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Flashcards in Nervous System Deck (33)
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Two Main Divisions

1. Central Nervous System (CNS)
-Brain + Spinal Cord
2. Peripheral Nervous System (PNS)
-Cranial Nerves
-Spinal Nerves
-Further subdivided into the somatic and autonomic nervous systems


CNS: Brain

-largest organ of the nervous system
-located in the cranium
-four major structures
1. cerebrum
2. cerebellum
3. diencephalon
4. brain stem
-integration of almost every physical mental activity of the body


CNS: Spinal Cord

-long narrow column of neural tissue within the spinal cavity or canal
-extending from the brain stem to the second lumbar vertebra in the spinal column
-protected by the bony structure of the vertebral column
-protected and nourished by the meninges
-relay station for sending and receiving electrical signals between the brain and body


CNS: Meninges

Three layers of protective membrane covering the brain and spinal cord
1. Dura mater (outermost layer)
2. Arachnoid (middle layer)
3. Pia Mater (innermost layer)


Peripheral Nervous System (PNS)

Cranial Nerves
-12 pairs that emerge from the brainstem
-named according to location or function
Spinal Nerves
-38 pairs that emerge from the spinal cord
-named according to the vertebra from which they exit
Defined by the direction in which impulses travel:
-Sensory (afferent) neurons---to the CNS
-Motor (efferent) neurons---away from the CNS


PNS: Motor Neurons send impulses:

-Somatic nervous system (SNS)
-Autonomic Nervous System (ANS)


PNS: Motor Neurons send impulses; Somatic Nervous System (SNS)

regulates skeletal (striated) muscles (voluntary actions) such as walking and talking
(how you move)


PNS: Motor Neurons send impulses; Autonomic Nervous System (ANS)

regulates visceral (smooth) muscles (involuntary actions) such as heart rate and peristalsis (relaxation of muscles and intestine or another canal, push canal forward), and secretory activity
-consists of 2 subdivisions that regulate involuntary body functions and usually oppose the action of the other:
1.Sympathetic- fight or flight
2.Parasympathetic- rest + digest


PNS: Motor Neurons send impulses; Autonomic Nervous System 2 Subdivisions: Sympathetic

(fight or flight)
increases heart rate, constricts blood vessels, and raises blood pressure to deal with a crisis


PNS: Motor Neurons send impulses; Autonomic Nervous System 2 Subdivisions: Parasympathetic

(rest + digest)
slows heart rate, increases glandular secretions, relaxes sphincters


Cellular Structure Of The Nervous System: Neuron

-individual nerve cell
-interconnecting to form complicated networks called nerves that transmit electrical impulses throughout the body


Cellular Structure Of The Nervous System: Neuroglia

-Glial cells that provide a supportive framework for neurons
-responsible for protecting against infection by performing phagocytosis (engulfing and digesting unwanted substances; like a Pacman)
-unable to transmit electrical impulses


Four Types of Neuroglial Cells

1. Astrocytes
2. Microglia
3. Oligodendrocyte
4. Ependyma


Neuroglial Cell: Astrocyte

-star-shaped cell
-numerous radiating extensions for attachment that are wrapped around the brain and capillaries
-part of the blood-brain barrier, which prevents harmful substances from diffusing into the brain


Neuroglial Cells: Microglia

-small interstitial cells
-phagocytic in nature, engulfing cellular debris, waste products, and pathogens within nerve tissue
-increase in number during injury or infection as cells migrate to the infected or injured area


Neuroglial Cells: Oligodendrocyte

-resembling an astrocyte but smaller with fewer extensions
-responsible for forming and maintaining the myelin sheath on neurons


Neuroglial Cells: Ependyma

-cells that line the ventricles of the brain and central canal of the spinal cord
-responsible for production of cerebral spinal fluid and assistance in its circulation


Spinal Cord Injury

spinal injury or disease resulting in a lack of or decrease in function or feeling
-degree of dysfunction related to site of injury on the spinal cord (higher site associated with greater dysfunction)
(the higher the injury, the worse it is; everything below is done, no function)


Spinal Cord Injury: Signs + Symptoms

-loss or decrease of feeling or function
-history of trauma (such as car accident or gun shot wound)
-occasionally, exaggerated reflexes or spasms
-possible loss of motor and sensory functions in the legs and trunk (paraplegia)
-possible loss of bowel, bladder, and sexual function (quadriplegia)


Spinal Cord Injury: Treatments

-restoration and stabilization of the injured spinal area
-halo brace to immobilize the head ad neck vertebrae
-decompression of compressed neurological structures
-prevention of secondary complications (contractures, pressure, ulcers)
-cooling of the affected portion of the spine



any disorder of the cerebral blood vessels that causes a loss of consciousness due to oxygen deprivation of brain tissue
-sometimes called cerebrovascular accident (CVA) or brain attack
-manifestations appearing on opposite side of the body from the brain hemisphere affected
ex: left-sided weakness from injury to right hemisphere of the brain


Types of Strokes

1. Ischemic
2.Intracerebral hemorrhage
3. Subarachnoid hemorrhage


Types of Strokes: Ischemic

blockage of carotid arteries (arteries that supply the head and neck with oxygenated blood) by plague or thrombus, resulting in insufficient blood flow to the brain


Types of Stroke: Intracerebral Hemorrhage

-rupture of vessels in the brain
-compression and destruction of brain structures from released blood
(intracerebral = cerebrum= brain)


Types of Stroke: Subarachnoid Hemorrhage

-release of blood into the space surrounding the brain
-commonly caused by a ruptured aneurysm (an excessive localized enlargement of an artery caused by a weakening of the artery wall)
-usually fatal


Stroke: Signs + Symptoms

-Hemiparesis- half weakness
-Ataxia- discoordination of muscle movements
-Aphasia- speaking difficulty
-loss of consciousness
-blurred vision
-commonly preceded by a transient ischemic attack (TIA) (Signs + Symptoms of a mild stroke that resolve within 24 hours)


Stroke: Treatment

-CT scan to determine the type and extent of stroke
-"clot busters" to dissolve clots
-Antihypertensive to control blood pressure
-physical, occupational, and speech therapy


Alzheimer's Disease (AD)

-most common form of dementia
-interference with memory, learning, and, eventually, the ability to function
-associated with neuritic "plagues" that form in a small area of the brain and, eventually, spread
-definitive diagnosis only possible on autopsy (a postmortem examination to discover the cause of death or the extent of disease)


Alzheimer's Disease (AD): Signs + Symptoms

-diminished interest in daily activity, acquaintances, and surroundings
-getting lost on familiar routes
-personality changes
-loss of social skills


Alzheimer's Disease (AD): Treatments

-primarily supportive
-altering the environment to ensure the patients safety
-support of family members and caregivers
-medical management, considering potential adverse effects (A harmful or abnormal result).