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CHAPTER 10 Chapter 10 is titled “Nervous System” in The Language of Medicine textbook. General Structure of the Nervous System: If you recall from anatomy, the general structure of the nervous is divided into 2 major divisions: the central nervous system and the peripheral nervous system   

The central nervous system consists of the brain and the spinal cord The peripheral nervous system consists of the cranial nerves, the spinal nerves, and the autonomic nerves There is a figure in your textbook that shows you the 2 major divisions and also how the autonomic nerves are divided into the parasympathetic and sympathetic nerves

Neurons, Nerves, and Glial Cells: 

Looking at a few terms for review, starting with a neuron o A neuron is an individual nerve cell that cannot be seen with the naked eye o It is a microscopic structure o However a series of neurons make up a nerve that can be seen with the naked eye o Parts of a neuron include the stimulus which begins as an impulse, and this occurs in the branching fibers of a neuron called dendrites o From there, the nervous impulse moves from the dendrites into the cell body in one direction o The cell body contains the cell nucleus o From there extending from the body, you have the axon o The axon carries the impulse away from the cell body o Sometimes axons are covered by fatty tissue, a sheath, referred to as the myelin sheath o From there, the nervous impulse passes through the axon and leaves the cell via the terminal end fibers o You have this gap or space between nerves or neurons called a synapse where the impulse will jump, and transfer that impulse

The Brain: Under the brain section, you have a few terms that you need to review 

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You want to know that the middle of the cerebrum has spaces or canals that we refer to as ventricles o You also have ventricles in your heart as well Cerebrospinal fluid (CSF) is a watery fluid that flows around the brain and spinal cord, and the purpose of this fluid is to serve as a cushion to protect the brain and spinal cord from shock o It is usually clear and colorless o Sometimes a physician would remove CSF for diagnostic or therapeutic purposes

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Diagnostic purposes to remove CSF would be to determine whether the patient has meningitis Therapeutic purposes to remove CSF would be if a patient has hydrocephalus

This is where the patient may have an accumulation of CSF in the brain and they have to remove some of the CSF in order to relieve pressure on the brain  The procedure to remove CSF is called a lumbar puncture  It is also called a lumbar tap or a spinal tap or spinal puncture, all the same thing There is a table in your textbook that summarizes the functions of the parts of the brain o You do need to know all of the structures of the brain including the cerebrum, thalamus, hypothalamus, cerebellum, pons, and medulla oblongata o So you need to know the functions of each of these parts of the brain 

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The Spinal Cord and Meninges: 

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The spinal cord is part of the nervous system o The only combining form we have for spinal cord is myel/o o Remember we have multiple combining forms for spinal column including spin/o, vertebr/o, and rachi/o, however remember the spinal column is part of the musculoskeletal system, the backbone or vertebrae o But when we refer to the spinal cord, that’s part of the nervous system The meninges are 3 layers of connective tissue that surround the brain and the spinal cord o There is a picture in your textbook to show the meninges  The outermost layer is called the dura mater, then beyond that you have a space called the subdural space  The second layer surrounding the brain and spinal cord is the arachnoid membrane  Then below that, you have the subarachnoid space  And then the third inner layer is called the pia mater, which is a more delicate layer

Vocabulary: You need to know the following Vocabulary terms listed in your textbook:       

Arachnoid Membrane Autonomic Nervous System Axon Brainstem Cell Body Central Nervous System (CNS) Cerebellum

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Cerebral Cortex Cerebrospinal Fluid (CSF) Cerebrum

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Cranial Nerves Dendrite

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Dura Mater Ganglion Hypothalamus Medulla Oblongata Meninges Myelin Sheath Nerve Neuron Parasympathetic Nerves Peripheral Nervous system Pia Mater Pons Spinal Nerves Stimulus Sympathetic Nerves Synapse Thalamus Ventricles of the Brain

Combining Forms: Organs & Structures For the terminology regarding the combining forms for the organs and structures of the nervous system, you need to know all of them listed in your textbook:   

cerbell/o means cerebellum cerebr/o means cerebrum dur/o means dura mater

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encephal/o means brain o Remember cephal/o is head gli/o means glial cells lept/o means thin, slender mening/o, meningi/o mean membranes, meninges o I want to point out the term myelomeningocele, if you remember the suffix –cele means protrusion or herniation, so when you have an infant that is born with a condition called spina bifida, it is an imperfect union where the vertebrae does not fuse and there is a gap

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In spina bifida, you can have a condition called meningocele, and this is where the meninges are protruding through that space o If you have a condition called myelomeningocele, remember myel/o means spinal cord, so this is more severe, in addition to the meninges that are protruding, you also have parts of the spinal cord my/o means muscle myel/o means spinal cord o In another chapter, myel/o also means bone marrow, it just depends on how the word is used o

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neur/o means nerve pont/o means pons radicul/o means nerve root (of spinal nerves) thalam/o means thalamus thec/o means sheath (refers to meninges) vag/o means vagus nerve (10th cranial nerve)

Combining Forms and Suffixes: Signs & Symptoms For the terminology regarding the combining forms or suffixes for signs and symptoms of the nervous system, you need to know all of them listed in your textbook: 

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alges/o, -algesia as a suffix, means excessive sensitivity to pain o The key term here is pain, because an analgesic would be pertaining to no pain, without pain o We refer to analgesics to pain killers, medications that numb the pain -algia as a suffix, means pain o We have the term cephalgia, the medical term for pain in the head, or a headache caus/o means burning comat/o means deep sleep (coma) esthesi/o, -esthesia means feeling, nervous sensation o Don’t confuse –algia which is excessive sensitivity to pain as –esthesia which is felling or a nervous sensation, feeling anything o When we talk about anesthesia, an- is a prefix that means no, not, or without, so anesthesia is without any feeling. This is what happens when a patient is administered an anesthetic. kines/o, kinesi/o, -kinesia, -kinesis, -kinetic means movement o Depending on the prefix added, it changes the meaning o For example, brady- means slow, so bradykinesia means slow movement -lepsy means seizure lex/o means word or phrase -paresis means weakness

So someone who has hemiparesis, hemi- means one half, so this would mean you have a weakness of one half, whether it’s the left side or right side of the body. We refer to this weakness as partial paralysis. -phasia means speech o Someone who has aphasia, means no, not speaking o You might find patients who have a stroke that may be left with a manifestation of aphasia, they may not be able to speak -plegia means paralysis (loss or impairment of the ability to move parts of the body) o Note it is a suffix that is different from –paresis o Remember –paresis is slight paralysis, partial paralysis, or weakness, whereas – plegia is paralysis, a loss of the ability to move parts of the body. o You do need to know the difference between hemiplegia, paraplegia, and quadriplegia  Hemiplegia affects the right half or left half of the body  Often a patient that might have a stroke might be left with paralysis on one side of the body  Because of the way the body is wired, hemiplegia is contralateral to the brain lesion  What this means is that if a patient has a stroke on the right side of the brain, and they are left with paralysis, the paralysis will be contralateral, meaning opposite side, so the paralysis would be on the left side of the body  Paraplegia means that the patient might have a stroke, and they are paralyzed, and para- means they are paralyzed on one side  However, the term means that we have paralysis of both legs, and it is caused by an injury of the spinal cord  So someone who is a paraplegic would be paralyzed from the waist down, and we know that the reason for it would have to do with a spinal cord injury usually of the lumbar area  Quadriplegia, you think quad- means 4, here all 4 extremities would be effected  This would be paralyzed from the neck on down  We know the level of injury would be at the cervical or neck area, and everything below that would be paralyzed  So to review:  Hemiplegia would be paralyzed on the left or right side of the body with a brain lesion on the opposite side.  Paraplegia would be paralyzed from the waist on down and spinal cord injury in the lumbar area  Quadriplegia is paralyzed from the neck down, all 4 extremities are paralyzed, and lesion in the cervical area of spinal cord or neck o

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-praxia means action -sthenia means strength syncop/o means to cut off, cut short o You need to know the definition of the word Syncope  It is the medical term for fainting - the sudden and temporary loss of consciousness due to inadequate flow of blood to the brain tax/o means order or coordination o Someone who has ataxia would have no coordination

Pathology: The next section in your textbook discusses the pathology or disorders that affect the nervous system. Neurological disorders are classified in different categories 

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We will go over the common ones in each of the categories: o Congenital o Degenerative, movement, and seizure o Infectious o Neoplastic o Traumatic o Vascular They are categorized by the etiology or the cause of the particular nervous system disorder Often you will find is that many of these conditions we don’t know what the cause is, and therefore we may not have a handle on a cure

Congenital Disorders The first section deals with congenital disorders. Congenital means present at birth. 

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The first disorder we will talk about is hydrocephalus, and it is not always congenital, but it can be congenital o For example, it can be acquired if someone in an automobile accident and has an accumulation of CSF in the brain o Also sometimes other conditions like cancers and infections can cause it o The definition is an abnormal accumulation of fluid (CSF) in the brain o Literally, if we looked at the word hydrocephalus, cephal/o is the term for head, and hydro is water or fluid We already mentioned spina bifida o Again the definition is congenital defects in the lumbar spinal column caused by imperfect union of vertebral parts o It is congenital, so a baby would be born with it o Your textbook provides a picture that shows a good example of the different types of spina bifida

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Picture A portrays spina bifida, Picture B portrays spina bifida with a meningocele where the meninges protrude, and Picture C portrays spina bifida with myelomeningocele where both the spinal cord and the meninges protrude You can have varying degrees of spinia bifida.

Degenerative, Movement, and Seizure Disorders  

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You will see a few eponyms. Eponyms again are terms that are named after a person, usually a physician. Alzheimer Disease also abbreviated as AD o It is a brain disorder where you have gradual and progressive mental deterioration o You may also see personality changes, and impairment of daily functioning o Also, you may see varying degrees of this disease o We are still learning a lot about this disease Amyotrophic Lateral Sclerosis, also abbreviated as ALS o Another name for ALS is Lou Gehrig Disease o Lou Gehrig was a famous baseball player who was struck with this condition o This has to do with the degeneration of the motor neurons, and affects the spinal cord, and also the brain stem o The cause and cure for ALS is unknown Epilepsy is a chronic brain disorder characterized by recurrent seizure activity o You may have a patient who experiences one seizure that does not mean they have epilepsy o Normally, a diagnosis of epilepsy is after recurrent and chronic seizure activity o There are medications that are very helpful for epilepsy o You do need to know the 2 different types of epilepsy  The first is called tonic-clonic seizures, the old terminology was grand mal seizures or ictal events  This is the more severe type of epilepsy, where there is a sudden loss of consciousness, the patient falls down, stiffening of muscles, jerking movements, full blown seizure  The milder form of epilepsy is called Absence seizures where the patient experiences momentary, kind of comes and goes, cloudiness, the lose track of where they are The old term for this was petite mal seizures, but now the preferred term is called absence seizures Huntington Disease or Huntington chorea is a hereditary disorder marked by degenerative changes in the cerebrum leading to abrupt involuntary movements and mental deterioration o We refer to Parkinson disease where a person experience tremors, but with Huntington disease you have something more pronounced, often referred to as jerky movements of the arms and legs, even dance like 

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Multiple Sclerosis also abbreviated MS is when you have destruction of the myelin sheath on neurons in the CNS and it’s replaced by plaques of sclerotic (hard tissue) o This would affect the electrical impulses from neuron to neuron o MS occurs in young people, and we still don’t have a handle on what causes it o There are drugs that are being used with varying degrees of success Myasthenia Gravis also abbreviated MG, this is an autoimmune disease that not only affects the nervous system, but also the muscles o It is a neuromuscular disease that results in a weakness of the voluntary muscles o It is a chronic disease and there are some types of treatment that are helpful for MG Palsy means paralysis, and in this case there is partial or complete loss of motor function o There are a couple of different types of palsy o For example cerebral palsy, where there is partial paralysis, lack of muscular coordination, due to a loss of oxygenated blood getting to the brain o There is also a less severe type of palsy called Bell’s Palsy  This is paralysis on one side of the face, and there is a good treatment for Bell’s palsy, but not for Cerebral Palsy Parkinson Disease is defined as a degeneration of neurons in the basal ganglia, occurring in later life and leading to tremors, weakness of muscles, and slowness of movement o One of the interesting things about this disease is that there is not a particular type of lab test or diagnostic test that can diagnose it o It begins with some simple observations by the physician o For example, if a patient is experiencing symptoms and they know something is wrong, they will go to see a physician o Some of the primary symptoms have to do with tremors, shaking in the hands, arms, legs, jaw, and face, some rigidity and stiffness of the limbs and trunk, bradykinesia (short shuffling gait when they walk), there posture is not erect, and when you look at their face it is referred to a mask-like face meaning, the patient does not blink, they have a stare about them o The physician might have the patient walk, and observe the body posture o Normally when we walk there is a natural swing with the arms, but with a Parkinson patient, the arms are very stiff and have little movement Tourette Syndrome is involuntary, spasmodic, twitching movements; uncontrollable vocal sounds; and inappropriate words o So the patient is unable to prevent having these uncontrollable vocal sounds, it may be something as simple as clearing the throat, but it is repetitive o Also, when they say inappropriate words, their verbal outbursts are uncontrollable

Infectious Disorders 

The first disorder is Herpes Zoster also known as Shingles o This is a viral infection affecting peripheral nerves

Reactivation of the chickenpox virus (herpes varicella-zoster) which remains in the body after the person had chickenpox Meningitis is inflammation of the meninges also called leptomeningitis o You can have different types of meningitis Human Immunodeficiency Virus Encephalopathy also known as HIV encephalopathy o This is when a patient who has AIDS develops brain disease and dementia, which is the encephalopathy part o

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Neoplastic Disorders  

Neoplastic means new growth Brain Tumor is an abnormal growth of brain tissue and meninges o When we hear the word tumor, this can mean malignant or benign

Traumatic Disorders    

These are disorders caused by external injury or trauma. Cerebral Concussions is a type of traumatic brain injury caused by a blow to the head Cerebral Contusion is bruising of the brain tissue as a result of direct trauma to the head o The medical term from bruising on the inside of the body is contusion There is also a medical term that is not in your book, but I would add it to traumatic disorders. The term is Coma o This is a loss of consciousness, it can be reversible or irreversible

Vascular Disorders  

There are a lot of terms in this section that you need to be familiar with, and you will see again. Cerebrovascular Accident also abbreviated as CVA o The abbreviation CVA does not stand for cardiovascular accident, be careful with this abbreviation  Cardi/o is heart, whereas cerebr/o is brain  In this case we are referring to the brain o This is a disruption in the normal blood supply to the brains, also known as a stroke  Another term for a stroke is a cerebral infarction  3 types of strokes:  Thrombus or thrombotic type - caused by plaques that occlude the cerebral arteries, arteries that take blood to the brain o Think of the word thrombus which means blood clots, so you have these thrombi and plaque that is obstructing the arteries, which would block them over time, causing an occlusion, minimizing the amount of oxygenated blood that can get to the brain

If the patient is fortunate enough, they may experience a condition called transient ischemic attack, also abbreviated as TIA, is the medical term for a mini stroke  It is a short episode where it is sort of a warning sign or symptom that an impending stroke is going to occur  So if patients are diagnosed with TIA, it may be that the physician would have an opportunity to remove the clot before it obstructed the cerebral vessel and the vein Embolic Stroke – can embolus (dislodged thrombus) travels to cerebral arteries and occludes a small vessel o Embolic stroke VS thrombotic stroke  They both have blood clots or plaque occluding the arteries, but the difference is a thrombus is a stationary blood clot which may grow over time to occlude the vessel, but an embolus is a floating clot, one that is dislodged and then moves further and obstructs a smaller vessel  So think of an embolus as a floating clot, and it can happen very suddenly where it will occlude a vessel  So for example, the thrombus may break off into pieces, and start floating around and become an embolus Hemorrhagic – blood vessel, such as cerebral artery, breaks and bleeding occurs o This is a little different because ins...