Nervous system cards

Nervous System

Contains about 10 billion neurons. Controls both voluntary (somatic) and involuntary (autonomic) actions. Uses fast electrical signals from receptors.

Central Nervous System (CNS)

Brain and spinal cord

Peripheral Nervous System (PNS)

12 pairs of Cranial nerves, 31 pairs of Spinal nerves, Plexuses (nerve networks), Nerves throughout the body

Autonomic Nervous System (ANS)

controls involuntary actions

Sympathetic

“fight-or-flight;” increases heart rate/blood pressure, redirects blood.

Parasympathetic

“rest-and-digest;” slows heart, lowers blood pressure, aids digestion; maintains balance.

Sensory/Afferent nerves

Send signals to the CNS.

Motor/Efferent nerves

Send signals from the CNS to muscles/glands.

Mixed nerves

Carry both sensory and motor signals.

Dendrites

receive signals.

Cell body (soma)

main part with nucleus.

Axon

sends signals away. Covered by Myelin sheath (insulation, made by oligodendroglia in CNS, Schwann cells in PNS).

Neurilemma

(outer Schwann cell layer in PNS) helps repair.

Terminal end fibers

release neurotransmitters (chemicals like acetylcholine, dopamine, GABA) into a synapse (gap) to the next cell.

Ganglion (pl. ganglia)

Group of neuron cell bodies in the PNS.

Glial (neuroglial) cells

support cells that don't transmit signals; form CNS tissue.

Astrocytes

manage brain environment, help form Blood–Brain Barrier.

Microglia

clean up debris.

Oligodendroglia

create CNS myelin.

Ependymal cells

line brain cavities (ventricles) and spinal cord canal; help make/move CSF.

Gyri

Raised folds.

Sulci

Grooves.

Cerebral cortex

Outer gray matter (neuron cell bodies).

Frontal

movement, behavior, personality.

Parietal

touch, pain, temperature.

Temporal

hearing, smell; Wernicke area (understanding language).

Occipital

vision.

Broca area (frontal lobe)

speaking.

Cerebellum

Controls voluntary movement, balance, posture.

Thalamus

relays sensory info (like pain) to cortex.

Hypothalamus

controls body temperature, hunger, sleep, emotions, hormones; monitors ANS.

Midbrain

connects cerebrum to lower brain, involved in visual/auditory reflexes.

Pons

connects cerebrum and cerebellum; controls facial/eye movements.

Medulla oblongata

connects brain to spinal cord; controls vital functions (heart rate, breathing, blood vessel size).

Ventricles

Four fluid-filled cavities containing cerebrospinal fluid (CSF), which cushions the CNS.

Spinal Cord

Extends from medulla to around. Central butterfly-shaped gray matter (neuron cell bodies) surrounded by white matter (nerve fibers).

(lower back)

vertebra

Dorsal root

carries sensory signals to spinal cord, has dorsal root ganglion.

Ventral root

carries motor signals away from spinal cord.

Cauda equina

bundle of nerves at the end of the spinal cord.

Dura mater

tough outer layer; epidural space above it, subdural space below.

Arachnoid membrane

middle, web-like layer; subarachnoid space below it contains CSF.

Pia mater

thin, inner layer wrapped tightly around brain/spinal cord.

Acetylcholine

first discovered neurotransmitter.

Blood–Brain Barrier (BBB)

protects brain from harmful substances.

Receptor

converts a stimulus into an electrical signal.

Sciatic nerve

longest nerve in the body; causes sciatica pain.

Stimulus (plural stimuli)

anything that causes a response.

cerebell/o

cerebellum

cerebr/o

cerebrum

dur/o

dura mater

encephal/o

brain

gli/o

glial cells

lept/o

thin/slender

mening/o, meningi/o

meninges

myel/o

spinal cord

neur/o

nerve

pont/o

pons

radicul/o

nerve root

thalam/o

thalamus

thec/o

sheath

vag/o

vagus nerve

alges/o

-algesia– pain sensitivity

caus/o

– burning sensation

esthesi/o

– sensation

kines/o

-kinesia/-kinesis– movement

seizure

-lepsy

slight paralysis

-paresis

complete paralysis

-plegia

lex/o

– word/phrase (e.g., dyslexia)

Speech

-phasia

Action

-praxia

syncop/o

to cut off (syncope, fainting)

Congenital

(present from birth)

Hydrocephalus

too much CSF in brain, causing swelling.

Cystica

– spinal cord/meninges protrude.

Occulta

– hidden spinal defect, seen on X-ray.

Alzheimer disease (AD)

– progressive memory loss and cognitive decline.

Amyotrophic lateral sclerosis (ALS)

– gradual muscle weakness and atrophy due to nerve cell death.

Epilepsy

– recurring seizures.

Huntington disease

– inherited disorder causing uncontrolled movements and dementia.

Multiple sclerosis (MS)

– immune system attacks brain/spinal cord myelin, causing various symptoms.

Myasthenia gravis (MG)

– autoimmune disease causing muscle weakness that worsens with activity.

Palsy

– paralysis (e.g., Bell palsy, cerebral palsy).

Parkinson disease

– brain disorder causing tremors, stiffness, and difficulty with balance/coordination due to dopamine deficiency.

Tourette syndrome

– causes involuntary tics and vocal sounds.

Herpes zoster (shingles)

– painful rash caused by reactivation of chickenpox virus.

Meningitis

– inflammation of the meninges, usually from infection.

HIV encephalopathy

– brain issues caused by HIV infection, leading to cognitive and motor problems.

Cerebral concussion

– temporary brain dysfunction after head injury, no visible major damage; rest is vital.

Cerebral contusion

– bruised brain tissue, can cause bleeding (hematomas) under dura (subdural) or above dura (epidural).

Vascular

(blood vessel related)

Thrombotic

(clot forms in brain vessel)

Embolic

(clot travels to brain vessel)

Hemorrhagic

(blood vessel bursts in brain)

Transient Ischemic Attack (TIA)

– mini-stroke, temporary symptoms, a warning sign for stroke.

Cerebral angiography

X-ray of brain arteries.

CT scan

quick scan for bleeding or fractures.

MRI

detailed soft tissue images; good for showing demyelination, tumors.

MRA

MRI for blood vessels, no contrast needed.