Nerve and muscle
The action potential, the neuromuscular junction and contraction of skeletal, cardiac and smooth muscle.
16 pages
Exam priority: high
- Impulse conduction and myelinMechanism · Myelin wraps the axon like insulation so the signal jumps from gap to gap; that makes it many…
- Skeletal muscle excitation–contraction couplingMechanism · The electrical signal dives into the muscle fiber through tiny tubes and makes an internal store…
- Sliding filaments and the cross-bridge cycleMechanism · Muscle shortens because tiny myosin heads grab actin, pull, let go and grab again, burning one…
- The nerve action potentialMechanism · A nerve signal is a brief, all-or-none flip of the voltage across the cell membrane, driven by…
- The neuromuscular junctionMechanism · Where a motor nerve meets a muscle fiber, it releases acetylcholine; each nerve impulse reliably…
Exam priority: medium
- Fast and slow fibers, energy and fatigueConcept · Slow red fibers run on oxygen and last for hours; fast white fibers are powerful but tire…
- Length–tension and force–velocity relationshipsConcept · A muscle is strongest at a middle length and when it moves slowly; stretched too much, squeezed…
- Motor units, recruitment and summationConcept · A muscle grades its force by switching on more nerve–fiber groups and by firing them faster…
- Recording membrane potentials, local potentials and repetitive firingMechanism · Small stimuli make small local voltage changes that fade with distance; only when they reach…
- Refractory periods and excitabilityConcept · Right after firing, a nerve cannot fire again for a moment
- Skeletal, cardiac and smooth muscle comparedTable to know · The body has three muscle types: skeletal for movement, cardiac for the heartbeat and smooth for…
- Smooth muscle contractionMechanism · Smooth muscle in vessels, airways and gut squeezes slowly and can hold tone for hours using very…
- Smooth muscle innervation and electrical activityMechanism · Smooth muscle is switched on by nerves that release transmitter from beads along the axon, by…
- Types of nerve fibersTable to know · Nerves carry fibers of different thickness: thick fast ones for movement and touch, thin slow…
For completeness
- Muscle hypertrophy, atrophy and remodelingConcept · Muscle grows with load and shrinks with disuse, illness or age, because it constantly builds and…
- Muscle mechanics: contraction types, work, efficiency and leversConcept · Muscles turn ATP into force and movement, wasting most of it as heat, and act on bones as levers…
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Educational physiology content; not a diagnostic or treatment guide and no substitute for a health professional's advice. Values are approximate references. No doses are given.
Representative model, for educational purposes only.