Answer
Responsiveness
Responsiveness or excitability is the is the capacity of living cells to respond or react to stimuli. These stimuli include chemical, stretch, thermal, visual, gustatory, equilibrium stimuli, The cellular response is usually in the form of electrical changes across semipermeable cell membranes. Muscle cells, and nerve cells exhibit the highest levels of responsiveness.
Importance. This facilitates awareness of environments and enables generation of changes to maintain
dynamic homeostasis.
Conductivity. This is the ability of a cell to propagate an excitation( electrical change) that was initiated by an adequate stimulus. The excitation usually travels as a wave along the cell, and may lead to contraction or secretion.
Importance: Conductivity is necessary for propagation of a stimulus to coordinate contraction of
muscle cells, as in pulsing of heart chambers.
Contractility. When a muscle cell is stimulated adequately the usual response is to shorten or contract
(reduce longitudinal dimension). This usually causes movement because the pull, if adequate, brings origin and insertion closer together.
Importance: This is necessary for shortening muscles and causing movement through flexion or
extension. Breathing, circulation, speech , mastication, peristalsis, and elimination all depend on the
movements of skeletal and/or smooth muscles. l
Work Step by Step
Extensibility: This is the property of muscle cells that enables them to be stretched. Other cells, if stretched significantly, rupture or are deformed. Muscle cells can usually be safely extended several fold their contracted lengths.
Importance. Facilitates contraction of muscles. Muscles may lose their extensibility and become
permanently contracted or spastic. Spastic muscles cannot cause movement.
Elasticity. When a muscle cell is stretched and the stress is released, the muscle cell recols, or returns to a
shorter length. This exemplifies the quality of elasticity.
Importance: Elasticity enables a muscle to recover its resting
compactness.
