Acalculia – Inability to calculate
Accommodation – Act of refocusing the visual image
Acromegaly – Overgrowth of the skeleton and organs caused by excessive release of growth hormone from a pituitary tumour
Acuity – Resolving power
Action potential – Transient reversal of the resting potential that is propagated along the axon
Adenoma – Benign tumour
Adhesion – Scarring of tissues, fixing them together
Adipsia – Inability, or loss of desire, to drink
Aetiology – Relating to the cause of disease
Afferent – Carrying towards (e.g. cerebellar afferent neurones carry impulses to the cerebellum)
Agnosia – Inability to recognise objects
Agraphia – Inability to write
Akinesia – Loss, or slowness, of movement
Alexia – Inability to read
Amnesia – Loss of memory
Anastomosis – Intercommunication between vessels (e.g. circulus arteriosus or circle of Willis)
Aneurysm – Abnormal dilatation of an artery
Angioma – Congenital swollen collection of blood vessels
Angiography – Demonstration of the arterial system after injection of an opaque medium
Anomia – Inability to name objects
Antidiuretic – An agent that reduces the volume of urine produced by the kidney
Aphagia – Inability, or loss of desire, to eat
Aphasia – Loss of ability to use language
Apraxia – Loss of skilled movements despite preservation of power, sensation and coordination
Arachnoid mater – Middle of the three meningeal layers enveloping the central nervous system
Areflexia – Loss of reflexes
Arthritis – Inflammation of one or more joints
Astrocyte (astroglial cell) – A type of neuroglial cell (q.v.) that may form the blood–brain-barrier
Ataxia – Loss of ability to coordinate voluntary movements
Atrophy – Wasting or degeneration
Axon – The nerve fibre carrying impulses away from the cell body
Baroreceptor – Neuronal sensory ending that detects changes in arterial blood pressure
Biopsy – Tissue sample taken from a patient for the diagnosis of disease
Blood–brain barrier – A selectively permeable barrier between the circulating blood and the brain believed to be formed by astrocytes
Bulimia – Overeating disorder
Bradykinesia – Slowness of movement
Brain stem – The stalk-like portion of the brain connecting the cerebral hemispheres with the spinal cord
Bulbar palsy – Weakness of tongue, pharynx and larynx resulting from disease of the lower cranial nerves
Cataract – Opacity of the lens of the eye, leading to deterioration of vision
Cell body – The part of the neurone that contains the nucleus and possesses dendritic and axonal processes
Central nervous system – The brain and spinal cord
Cephalic – Relating to the head
Cerebrum – The largest, most highly developed part of the brain comprising two cerebral hemispheres
Cerebrospinal fluid (CSF) – The clear watery fluid that surrounds the brain and spinal cord
Chemoreceptor – Neuronal sensory ending that detects changes in the chemical composition of circulating blood
Chiasma – Decussation or crossing over of nerve fibres (e.g. optic chiasma)
Chorea – Involuntary, abnormal movements of the face and limbs
Collateral – A side-branch of a nerve or blood vessel
Coma – Prolonged and unnatural state of unconsciousness
Computed tomography (CT) – Imaging technique utilising X-rays to visualise the structure of the nervous system
Concussion – Loss of consciousness caused by head injury
Contralateral – Relating to the opposite side
Contusion – Bruising
Convulsion – Involuntary contraction or spasm of muscles
Cordotomy – Neurosurgical procedure to destroy specific pathways in the spinal cord
Craniopharyngioma – Congenital tumour of the base of the brain
Craniotomy – Neurosurgical procedure to open the cranial cavity
Cushing’s disease – Overgrowth of the adrenal glands causing excessive release of corticosteroid hormones
Decussation – Crossing over of nerve fibres from one side of the CNS to the other (e.g. pyramidal decussation)
Dementia – Loss of mental abilities
Demyelination – Loss of the myelin sheath surrounding neuronal axons
Dendrite – Branching process of a neurone that receives information from other neurones and conducts electrical changes to the cell body
Diabetes insipidus – Failure of the posterior pituitary gland causing reduced release of antidiuretic hormone
Diabetes mellitus – A disorder of carbohydrate metabolism caused by lack of insulin
Dorsal root ganglion – Location of cell bodies of primary afferent neurones entering the spinal cord through the dorsal roots of spinal nerves
Dura mater – Outermost of the three meningeal layers that envelop the central nervous system
Dysarthria – Inability to pronounce
Dysphagia – Inability to swallow
Dysphonia – Inability to produce the voice
Echocardiography – The use of ultrasound to display the action of the heart
Efferent – Carrying away from (e.g. striatal efferent fibres carry impulses away from the striatum)
Electroencephalography (EEG) – Technique to detect the surface electrical activity of the brain
Electromyography – Technique to determine the electrical activity of muscles
Emetic – Causing nausea and vomiting
Encephalopathy – Disorder of the brain
Entrapment neuropathy – Nerve injury caused by compression of a nerve within a tunnel or at a change in direction
Ependymal cells (ependyma) – Epithelial cells lining the ventricular system
Epilepsy – Paroxysmal attack of disturbed consciousness and sensorimotor function resulting from abnormal electrophysiological discharges of the brain
Fasciculation – Spontaneous contraction of denervated motor units, visible on inspection
Fasciculus – Bundle of nerve fibres (e.g. medial longitudinal fasciculus)
Febrile – Refers to raised body temperature (fever)
Fibrillation – Spontaneous contraction of denervated muscle fibres, detected on electromyography
Foramen – An opening (e.g. foramen magnum)
Ganglion – A collection of nerve cell bodies outside the CNS (e.g. dorsal root ganglion)
General paralysis of the insane (GPI) – Disease of the frontal lobes caused by late neurosyphilis
Glia – see Neuroglia
Glioma – Tumour derived from glial cells
Haematoma – Blood clot
Haemorrhage – Escape of blood from a ruptured blood vessel
Hallucination – Abnormal perceptual experience
Hemianopia – Loss of sight affecting one half of the visual field (e.g. bitemporal hemianopia)
Hemiparesis – Weakness of one side of the body
Hemiplegia – see Hemiparesis
Hepatolenticular degeneration (Wilson’s disease) – Inherited disease of copper metabolism affecting the liver and brain
Herpes zoster – Virus causing shingles (q.v.)
Huntington’s disease – Inherited degenerative disease of the brain causing chorea (q.v.) and dementia (q.v.)
Hydrocephalus – Abnormal amount of cerebrospinal fluid within the ventricles of the brain
Hyperacusis – Increased hearing sensitivity
Hyperreflexia – Abnormal increase in reflex activity
Hypertonia – Abnormal increase in muscle tone
Hypertrophy – Enlargement of tissues
Hypothyroidism – Underactivity of the thyroid gland causing reduced release of thyroid hormone
Hypotonia – Abnormal decrease in muscle tone
Idiopathic – Of unknown cause
Infarction – Death of tissue resulting from impairment of its circulation
Intervertebral – Between two vertebrae
Ipsilateral – Relating to the same side
Kinaesthesia – Perception of movement
Lamina – A thin layer (e.g. internal medullary lamina)
Lesion – Site of disease or damage
Lobectomy – Surgical resection of lobe of the brain
Lumen – A space or cavity
Lymphoma – Tumour of the lymphoid system
Magnetic resonance imaging (MRI) – Technique to image structure that does not employ ionising radiation
Mastication – The act of chewing
Miosis – Pupillary constriction
Meninges – connective tissue sheaths surrounding the CNS, namely dura mater, arachnoid mater and pia mater
Meningitis – Inflammation of the meninges
Meningioma – A tumour arising from the fibrous coverings (meninges) of the brain
Metastasis – Spread of tumour to distant sites
Microglia – A type of neuroglial cell (q.v.), having a mainly phagocytic function in the response to brain damage or injury
Migraine – Paroxysmal headache
Motor neurone disease – Degenerative disease of upper and lower motor neurones, causing paralysis
Multiple sclerosis – Immune disease of the CNS, causing relapsing disorder of nervous function
Muscular dystrophy – Inherited degeneration of muscles, causing progressive paralysis
Myasthenia gravis – Immune disorder of the neuromuscular junction, causing muscular fatigue
Myelin – A sheath of protein and phospholipid around the axons of certain neurones
Myopathy – Disease of muscle
Narcolepsy – Paroxysmal sleep attacks
Necrosis – Death of tissue
Neoplasia – Tumorous overgrowth of tissue
Neurofibromatosis – Inherited disease causing tumours of meninges, CNS, peripheral nerves and skin
Neuroglia (neuroglial cell) – non-neural supporting cells of the CNS comprised of oligodendrocytes, astrocytes, microglia and ependymal cells (q.v.)
Neuroma – Tumour derived from nerve cells
Neurone – The principle functional cell of the nervous system, specialised to integrate and transmit nerve impulses
Neuropathy – Disease of nerve cells
Neurosyphilis – Infection of the nervous system by a spirochaete
Neurotransmitter – Chemical substance stored within vesicles (q.v.) in presynaptic nerve endings and released on depolarisation to act upon postsynaptic receptors
Nociception – Sensitivity to noxious stimuli
Nucleus – Structure within a cell that contains chromosomal DNA; also a collection of nerve cell bodies within the CNS (e.g. dentate nucleus)
Nystagmus – To-and-fro movements of the eyes
Oedema – Swelling caused by accumulated fluid
Oligodendrocyte (oligodendroglia) – A type of neuroglial cell (q.v.) that produces the myelin sheath in the CNS
Oligodendroglioma – Tumour derived from oligodendroglia
Ophthalmoscopy – Clinical examination of the eye with an ophthalmoscope
Pallidum – Globus pallidus
Palsy – Weakness
Papilloedema – Swelling of the optic nerve(s)
Paraesthesia – Tingling sensations (‘pins and needles’)
Paralysis – Muscle weakness of varying severity
Paraphasia – Use of incorrect word
Paraplegia – Weakness or paralysis of the legs
Paresis – Muscular weakness
Parkinson’s disease – Disease of the basal ganglia causing akinesia (q.v.), rigidity (q.v.) and tremor (q.v.)
Paroxysm – Sudden attack
Peripheral nervous system – All parts of the nervous system excluding the brain and spinal cord (CNS)
Photophobia – Intolerance to light
Pia mater – Innermost of the three meningeal layers that envelop the central nervous system
Plexus – Structure consisting of interwoven nerves (e.g. brachial plexus) or blood vessels (e.g. choroid plexus)
Poliomyelitis – Viral infection of motor neurones of the spinal cord and brain stem
Positron emission tomography (PET) – Technique for imaging the function of the brain
Prolapse – Displacement from normal anatomical position
Proprioception – The detection of position and movement of body parts
Pseudobulbar palsy – Weakness of the tongue, pharynx and larynx caused by disease of the corticobulbar tracts
Psychosis – Abnormal mental state with altered precepts (hallucinations) and false ideas (delusions)
Ptosis – Abnormal drooping of the eyelid
Quadriplegia – Paralysis affecting all four limbs
Radiculopathy – Disease of the nerve roots
Receptor – Specialised element of the cell membrane that binds neurotransmitter substances (or exogenous drugs) bringing about a change in membrane permeability or an intracellular response
Resting potential – The electrical potential across the membrane of a nerve cell at rest
Rheumatic fever – Immune disease of the joints, heart and brain following bacterial infection
Rigidity – Increased resistance to passive movement of the limbs throughout their range
Schizophrenia – Disease of the brain causing psychosis (q.v.)
Seizure – Sudden disturbance of consciousness or sensorimotor function
Shingles – Infection of the ganglia of cranial and spinal nerves by herpes zoster virus (q.v.)
Single photon emission tomography (SPECT) – Technique for imaging the function of the brain
Somatic – Relating to body parts other than the viscera
Somatotopic – The orderly representation of body parts in the CNS
Spasticity – Increased resistance to passive movement of the limbs when muscles are initially stretched
Spondylosis – Degeneration of the spine
Stroke – Sudden neurological deficit caused by disease of the circulation to the brain
Sydenham’s chorea – Manifestation of rheumatic fever (q.v.) affecting the basal ganglia and causing involuntary movements
Synapse – The gap between neurones across which nerve impulses pass by release of a neurotransmitter
Synaptic vesicle – Structure within the presynaptic ending that contains neurotransmitter substance which is released on depolarisation
Syncope – Fainting attack
Syndrome – Group of signs and symptoms which characterise a disease
Syringobulbia – Expanding cavity (syrinx) within the medulla
Syringomyelia – Expanding cavity within the spinal cord
Syrinx – An abnormal cavity in the spinal cord
Thalamotomy – Neurosurgical destruction of part of the thalamus
Terminal bouton – specialised presynaptic ending of an axon
Thrombosis – Coagulation of blood in artery or vein
Tract – An aggregation of nerve cell processes having more or less the same origin and destination (e.g. corticospinal tract)
Tremor – Trembling of head or limbs
Tumour – A swelling or morbid enlargement; a mass of abnormal tissue resulting from uncontrolled cell growth (neoplasm)
Vesicle – see Synaptic vesicle