S13 Diseases of the Nervous System

nervous system

coordinates and controls all of the body’s functions and plays a central role in maintaining homeostasis

Central nervous system

part of the nervous system containing the brain and spinal cord

peripheral nervous system

part of the nervous system that comprises of the nerves outside the CNS

motor nerves

nerves that carry information from the CNS to muscles and glands

sensory nerves

nerves that carry sensory information from sense receptors to the CNS

nerves

carry information to and from the CNS

neuron

basic unit of the nervous system; aka nerve cell

dendrites

filamentous extensions that are attached to the nerve cell body

carry information toward the cell body

axon

part of the nerve cell body that carries information away from the cell body

myelin

lipoprotein coverings that insulate and protect neurons

interneuron

neuron that carries nervous impulses between neurons

sensory neurons

neurons that detect environmental stimuli, such as touch, light, and pain, and transmit messages to the brain or spinal

brain

integrates and stores information, interprets sensory input, and directs all body functions

meninges

layers of tissue that protect nerve tissue in the brain and spinal cord

pia mater

innermost layer of the meninges

arachnoid

middle layer of the meninges

dura mater

outermost and toughest layer of the meninges

subdural space

area between the dura mater and the arachnoid membrane

subarachnoid space

area between the arachnoid membrane and the pia mater that is filled with cerebrospinal fluid

cerebrospinal fluid

clear liquid in the meninges that is composed of water, protein, glucose and minerals

cerebrum

largest part of the brain

cerebral cortex

outer region of the cerebrum — distinctively wrinkled region described as gray matter

basal ganglia

located in the inner part of the cerebrum — controls muscle coordination and steady movement

frontal lobe

part of the brain that controls cognitive action, voluntary muscle actions and the muscles of speech

temporal lobe

part of the brain responsible for senses and the ability to understand spoken language

occipital lobe

part of the brain that interprets visual input

thalamus

located below the cerebrum — relays sensory information to the correct areas of the cerebral cortex

hypothalamus

part of the brain, below the thalamus that controls vital body functions — serves as the intermediary part between nervous system and endocrine system

cerebelum

below occipital lobe, controls smooth voluntary movements by coordinating sensory input with muscle actions

medulla

part of the brain that bridges the brain with the spinal cord — helps regulate heart and respiratory rate AND controls smooth muscles of blood vessels

spinal cord

carries nerve impulses between the brain and the body

ganglia

bundles of neuron cell bodies outside the CNS

somatic system

part of the PNS that controls voluntary muscle actions AND receives input from sensory receptors and organs

autonomic nervous system (ANS)

part of the PNS that controls glands and involuntary muscles

sympathetic subdivision

a subdivision of the autonomic nervous system that is composed of nerves that arise from the thoracic and lumbar areas of the spinal cord — prepares organs and gland for “flight or fight”

parasympathetic subdivision

a subdivision of the autonomic nervous system that includes nerves arising from the cranial and sacral regions

enteric subdivision

subdivision of the autonomic nervous system that consists of a network of nerves in the abdomen that control GI organs

electroencephalography (EEG)

records the brain’s electrical activity

traumatic brain injury

damage to the brain resulting from external physical forces

concussion

traumatic brain injury that results from a blow to the head or sudden shaking or movement

closed severe traumatic brain injury

severe traumatic brain injury that result from sudden movement of the brain in the skull

open severe traumatic brain injury

severe traumatic brain injury that results from penetrating wounds caused by firearms or sharp objects

epilepsy

CNS disorder characterized by abnormal electrical activity in the brain - may cause seizures

stroke

sudden interruption of blood flow to part of the brain caused by blood clot or burst blood vessel within the brain

ischemic strokes

strokes caused by blood clots

hemorrhagic strokes

strokes caused by burst blood vessel

transient ischemic attack (TIA)

mini stroke — temporary interruption of blood flow to the brain

trigeminal neuralgia

severe chronic pain resulting from dysfunction of the trigeminal nerve; most painful medical condition ever reported

trigeminal nerve

fifth central nerve — transmits sensory info from face and jaw

Bell’s palsy

paralysis of facial muscles caused by inflammation of the facial nerves

meningitis

acute inflammation of the first two meninges that cover the brain and spinal cord

encephalitis

inflammation of the brain most often caused by virus

poliomyelitis or polio

cripplin, potentially fatal viral infection; eradicated mostly by vaccination

rabies

viral infection of the brain in wild mammals - virus moves through the brain and into spinal cord

shingles

acute painful inflammation of sensory neurons caused by reactivation of the latent chickenpox virus

postherpetic neuralgia

pain that continues after shingles rash has been cleared

tetanus

condition of acute muscle rigidity and paralysis caused by bacterial nerve toxin

trismus

flexed and rigid jaw seen in tetanus

botulism

condition of muscle weakness and paralysis caused by a bacterial nerve toxin

botulinum toxin

nerve toxin produced by the bacterium Clostridium botulinum that binds motor neurons and prevents them from sending signals to muscles for contraction

Reye syndrome

uncommon but potentially disabling or fatal neurological illness that occurs in children after a viral infection — common in children who use aspirin during flu and chickenpox infections

degenerative disease

diseases that produce progressive loss of function in organs of the nervous system over time

Alzheimer’s disease

most common form of dementia - results in progressive destruction of memory and nearly all other important brain functions

multiple sclerosis

chronic, progressive, degenerative disorder of the CNS — nerve inflammation and myelin destruction

amyotrophic lateral sclerosis (ALS)

serious terminal disease characterized by progressive loss of motor function

Parkinson’s disease

degenerative disease characterized by progressive loss of control over muscle coordination and movement

essential tremor

disorder characterized by shaking of hands and head, especially during voluntary movement

huntington’s chorea

progressive degenerative disease of the brain that affects motor and cognitive function

spina bifida

type of neural tube defect, where the spinal cord failed to fuse correctly, producing weak spots over the spinal cord

hydrocephalus

condition of buildup of cerebrospinal fluid around the brain - among the most common birth defect

cerebral palsy

congenital disorder characterized by impaired muscle movement, tone and posture

brain tumor

abnormal masses of tissue growth in the brain