HAN 312 nervous system and special senses

what does the CNS contain?

the brain and spinal cord

what does the PNS contain?

cranial nerves (12 pairs), spinal nerves (31 pairs), autonomic nerves (parasympathetic/sympathetic nerves)

cerebrum

largest and uppermost portion of the brain, divided into right and left halves (called cerebral hemispheres)

what is the cerebral cortex

surface nerve cells, gray matter, controls higher mental functions (speech, vision, smell, movement, hearing, and thought)

frontal lobe

front portion of the cerebrum that controls voluntary muscle movement and is involved w/ emotions

occipital lobe

back portion of the cerebrum that controls vision

parietal lobe

middle top portion of the cerebrum involved in perception of touch, temperature and pain

temporal lobe

portion of the cerebrum below the frontal lobe, controls senses of hearing, memory creation, and helps you understand language

diencephalon

area deep within the brain that contains the thalamus, hypothalamus, and pituitary gland. Responsible for directing sensory info to the cortex

thalamus

inetegrates and monitors impulses from the skin

hypothalamus

beneath the thalamus, controls body temp, sleep, appetite, sexual desire, and hormones (released from pituitary gland)

ganglion

group of nerve cell bodies located along the pathway of a nerve

plexus

interlacing network of nerves

neurotransmitters

chemical messenger released into a synapse by a neuron, either stimulates or inhibits another cell

brainstem

connects the brain to the spinal cord, assists in breathing, heart rhythm, vision, and consciousness

midbrain

mesencephalon, uppermost part of the brainstem that connects the brainstem to the cerebellum, controls sensory processes

pons

bridges cerebrum and cerebellum w/ the rest of the brain, houses nerves for the face and eyes

medulla oblongata

part of the brainstem that connects the brain, and the spinal cord, controls respiration, heartbeat, and blood vessel size

ventricle

one of the 4 interconnected cavities within the brain that contain and secrete CSF

CSF

colorless fluid that circulates in brain and spinal cord, acts a protector and transports nutrients

meninges

membranous covering of the brain and spinal cord

dura mater

strong, fibrous, outermost layer of the meninges, subdural space

arachnoid

delicate fibrous membrane forming the middle layer of the meninges, subarachnoid space

pia mater

thin inner layer of the meninges that attaches directly to the brain and spinal cord

neurons

individual nerve cells that make up the basic structure of the nervous system and conduct impulses (~10 billion in adults)

collect into macroscopic nerves

anatomical portions of a neuron:

• dendrite

• cell body

• cell nucleus

• axon

• myelin sheath

terminal end fibers (secrete neurotransmitters across synapses)

nerves

cordlike structure that transmits stimuli

AFFERENT/sensory nerves

carry messages toward the brain

EFFERENT/motor nerves

carry messages away from the brain

mixed nerves

carry both sensory and motor fibers

dorsal root

carries sensory impulses towards the spinal cord/brain

ventral root

carries motor impulses away from the brain/spinal cord to muscles or glands

how many cranial nerves are there

12 pairs of nerves that emerge from the cranium

ex: vagus nevre (CN X) which branches reach to larynx, trachea, bronchi, lungs, aorta, esophagus, and stomach

how many spinal nerves are there

31 pairs that emerge from the spine

ex: sciatic nerve extending from base of spine down the thigh, lower leg, foot

what cells are in the CNS?

astrocytes, oligodendrocytes, ependymal cells, microglia

what cells are in the PNS?

satellite cells, schwann cells

astrocytes

provide structural and metabolic support, repair cells

oligodendrocytes

myelinate axons and insulate electrical impulses

ependymal cells

produce and moves CSF

microglia

defense and immune response

satellite cells

provides structural and metabolic support for cell body of neurons

schwann cells

myelinate axons and insulate electrical impulses

esthesi/o

sensation, perception

phas/o

speech, word, phrase

lex/o

muscle

my/o

muscle

kines/o

movement

cephal/o

head

-phrenia

the mind

-phasia

speech

-praxia

action

-sthenia

strength

alges/o

excessive sensitivity to pain

esthesi/o

nervous sensation

syncop/o

cut off

somn/o

sleep

-algia

pain

-algesia

excessive sensitivity to pain

-ictal, -lepsy

seizure

parietal or incomplete paralysis

-paresis

-plegia

paralysis

what is cerebral palsy

defect of motor power and coordination related to damage to the brain that occurred prenatally, perinatally, or in the first 3 years of life

what is hydrocephalus

condition involving increased CSF, leads to enlargement of cerebral ventricles and increase in intracranial pressure (ICP) may cause cranial enlargement

what is spina bifida

protruding from the skin on the spine, can either be mole, simple, patch of hair, or a external protruding sac containing meninges and CSF, *often associated with hydrocephalus and paralysis

epilepsy

disorder involving seizure activity and alterations of consciousness

postictal

pertaining to following a seizure

alzheimer disease

a degenerative progressive brain disease that results in impairment of language function, inability to calculate and deterioration of judgement

amyotrophic lateral sclerosis (ALS)

progressive deterioration of motor nerve cells, leads to muscle weakness and eventually paralysis and death

huntington’s disease

genetic, progressive deterioration of nerve cells, usual presentation around 30-40 yrs old

multiple sclerosis (MS)

common disorder of the central nervous system that causes sclerotic patches (plaques) in the brain and spina; cord

parkinson’s disease

degenerative disorder of the CNS that often impairs the sufferer’s motor skills and speech, most notably characterized by tremors of the limbs

bell palsy

paralysis of facial muscles, often on one side of the face, caused by a dysfunction of a cranial nerve can have an infectious etiology

Tourette syndrome

characterized by intermittent motor and vocal manifestations referred to as “tics” often begins in childhood

herpes zoster/shingles

painful viral infection (varicella) affecting peripheral nerves, causes eruption of blisters that follows the course of the affected nerves

meningitis

inflammation of the meninges, can be bacterial

poliomyelitis

inflammation of the gray matter of the spinal cord which can lead to temporary or permanent paralysis

HIV encephalopathy

dementia caused by HIV

cerebral contusion

bruising of brain tissue secondary to trauma to the head, may be associated w/ skull fracture

epidural hematoma

a collection of blood above the dura mater resulting from a broken blood vessel

subdural hematoma

a collection of blood below the dura mater resulting from a broken blood vessel

subarachnoid hemorrhage

a collection of blood within the subarachnoid space resulting from a broken blood vessel

cerebrovascular accident (CVA)/ stroke

damage to the brain caused by interruption of blood supply to a region of the brain

embolic

obstruction or occlusion of a vessel in the brain by an ambolus

thrombotic

clot within a blood vessel of the brain

cerebral aneurysm

widening of a blood vessel in the brain, usually due to a weakness in the wall of the artery

transient ischemic attack (TIA)

sudden, brief, and temporary cerebral dysfunction usually caused by interruption of blood flow to the brain

ischemic

lack of blood flow

narcolepsy

recurring episodes of REM sleep during the day and often disrupted nocturnal sleep

radiculopathy

disease of the nerve roots

babinski sign

toe movement elicted by manipulation in a neurologic test performed on the sole of the foot to indicate injury to the brain or spinal nerves

deep tendon reflex (DTR)

evaluation of the response of a muscle to stimuli to provide info on the integrity of the central and peripheral nervous system

glasgow coma scale (GCS)

a neurologic scale used to assess lvl of conciousness

cerebral angiography

radiography of blood vessels in the brain after injection of radiopaque contrast material

evoked potential studies

diagnostic tests that use an EEG to record changes in brain waves during various stimuli

craniotomy

incision to skull to access brain

craniectomy

excision of part of the cranium to access the brain

laminectomy

excision of the thin plate of the vertebra to relieve pressure on the spinal cord

neuroplasty

surgical repair on nerves

what is the sclera of the eye

tough outer layer of the eye (Whites of the eye)

cornea

transparent outer covering of anterior portion of eye

aqueous humor

watery fluid within anterior chamber of eye