Term
| The nervous system consists of two divisions |
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Definition
| central nervous system (CNS), including the brain and spinal cord, and the peripheral nervous system, which includes cranial and spinal nerves. |
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Term
| The peripheral nervous system can be further divided into |
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Definition
| somatic, or voluntary, nervous system, and the autonomic, or involuntary, nervous system |
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Term
| The function of the nervous system is |
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Definition
| control of all motor, sensory, autonomic, cognitive, and behavioral activities. The nervous system has approximately 10 million sensory neurons that send information about the internal and external environment to the brain and 500,000 motor neurons that control the muscles and glands |
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Term
| The basic functional unit of the brain |
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Definition
the neuron
The dendrite is a branch-type structure with synapses for receiving electrochemical messages. The axon is a long projection that carries impulses away from the cell body |
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Term
communicate messages from one neuron to another or from a neuron to a specific target tissue. manufactured and stored in synaptic vesicles
They enable conduction of impulses across the synaptic cleft. action is to potentiate, terminate, or modulate a specific action, and it can either excite or inhibit the activity of the target cell |
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Definition
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Term
1)agnosia
2)ataxia
3)autonomic nervous system
4)axon
5)Babinski reflex (sign) |
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Definition
1)loss of ability to recognize objects through a particular sensory system; may be visual, auditory, or tactile
2)inability to coordinate muscle movements, resulting in difficulty in walking, talking, and performing self-care activities
3)division of the nervous system that regulates the involuntary body functions
4)portion of the neuron that conducts impulses away from the cell body
5)a reflex action of the toes, indicative of abnormalities in the motor control pathways leading from the cerebral cortex |
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Term
1)parasympathetic nervous system
2)sympathetic nervous system |
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Definition
1)division of the autonomic nervous system active primarily during nonstressful conditions, controlling mostly visceral functions
2)division of the autonomic nervous system with predominantly excitatory responses, the “fight-or-flight” system |
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Term
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Definition
| test for cerebellar dysfunction requiring the patient to stand with feet together, eyes closed and arms extended; inability to maintain the position, with either significant stagger or sway, is a positive test |
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Term
| Acetylcholine (major transmitter of the parasympathetic nervous system) |
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Definition
Source:Many areas of the brain; autonomic nervous system
Action: Usually excitatory; parasympathetic effects sometimes inhibitory (stimulation of heart by vagal nerve) |
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Term
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Definition
Source:Brain stem, hypothalamus, dorsal horn of the spinal cord
Action:Inhibitory, helps control mood and sleep, inhibits pain pathways |
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Term
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Definition
Source:Substantia nigra and basal ganglia
Action:Usually inhibits, affects behavior (attention, emotions) and fine movement |
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Term
| Norepinephrine (major transmitter of the sympathetic nervous system) |
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Definition
Source:Brain stem, hypothalamus, postganglionic neurons of the sympathetic nervous system
Action:Usually excitatory; affects mood and overall activity |
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Term
| Gamma-aminobutyric acid (GABA) |
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Definition
Source:Spinal cord, cerebellum, basal ganglia, some cortical areas
Action:Excitatory |
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Term
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Definition
Source:Nerve terminals in the spine, brain stem, thalamus and hypothalamus, pituitary gland
Action:Excitatory; pleasurable sensation, inhibits pain transmission |
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Term
| The brain is divided into three major areas: |
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Definition
| cerebrum, the brain stem, and the cerebellum |
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Term
| This part of the brain is composed of two hemispheres, the thalamus, the hypothalamus, and the basal ganglia.connections for the olfactory (cranial nerve I) and optic (cranial nerve III) nerves are found |
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Definition
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Term
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Definition
| the midbrain, pons, medulla, and connections for cranial nerves II and IV through XII |
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Term
| This part of the brain is located under the cerebrum and behind the brain stem |
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Definition
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Term
| The two hemispheres are joined at the lower portion of the fissure by the |
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Definition
corpus callosum - a thick collection of nerve fibers that connects the two hemispheres of the brain and is responsible for the transmission of information from one side of the brain to the other. Information transferred includes sensation, memory, and learned discrimination.
** Right-handed people and some left-handed people have cerebral dominance on the left side of the brain for verbal, linguistic, arithmetical, calculating, and analytic functions. |
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Term
Cerebrum
-gyri-
-gray matter-
-White matter- |
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Definition
The outside surface of the hemispheres has a wrinkled appearance that is the result of many folded layers or convolutions called gyri, which increase the surface area of the brain, accounting for the high level of activity carried out by such a small-appearing organ.
The external or outer portion of the cerebrum (the cerebral cortex) is made up of gray matter approximately 2 to 5 mm in depth; it contains billions of neurons/cell bodies, giving it a gray appearance.
White matter makes up the innermost layer and is composed of nerve fibers and neuroglia (support tissue) that form tracts or pathways connecting various parts of the brain with one another (transverse and association pathways) and the cortex to lower portions of the brain and spinal cord (projection fibers) |
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Term
| cerebral hemispheres are divided into pairs of lobes |
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Definition
| frontal, parietal, temporal, and occipital lobes |
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Term
the largest lobe, located in the front of the skull. The major functions of this lobe are concentration, abstract thought, information storage or memory, and motor function. It also contains Broca's area, critical for motor control of speech.
is also responsible in large part for a person's affect, judgment, personality, and inhibitions |
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Definition
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Term
| predominantly sensory lobe located near the crown of the head. This lobe analyzes sensory information and relays the interpretation of this information to the thalamus and other cortical areas. It is also essential to a person's awareness of the body in space, as well as orientation in space and spatial relations |
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Definition
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Term
| contains the auditory receptive areas located around the temples. This lobe contains a vital area called the interpretive area that provides integration of somatization, visual, and auditory areas and plays the most dominant role of any area of the cortex in thinking |
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Definition
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Term
| the posterior lobe of the cerebral hemisphere located at the lower back of the head, is responsible for visual interpretation |
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Definition
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Term
1)basal ganglia
2)The thalamus |
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Definition
1)masses of nuclei located deep in the cerebral hemispheres that are responsible for control of fine motor movements, including those of the hands and lower extremities.
2)lies on either side of the third ventricle and acts primarily as a relay station for all sensation except smell. All memory, sensation, and pain impulses also pass through this section of the brain |
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Term
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Definition
| located anterior and inferior to the thalamus. lies immediately beneath and lateral to the lower portion of the wall of the third ventricle. It includes the optic chiasm (the point at which the two optic tracts cross) and the mamillary bodies (involved in olfactory reflexes and emotional response to odors). The infundibulum of the hypothalamus connects it to the posterior pituitary gland. The hypothalamus plays an important role in the endocrine system because it regulates the pituitary secretion of hormones that influence metabolism, reproduction, stress response, and urine production. It works with the pituitary to maintain fluid balance and maintains temperature regulation by promoting vasoconstriction or vasodilatation. |
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Term
| the site of the hunger center and is involved in appetite control. It contains centers that regulate the sleep–wake cycle, blood pressure, aggressive and sexual behavior, and emotional responses (ie, blushing, rage, depression, panic, and fear). The hypothalamus also controls and regulates the autonomic nervous system. |
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Definition
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Term
Brain Stem
-midbrain-
-pons-
-medulla oblongata - |
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Definition
consists of the midbrain, pons, and
medulla oblongata
midbrain connects the pons and the cerebellum with the cerebral hemispheres; it contains sensory and motor pathways and serves as the center for auditory and visual reflexes. Cranial nerves III and IV originate in the midbrain. The pons is situated in front of the cerebellum between the midbrain and the medulla and is a bridge between the two halves of the cerebellum, and between the medulla and the cerebrum. Cranial nerves V through VIII connect to the brain in the pons. The pons contains motor and sensory pathways. Portions of the pons also control the heart, respiration, and blood pressure.
The medulla oblongata contains motor fibers from the brain to the spinal cord and sensory fibers from the spinal cord to the brain. Most of these fibers cross, or decussate, at this level. Cranial nerves IX through XII connect to the brain in the medulla. |
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Term
| separated from the cerebral hemispheres by a fold of dura mater, the tentorium cerebelli. has both excitatory and inhibitory actions and is largely responsible for coordination of movement. It also controls fine movement, balance, position (postural) sense or proprioception (awareness of where each part of the body is), and integration of sensory input. |
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Definition
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Term
| The layers of the meninges are |
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Definition
| dura, arachnoid, and pia mater |
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Term
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Definition
| outermost layer; covers the brain and the spinal cord. It is tough, thick, inelastic, fibrous, and gray. There are four extensions of the dura: the falx cerebri, which separates the two hemispheres in a longitudinal plane; the tentorium, which is an infolding of the dura that forms a tough, membranous shelf; the falx cerebelli, which is between the two lateral lobes of the cerebellum; and the diaphragm sellae, which provides a “roof” for the sella turcica. The tentorium supports the hemispheres and separates them from the lower part of the brain. When excess pressure occurs in the cranial cavity, brain tissue may be compressed against the tentorium or displaced downward, a process called herniation. Between the dura mater and the skull in the cranium, and between the periosteum and the dura in the vertebral column, is the epidural space, a potential space. |
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Term
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Definition
| the middle membrane; an extremely thin, delicate membrane that closely resembles a spider web (hence the name arachnoid). It appears white because it has no blood supply. The arachnoid layer contains the choroid plexus, which is responsible for the production of cerebrospinal fluid (CSF). This membrane also has unique finger-like projections, arachnoid villi, that absorb CSF. In the normal adult, approximately 500 mL of CSF is produced each day; all but 125 to 150 mL is absorbed by the villi (Hickey, 2003). When blood enters the system (from trauma or hemorrhagic stroke), the villi become obstructed and hydrocephalus (increased size of ventricles) may result. The subdural space is between the dura and the arachnoid layer, and the subarachnoid space is between the arachnoid and pia layers and contains the CSF. |
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Term
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Definition
| the innermost membrane; a thin, transparent layer that hugs the brain closely and extends into every fold of the brain's surface |
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Term
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Definition
| choroid plexus of the lateral, third, and fourth ventricles. The ventricular and subarachnoid system contains approximately 150 mL of fluid; each lateral ventricle normally contains 25 mL of CSF |
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Term
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Definition
| The brain does not store nutrients and has a high metabolic demand that requires the high blood flow. The brain's blood pathway is unique because it flows against gravity; its arteries fill from below, and the veins drain from above. In contrast to other organs that may tolerate decreases in blood flow because of their good collateral circulation, the brain has poor collateral blood flow, which may result in irreversible tissue damage when blood flow is occluded for even short time periods. |
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Term
| Anatomy of the Spinal Cord |
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Definition
The spinal cord and medulla form a continuous structure extending from the cerebral hemispheres and serving as the connection between the brain and the periphery.
it extends from the foramen magnum at the base of the skull to the lower border of the first lumbar vertebra, where it tapers to a fibrous band called the conus medullaris.
The spinal cord is surrounded by the meninges, dura, arachnoid, and pia layers. Between the dura mater and the
vertebral canal is the epidural space |
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Term
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Definition
| The spinal cord is an H-shaped structure with nerve cell bodies (gray matter) surrounded by ascending and descending tracts (white matter)The lower portion of the H is broader than the upper portion and corresponds to the anterior horns. The anterior horns contain cells with fibers that form the anterior (motor) root end and are essential for the voluntary and reflex activity of the muscles they innervate. The thinner posterior (upper horns) portion contains cells with fibers that enter over the posterior (sensory) root end and thus serve as a relay station in the sensory/reflex pathway. |
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Term
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Definition
| The thoracic region of the spinal cord has a projection from each side at the crossbar of the H-shaped structure of gray matter called the lateral horn. It contains the cells that give rise to the autonomic fibers of the sympathetic division. The fibers leave the spinal cord through the anterior roots in the thoracic and upper lumbar segments. |
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Term
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Definition
There are six ascending tracts
-- Two conduct sensation, principally the perception of touch, pressure, vibration, position, and passive motion from the same side of the body. Before reaching the cerebral cortex, these fibers cross to the opposite side in the medulla. The two spinocerebellar tracts conduct sensory impulses from muscle spindles, providing necessary input for coordinated muscle contraction. They ascend essentially uncrossed and terminate in the cerebellum.
--The last two spinothalamic tracts are responsible for conduction of pain, temperature, proprioception, fine touch, and vibratory sense from the upper body to the brain. They ascend, cross to the opposite side of the brain, and terminate in the thalamus |
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Term
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Definition
| The two corticospinal tracts conduct motor impulses to the anterior horn cells from the opposite side of the brain and control voluntary muscle activity. The three vestibulospinal tracts descend uncrossed and are involved in some autonomic functions (sweating, pupil dilation, and circulation) and involuntary muscle control. The corticobulbar tract conducts impulses responsible for voluntary head and facial muscle movement and crosses at the level of the brain stem. The rubrospinal and reticulospinal tracts conduct impulses involved with involuntary muscle movement. |
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Term
Vertebral Column
The bones of the vertebral column surround and protect the spinal cord and normally consist |
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Definition
7 cervical,
12 thoracic, and 5 lumber vertebrae,
the sacrum (a fused mass of 5 vertebrae), and terminate in the coccyx.
Nerve roots exit from the vertebral column through the intervertebral foramina (openings). The vertebrae are separated by disks, except for the first and second cervical, the sacral, and the coccygeal vertebrae.
Each vertebra has a ventral solid body and a dorsal segment or arch, which is posterior to the body.
The arch is composed of two pedicles and two laminae supporting seven processes. The vertebral body, arch, pedicles, and laminae all encase and protect the spinal cord |
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Term
| The Peripheral Nervous System |
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Definition
| The peripheral nervous system includes the cranial nerves, the spinal nerves, and the autonomic nervous system. |
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Term
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Definition
Twelve pairs of cranial nerves emerge from the lower surface of the brain and pass through the foramina in the skull.
Three are entirely sensory (I, II, VIII),
five are motor (III, IV, VI, XI, and XII),
and four are mixed (V, VII, IX, and X),
because they have both sensory and motor functions |
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Term
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Definition
| composed of 31 pairs of spinal nerves: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. Each spinal nerve has a ventral root and a dorsal root |
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Term
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Definition
dorsal roots are sensory and transmit sensory impulses from specific areas of the body known as dermatomes to the dorsal ganglia
sensory fiber may be somatic, carrying information about pain, temperature, touch, and position sense (proprioception) from the tendons, joints, and body surfaces; or visceral, carrying information from the internal organs. |
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Term
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Definition
| are motor and transmit impulses from the spinal cord to the body, and these fibers are also either somatic or visceral. The visceral fibers include autonomic fibers that control the cardiac muscles and glandular secretions |
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Term
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Definition
regulates the activities of internal organs such as the heart, lungs, blood vessels, digestive organs, and glands.
Maintenance and restoration of internal homeostasis is largely the responsibility of the autonomic nervous system.
There are two major divisions:
the sympathetic nervous system, with predominantly excitatory responses, most notably the “fight or flight” response, and the parasympathetic nervous system, which controls mostly visceral functions. |
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Term
| I (olfactory) |
Sensory
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Sense of smell
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Definition
| II (optic) |
Sensory
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Visual acuity and visual fields
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Term
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III(oculomotor)
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Motor
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Muscles that move the eye and lid, pupillary constriction, lens accommodation
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Definition
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IV (trochlear)
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Motor
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Muscles that move the eye
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Term
| V (trigeminal) |
Mixed
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Facial sensation, corneal reflex, mastication
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Definition
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VII(abducens)
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Motor.
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Muscles that move the eye
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Term
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VII
(facial)
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Mixed
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Facial expression and muscle movement, salivation and tearing, taste, sensation in the ear
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Definition
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VIII (acoustic)
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Sensory
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Hearing and equilibrium
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Term
| IX (glossopharyngeal) |
Mixed
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Taste, sensation in pharynx and tongue, pharyngeal muscles, swallowing
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Definition
| X (vagus) |
Mixed
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Muscles of pharynx, larynx, and soft palate; sensation in external ear, pharynx, larynx, thoracic and abdominal viscera; parasympathetic innervation of thoracic and abdominal organs
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Term
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XI (spinal accessory)
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Motor
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Sternocleidomastoid and trapezius muscles
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Definition
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XII (hypoglossal)
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Motor
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Movement of the tongue
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Term
autonomic nervous system innervates most body organs
regulated by centers in the spinal cord, brain stem, and hypothalamus |
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Definition
The autonomic nervous system has two neurons in a series extending between the centers in the CNS and the organs innervated.
The first neuron, the preganglionic neuron, is located in the brain or spinal cord, and its axon extends to the autonomic ganglia.
There, it synapses with the second neuron, the postganglionic neuron, located in the autonomic ganglia, and its axon synapses with the target tissue and innervates the effector organ. Its regulatory effects are exerted not on individual cells but on large expanses of tissue and on entire organs. The responses elicited do not occur instantaneously but after a lag period. These responses are sustained far longer than other neurogenic responses to ensure maximal functional efficiency on the part of receptor organs, such as blood vessels |
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