Neurological Disorders Vocabulary

Flashcards covering key vocabulary and concepts from the Neurological Disorders lecture.

Etiology

The underlying cause of a disease.

Pathology and Pathogenesis

How the organ/system physiology is disrupted and how it gets progressively worse.

Clinical manifestations

Physical result of some type of illness or infection.

All or None

Nerve signals are 100% every time.

Threshold of sensitivity

To get a nerve to send a signal down the axon, a threshold of sensitivity needs to be overcome

Action Potential

The signal traveling down the axon.

White matter

Transmits signals faster (saltatory) than gray matter (continuous).

Gray matter

Is unmyelinated.

Synapse

The space between the nerve sending and the nerve receiving.

Neurotransmitters

Are released by the sending nerve (presynaptic) to flow across the synapse and bind to the receiving nerve (postsynaptic).

Na

More abundant outside and think of it as more positive.

K

More abundant inside and think of it as less positive.

Sodium and Calcium

Two ions are critical to nerve innervation and transmission

Sodium

Is the initiating ion for depolarization of the membrane.

Calcium

Initiates the release of the Neurotransmitter at the synapse.

Chemical Neural Activity

Binding of neurotransmitters (ligands) to receptors on postsynaptic membranes (ACh), GABA, Dopamine, serotonin, norepinephrine

Electrical Neural Activity

Charges from ions can drive impulse activity down axon (i.e. Na/K) OR inhibit activity (Cl)

Mechanical Neural Activity

Pressure on membranes or membrane distortion causes depolarization

Stimulatory impulse

When the ligand binds to its receptor, it causes Na or Ca to get in and depolarization occurs. Examples include norepinephrine, glutamate.

Inhibitory stimulus

Is produced by binding of neurotransmitter (ligand) like GABA or glycine to receptor on the postsynaptic membrane are repress impulse by keeping membrane potential at or below -70 mV.

Purely Neural Disorders

Areas of the cerebrum are affected resulting in specific effects or behaviors

Trauma Neural Disorders

areas of the cerebrum are affected resulting in specific effects or behaviors

Somatosensory and Somatomotor disorders

Basically, there is a faulty connection between incoming signals and outgoing signals

Causes of Neural Disorders

Degenerative changes, Metabolic imbalances, Structural changes, Cancers, Inflammation

Neuronal hyperactivity

ex. Seizure.

Decreased neuronal activity

ex. Post-stroke

Hemiplegic Gait

Arm and leg on one side affected

Cerebellar Ataxia

Cerebellum and connections are affected

Spinal Muscular Atrophies (SMA)

Selective degeneration of motor neurons – childhood onset

Amyotrophic lateral sclerosis (ALS)

Most common form of motor neuron disease in adults

Symptoms of Parkinson Disease

Muscle rigidity, Bradykinesia, Tremor, Postural instability

Lewy bodies

Filamentous aggregates if alpha-synuclein

Familial Parkinson Disease

Mutations in glucocerebrosidase enzyme (Gcase)

Myasthenia Gravis

Autoimmune disorder of neuromuscular transmission

Major clinical features of Myasthenia Gravis

Fluctuating fatigue, Weakness that improves with rest and Ach inhibitors, Muscles with small motor units (like eye) is affected

Circulating antibodies

Antibodies block Ach binding which blocks receptor activation

Seizures

Sudden recurrence of symptom disturbances in cerebral function by an abnormal asynchronous discharge of cortical neurons

Epileptogenic neurons

Very sensitive to most types of changes and Fire frequently with greater amplitude

Prodroma

initial symptoms.

Tonic phase

Contraction with increased muscle tone, loss of consciousness

Clonic phase

Relaxation and contractions alternate until ATP is exhausted

Status epilepticus

State of continuous seizures >5m

General tonic-clonic seizures

Sudden loss of consciousness followed by rapid tonic muscle contraction

Absence Seizures

Childhood and remit by adulthood; Lapse in consciousness for several seconds +/- postural changes

Dementia

Acquired decline in intellectual function

Dementia

Affects 5-20% of people over 65 and NOT PART OF THE NORMAL AGING PROCESS

Alzheimer Disease

Most common cause of Dementia

Clinical Features of Alzheimer Disease

Impairment of learning and recent memory occurs initially

Anomia

Can’t find your words

Aphasia

Can’t understand or express speech

Acalculia

Loss of ability to perform math

Apraxia

Cannot perform learned/skilled movements/activities

Alzheimer Pathology

Neuritic plaques,Neurofibrillary tangles, Neuronal and synaptic loss

Stroke

Clinical syndrome characterized by the sudden onset of focal neurological deficit that persists for at least 24h

Ischemic stroke

Vascular occlusion interrupts blood flow to a brain region

Hemorrhagic stroke

Pattern of deficits is less predictable due to multiple factors

Ischemic stroke

Thrombus or embolus causes occlusion of large arteries like carotids, middle cerebral or basilar arteries

Epidural or Subdural hematomas

Occur as sequelae of head injury

Epidural hematoma

due to damage to an artery

Subdural hematoma

Arise from venous blood leaks from cortical veins in subdural space

Subarachnoid hemorrhage

Occurs from head trauma blood flowing into arachnoid space or rupture of arterial aneurysm

Intraparenchymal hemorrhage

Could occur due to acute elevations in blood pressure or from a variety of vessel weakening disorders