Nervous System, Senses & Behavioral Health

This is Unit Twelve of Medical Terminology, Part One: the nervous system and the eye. Part Two takes the ear and the neurological findings, and Part Three the behavioral health vocabulary. The order is the one every system unit follows. Combining forms first, then the suffixes belonging to this system, then the terms built from both. No new machinery arrives here — the joining rules from Unit One and the universal suffixes from Unit Two do all of the work. Two things make this range harder than the systems before it. The first is that several forms name a structure outside the nervous system as well. Medull slash o names the lowest region of the brainstem, and it also names the inner portion of a kidney. The second is the doublets. Greek and Latin each supplied a word for the mind, a word for the eye, and a word for tears, and both members of every pair survived into clinical use. Neither member is a variant of the other. The eye run then closes on three refractive terms: near sharp and distant blurred, distant sharp and near blurred, and the loss of near focus that arrives with age. By the end you will be able to do five things. One: name the combining forms from nerve to brainstem, and say which of them reach outside the nervous system. Two: say what the coverings and supporting-cell forms name, and give the plural each one takes. Three: tell the nervous-system suffixes apart — complete against partial, planning against power, coordination against weakness. Four: give the Greek form and the Latin form for one structure, and say why both remain current. Five: build and read a vision-condition term, and tell the three refractive terms apart.

Four combining forms, and they nest. Neur slash o names the tissue; encephal slash o names the organ; cerebr slash o and cerebell slash o name two regions inside that organ. The last two differ by three letters and name different structures, which is the first place in this unit where a decode goes wrong on spelling alone.

The root under everything.

MedTerm 0751 neur/o: Nerve

Neur slash o names a nerve or nerve tissue, and every term in this unit reaches back to it. Neuritis is inflammation of a nerve, built on the suffix itis from Unit Two. The form names the tissue itself, not the brain or the cord that tissue connects to.

The whole brain.

MedTerm 0752 encephal/o: Brain

Encephal slash o names the brain. An electroencephalogram is a record of the brain's electrical activity, using the suffix gram from Unit Two for a record. The form opens with an en that looks silent on the page and is fully sounded when the term is spoken.

The largest portion.

MedTerm 0753 cerebr/o: Cerebrum

Cerebr slash o names the cerebrum, the largest portion of the brain. A cerebrovascular accident involves the blood vessels of the cerebrum. Cerebrum and encephalon are not interchangeable: cerebrum names one part of the brain, and encephalon names the whole of it.

The region at the back.

MedTerm 0754 cerebell/o: Cerebellum

Cerebell slash o names the cerebellum, the region at the back of the brain that coordinates movement. Cerebellar means pertaining to the cerebellum. Cerebrum and cerebellum differ by three letters and name different structures, so in a written term the spelling is the whole of the difference.

Four more forms, and two of them carry irregular plurals the course numbered in Unit One rather than here. One meninx becomes meninges under the nx to nges rule; one ganglion becomes ganglia under the on to a rule. The plural entries sit in Unit One, and this is where they are cashed.

The membranes.

MedTerm 0755 mening/o: Meninges

Mening slash o names the meninges, the membranes covering the brain and the spinal cord. Meningitis is inflammation of those membranes. The singular is one meninx and the plural is meninges, following the nx to nges rule given at entry forty-two in Unit One.

The outermost layer.

MedTerm 0756 dur/o: Dura Mater

Dur slash o names the dura mater, the outermost and toughest of the meninges. Epidural means upon or outside the dura mater, using the prefix epi from Unit Three. The form names one layer of the meninges rather than all three of them together.

The supporting cells.

MedTerm 0757 gli/o: Glial Cells

Gli slash o names glial cells, the supporting cells of nervous tissue. A glioma is a tumour arising from glial cells. Glial cells support neurons and do not conduct impulses themselves, so a term built on gli slash o is not a term about signalling.

The clusters outside.

MedTerm 0758 ganglion/o: Ganglion

Ganglion slash o names a ganglion, a cluster of nerve cell bodies lying outside the brain and the spinal cord. A ganglionic blocker acts on those clusters. One ganglion becomes several ganglia, following the on to a plural rule and its relatives at entry thirty-nine.

Three forms naming places, and two of them carry a second meaning with nothing to do with nerves. Radicul slash o invites confusion with the word root of Unit One, and medull slash o names an inner region in organs the nervous system does not include. Both warnings are about a form doing double duty.

Where a nerve leaves.

MedTerm 0759 radicul/o: Nerve Root

Radicul slash o names a nerve root, the point where a nerve leaves the spinal cord. Radiculopathy is disease of a nerve root. The form names the root of a nerve, not the word root that entry two defines — two unrelated senses of one ordinary English word.

The sensory relay.

MedTerm 0760 thalam/o: Thalamus

Thalam slash o names the thalamus, the brain region that relays sensory information. Hypothalamus names the region lying below the thalamus. The prefix hypo is doing positional work in that term rather than naming a deficiency, which is the sense it usually carries elsewhere.

The base of the brainstem.

MedTerm 0761 medull/o: Medulla

Medull slash o names the medulla, and in brain terms the medulla oblongata at the base of the brainstem. Medullary means pertaining to the medulla or to an inner portion. The same form names the inner region of other organs, the kidney among them.

Seven entries, and this is the run where the unit's precision lives. A combining form and its matching suffix, then five suffixes that look interchangeable and are not. Complete loss against partial loss, the planning of a movement against the power to make one, and disordered coordination against either of those.

Sensation as a root.

MedTerm 0762 esthesi/o: Sensation

Esthesi slash o names sensation or feeling. Anesthesiology is the study of producing loss of sensation, built with the suffix ology from Unit Two. The form names the sensation itself and not the nerve carrying it, so an esthesi term describes what is felt rather than the tissue that delivered it.

Sensation as a suffix.

MedTerm 0763 -esthesia: Sensation

The suffix esthesia names a condition of sensation, described by whatever prefix precedes it. Anesthesia is the absence of sensation; paresthesia is an abnormal sensation. The suffix alone is neutral, so the prefix carries the entire meaning — a against para, and nothing else in the term changes.

Complete loss.

MedTerm 0764 -plegia: Paralysis

The suffix plegia names paralysis, a complete loss of voluntary movement. Hemiplegia is paralysis of one side of the body. Plegia states that the loss is complete, and a related suffix at the next number names partial loss, which is the distinction the pair exists to hold.

Partial loss.

MedTerm 0765 -paresis: Partial Paralysis

The suffix paresis names partial paralysis or muscular weakness. Hemiparesis is weakness on one side of the body. Plegia is complete and paresis is partial, and the same prefixes attach to both — so a matched term exists in either degree, hemiplegia beside hemiparesis.

A sudden attack.

MedTerm 0766 -lepsy: Seizure

The suffix lepsy names a seizure or a sudden attack. Narcolepsy names a condition of sudden attacks of sleep. Lepsy names the sudden event and not the condition producing it, so the suffix reports what happened rather than why it happened.

Purposeful movement.

MedTerm 0767 -praxia: Purposeful Movement

The suffix praxia names the ability to perform purposeful movement. Apraxia is the inability to perform it, built with the prefix a from Unit Three. Praxia concerns the planning of a movement where plegia concerns the power to make one, so the two suffixes describe failures at different points.

Coordination.

MedTerm 0768 -taxia: Coordination

The suffix taxia names muscular coordination, and its own link points back to the cerebellum at 0754, the region that coordinates movement. Ataxia is a lack of muscular coordination. Ataxia names disordered coordination: it is not weakness, which is paresis, and it is not paralysis, which is plegia.

Five entries, and four of them are two doublets. Greek gave psych slash o and ophthalm slash o; Latin gave ment slash o and ocul slash o. Both members of each pair are current, and neither is a mistake for the other. The fifth entry separates the eye as an organ from vision as a function.

The Greek form.

MedTerm 0769 psych/o: Mind

Psych slash o names the mind or mental processes, and it comes from Greek. Psychology is the study of the mind. The initial p is silent, so every term built on this form is spoken beginning with an s sound, which entry twenty-nine treats as a general rule.

The Latin form.

MedTerm 0770 ment/o: Mind

Ment slash o also names the mind, and it comes from Latin. Mental means pertaining to the mind. Psych slash o is Greek and ment slash o is Latin, and both name the same thing — the pattern Unit One numbered as two roots for one structure.

The Greek eye.

MedTerm 0771 ophthalm/o: Eye

Ophthalm slash o names the eye and comes from Greek. Ophthalmology is the study of the eye. The form carries two h's, one after the p and one after the t, and the first of those is the letter most often dropped in error.

The Latin eye.

MedTerm 0772 ocul/o: Eye

Ocul slash o also names the eye, and it comes from Latin. Intraocular means within the eye, using the prefix intra from Unit Three. Ophthalm slash o and ocul slash o name one organ, as the Greek and Latin pairs throughout this course do.

Sight as a function.

MedTerm 0773 opt/o: Vision

Opt slash o names vision or sight. An optometrist measures vision, using the suffix meter from Unit Two. Opt slash o names the function where ocul slash o and ophthalm slash o name the organ — a distinction that decides which form a term needs.

Seven forms, running from the front of the eye to the back and then out to the lid and the tear apparatus. The last two are the third Greek and Latin doublet in this range, and they arrive here rather than beside the first two because the book numbers the parts of the eye in between.

The clear front.

MedTerm 0774 corne/o: Cornea

Corne slash o names the cornea, the clear covering at the front of the eye. Corneal means pertaining to the cornea. A second combining form, kerat slash o, also names the cornea — and it names horny skin tissue too, which is how Unit Five introduced it.

The coloured ring.

MedTerm 0775 irid/o: Iris

Irid slash o names the iris, the coloured ring surrounding the pupil. Iritis is inflammation of the iris. The combining form takes a d that the English word iris does not carry, so the built term and the plain word diverge in spelling at that letter.

The light-sensing layer.

MedTerm 0776 retin/o: Retina

Retin slash o names the retina, the light-sensing layer at the back of the eye. Retinopathy is disease of the retina. The retina senses light; the cornea and the lens focus it — two different jobs, and terms built on those forms are not interchangeable.

The white outer coat.

MedTerm 0777 scler/o: Sclera

Scler slash o names the sclera, the white outer coat of the eye, and the same form also names hardness. Scleritis is inflammation of the sclera. That second sense gives the suffix sclerosis, meaning hardening, which the course numbered in Unit Two, and both senses are current in clinical use.

The lid.

MedTerm 0778 blephar/o: Eyelid

Blephar slash o names an eyelid, and it takes the ph spelling that its Greek origin gives it. Blepharoptosis is drooping of an eyelid, built on the suffix ptosis from Unit Two. The form names the lid itself and not the lashes carried on it, so a blephar term describes the structure rather than the hair.

Tears, from Latin.

MedTerm 0779 lacrim/o: Tears

Lacrim slash o names tears or the tear apparatus, and it comes from Latin. The lacrimal gland produces tears. A second combining form names the same structure and comes from Greek, which makes this the third Greek and Latin pair in the range.

Tears, from Greek.

MedTerm 0780 dacry/o: Tears

Dacry slash o also names tears, and it comes from Greek. Dacryocystitis is inflammation of the tear sac. Lacrim slash o and dacry slash o name one structure, as the mind pair and the eye pair earlier in this part do, and both members stay in use.

Four entries to close. One suffix that turns a root or a prefix into a condition of sight, then the three refractive terms built on it. Two of them are opposites of each other and the third arrives with age, and telling the third from the second is where the run does its real work.

The suffix.

MedTerm 0781 -opia: Vision Condition

The suffix opia names a condition of vision, described by whatever root or prefix precedes it. Diplopia is double vision. Opia names the condition where opt slash o names the function itself — the same organ-and-function split that separated ocul slash o from opt slash o.

Near sharp, distant blurred.

MedTerm 0782 Myopia

Myopia is a condition in which near objects are seen sharply and distant objects are blurred. It is commonly called nearsightedness. The root my here names closing or squinting and not muscle, so the my of myopia and the my of a muscle term are unrelated.

Distant sharp, near blurred.

MedTerm 0783 Hyperopia

Hyperopia is a condition in which distant objects are seen sharply and near objects are blurred. It is commonly called farsightedness. Myopia and hyperopia are opposites, and both of them name refractive conditions rather than disease of any structure named earlier in this part.

The one that arrives with age.

MedTerm 0784 Presbyopia

Presbyopia is the gradual loss of the eye's ability to focus on near objects, associated with aging. The root presby names old age. Presbyopia and hyperopia both affect near vision and arise differently, so the shared symptom does not make them the same condition.

Five things to carry out of Part One. Neur slash o names nerve tissue, encephal slash o the whole brain, cerebr slash o the largest portion of it, and cerebell slash o the region at the back that coordinates movement. Cerebrum and cerebellum differ by three letters. Medull slash o names the base of the brainstem and also the inner region of other organs, the kidney among them. Mening slash o names the membranes covering brain and cord, dur slash o the outermost and toughest of those three layers, gli slash o the supporting cells that do not conduct, and ganglion slash o a cluster of cell bodies lying outside brain and cord. One meninx becomes meninges; one ganglion becomes ganglia. The suffixes are separated by degree and by kind. Plegia is complete loss of voluntary movement and paresis is partial, with the same prefixes on both. Praxia is the planning of a movement and plegia the power to make one. Taxia is coordination, so ataxia is neither weakness nor paralysis. Esthesia stays neutral until a prefix is added to it. Three doublets ran through this part. Psych slash o and ment slash o name the mind, ophthalm slash o and ocul slash o name the eye, lacrim slash o and dacry slash o name tears. Greek and Latin in each pair, and both members current. Opt slash o stands apart from all of them, naming the function rather than the organ. The suffix opia builds a condition of sight from a root or a prefix. Myopia is near sharp and distant blurred; hyperopia is its opposite; presbyopia is the loss of near focus that comes with age. Hyperopia and presbyopia both affect near vision and arise differently. Part Two opens the ear at ot slash o and takes the neurological findings, and Part Three closes the unit on the behavioral health vocabulary.