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171 Cards in this Set
- Front
- Back
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Dermatome |
An area of skin that is innervated by afferent axon fibres. |
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Slow Adapting Sensory Receptors |
Aka tonic receptors. Detect strength of a stimulus and are important when maintaining information about a stimulus is valuable |
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Fast Adapting Sensory Receptors |
Aka phasic receptors. Detect changes in stimuli and are useful when important to signal changes in stimuli or to stop paying attention to stimuli |
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First Order Neurone |
Peripheral receptor --> spinal cord (synapse) |
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Second Order Neurone |
Spinal cord --> decussates --> ascends --> thalamus (synapse) |
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Third Order Neurone |
Thalamus --> somatosensory cortex |
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Nociception |
Sensory component of pain |
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First Pain |
Feels sharp, fast transmission via A delta fibres |
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Second Pain |
Dull/burning, slow transmission via C fibres |
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Hyperalgesia |
Enhanced painful response to a normally painful stimulus |
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Allodynia |
Painful response to a normally, non-painful stimulus due to a shifted pain threshold |
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Primary Hyperalgesia |
Increased pain sensitivity in damaged tissue |
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Secondary Hyperalgesia |
Increased pain sensitivity distant from the site of injury |
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Glaucoma |
Increased pressure in the anterior compartment of the eye due to decreased reabsorption of aqueous humour |
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Optic Disc |
Blind spot on the retina where the optic nerve leaves the eye |
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Macula |
Central retina |
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Fovea |
All photoreceptors here are cones (no rods), meaning low sensitivity but high visual acuity |
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Phase Locking |
Responses can only occur with frequency equal to or higher than that at which a neurone can fire action potentials |
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Sclera |
Outemost layer of the eye |
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Uveal Layer |
Middle layer of the eye. Mostly choroid but most anteriorly is ciliary body. |
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Retina |
Innermost layer of the eye. An outgrowing of the CNS |
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Myopia |
Short sightedness. Eyeball is elongated. Correct with concave lens. |
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Hypermetropia |
Long sightedness. Eyeball is shorter. Correct with a convex lens. |
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Glue Ear |
Middle ear becomes filled with fluid |
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Papilloedema |
Swelling of the optic disc due to raised intracranial pressure causing stasis of axoplasmic flow. |
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Reflex |
Normally protective motor patterns generated in the spinal cord. closed loop with no input from higher centres. |
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Rhythmic Motor Patterns |
Combination of reflex and voluntary motor patterns. e.g. chewing, walking, breathing. |
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Voluntary Motor Patterns |
Purposeful, goal directed movements with command from higher centres. |
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Area 4 |
Cortical motor area that is responsible for distal muscle and fine motor control. It has the lowest stimulus threshold due to strong synaptic links. |
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Area 6/Premotor Area |
Cortical motor areathat is involved in more complex movements. Proximal muscle control, balance, gait, preparation for movement, planning, initiation and bimanual coordination. |
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Comparator |
Identify and correctdiscrepancies between descending motor signals (intended movement) and ascending afferent information (actual movement). |
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Timer |
Sequence of motor activation to give smooth performance of movements followed by appropriate postural adjustment and maintenance. |
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Predictor |
Enabling rapid execution of movements based on prior experience and expectation |
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Motor memory |
Instigating learned motor sequences when appropriate |
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Posture Regulation |
Indirect by adjusting major descending motor output |
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Hemiballismus |
Caused by damage to the substantia nigra. Violent flailing limb movement on the contralateral side to the damage. |
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Tardive Dyskinesia |
Caused by increased sensitivity of dopamine receptors due to long term use on antipsychotics. Uncontrolled movement of facial and trunk muscles. |
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Arousal |
A state of wakefulness |
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Consciousness |
Arousal + content. awareness of both self and external environment determined by a motor response to internal or external stimulus |
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Coma |
Total absenceof awareness of both self and external environment |
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Oculovestibular Reflex |
Cold water in one ear results in a slow deviation of gaze to the side of cooling then fast phase opposite |
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Oculocephalic Reflex |
Move head - conscious eyes move with head, unconscious eyes stay in original position. |
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Physical Dependance |
Anxiety, insomnia, cramps, tachycardia, piloerection, diarrhoea |
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Psychological Dependance |
Compulsive behaviour, anxiety, depression |
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Epilepsy |
A tendency toward recurrent seizures unprovoked by systemic or neurological traits |
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Epileptogenesis |
Sequence of events that converts a normal neuronal network into a hyperexcitable network |
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Seizure |
The clinical manifestation of an abnormal and excessive excitation of a population of cortical neurones. Abnormal, synchronous, paroxysmal neuronal discharge in the brain causing abnormal function |
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Status Epilepticus |
An epileptic seizure that lasts for 30/10 mins or longer, or a series of seizures without regaining consciousness in between |
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Beta Waves |
>14Hz active wakening, dreaming |
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Alpha Waves |
8-13Hz quiet waking |
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Theta Waves |
4-7Hz sleep |
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Delta Waves |
<4Hz deep sleep, coma |
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Sleep Paralysis |
During REM if dreaming of moving the motor cortex demands movement. The brainstem inhibits spinal motor neurones causing paralysis except for eyes and breathing. |
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Narcolepsy |
Suddenly fall asleep |
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REM Sleep Behaviour Disorder |
Loss of some sleep paralysis causing individuals to act out dreams |
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Ageing |
The gradual changes in the structure and function that occur with time, that do not result from disease or gross accidents, and lead to the increased probability of death as the person grows older. |
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Bradykinesia |
Slowness and impersistence of movement, less facial expressiveness, small writing, flexed trunk, Simian arm posture. |
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Aphonia |
Low volume of speech or the absence of spoken language due to muscle weakness and vocal cord paralysis |
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Dysarthria/Anarthria |
Failure of articulation. Causes: partial vocal cord paralysis, oropharyngeal problems, badly fitting dentures, cerebellar or brainstem pathology |
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Aphasia |
Inability to transfer through into language due to poor comprehension, impaired expression or various combinations (Broca's, Wernicke's) |
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Emotion/Affect |
Combination of psychological and physiological responses to a stimulus |
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Depression |
Inability to experience pleasure or be happy, disorder of mood/affect |
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Anxiety Disorder |
An inappropriate or excessive anticipatory manifestation of the fear response to a stressor |
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Schizophrenia |
A severe psychiatric disorder characterised by disorder of though, perception and mood |
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Learning |
Acquisition of knowledge |
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Memory |
Retention of knowledge |
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Declarative Memory |
Memory that you are consciously aware of, able to describe in words. This fades with time - not lost but becomes more difficult to retreive. May be semantic (facts) or episodic (with a time element). |
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Non-Declarative Memory |
Memory of skills, habits and behaviours - procedural memory of motor tasks. |
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Retrograde Amnesia |
Loss of events before the trauma |
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Ribot's Law |
In the case of retrograde amnesia, more recent memories are more likely to be lost than remote ones. |
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Anterograde Amnesia |
Inability to form new memories |
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Anaesthesia |
The abolition of sensation |
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Triad of General Anaesthesia |
Unconsciousness, analgesia, muscle relaxation |
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Lipid Theory |
Lipid solubility is an important factor in general anaesthesia. Concentration in cell membrane of 0.05mM gives analgesia. Lipid volume expanded by 0.4%. High pressure reverses. |
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Protein Theory |
Proteins are targets and lipid solubility is required for access to binding domains in hydrophobic pockets |
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Cut off Phenomenon |
Increased chain length of general anaesthetics increases lipid solubility but does not increase anaesthetic potency and this stops at C13 |
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Stereoselectivity |
Identical lipid solubility but potentially different anaesthetic potencies |
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Minimum Alveolar Concentration |
A measure of anaesthetic potency in man. The concentration of anaesthetic in the alveoli required to produce immobility in 50% of patients when exposed to a noxious stimulus. |
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Pain |
An unpleasant sensory and emotional experience with actual or potential tissue damage |
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Features in the Midbrain |
Superior colliculus, substantia nigra, red nucleua, oculomotor nucleus, inferior colliculus, trochlear nucleus, superior cerebellar peduncle, cerebral aqueduct runs through |
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Features in the Pons |
Superior cerebellar peduncle, corticospinal/corticobulbar/pontocerebellar fibres, trigeminal nerve leaves, 4th ventricle runs through |
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Features in the Medulla |
Inferior cerebellar peduncle, pyramids, NTS, dorsal motor nucleus of vagus, hypoglossal nucleus and nerve, inferior olivary nucleus, 4th ventrical rostrally, fasciculus cunteatus, fasciculis gracilis |
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On Ganglion/Bipolar Cells |
Depolarised in light, hyperpolarised in dark |
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Off Ganglion/Bipolar Cells |
Hyperpolarised in light, depolarised in dark |
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Direct Transmission Through Retina |
Photoreceptor --> bipolar cell --> ganglion cell |
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Indirect Transmission Through Retina |
Input from receptive field --> horizontal and amacrine cells --> bipolar and ganglion cells --> opposite electrical response to that in the centre --> contrast image borders |
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Ageusia |
Loss of sense of taste |
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Middle Ear Attenuation Reflex |
Contraction of tensor tympani and stapedius muscles in order to decrease movement of ossicles and therefore decrease middle ear conduction. |
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Characteristic Frequency |
The frequency at which a neurone responds to the smallest sound intensity |
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Tonotopy |
Special arrangement of structures that subserve various frequencies as in the auditory pathway Lower frequency - anterior cochlear nucleus Higher frequency - posterior cochlear nucleus |
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Phase Locking |
Responses can only occur with frequency equal to or higher than than at which a neurone can fire action potentials |
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Closed Angle Glaucoma |
When the iris adheres to the cornea blocking the reabsorption of aqueous humour. |
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Open Angle Glaucoma |
When reabsoprtion of aqueous humour is reduced due to sclerosis of small veins/ This results in smaller increasing pressure of a longer period of time |
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Treatment of Glaucoma |
Surgery to open the angle Beta blockers to decrease the production of aqueous humour PG analogues to increase blood drainage |
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Cortical Dysgenesis |
Poor formation of the cortex |
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Lissencephaly |
Smooth cortex, disorganised layers, fewer neurones resulting in significant functional impairment and decreased lifespan |
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Axon Guidance |
Axons extend and grow towards correct targets |
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Fasciculation |
Groups of axons grow together to form white matter tracts |
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Nystagmus |
Jerking eye movements - normal when at the very periphery, pathological when |
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Hypokinetic Motor Dysfunction |
e.g. Parkinsons |
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Hyperkinetic Motor Dysfunction |
e.g. Huntingtons, Hemiballism, Tardive Dyskinesia |
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Huntingtons |
Loss of striatal output neurones in the indirect basal ganglia pathway resulting in suppression of the substantia nigra so the direct pathway predominates. This means there is less output from the basal ganglia and therefore increased movement. |
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Huntingtons Inheritance |
Autosomal dominant CAG repeat Shows anticipation |
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Parkinsons |
Loss of dopamine in basal ganglia resulting in excessive inhibitions of the thalamocortical pathways and therefore less moevement. |
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Clouding of Consciousness |
Lack of attention, slow thinking, confusion, memory loss, drowsiness |
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Delirium |
Lack of attention, slow thinking, confusion, memory loss, drowsiness, disorientation, hallucination |
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Stupor |
Sleep-like state, rousable with vigorous stimulation |
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Hypersomnia |
Excessive drowsiness, intermittent waking |
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Decorticate |
Abnormal flexion of arms and extension of legs. Indicative of hemispheric dysfunction |
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Decerebrate |
Abnormal extension of arm and leg. Indicative of upper brainstem dysfunction |
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Flaccidity in coma |
Indicates pontine medullary damage |
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Signs of Cerebellar Dysfunction: DANISHP |
D - dydiadochokinesia A - ataxia N - nystagmus I - intention tremor S - slurred speech H - hypotonia P - past pointing |
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Dydiadochokinesia |
Inability to perform rapid alternating movements |
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Variability of Dependance |
Drug - degree of reward User - absorption/metabolism Environmental - peer pressure |
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Tolerance Mechanisms |
Innate - genetics Metabolic Behavioural Pharmacodynamics |
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Behavioural Tolerance |
Learn to behave normally even though under the influence |
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Pharmacodynamic Tolerance |
Cell biology changes so that more receptors need to be activated for the same effect |
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Mechanism of Action of Opiates |
Bind to GABAergic u opioid receptors in CNS --> dopamine release |
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Treatment for Opioid Overdose |
Naloxone - blocks opioid receptors |
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Treatment for Opioid Dependance |
Methadone - u receptor agonist with a longer half life, slower physical symptoms of withdrawal, don't get a good rush from heroin so less incentive Psychotherapy |
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Caffeine Withdrawal Syndrome |
Lethargy, irritability, headache |
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Mechanism of Action of Caffeine |
PDE inhibitor --> increased cAMP Adenosine receptor antagonist --> awake |
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Mechanism of Action of Cocaine |
Inhibits catecholamine uptake (dopamine, noradrenaline) --> reward |
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Mechanism of Action of Amphetamines |
Catecholamine release --> reward |
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Mechanism of Action of MDMA |
5-HT release --> reward |
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Post Traumatic Stress Disorder |
Triggered re-induction of a strongly emotional memory causes anxiety |
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Mechanism of Action of Benzodiazepines |
Aloosterically binds to GABAa receptor in prefrontal cortex --> increases GABA affinity -->increases Cl- influx --> hyperpolarisation --> less active neurones |
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Anxiolytic |
Reduces anxiety and aggression |
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Hypnotic |
Sleep inducing |
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Benzodiazepine Withdrawal Symptoms |
Increased anxiety, tremor, seizure, insomnia, depression |
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Mechanism of Action of Buspirone |
5-HT partial agonist |
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Monoamine Theory of Depression |
Depression is due to hypoactivity at monoaminergic (NAd and 5-HT) synapses in the brain. |
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Evidence for the Monoamine Theory of Depression |
Antidepressants increase the levels of monoamines in the brain within minutes |
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Evidence Against the Monoamine Theory of Depression |
Antidepressant take >1-3 weeks to work Amphetamine releases monoamines, cocaine blocks monoamine reuptake but neither are antidepressants |
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Unwanted Effects of MAOIs |
Cheese reaction due to unmetabolised tyramine in diet (cheese, red wine, yeast extracts, fermented soya bean) Antimuscarinic effects Alpha-1 antagonism |
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Mechanism of Action of Tricyclic Antidepressants |
Inhibit uptake of 5-HT and NAd |
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Unwanted Effects of TCAs |
Antimuscarinic effects Sedative (histamine receptor 1 antagonism) |
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Stages of Anaesthesia |
Analgesia Delirium/Induction Phase Surgical Anaesthesia Medullary Paralysis |
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Induction Phase |
Excitement, delirium, incoherent speech, loss of consciousness, unresponsive to non-painful stimuli, muscle rigidity, spasmodic movements, cardiac arrhythmias, vomiting, choking |
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Surgical Anaesthesia |
Unresponsive to painful stimuli, breathing regular, abolition of reflexes, muscle relaxation, synchronised EEG |
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Medullary Paralysis |
Pupillary dilation, respiration/circulation ceases, EEG wanes --> death
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Divergent Connections |
To generate an epileptic seizure, excitatory neurones must make divergent connections into a synaptic network |
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Effective Synapses |
To generate an epileptic seizure, synapses need to be strong enough to drive a post synaptic effect |
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Minimum Aggregate |
To generate an epileptic seizure, the population of neurones involved must be large enough so that they can connect to almost every other neurone in the population within a few synapses. |
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Focal/Partial Seizures |
Originate in a specific part of the brain, localised to one hemisphere. Last for 10 secs to 2-3 mins Features dependent on location |
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Jacksonian March |
Seizure starts in one are of the brain and progresses to other areas
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Generalised Seizures |
Seizures involving synchronicity in both hemispheres |
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Simple Partial Seizures |
No altered consciousness |
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Complex Partial Seizures |
Altered consciousness |
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Causes of Epilepsy in Infancy and Childhood |
Birth injury Inborn errors of metabolism Congenital malformation |
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Causes of Epilepsy in Childhood and Adolescence |
Idiopathic Geneic syndromes CNS infection |
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Causes of Epilepsy in Adolescence and Young Adults |
Head trauma/Traumatic brain injury |
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Causes of Epilepsy in Older Adults |
Stroke Brain Tumour |
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Positive Symptoms of Schizophrenia |
Delusions Hallucinations Disorganised speech Grossly disorganised or catatonic behaviour "inserted thoughts" - thought disorder |
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Negative Symptoms of Schizophrenia |
Reduced expression of emotion Social withdrawal Cognitive impairment |
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Typical Neuroleptics |
Phenothiazines (e.g. chlorpromazine, fluphenazine) Butyrophenones (e.g. haloperidol, droperidol) Thioxanthines (e.g. flupenthixol, clopenthixol) |
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Mechanism of Action of Typical Neuroleptics |
Block dopamine receptors (D1 and D2) -->antipsychotic effect MAChR H1 alpha NAdR 5-HT |
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Mechanism of Action of Atypical Neuroleptics |
Dopamine receptor antagonists (sulpiride, amisulpiride) Multiacting receptor targeted agents (clozapine, olanzapine) Serotonin-dopamine antagonists (risperidone, zotepine, sertindole) |
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Dopaminergic Side Effects of Antipsychotics |
Anti-emetic - reduces nausea dues to D2R and H1R block Increased prolactin release (due to blocked dopamine) --> breast swelling, pain, lactation Extrapyramidal motor symptoms (acute - dystonias, chronic - tardive dyskinesia) |
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Dystonia |
Involuntary movements (face, tongue, neck), parkinsonian tremor. Due to dopamine receptor blockade in striatum Rapidly develops Reversible |
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Non-Dopaminergic Side Effects of Antipsychotics |
Antimuscarinic effects - dry mouth, constipation, visual disturbances Postural hypotension due to adrenoceptor block Sedation due to H1R block |
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Aetiology of Schizophrenia |
Hereditary (50% chance in identical twins) Environmental (cannabis) ? Slow viral infection, autoimmune, poor maternal nutrition, developmental abnormality Genetic predisposition with environmental trigger Dopamine hyperactivity |
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Evidence for the Dopamine Hypothesis of Schizophrenia |
Amphetamine abuse - releases dopamine - toxic psychosis - paranoid delusions, hallucinations, compulsive behaviours D2R agonists (apomorphine, bromocriptine) Too much L-DOPA |
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Grandmother Cell Hypothesis |
Every memory is assigned to a single neurone |
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MND/ALS |
Limb/bulbar paralysis on onset but sensation is spared Damage to ventral horn cells |
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Broca's/Expressive Aphasia |
Non-fluent speech Normal comprehension Poor naming and repetition |
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Broca's Area |
Inferior frontal lobe, adjacent to motor cortex for cranial nerves to mouth and larynx |
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Literal Paraphasic Speech |
Incorrect sound e.g. 'ren' for 'pen' |
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Verbal Paraphasic Speech |
Incorrect word e.g. 'fork' for 'pen' |
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Wernicke's Aphasia |
Fluent speech empty of meaning Comprehension impaired Often unaware/unconcerned |
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Anomia |
Inability to produce a specific name |
