Medical Terminology Chapter 14

severe form of senile dementia; cortical destruction causes variable degrees of confusion, memory loss, and other cognitive defects

Alzheimer disease

disk/o

a disk

spin/o

a thorn, spine

conducts motor impulses to the lateral rectus muscle of the eyeball

abducens

controls the trapezius and sternocleidomastoid muscles, permitting movement of the head and shoulders

accessory

cholinergic neurotransmitter; plays an important role in the transmission of nerve impulses at synapses and myoneural junctions

acetylcholine

inability to remain still; motor restlessness and anxiety

akathisia

loss or lack of voluntary motion

akinesia

the transmission of an impulse by a nerve fiber is based on the ___ ___ ___ _____; this means that no transmission occurs until the stimulus reaches a set minimum strength which can vary for different receptors; once the minimum is then transmitted via a synapse, a specialized knoblike branch ending, with the help of certain chemical agents, across a space separating the axon's end knobs from the dendrites of the next neuron or from a motor end plate attached to a muscle; this space is called a synaptic cleft and the chemical agents released are called neurotransmitters

all or none principle

controls involuntary bodily functions such as sweating, secretions of glands, arterial blood pressure, smooth muscle tissue, and the heart; the autonomic nervous system is primarily composed of efferent fibers from certain cranial spinal nerves and can be functionally divided into two divisions, the sympathetic and parasympathetic; these two divisions counteract each other's activity to keep the body in a state of homeostasis

autonomic nervous system

controls involuntary bodily functions such as sweating, secretion of glands, arterial blood pressure, smooth muscle tissue, and the heart; also stimulates the adrenal gland to release epinephrine (adrenaline) the hormone that causes the familiar adrenaline rush or the fight or flight response

autonomic nervous system (sympathetic division and parasympathetic division)

myel/o

bone marrow, spinal cord

consists of millions of nerve cells and fibers; it is the largest mass of nervous tissue in the body, weighing about 1380 g in the male and 1250 g in the female; enclosed by 3 membranes known collectively as the meninges; from the outside in, these are the dura mater, arachnoid. and pia mater; the major structures of the brain are the cerebrum, cerebellum, diencephalon, and the brainstem, which is composed of of the midbrain, pons, and medulla oblongata

brain

encephal/o

brain

governs sensory perception, emotions, consciousness, memory, and voluntary movements

brain

the lower part of the brain, adjoining and structurally continuous with the spinal cord; provides the main motor and sensory innervation to the face and neck via the cranial nerves; it consists of three structures: the mesencephalon or midbrain, the pons, and the medulla oblongata; the brainstem processes visual, auditory, and sensory information and plays an important role in the regulation of cardiac and respiratory function; it also regulates the central nervous system and is pivotal in maintaining consciousness and regulating the sleep cycle

brainstem

cyt/o

cell

attach to the brain and provide sensory input, motor control or a combination of these functions; they are arranged symmetrically, 12 to each side of the brain and generally are named for the area or function they serve

cranial nerves

provide sensory input and motor control or a combination of these

cranial nerves (12 pairs)

second portion of the brain and refers to the thalamus and hypothalamus

diencephalon

dur/o

dura, hard

phe/o

dusky

electr/o

electricity

controls the muscles of the face and scalp; the lacrimal glands of the eye and the submandibular and sublingual salivary glands; input from the tongue for the sense of taste

facial

esthesi/o

feeling

fibr/o

fiber

identified as the brain's major motor area and the site for personality and speech

frontal lobe

pallid/o

globus pallidus

provides general sense of taste; regulates swallowing; controls secretion of saliva

glossopharyngeal

gli/o

glue

poli/o

gray

cephal/o

head

controls the tongue; tongue movements

hypoglossal

lies beneath the thalamus and is a principal regulator of autonomic nervous activity that is associated with behavior and emotional expression; it also produces neurosecretions for the control of water balance, sugar and fat metabolism, regulation of body temperature and other metabolic activities; the pituitary gland is attached to the hypothalamus by a narrow stalk, the infundibulum

hypothalamus

serves as the principal regulator of autonomic nervous activity that is associated with behavior and expression; also contains hormones that are important for the control of certain metabolic activities such as maintenance of water balance, sugar, and fat metabolism, regulation of body temperature, sleep cycle control, appetite, and sexual arousal

hypothalamus

called central or associative neurons and are located entirely within the CNS; they function to mediate impulses between sensory and motor neurons

interneurons

cerebell/o

little brain

lob/o

lobe

acts as the cardiac, respiratory, and vasomotor control center; regulates and controls breathing, swallowing, coughing, sneezing, and vomiting as well as heartbeat and arterial blood pressure, thereby exerting control over the circulation of blood

medulla oblongata

connects the pons and the rest of the brain to the spinal cord; all afferent and efferent tracts from the spinal cord either pass and control of breathing, swallowing, coughing, sneezing, vomiting, the heartbeat, and blood pressure

medulla oblongata

mening/i

membrane, meninges

mening/o

membrane, meninges

located below the cerebrum and above the pons; has four small masses of gray cells known collectively as the corpora quadrigemina; the upper two of these masses, called the superior colliculi, are associated with visual reflexes such as the tracking movements of the eyes; the lower two, or inferior colliculi, are involved with the sense of hearing

midbrain

two way conduction pathway that acts as a relay center for visual and auditory impulses; found in the midbrain are four small masses of gray cells known collectively as the corpora quodrigemina; the upper two, called the superior colliculi, are associated with visual reflexes; the lower two, or inferior colliculi are involved with the sense of hearing

midbrain

ment/o

mind

contains centers for sensory input from all parts of the body and is known as the somesthetic area and the site for the interpretation of language; temperature, pressure, touch, and an awareness of muscle control are some of the sensory activities localized in this area

parietal lobe

links the central nervous system with other parts of the body

peripheral nervous system

provide sensory input system with other parts of the body

peripheral nervous system

the network of nerves branching throughout the body from the brain and spinal cord; there are 12 pairs of cranial nerves that attach to the brain and 31 pairs of spinal nerves connected to the spinal cord

peripheral nervous system

a broad band of white matter located anterior to the cerebellum and between the midbrain and the medulla oblongata; composed of fiber tracts linking the cerebellum and medulla to higher cortical areas; it also plays a role in somatic and visceral motor control, and contains important centers for regulating breathing

pons

links the cerebellum and medulla to higher cortical areas; plays a role in somatic and visual ceral motor control; contains important centers for regulating breathing

pons

stimulation of a nerve occurs at a _____

receptor

differ in structure from motor neurons because they do not have true dendrites; the processes transmitting sensory information to the cell bodies of these neurons are called peripheral processes, are sheathed, and resemble axons; they are attached to sensory receptors and transmit impulses to the CNS; after processing the information, the CNS can stimulate motor neurons in response to this sensory information; referred to as afferent nerves because they carry impulses from the sensory receptors to the synaptic endings in the CNS

sensory neurons

later/o

side

cran/i

skull

crani/o

skull

hypn/o

sleep

somn/o

sleep

conducts sensory impulses to the brain and motor impulses from the brain to body parts; also serves as a reflex center for impulses entering and leaving the spinal cord without involvement of the brain

spinal cord

controls muscles of the pharynx, larynx, thoracic and abdominal organs; swallowing, voice production, slowing of heartbeat, acceleration of peristalsis

vagus

vag/o

vagus, wandering

ventricul/o

ventricle

spondyl/o

vertebra

provides input for hearing and equilibrium

vestibulocochlear

groups of nerve fibers within the CNS that have the same origin, function and termination; the spinal cord contains afferent sensory tracts ascending to the brain and efferent motor tracts descending from the brain; the brain itself contains numerous tracts, the largest of which is the corpus callosum joining the left and right hemispheres

tracts

dendr/o

tree

provides sensory input from the face, nose, mouth, forehead, and top of the head; motor fibers to the muscles of the jaw (chewing)

trigeminal

conducts motor impulses to control the superior oblique muscle of the eyeball

trochlear

receives impulses from throughout the body, processes the information, and responds with an appropriate action; this activity can be at the conscious or unconscious level, depending on the source of the sensory stimulus; both the brain and spinal cord can be divided into gray matter and white matter; the gray matter consists of unsheathed cell bodies and true dendrites; the white matter is composed of myelinated nerve fibers; in the spinal cord, the arrangement of white and gray matter results in an H shaped core of gray bodies surrounded by tracts of nerve fibers interconnected to the brain; the reverse is generally true of the brain where the surface layer or cortex is gray matter and most of the internal structures are white matter

central nervous system

plays an important role in the integration of sensory perception and motor output; its neural pathways link with the motor cortex, which sends information to the muscle causing them to move, and the spinocerebellar tract, which provides feedback on the position of the body in space (proprioception); integrates these pathways using the constant feedback on body position to fine tune motor movement; research shows that the cerebellum also has a broader role in a number of key cognitive functions, including attention and the processing of language, music, and other sensory temporal stimuli

cerebellum

the second largest part of the brain; it occupies a space in the back of the skull, inferior to the cerebrum and dorsal to the pons and medulla oblongata; oval in shape and divided into lobes by deep fissures; it has a cortex of gray cell bodies and its interior contains nerve fibers and white matter connecting it to every part of the central nervous system; plats an important part in the coordination of voluntary and involuntary complex patterns of movement and adjusts muscles to maintain posture

cerebellum

brain and spinal cord are surrounded by this; colorless fluid is produced as a filtrate of blood by the choroid plexuses within the ventricles of the brain; cerebrospinal fluid circulates through the ventricles, the central canal, and the subarachnoid space; cerebrospinal fluid is removed from circulation by the arachnoid villi, which are small projections of the arachnoid membrane that penetrate the tough outer membrane, the dura mater; the arachnoid villi allow the fluid to drain into the superior sagittal sinus; the normal adult will have between 120 and 150 mL in circulation; the fluid serves to cushion the brain and spinal cord from shocks that could cause injury; it also helps to support the brain by allowing it to float within the supporting liquid; it also contains neurotransmitters such as monoamines, acetylcholine, and neuropeptides

cerebrospinal fluid

cerebr/o

cerebrum

evaluates and controls all sensory and motor activity; sensory perception, emotions, consciousness, memory and voluntary movements

cerebrum

representing seven eighths of the brain's total weight; contains nerve centers that evaluate and control all sensory and motor activity, including sensory perception, emotions, consciousness, memory, and voluntary movements; divided by the longitudinal fissure into two cerebral hemispheres, the right and left, that are joined by large fiber tracts (corpus callosum) that allow information to pass from one hemisphere to the other; the surface or cortex of each hemisphere is arranged in folds creating bulges and shallow furrows; each bulge is called a gyrus or convolution; a furrow is known as a sulcus; this surface is composed of gray, unmyelinated cell bodies and is known as the cerebral cortex; the cortex has been divided into lobes as a means of identifying certain locations; these lobes correspond to the overlying bones of the skull and are the frontal, parietal, temporal and occipital lobes

cerebrum

chrom/o

color

cause contractions in muscles and secretions from glands and organs; they also act to inhibit the actions of glands and organs, thereby controlling most of the body's functions; can be described as being efferent processes because they transmit impulses away from the neural cell body to the muscles or organs to be innervated; consist of a nucleated cell body with protoplasmic processes extending away from it in several directions; these processes are known as the axons and dendrites; most axons are long and are covered with a fatty substance, the myelin sheath, which acts as an insulator and increases the transmission velocity of the nerve fiber it surrounds; axons may be as long as several feet and reach from the cel body to the area to be activated; dendrites resemble the branches of a tree, are short, unsheathed, and transmit impulses to the cell body; neurons usually have several dendrites and only one axon

motor neurons

my/o

muscle

neur/o

nerve

a single elongated process, the axon of a neuron; nerve fibers of the peripheral nervous system are wrapped by protective membranes called sheaths; the PNS has two types of sheaths: myelinated and unmyelinated, which are formed by accessory cells; myelinated fibers have an inner sheath of myelin, a thick, fatty substance and an outer sheath, or neurilemma, composed of Schwann cells; unmyelinated fibers lack myelin and are sheathed only by the neurilemma; nerve fibers of the CNS do not contain Schwann cells; therefore, damage to fibers of the CNS is permanent, whereas damage to a peripheral nerve can be reversible

nerve fiber

conduct impulses from one location to another

nerve fibers and tracts

a collection of nerve fibers, outside the CNS; nerves are usually described as being sensory or afferent (conducting to the CNS) or motor or efferent (conducting away from the CNS to muscles, organs, and glands)

nerves

usually described as having two interconnected divisions: the central nervous system and the peripheral nervous system; the CNS includes the brain and spinal cord; it is enclosed by bones of the skull and spinal column; the PNS consists of the network of nerves and neural tissues branching throughout the body from 12 pairs of cranial nerves and 31 pairs of spinal nerves; the nervous system has two principal tissue types; these tissues are made of neurons or nerve cells and their supporting tissues, collectively called neuroglia; neurons are the structural and functional units of the nervous system; these cells are specialized conductors of impulses that enable the body to interact with its internal and external environments; there are several types of neurons

nervous system

act as supporting tissue

neuroglia

structural and functional nits of the nervous system act as specialized conductors of impulses that enable the body to interact with its internal and external environments

neurons (nerve cells)

narc/o

numbness, sleep, stupor

the primary interpretive processing area for vision; directly posterior to the temporal lobe

occipital lobe

conducts motor impulses to four of the six external muscles of the eye and to the muscle that raises the eyelid

oculomotor

detects and provides the sense of smell

olfactory

provides vision

optic

papill/o

papilla

very long fibers branching from cranial nerves III, VII, IX, and X along with long fibers of sacral nerves II, III, and IV form the first of the parasympathetic division; cell bodies for these long fibers are located in the brain and spinal cord; these long fibers extend to ganglia located near the organs to be innervated; works to conserve energy and innervate the digestive system; when activated, it stimulates the salivary and digestive gland, decreases the metabolic rate, slows the heart rate, reduces blood pressure, and promotes the passage of material through the intestines along with absorption of nutrients by the blood

parasympathetic division

has an H shaped gray area of cell bodies encircled by an outer region of white matter; the white matter consists of nerve tracts and fibers providing sensory input to the brain and conducting motor impulses from the brain to spinal neurons; the adult spinal cord is about 44 cm long and extends down the vertebral canal from the medulla to terminate near the junction of the first and second lumbar vertebrae; between the 12th thoracic and L1 is a region known as the conus medullaris, where the spinal cord becomes conically tapered; the filum terminale or terminal thread of fibrous tissue extends from the conus medullaris to the second sacral vertebrae; the cauda equina (known as the horse's tail) is the terminal portion of the spinal cord that forms the nerve fibers that are the lumbar, sacral, and coccygeal spinal nerves; the functions of the spinal cord are to conduct sensory impulses to the brain, to conduct motor impulses from the brain, and to serve as a reflex center for impulses entering and leaving the spinal cord without direct involvement of the brain

spinal cord

31 pairs distributed along the length of the spinal cord and emerging from the vertebral canal on either side through the intervertebral foramina; at the point of attachment, each nerve is divided into two roots; the dorsal or sensory root is composed of afferent fibers carrying impulses to the cord and the ventral root contains motor fibers carrying efferent impulses to muscles and organs; named for the region of the vertebral column from which they exit, there are eight pairs of cervical spinal nerves, 12 pairs of thoracic spinal nerves, five pairs of lumbar spinal nerves, five pairs of sacral spinal nerves, and one pair of coccygeal spinal nerves; a short distance form the cord, the fibers of the two roots unite to form a spinal nerve; having formed a single nerve composed of afferent and efferent fibers, each spinal nerve are the dorsal rami and ventral rami, the dorsal rami (branches) carry motor sensory fibers to the muscles and skin of the back and serve an area from the back of the head to the coccyx; the ventral rami, serving a much larger area, carry both motor and sensory fibers to the muscles and organs of the body, including the arms, legs, hands, and feet

spinal nerves

carry impulses to the spinal cord and to muscles, organs, and glands

spinal nerves (3 pairs)

branches from the ventral roots of the 12 thoracic and the first three lumbar spinal nerves form the first part of this; the cell bodies of these nerve fibers are located in the gray matter of the spinal cord; just outside the spinal cord, axons of these nerve cells leave the spinal nerves and enter almost immediately into masses of nerve cell bodies, the sympathetic ganglia, which form a chain that runs next to the vertebral column; this chain of about 23 ganglia runs from the base of the head to the coccyx and is known as the sympathetic trunk; within the ganglia of the sympathetic trunk, fibers from the spinal nerves synapse with ganglionic nerve cell bodies; these ganglionic neurons produce long axons that reach to the parts of the body to be innervated; this arrangement, characteristic of autonomic nerves, creates a two neuron chain as opposed to single neuron control of regular motor nerves; because of the arrangement in which sympathetic fibers from spinal nerves synapse with many cell bodies in the sympathetic ganglia, they tend to produce widespread innervation when activated; this condition has been described as preparing the individual for fight or flight; during the fight or flight response, a person experiences increased alertness, increased metabolic rate, decreased digestive and urinary function, an increase in respiration, blood pressure, and heart rate, and a corresponding warming of the body that can activate the sweat glands; stimulates the adrenal gland to release epinephrine (adrenaline) the hormones that causes the familiar adrenaline rush

sympathetic division

contains centers for hearing, smell, and language input

temporal lobe

relay center for all sensory impulses (except olfactory) being transmitted to the sensory areas of the cortex and relays motor impulses from the cerebellum and the basal ganglia to motor areas of the cortex, thought to be involved with emotions and arousal mechanisms

thalamus

the larger of the two divisions of the diencephalon and is actually two large masses of gray cell bodies joined by a third or intermediate mass; serves as a relay center for all sensory impulses (except olfactory) being transmitted to the sensory areas of the cortex; besides its sensory function, the thalamus also relays motor impulses from the cerebellum and the basal ganglia to motor areas of the cortex; some impulses related to emotional behavior are also passed from the hypothalamus, through the thalamus, to the cerebral cortex

thalamus

lamin/o

thin plate