Lab 6 + 7 - Neurophysiology & Neuromuscular Physiology Flashcards
Dendrites
branch from cell body and receive input from other neurons
Cell Body
contains nucleus and endoplasmic reticulum
- important for making proteins involved in neurotransmission
Axon Hillock
beginning of an axon, initiates action potentials
- -55 mV is threshold
- voltage-gated sodium channels open at threshold
- action potential propagates down axon
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Axon
branch coming off the cell body, propagates action potential
Axon Terminals
release neurotransmitter on arrival of an action potential (pass information)
Excitatory Neurostrasmitters
- open ligand-gated channels to allow sodium in to depolarize neuron
- depolarization heads towards hillock through the grated potential
Action Potential Generation
- elicited at axon hillock and propagated along the axon
What if voltage-gated sodium channels were blocked?
- no propagation occuring
- toxin would block voltage gated sodium channels prevent propagation
Exocytosis
- voltage-gated calcium channels open in the button
- calcium triggers exocytosis of excitatory neurotransmitters
(1) a nerve impulse initiates voltage-gated calcium channels to open up
(2) calcium triggers exocytosis driving neurotransmitters into synaptic cleft
(3) if a neuron generates more action potentials over a short period of time there is an increase in calcium entry into axon terminal, and thus, more neurotransmitters are released
Spatial Summation
- multiple neurons working together so that a high enough frequency (number per second) of action potentials can be generated to get the postsynaptic neurons to threshold
Inhibitory Neurotransmitters
- many different types
- hyperpolarize (make more negative) neurons which make generating an action potential harder
- “inhibit” them
Epimysium
surrounds the whole muscle
Epi = outside
Perimysium
surrounds a fascicle
Peri = surrounding/around
Endomysium
surrounds a muscle fiber
Endo = within
Myofibirl
contractile organelle that runs the length of the myocyte
- made of repeating segments called sarcomeres
- coming off z-disc is thin filament actin
- coming off m-line is thick filament myosin
Sliding Filament
how myosin and actin interact
- calcium and ATP allow for interaction
- head will continue cycling, pulling actin towards m-line
- sarcomeres will shorten –> myofibrils will shorten –> muscel fibers will shorten –> muscle will shorten (contraction)
- crossbridging
- pul together to build cross bridge
- more cells = more crossbridging
Neuromuscular Junction
- exocytosis occurs in the axon terminal
- neurotransmitters go into synaptic cleft
- sarcolemma have ACh receptors
- End Plate potential: how much acetylcholine (ACh) is available
Motor Unit
- motor unit with more attachments has greater potential to generate more force
- work in conjunction “recruitment”
- overall greater force output
The Size Principle
smaller particles are recruited first, as time increases, bigger motor units get recruited
Electromyographic
recording electrical activity to identify muscle potential
EMG Data
Method:
Intermuscular: needle is used to stimulate muscle
- more invasive
- validity is increased
Surface: leads read muscle stimulation
Graph:
Raw: scribbled lines
Intergrated: easier to see trends, more meaningful
Maximal Volitional Contraction (MCV)
the maximal force-generating capacity of a muscle or group of muscles in humans
