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HIMAA unit 7
Nervous System
Question | Answer |
---|---|
what does the central nervous system contain (CNS)? | Brain and spinal cord The spinal cord carries messages from the body to the brain, where they are analysed and interpreted. Response messages are then passed from the brain through the spinal cord and to the rest of the body. |
What are the Peripheral nervous system (PNS)? | Connects the CNS to other parts of the body, and is composed of nerves (bundles of neurons.) Can be divided into the somatic and the autonomic nervous system. |
What is the Somatic (sensory) nervous system (voluntary)? | Relays information to and from the skin and skeletal muscles. includes all nerves controlling the muscular system and external sensory receptors. It consists of cranial nerves & spinal nerves. |
What is the Autonomic nervous system (ANS) [voluntary]? | Relays information to internal organs. regulates activities that are automatic or involuntary. Maintains homeostasis. |
What does the Sympathetic nervous system do? | Controls organs in times of stress. |
What does the Parasympathetic nervous system do? | Controls organs when body is at rest. |
What does the nervous system contain? | Central nervous system; peripheral nervous system; somatic nervous system; autonomic nervous system; Sympathetic nervous system & Parasympathetic nervous system. |
Where can you find the CNS? What is it encased in? | The CNS is encased in bone - the brain within the skull and the spinal cord, which is continuous with the brain, emerges from an opening at the base of the skull, & runs down the spinal canal between the vertebrae. |
The brain and sinal cord are covered by a series of tough membranes called? | Meninges, which protects these organs from rubbing against the bones of the skull and spine. |
What is cerebrospinal fluid? | For further protection, the brain and spinal cord float in a sea of Cerebrospinal fluid within the skull and spine. |
This cerebrospinal fluid (cushioning fluid) is produced by? And is located where? | produced by Choroid plexus tissue and is located within the brain, and flows through a series of cavities (ventricles) out of the brain & down along the spinal cord. |
What do Cranial nerves (CN) do? | take impulses to and from the brain. There are 12 pairs of cranial nerves, which emerge from and enter into the skull. Each pair of cranial nerves has a number and name and distinct functions. |
I Olfactory Nerve | smell |
II Optic nerve | vision |
III Oculomotor nerve | Eyelid and eyeball movement |
IV Trochlear nerve | controls superior oblique muscle which turns eye downward and laterally |
V Trigeminal nerve | Chewing; face and mouth touch and pain |
VI Abducens nerve | turns eyes laterally |
VII Facial nerve | controls most facial expressions secretion of tears & saliva taste |
VIII Vestibulocochlear (auditory) nerve | hearing balance |
IX glossopharyngeal nerve | taste controls some muscles used in swallowing |
X vagus nerve | main nerve of the parasympathetic nervous system taste |
XI (spinal) accessory nerve | controls muscles used in head and shoulder movements swallowing There are 31 spinal nerves, which emerge from the spinal cord. The nerves are named accordingly to their respective vertebrae. EAch spinal nerve consists of a DORSAL ROOT + VENTRAL ROOT. |
XII hypoglossal nerve | controls tongue movements |
Spinal nerves also regulates ? | Reflexes. A reflex is the simplest response to a stimulus. |
What is a reflex arc? | is an automatic, involuntary reaction to a stimulus. Eg. Dr taps your knee with a rubber hammer - testing your reflex (knee-jerk). Involuntary, with CNS being informed but not consciously controlling the response. Eg: include balance, blinking, stretch. |
list an example of the sympathetic nervous system and parasympathetic nervous system | 1. the heart rate is speeded up by the sympathetic nervous system whilst it is slowed down by the parasympathetic nervous system. |
Anaesthesia (anesthesia) | loss of sensation; may be associated with unconscious or may be drug-induced. |
analgesia | lack of sensitivity to pain. Medication may also be used to reduce the sensitivity to pain. |
aphasia | loss or impairment of the ability to speak, and of language comprehension. |
expressive aphasia/motor aphasia | the patient understands written and spoken words and knows what he/she wants to say, but is unable to use the muscles that coordinate speech. |
receptive aphasia/sensory aphasia | the patient is unable to comprehend written or spoken words |
aphonia | loss of the voice, inability to produce vocal sounds, due to paralysis or overuse of the laryngeal nerves |
ataxia | failure of muscular co-ordination |
aura | peculiar sensation appearing before more definite symptoms e.g. epileptic seizure. |
convulsion | paroxysms of involuntary muscular contractions, in the form of a violent spasm or series of jerkings of the voluntary muscles of the face, trunk, or extremities. |
dysarthria | imperfect articulation of speech, due to incoordination of speech muscles. |
dyskinesia | abnormal involuntary movement and impairment of the power of voluntary movement. |
dyspasia | difficulty speaking |
hyperaesthesia (hyperesthesia) | increased or abnormal acuteness of sensitivity to touch, pain, or other sensory stimuli |
motor neurone disease (MND) - also called motor neuron disease | a group of related neurological disease characterised by progressive degeneration of motor neurones which control voluntary muscles needed for co-ordination and movement. No cure or effective treatment. Average life expectancy 2-3 yrs from diagnosis. |
What drug may extend survival time of motor neuron disease by an average of 9-12 months and keep people in the milder stages of disease for longer, thus contributing to quality of life?? | Riluzole |
There are four types of motor neuron disease. What are they? | 1.Progressive lateral sclerosis (PLS) 2. Progressive pseudobulbar palsy (PPP) 3. progressive muscular atrophy (PMA) 4. Amyotrophic lateral sclerosis (ALS) |
Progressive lateral sclerosis (PLS) | Upper motor neurones alone are affected with limb involvement being predominant |
progressive pseudobulbar palsy (PPP) | upper motor neruones alone are affected with brain stem involvement being predominant. It affects the muscles of the tongue, lips, palate, pharynx and larynx, which leads to difficulties in chewing, swallowing and talking. |
progressive muscular atrophy (PMA) | lower motor neurones alone are affected. Characterised by muscle wasting and weakness which may begin in the hands and eventually affect the rest of the body, loss of weight, and twitching in the limbs and tongue. |
Amyotrophic lateral sclerosis (ALS) | both upper and lower motor neurones are involved. Characterised by muscle wasting, weakness and stiffness, overactive reflexes and rapidly changing emotions. This is the most common form and is known as Lou Gehrig's disease in North America. |
Neurofibromatosis, von Recklinghausen's disease | familial condition of the nervous system, characterised by multiple neurofibromas and patches of pigmentation. |
Poliomyelitis | a contagious viral disease causing inflammation of the grey matter of the spinal cord, injuring or destroying the nerve cells that control the muscles and sometimes leading to paralysis. Paralysis most ofter affects the legs but also affect any muscles. |
post-polio syndrome (PPS) | is a disorder of the nervous system that appears in people who experienced paralytic poliomyelitis, usually 15-40 years after the original illness. The main symptoms are new progressive muscle weakness, severe fatigue and pain in muscles and joints. |
Nystagmus | involuntary rapid rhythmic movement of the eyeball |
Paralysis | temporary or permanent loss of motor control |
Two types of paralysis are? | Flaccid paralysis - lax or absent muscle control of individual muscles or muscle groups. Spastic paralysis - stiff and awkward muscle control of a limb as a whole, caused by a central nervous system disorder. |
Paraesthesia (paresthesia) | heightened or abnormal sensation such as numbness, prickling, tingling or 'pins and needles'. |
Seizure [a tendency to have recurrent seizures leads to the diagnosis of epilepsy] | a sudden burst of excess electrical activity in the brain, causing a temporary disruption in the normal message passing between brain cells. Seizures may be caused by acute events including infection, head injury, chemical imbalance, stroke, brain tumour |
Tic | involuntary contractions and twitching |
Tinnitus | a noise in the ears, as ringing, buzzing or roaring. |
Vertigo | a sensation of rotation or movement of one's self or of one's surroundings. |
Bell's Palsy | paralysis, usually on one side of the face only, due to a disorder of the facial nerve (seventh cranial nerve), most commonly caused by viral infection of the nerve. |
Symptoms of Bell's Palsy | Droopy eyelid, dry eye or excessive tears Facial paralysis, twitching or weakness Drooping corner of mouth, dry mouth, impaired taste |
Causalgia | post-traumatic peripheral nerve pain, diffuse burning pain especially in the hand or foot which may be aggravated by slight stimuli or emotional response. |
Ganglionitis | Inflammation of a ganglion (any group of nerve cell bodies in the central or peripheral nervous system) |
Guillain-Barre syndrome (GBS), acute idiopathic polyneuropathy | an autoimmune condition in which the person's nerves are attacked by the body's own immune defence system. The syndrome appears to be triggered by acute viral or bacterial illnesses, such as respiratory or gastrointestinal infections 1-3 wks earlier. |
Herpes zoster | viral disease, caused by herpes zoster virus, affecting the peripheral nerves. Pain and blisters appear over the skin in the distribution area of the affected nerve. Also called shingles. |
Migraine | a type of headache that appears to originate in the blood vessels of the head. Migraines usually last 4-72 hours. Often accompanied by vertigo, nausea and vomiting, photophobia and scintillating appearances of light. |
Types of Migraine are? | classic migraine, common migraine, cluster headache, hemiplegic migraine, ophthalmoplegic migraine and ophthalmic migraine. |
Polyneuritis, polyneropathy | inflammation of many nerves. Many nerves are inflamed at the same time. |
Radiculitis | inflammation of the spinal nerve roots |
Sciatica | pain in the lower back and hip radiating down the back of the thigh into the leg, along the path of the sciatic nerve. Due to compression of nerve roots that join to form the sciatic nerve, often caused by herniated lumbar disc compromising a nerve root. |
Trigeminal neuralgia (TN) This disorder is common in women more than men, and rarely affects anyone younger than 50 | pain in the areas innervated by one or more branches (ophthalmic, maxillary and mandibular) of the fifth cranial nerve. Pain is characterised by a sudden, severe, electric shock-like or stabbing pain typically felt on one side of the jaw or cheek. |
Ganglionectomy | Excision of a ganglion. A ganglion refers to a mass of nervous tissue composed principally of neuron cell bodies and lying outside the brain or spinal cord (pleural - ganglia). |
Nerve decompression | splitting of the fibrous or bony containment of a compressed nerve |
nerve graft | the transplantation of a portion of nerve to replace a defect in another nerve |
neuroanastomosis | surgical communication between nerve fibres |
neuroplasty | plastic repair of a nerve |
neurorrhaphy | suture of an injured nerve |
neurotomy | transection or cutting of a nerve |
rhizotomy | incision into a nerve root |
sympathectomy | excision of part of a sympathetic nerve |
Transposition of nerve | moving a nerve to a more favourable position, e.g., out of an area of constriction |
Reflex testing | test performed to observe the body's response to a stimulus. * Deep tendon reflexes - involuntary muscle contraction after percussion at a tendon. eg. knee jerk * Babinski's sign or reflex - plantar surface of the toe is stroked [may indicate disease] |
Hemiplegia | paralysis of either the right or left side of the body resulting from an injury to the brain (e.g. stroke). The hemiplegia is contralateral to the brain injury or lesion - if lesion on right side of brain, left side of body affected and vice versa. |
Paraplegia | paralysis of both legs and the lower part of the body caused by injury or disease of the spinal cord, usually at the lumbar level. |
quadriplegia | paralysis of all four limbs, due to injury of the spinal cord at the cervical level. |
Cerebral abscess | an abscess of the brain, generally secondary to ear infection, sinusitis or other infections. |
Cerebral arteriovenous malformation (AVM) | Structural vascular defect, generally found in young patients with subarachnoid haemorrhage and epilepsy. |
Cerebrovascular disease (CVD) | broad term referring to any functional abnormality of the brain caused by disorders of the blood vessels vascularising the brain. These conditions may lead to a cerebrovascular accident. |
Two conditions of cerebrovascular disease are: | Cerebral atherosclerosis - atheromatous plaques in cerebral arteries leading to reduced cerebral circulation. Cerebral arteriosclerosis - hardening of the arteries of the brain. |
Cerebrovascular accident (CVA) - "STROKE" | Damage to an area of the brain. Depending upon the area of the brain involved, the patient may suffer paralysis, loss of speech or loss of vision. There are 5 types of CVA's. |
What are the 5 types of CVA's? | 1. Cerebral aneurysm 2. Cerebral thrombosis 3. Cerebral embolism 4. Cerebral haemorrhage 5. Cerebral infarction |
Cerebral aneurysm | localised dilation or widening of a blood vessel of the brain resulting in thinning and weakening of the vessel wall, which may rupture causing internal bleeding. |
Cerebral thrombosis | formation of a thrombus (blood clot) in one of the blood vessels of the brain. commonest cause of CVA's |
Cerebral embolism | the sudden blocking of one of the arteries supplying the brain by an embolus (fragments of a blood clot, air bubble etc) that has been brough to the brain via the blood stream. It suddenly obstructs a blood vessel depriving brain tissue of oxygen |
Cerebral haemorrhage | a bleeding into the cerebrum |
Cerebral infarction | local necrosis (death) of brain tissue due to loss of blood supply |
transient ischaemic (ischemic) attack (TIA) no. 1 | a short period of insufficient blood supply to the brain can have the same signs and symptoms as a stroke such as weakness in an arm, a partial loss of vision, but the problem lasts less than 24 hours. |
TIA's no. 2 | People who get TIA's are at increased risk of having a stroke in the future. Due to a developing thrombosis or cerebral atherosclerosis, before the blood vessel is totally occluded (blocked). Also called 'reversible ischaemic neurological deficit (RIND) |
Intracranial haemorrhage | bleeding within the cranium, may be extradural, subdural, subarachnoid or intracerebral. |
Intracranial haematoma | a local mass of blood formed following haemorrhage (hemorrhage). Epidural and subdural haematomas, located above and below the dura mter, are usually due to head injury. |
encephalocele | protrusion of the brain or part of it through the skull |
epilepsy | chronic brain disorder characterised by recurrent seizure activity due to excessive neuronal discharge, and usually associated with some alteration of consciousness. Seizures can be divided into two major groups. |
Two major groups of epilepsy - name one | Partial seizures - the seizure activity starts in one area of the brain and may spread to other regions of the brain. Also known as 'focal seizures'. About 60% of people with epilepsy have these; very subtle or bizarre; may go unnoticed. |
Partial seizures divided into two groups: | 1. simple partial seizures - no loss of awareness or consciousness 2. complex partial seizures - change in awareness or behaviour. People are conscious but may behave in odd ways (such as walking around without apparent purpose; plucking at their clothe |
Name no. 2 major group of epilepsy | Generalised seizures involve both halves of the brain simultaneously and are sometimes associated with loss of consciousness. They include 4 types. |
Name four types of generalised seizures | 1. tonic-clonic seizures 2. absence seizures 3. myoclonic seizures 4. atonic seizures |
Tonic-clonic seizures | the body stiffen (tonic) and then jerks repeatedly (clonic). There is an associated loss of consciousness. These used to be called grand mal. |
absence seizures | the person stares blankly for a few seconds. These mostly affect children and adolescents. Although there is a brief loss of consciousness, lasting for up to 30 seconds, there is no change in body position. These used to be called petit mal. |
myoclonic seizures | involves the abrupt jerking of muscle groups. In their severe form they can throw the individual to the ground. |
Atonic seizures | involves a sudden loss of posture or tone in limbs or the whole body. |
Reye's syndrome (potentially fatal) | disease of the brain (severe oedema and raised intracranial pressure) and the liver (fatty infiltration and dysfunction). Affects children. Cause unknown; typically appears following certain viral diseases eg. chickenpox; influenza type A. |
spinal cord injury | trauma to spinal cord produced by fracture or dislocation of spine may lead to paralysis |
Carotid artery ligation | tying a carotid artery |
carotid endarterectomy | removal of lining of the carotid artery in cerebrovascular disease |
cordotomy, chordotomy | surgical division of certain tracts of the spinal cord for the relief of pain. |
Craniectomy | removal of part of the skull |
Craniotomy | Opening of the skull |
Cranioplasty | Surgical correction of defects of the skull |
Cryoneurosurgery | the destruction of tissue or lesions of the nervous system by application of extreme cold. |
Decompression of Brain | removal of a portion of the skull to relieve intracranial pressure |
Decompression of spinal cord | removal of bone fragments or lesions to relieve pressure |
Discectomy | removal of an intervertebral disc |
Laminectomy | excision of one or more laminae of vertebrae |
Lobectomy | excision of one of the lobes of the brain. |
Lobotomy | cutting into a lobe of the brain, usually frontal lobe, to alter brain function by severing connecting nerve fibres between certain areas. |
Skull tongs or halo traction | method of exerting traction through the head eg. for treatment of cervical spinal fractures. |
traction | the exertion of a pulling force, as applied to a fractured bone or dislocated joint to maintain proper position and facilitate healing. |
Trephination or burr holes | methods of approach to the brain, cutting a circular opening or boring a hole through the skull bone using a trephine. |
Ventricular shunt | (for hydrocephalus) - surgically created detour channels to relieve the accumulation of cerebrospinal fluid eg. ventriculoperitoneal, ventriculoartrial, ventriculocisternostomy |
CVD | Cerebrovascular disease |
DT's | Delirium tremens |
LOC | Loss of consiousness |
PNS | Peripheral nervous system |
CNS | Central nervous system |
SDH | Subdural haemorrhage (hemorrhage) or subdural haematoma (hematoma) |
SNS | Sympathetic nervous system |