Neurophysiology* Flashcards

Question

Human cortex - area 4 role and function? area 6 role, function and split into with their functions? area 5 and 7 function and inputs? prefrontal and parietal cortex role and relation to area 6?

Answer 1

Area 4: - innervate specific contralateral muscles - primary motor cortex Area 6: - drive complex movements on either side of body - premotor area (PMA) and supplementary motor area (SMA) - SMA innervates distal motor units - PMA innervate proximal motor units via reticulospinal Area 5/7: post parietal cortex - form mental image of body in space formed from somatosen, proprio and visual inputs P and P: - decisions are taken about what actions to take - axons converge to area 6 and encode the actions which is converted to how it'll be carried out - axons from area 6 go to area 4 for the action to be performed

Answer 2

Loop: - information loop cycles from cortex through thalamus basal ganglia back to SMA Area 6: - input comes from ventral lateral nuc in dorsal thalamus called the VLo (from the basal ganglia) Anatomy: - putamen - substantia nigra - subthalamus - globus pallidus - VLo - SMA Process: - cortex to putamen (excite) - putamen to globus (inhib) - globus to VLo (inhib) - VLo to SMA (excite) - positive feedback loop ('Go' signal for voluntary movement) PMC: - by pyramidal neurons - inputs from thalamus - burst of activity before and after to encode force and direction - precision encoded by population of neurons - larger population input creates finer control

Answer 3

Lesions: - ataxia Form: - corticopontocerebellar projection Connections: - connect cortex, pontine nuc and cerebellum - back to cortex via ventrolateral thalamus Function: - instruct direction, timing and force of movements Lateral: - move through basal ganglia and VLo via involve of feedback loop via pons, cerebellum, thalamus back to cortex

Answer 4

``` Sensory - dorsal root ganglion Motor: - in CNS Autonomic - pre (in CNS) and post (in ganglion) ganglion ```

Answer 5

``` Function: - smell Pathway: - recep in olfactory epith of nasal cavity, olfactory nerve passes through the cribriform plate of ethmoud and enter olfactory bulb in ant cranial fossa Fractured: - loss of smell tearing nerve ```

Answer 6

``` Function: - vision Pathway: - enters optic canal, nerves join forming optic chains, fibres cross to form the optic tract Increased: - causes papilloedema R optic nerve: - blindness of R eye Optic chaisma: - loss of peripheral vision (bitemporal hemianopsia) Optic tract: - causes blindness in left temp and right nasal fields (left homonymous hemianopsia) ```

Answer 7

``` Functions: - somatic via extraocular muscles (sup, medial, inf erectus and inf oblique) and eyelid (levator palpebrae superioris) - autonomic motor - parasymph to pupil causing constriction to ciliary muscles Pathway: - merges from midbrain and exits via SOF Drooping: - ptosis Eyeball movement: - abducted and pointing down - no pupillary reflex - no accomodation of lens ```

Answer 8

Function: - somatic motor of extraocular (superior oblique moves eye down) Pathway: - emerges form the dorsal surface of mid brain and exits via SOF Diplopia: when looking down - double vision

Answer 9

Function: - somatic extraocular; lateral erectus abducts eye) Pathway: - emerges between pins and medullary exits via SOF Diplopia: medial deviation - double vision

Answer 10

Pathway: - emerges from the pins, travels via the trigeminal ganglion and exits via SOF Innervates: - cornea, forehead, scalp, eyelids, nose and mucosa of nasal cavities and sinuses

Answer 11

Pathway: - emerges from the pins, travels via the trigeminal ganglion and exits via the foramen rotundum Innervation: - face over maxilla, maxillafybteeth, TMJ, mucosa of nose, maxillary sinuses and palate

Answer 12

Pathway: - emerges from the pond, travels via the trigeminal ganglion and exits via the foramen ovale Innervates: - sensory; face over mandible, mandibular teeth, TMJ, mucosa kd mouth and ant 2/3 of tongue - motor; mastication, tensor veli palatini and tensor tympani Damage: - paralysis of masticatory muscles - loss of corneal or sneezing refelx - loss sensation to face - trigeminal neuralgia

Answer 13

Fucntions: - somatic; muscles of facial expression, scalp, stapedius - autonomic; submand and sublingual glands, lacrimal, nose and palate glands - special; taste from ant 2/3 of tongue and soft palate - general; EAM Bell's palsy: - can't frown, clear eyelids or bare teeth Pathway: - emerges from between pons and medulla and exits via IAM, dividing into vestibule and cochlear nerves

Answer 14

Innervation: - special; vestibular sensation from semicircular ducts, cuticle, saccule fibes sense of position and movement - general; hearing from spinal organ Pathway: - emerges from between pons and medulla and exits via IAM, dividing into vestibule and cochlear nerves Ringing: tinnitus Deafness: conductive or sensorineural Loss of balance: vertigo Nystagmus: involuntary rapid eye movements

Answer 15

Innervations: - special; taste from post 3rd of tongue - general; sensations from middle ear and post oral cavity - visceral; sensation from carotid body and sinus (Pa) - autonomic; parasymph of parotid - somatic; to stylopharyngeus helps with swallowing Pathway: - emerges from medulla and exits via jugular foramen Loss of: - assoc with injuries to X and IX (jugular foramen syndrome

Answer 16

Innervations: - special; taste from epiglottis and palate - general; sensation from auricle and EAM - visceral; pharynx, larynx, trachea, bronchi, heart, oesophagus, stomach and intestine - autonomic motor; para innervation of muscles in bronchi, gut and heart - somatic; pharynx, larynx, palate and oesophagus Pathway: - emerges from medulla and exits via jugular foramen Pharyngeal: - difficult in swallowing Laryngeal: - difficult in speaking

Answer 17

Innervates: - somatic motor; striated muscle of soft palate, pharynx and larynx also SCM and trapezius Pathway: - medulla and large spinal roots exit via jugular foramen Loss of function: - weakness in head turning and shrugging shoulder

Answer 18

Innervates: - somatic motor to muscles of tongue Pathway: - from the medulla and exits via the hypoglossal canal Tongue: - atrophy of ipsilateral half of tongue, tip deviates towards affected side

Answer 19

Tissue damage - nociceptive pain Inflammatory pain - inflammatory mediators Nerve injury - neuropathic pain Dysfunctional pain has an unknown stimuli (lower back pain)

Answer 20

Stimulus detected by sensory nerve endings and AP is propagated Passes to the dorsal root ganglion and passes into the SC via synaptic transmission Processing and plasticity in the spinal dorsal horn Trvalss up the SC vis the spinothalamic and spinoparacbtachial tract into the limbic, thalamus and cortex

Answer 21

``` Adelta: thermal and mechanical pain - small - thin - 5-15ms - high and low - rapid sharp and localised pain - initial pain C fibres: mechanical, thermal and chemical - smallest - unmyelinated - <2ms - high - low, diffuse and dull pain - delayed pain ```

Answer 22

From NGF - adelta produce CGRP and sub P From GDNF - c fibres non-peptergic Enter different pain of the brain

Answer 23

Starts at the trigeminal ganglion entering the pons Drops into the medulla where the spinal nucleus of V is present Rises through the pons and medulla to the ventroposteromedial nuc of trigeminal to the primary sensory area

Answer 24

Allodynia: - increased response to normally non-painful stimuli Hyperalgesia: - exaggerated response to normally painful stimuli

Answer 25

Peripheral in the skin and muscles | Central is in the dorsal horn

Answer 26

``` Receptors: in response to stimuli - ligands-gated chs - GPCR (PGE2 and bradykinin) - tyrosine kinase receptor New receptors: - volt-gated chs And so the area becomes super-excitable due to upregulatuon (Receptor and channel sensitisation with gene expression) ```

Answer 27

Def: - increase in the excitabiltuy of neurons within the central nervous system so that normal inputs begin to produce abnormal responses 2 phases: - immediate but relatively transient phase - slower onset but longer-lasting phase Expression: - presynaptic release of glutamate, sub P and CGRP - greater receptor expression such as NMDA - lower threshold and opening chs therefore increasing excitabiltiy

Answer 28

Source: - pain can originate from the maxillary sinus due to their close proximity Vice: - previous treatment can also cause maxillary sinus pain Mexh: - nerve damage or long-term sensitisation

Answer 29

C fibres activated synapsing and sending pain stimuli to the brain Abeta can also be stimulated such as rubbing which activates the inhibitory internecine which inhibits the C fibres post synaptic connection and so inhibiting the pain stimuli to the brain

Answer 30

Rubbing activates Abeta which activates inhibitory interventions that inhibit 2nd order dorsal horn neurons inhibiting pain signalling

Answer 31

Electrim stim of periaqueductal grey reduces pain severity Morphine produces the same reaction Naloxone administration inhibits both 1 and 2 Mechanism: - morphine binds to opioid receptors - release of endorphins/enkephalins - naloxone blocks opioid receptors

Answer 32

Pain: - causes pain from sensory 1st order neurons - passes into dorsal horn and synapses to another neurons to the thalamus PAG - stimulated to activate an opiate interneurone which inhibits the signalling of the 1st order sensory neurons Opiate: - block NuT reelase from 1st order afferent pre-synapic - inhibit 2and order afferent post synaptic

Answer 33

``` Centre: emotion/stress/arousal - cortex - hypothalamus - thalamus Can either activate or inhibit PAG ```

Answer 34

``` Examples - aspirin - paracetamol - ibuprofen Mechanism: - action to inhibit COX to stop the conversion of arachidonic acid to prostaglandins Low: - due to bradykinin which increases the synthesis of prostaglandins ```

Answer 35

``` Defintion: - awareness of position of body parts in relation to each other and surroundings Type: - muscle spindles - golgi tendon organs - joint receptors Trigeminal: - muscles of mastication (spindles) - PDLMs - TMJ receptor ```

Answer 36

``` Extrafusal: - bulk of fibre and contractile - supplies by a-motor neurons Intrafusal: - spindle, specialised within a CT capsule ```

Answer 37

``` Information about muscle length Act to maintain muscle length Load compensation Example: - glass filling - bicep spindle stretch - increased motor neuron drive to bicep - muscle length maintained ```

Answer 38

``` Cell body: - trigeninal mesencephalic nuc Afferent: - V motor nic - cerebellum and cerebral cortex ```

Answer 39

Cause contraction of intrafusal Maintain tension in spindle and afferent activity Alpha and gamma co-activation

Answer 40

Found: - in tendons in series with muscle fibres - role in inhibitory reflex prevention of CS stretch of muscles

Answer 41

Pacinian - ligaments- acceleration Golgi - ligament- position Ruffini - capsule - movement

Answer 42

End portions are contractile - head innervated by afferent II (activated by stretch, detects fibre length) - tail innervated by gamma efferent - middle is the non-contractile central portion which can be stretched and is innervates by Ia (afferent - detects length of fibre and speed of change)

Answer 43

``` Receptor to afferent neurons Synapses in SC To an efferent neurons and effector Latency: - time relayed to speed and distance - delay at synapse (0.2ms) ```

Answer 44

Vertical: - move mandible relative to maxilla in vertical plane - jaw jerk (opening and unloading) Horizontal: - move mandible relative to maxilla in protrusive, recursive or lateral direction

Answer 45

``` Reflex: - phasic stretch Stimuli: - sudden jaw opening Response: - activation of jaw closing muscle Monosynaptic: - jaw closing muscle spindles - jaw closing motorneurones Clinical stimulus: - chin tap Receptor: - muscle spindle Synapse: - 1 in V motor nuc Effect: - contraction of masseter muscle Latency: - 8ms Role: - phasic: load compensation during chewing and stabilise jaw during vigour head movement - tonic: resist gravity and maintain posture ```

Answer 46

Resting with teeth apart Maintained: - minimal muscle activity or governed by muscle elasticity Remains reproducible throughout life in dentate and edentulous subjects Important reference for position and height for dentures

Answer 47

``` Active - stretch reflex Passive - tissue elasticity Relevance: - altered jaw relationships - vertical jaw relationship ```

Answer 48

``` Stimuli: - mech or noxious stimuli in mouth - noxious around mouth or elsewhere in body Responses: - act of jaw opening (sub-primates only) - inact of jaw closing Pathway: - trisynaptic or polysnaptic - mechanoreceptive or nociceptors - interneurones - jaw closing and opening motorneurones ```

Answer 49

Nociceptors and mechanoreceptors recieve stimulus Passes to trigeminal ganglion Both interaction with supratrigeninal nuc Reticular formation Act inhibitory on V motor nic Causing muscle

Answer 50

Protective: - restrain buildup of forces between teeth during mastication - prevent overloading of periodontium, muscle and TMJ Facilitate jaw opening to expel noxious material and minimise damage to lips

Answer 51

``` Stimulus: - sudden jaw closure following hard biting Response: - inact of jaw closing muscles - activation of jaw opening muscles Pathway: - jaw closing muscle spindles - interneurons - jaw muscle motor neurons ```

Answer 52

Pathway: - jaw closing muscle activates and synapses with V mesencepahlic nuc act V motor nuc - activates jaw opening muscles During laoding: - jaw opening muscle is not stimulated Loading removed: - jaw closing muscle doesn't stimulate the reflex Fucntion: - protection of antagonist teeth against each other

Answer 53

Reflex horizontal movements of jaws in response to mechanical stimuli Roles in canine guidance

Answer 54

Pain: - common reason for people to seek dental treatment - prevents people from obtaining optimal dental care - big impact on life Innervation: - sensory innervation to the face and mucous mem - motor innervation to muscles of mastication Branches: - ophthalmic, maxillary and mandibular

Answer 55

Primary afferent neurons to 1st synapse | 1st synapse to thalamus then to the cerebral cortex

Answer 56

``` Tracer: - HRP and fluorescent dyes Electrophysiological: - exciting the nuc from peripheral stimuli Neurological: - happens if nuc destroyed by disease ```

Answer 57

Trigeminal primary afferent neurons synapses with the trigeminal sensory nuc (trigeminal ganglion present) From the nuc to the thalamus via the trigeminothalamic tract (synapses with the thalamus) Thalamus to the somatosensory cortex

Answer 58

Found: - brainstem Primary afferents: - V1, V2 and V3 (large myelinated afferents) Second order neurons: - cross the midline to join VTTT and terminate in VPM of thalamus - don't corss midline and joint DTTT and terminate in VPM of thalamus Function: - processing discriminative tactile and proprioceptive sensation

Answer 59

``` First: - axons from face in trigeminal ganglion Second: - pontine trigeminal nuc Trigeminal lemniscus Third: - ventral post thalamic nuc Neuron reaches the sensory cortex ```

Answer 60

``` Subdivisions: - V nuc oralis - V nuc interpolaris - V nuc caudalis Extension: - both nuc and tract extend caudally to about the third cervical segment of the SC ```

Answer 61

Located: - most caudal part, extending from SC to obex Primary afferent: - small, turn caudally and join spinal trigeminal tract (V1, V2 and V3) Second order neurons: - cross midline to joint TTT and terminate in VPM of thalamus Function: - processing pain and temp from the face, mouth and nose

Answer 62

For knowledge

Answer 63

``` First: - axon from face in the trigeminal ganglion to the second Second: - within the spinal trigeminal nuc Spinal lemniscus Third: - in ventral post thalamic nuc Leading to the sensory cortex ```

Answer 64

Primary afferent: - small, turn caudally and join STT (V1, V2 and V3) Second order neurons: - some to contralateral VPM and some to cerebellum Functions: - tactical information - pain and temp from the teeth and intraoral structures - reflexes (corneal)

Answer 65

``` Ophthalmic: - spinal tract fibres most ventral Mandibular: - spinal tract fibres most dorsal Maxillary: - spinal tract fibres in between Pain-temp: - area near centre of face more rostral - area towards the back of head more caudal ```

Answer 66

``` Located: - most rostral part Cell bodies: - jaw muscle spindles afferents - some mechanoreceptive afferents from PDL Primary afferents: - cell bodies within CNS - parent axon in V motor root (V3) Synapse: - in V motor nuc Second order neurons: - V motor neurons Function: - reflexes - nonconscious proprioception ```

Answer 67

``` Main sensory: - sensation of touch - conscious proprioceptive sensation - reflexes Nuc oralis: - tactile touch - sensation of pain - reflexes Nuc interpolaris: - reflexes Nuc caudalis: - sensations of hot, cold and pain ```

Answer 68

``` Located: - medial to MSN in pons Inputs: - Vms - motor cortex - hypothalamus Afferents: - exit via mtor root to mandibular division - supply muscles of mastication Damage: - ipsilateral muscle atrophy ```

Answer 69

``` Transport: - food from lips to cheek teeth Mastication Transport: - food from cheek teeth to back of tongue Swallowing ```

Answer 70

Functions: - breakdown food - stim salivary flow - contribute to taste and smell by releasing chemicals - growth and maintenance of oro-facial tissues Health: - poor dentition = poor mastication - poor mastication can lead to gut disorders - poor diet = poor dentition

Answer 71

Time: - 0.5-1.2 sec Phases: - opening - closing (fast - crushing) (slow - grinding) - intercuspal (tooth to tooth) Full cycle: - opening + closing + power stroke During opening: - working side head: rotates and moves slightly (Bennett Movement) - balancing side head: moves downwards, forwards and medially During closing: - working side head: moves medially (back to normal position in glenoid fossa), rotates back to normal orientation - balancing side head: moves upwards, backwards and laterally (back to normal position in glenoid fossa)

Answer 72

``` Working side: functional - to which mandible moves - where food is located Balancing side: non-functional - from which mandible moves ```

Answer 73

Food consistency: - tough or brittle Quality and quantity of tooth contact: - tall cusps and deep fossae (vertical chewing stroke) - flattened or worn teeth (broader chewing stroke) Presence or absence of pain: - TMJ pain (shorter, slower and irregular pathway) Sequence: - opening; mylohyoid, digastric and lateral pterygoid - closing; lateral pterygoid, temporalis, masseter and medial pterygoid

Answer 74

Definition: - the ability to breakdown food morsels into small particles - number of chewing strokes required to prepare a mouthful for swallowing - correlated with total occlusal contact area

Answer 75

``` Voluntary: - result of deliberate effort of will Reflex: - given sensory input evokes a stereotypes motor response Cyclical: - N/A ```

Answer 76

Peripheral influences act jaw and tongue reflexes that act masticatory muscle motor neurons which activate mastication Peripheral influences can also act the central neural pattern generator of the brainstem or high centres that act mastication downstream

Neurophysiology* Flashcards

(100 cards)