Flashcards
BMS153
Flashcards do conjunto (26)
- 1What is a reflex?Rapid involuntary stereotyped response to sensory stimulis. Inc. muscle contraction and glandular responses (eg lactation)
- 2Describe spinal reflexesNeed stim, quick (few synapses), involuntary, automatic (little higher input) & stereotyped(simple circuitry)
- 3Describe how the patellar reflex occursStim to knee -> Spinal nerve to ventral root ->direct synapse to motor -> Passes through dorsal root & dorsal root ganglion -> stims extensor muscle contraction
- 4Why does the patellar reflex occur?Thigh extensor muscle stretches, reflex corrects stretching - PROPRIOCEPTIVE system
- 5Describe the stretch reflexSensory fibre detects stretch and signals spinal cord -> Direct connection to motor neuron & AP contracts bicep -> At same time connection to inhibitory neuron inhibits m neurons in tricep so it relaxes (RECIPROCAL INHIBITION)
- 6What are muscle spindles?Proprioceptors (sense organs that monitor position and movement of body parts). Found in striated muscle esp ones involved in fine motor control
- 7Describe muscle spindle innervationInnervated by Ia sensory fibres which provide feedback on amount of muscle stretch occurring to alpha motor neurons innervating the surrounding muscles
- 8What are gamma motor neuronsTheir axons also innervate muscle spindles. Stim intrafusal (muscle) fibres to adjust spindle tension as extrafusal (muscle) fibres contract, so spindle is never slack
- 9Loss of proprioceptionIan Waterman- 1972 infection destroyed his proprioception. Has to monitor every action. Also lost kinesthesia (sense of body moving in space)
- 10Describe the Golgi Tendon OrganProprioceptor that detects muscle tension due to contraction.
GTO sensory (Ib) afferent activation activated inhibitory interneurons which inhibit alpha motor neurons of that muscle.
Prevents muscle contracting too much - 11Describe the flexor reflexFlexor muscles contract quickly to withdraw limb from injurious stimulus (eg. heat).
Results from activation of nociceptors. Postsynaptic reflec (multiple interneurons activate to sustain response --> PARALLEL AFTER DISCHARGE CIRCUIT) - 12Why do flexor reflexes often include contralateral elements?Because rapid withdrawal of a limb may lead to imbalance
- 13What is the role of inhibitory interneurons in the flexor reflex?Activate to relax extensor muscles (reciprocal inhibition)
- 14Describe the crossed extensor reflexPain in fight foot -> sensory activates excitatory and inhib. interneurons -> Ipsilat. m. neurons to flexor excite -> Ipsilat. flexor contracts -> Contralat. m. neurons to extensor excite -> Contralat. extensor contracts
- 15What effect does spinal cord severing have on activity alternation & what does this imply?Basic activity alternation continues, which implies local circuits generate patterns of alternating flexion and tension (central pattern generators)
- 16Nematode proprioceptionTRP4 loss leads to loopy swimming. DVA neuron detects body bending directly, repetitive spikes in swimming. DVA inhibits motor neurons
- 17Describe Meissner corpusclesLocation: Dermal papillae of skin (palm,eyelid/lips,tongue)
Modality: Light, touch, texture (movement)
Sensitive to 30-50 Hz
Adapt rapidly - 18Describe Pacinian CorpusclesLocation: dermis, joint capsules and viscera
Modality: Deep pressure, stretch, tickle, vibration
Sensitive to 250-350 Hz
Adapt rapidly - 19Describe Ruffini CorpusclesLocation: dermis, subcutaneous tissue, joint capsules
- 20Brain-->Spinal cordCranial/Rostral & caudal
- 21Top of arm/leg--->Bottom of arm/footProximal & Distal
- 22Head-->FeetSuperior, Inferior
- 23Front--> backAnterior/Ventral,Posterior/dorsal
- 24Middle of torso --> HandMedial,Lateral
- 25Same side of body/ Opposite side of bodyIpsilateral / contralateral
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