is a rapid extension of the leg at the knee

134
Q

Biceps reflex

A

rapid contraction of the biceps brachii in response to a sudden stretch of the biceps tendon

135
Q

Achilles reflex

A

examines the 1st 2 sacral segments of the spinal cord; results in plantar flexion when the calcaneus tendon is stretched

136
Q

Plantar reflex

A

common clinical test that examines the pyramidal tract of the brain, in addition to the peripheral nerves that are associated with the reflex arc; in adults, causes the toes to flex and move closer together

137
Q

White communicating rami

A

preganglionic neurons exit the spinal cord in the anterior (ventral) root of the spinal nerves along with somatic motor neurons, then exit from the spinal nerve to form these myelinated parts

138
Q

Sympathetic trunk ganglia

A

white communicating rami connect with this series of swellings extending alongside the vertebral column in the T1 through L2 region

139
Q

Splanchnic nerves

A

without the trunk ganglia, the axons may synapse with postganglionic neurons or they may alternatively pass through the sympathetic trunk ganglia without synapsing to emerge to form these nerves near abdominopelvic organs

140
Q

Gray communicating rami

A

postganglionic cell bodies are located within the sympathetic trunk ganglia & synapse with the preganglionic neurons; their axons may return to the spinal nerve by way of these unmyelinated parts

141
Q

Terminal (intramural) ganglia

A

axons of the cranial preganglionic neurons emerge from the brain stem within cranial nerves III, VII, IX, and X; from there, they extend to their target organs in the head region, where they terminate at synapses within postganglionic neurons in ___ ___

142
Q

Pelvic sphlanchnic nerves

A

axons of the sacral preganglionic neurons exit the spinal cord in the anterior (ventral) roots of S2-S4 via nerves known as ___ ___ ___