Lecture 16 - Movement and muscles Flashcards
what are bundles muscle fibres called? what are they surrounded by?
fascicles, perimysium
every action potential arriving at the neuromuscular synapse causes a contraction meaning it is a ….. ……. synapse
high fidelity
where does the action potential cause calcium to be released from ?
sarcoplasmic reticulum
what does calcium bind to when released from the sarcoplasmic reticulum?
troponin
during which period of a muscle contraction is there twitching as the neurotransmitter diffuses across the NMJ? how long is this period?
latent period, 5msec
what is kinaesthesia/proprioception?
awareness of position and state of our various body parts without vision
in fused tetanus, the rate of calcium release from the SR = the rate of what?
the rate of sequestering back causing constant contraction therefore
what are the 2 types of afferent fibres in muscle spindles? are the fibres extra or intrafusal?
1a and 2, intrafusal
what do muscle spindle fibres detect about muscles?
stretch
in muscle spindles what do group 1a afferents detect?
velocity of change of stretch
in muscle spindles what do group 2 afferents detect? what can’t they detect?
change in length of muscle (can’t detect relaxing)
what type of afferent fibres do golgi tendon organs have?
1b
what do 1a afferent fibres in golgi tendon organs detect?
sense force/tension in collagen fibres in tendons
which motoneurons do extrafusal fibres connect to?
alpha
which motoneurons do intrafusal fibres connect to?
gamma
cell bodies of motoneurons that innervate limb muscles are found in which layers within the spinal cord?
ventral layers
in a motor unit each neuron connects …… muscle fibres but each muscle fibre gets an input from …… neuron
multiple, one
in the recruitment of motor units the first unit recruited has to be …… than the 2nd one and so on. e.g first recruited is a type ….. muscle fibre and second is a type ….
smaller, 1, 2
name the 5 descending pathways
corticospinal, rubrospinal, reticulospinal, tectospinal, vestibulospinal
which 2 things does the corticospinal tract control?
voluntary movements and fine manipulative movements
what does the rubrospinal tract control?
the control of voluntary movements
what 4 things does the reticulospinal tract control?
posture, locomotion, voluntary movements, grasping
what does the tectospinal tract control?
head and neck movement
what does the vestibulospinal tract control? 2 things
posture and balance
name the 4 inputs to motoneurons
descending pathways, peripheral (Sensory), inputs from spinal interneurons, cutaneous
reciprocal inhibition in inputs from spinal interneurons is done by which group of fibres?
1a
the inhibitory tendon reflex is done by which group of nerve fibres?
1b
in cutaneous touch inputs to motoneurons which interneurons excite motoneurons?
d13
