neuro ch 10 acc

Nervous system

coordinates and controls all bodily activities with the brain as its center

Brain

central organ of the nervous system that controls life functions and thought

Brain death

cessation of brain function resulting in inability of the body to live independently

Central nervous system (CNS)

division of the nervous system consisting of the brain and spinal cord that receives processes and regulates bodily activity

Peripheral nervous system (PNS)

division of the nervous system consisting of cranial and spinal nerves that transmit signals to and from the CNS

Nerves

bundles of neurons connecting the brain and spinal cord with the rest of the body

Sensory organs

eyes ears nose skin and tongue that detect external stimuli

Neuron

basic functional cell of the nervous system that transmits impulses

Electrochemical process

method by which neurons transmit nerve impulses

Brain wave

pattern of electrical activity produced by neurons during activity rest and sleep

Tract

bundle of nerve fibers located within the brain or spinal cord

Ascending nerve tracts

carry nerve impulses toward the brain

Descending nerve tracts

carry nerve impulses away from the brain

Ganglion

cluster of nerve cell bodies outside the central nervous system

Ganglia

plural of ganglion

Ganglion cyst

benign tumor-like cyst using the same term

Innervation

supply of nerves to a specific body part

Plexus

network of intersecting spinal nerves

Plexuses

plural of plexus

Receptor

site in a sensory organ that receives stimulation

Stimulus

anything that excites a nerve and causes an impulse

Stimuli

plural of stimulus

Impulse

wave of excitation transmitted through nerve fibers and neurons

Reflex

automatic involuntary response to internal or external change

Reflex action

involuntary nervous system response

Deep tendon reflex

reflex involving muscle stretch

Afferent neuron

neuron that carries impulses toward the brain and spinal cord

Sensory neuron

alternate term for afferent neuron

Efferent neuron

neuron that carries impulses away from the brain and spinal cord

Motor neuron

alternate term for efferent neuron

Connecting neuron

neuron that links afferent and efferent neurons

Associative neuron

alternate term for connecting neuron

ACE

memory aid for neuron types afferent connecting efferent

SAM

memory aid for neuron functions sensory associative motor

Cell body

main portion of neuron containing nucleus

Dendrite

root-like process that receives impulses and conducts them to the cell body

Process

structure extending from a cell body

Axon

process that conducts impulses away from the neuron

Myelin sheath

white fatty tissue covering some axons

Terminal end fibers

branching fibers at the end of an axon leading impulses to the synapse

Synapse

space between two neurons or between a neuron and a receptor organ

Neurotransmitter

chemical substance that allows impulses to cross synapses

Acetylcholine

neurotransmitter influencing muscle action at neuromuscular junctions

Dopamine

neurotransmitter involved in mood thought and movement with excess linked to schizophrenia and Parkinson disease

Endorphins

naturally occurring brain substances that relieve pain

Norepinephrine

neurotransmitter and hormone that increases alertness blood pressure heart rate and glucose release during stress

Serotonin

neurotransmitter involved in sleep hunger pleasure recognition and mood

Glial cells

support cells that hold neurons in place supply nutrients insulate neurons and remove dead neurons

Myelinated

having a myelin sheath

Unmyelinated

lacking a myelin sheath

White matter

myelinated nerve fibers

Gray matter

unmyelinated nerve fibers forming cortex and spinal cord core

Meninges

three-layer membrane system enclosing brain and spinal cord

Meninx

singular form of meninges

Dura mater

thick tough outer meningeal layer

Epidural space

space between vertebral column and dura mater

Subdural space

space between dura mater and arachnoid membrane

Arachnoid membrane

spider-web-like middle meningeal layer

Subarachnoid space

space containing cerebrospinal fluid

Pia mater

delicate inner meningeal layer rich in blood vessels

Cerebrospinal fluid (CSF)

clear colorless fluid produced in ventricles that cushions and nourishes the brain and spinal cord

Ventricles

cavities in the cerebrum that produce cerebrospinal fluid

Cerebrum

largest and uppermost part of the brain responsible for thought judgment memory emotion and voluntary movement

Cerebral

pertaining to the cerebrum or brain

Cerebral cortex

outer gray matter layer of the cerebrum

Gyri

elevated folds of the cerebral cortex

Gyrus

singular of gyri

Sulci

grooves or fissures of the cerebral cortex

Sulcus

singular of sulci

Cerebral hemispheres

right and left halves of the cerebrum

Corpus callosum

structure connecting the cerebral hemispheres

Contralateral control

control of the opposite side of the body due to nerve fiber crossing

Frontal lobe

cerebral lobe controlling skilled motor function memory and behavior

Parietal lobe

cerebral lobe that interprets sensory information from skin tongue and muscles

Occipital lobe

cerebral lobe controlling vision

Temporal lobe

cerebral lobe controlling hearing smell and memory formation

Thalamus

structure that relays sensory impulses and filters signals to the cerebral cortex

Hypothalamus

regulatory center located below the thalamus

Regulatory functions of the hypothalamus

regulation of autonomic nervous system heart rate blood pressure respiratory rate digestive activity emotional responses body temperature hunger thirst water balance sleep-wake cycles pituitary gland and endocrine system

Cerebellum

brain structure coordinating balance posture and smooth movement

Brainstem

stalk-like structure connecting brain to spinal cord and controlling survival functions

Midbrain

brainstem structure conducting pathways and controlling eye and head reflexes

Pons

brainstem structure serving as a bridge and controlling reflexes

Medulla oblongata

lowest brainstem structure controlling respiration heart rate blood pressure swallowing coughing sneezing and vomiting

Spinal cord

long fragile structure transmitting impulses between brain and body

Peripheral nerves

nerves extending outward from the CNS

Autonomic nerve fibers

peripheral fibers carrying instructions to organs and glands

Sensory nerve fibers

peripheral fibers transmitting sensory stimuli to the brain

Somatic nerve fibers

peripheral motor fibers controlling voluntary muscles

Cranial nerves

twelve pairs of nerves originating from the brain

Olfactory nerve I

cranial nerve responsible for smell

Optic nerve II

cranial nerve responsible for vision

Oculomotor nerves III IV VI

cranial nerves controlling eye movement

Trigeminal nerve V

cranial nerve providing facial sensation and chewing

Facial nerve VII

cranial nerve controlling facial muscles

Vestibulocochlear nerve VIII

cranial nerve responsible for hearing and balance

Glossopharyngeal nerve IX

cranial nerve controlling tongue pharynx and tonsils

Vagus nerve X

cranial nerve controlling heart lungs bronchi and gastrointestinal tract

Accessory nerve XI

cranial nerve controlling sternocleidomastoid and trapezius muscles

Hypoglossal nerve XII

cranial nerve controlling tongue muscles