Chapter 7 Review Flashcards
Factors that affect the magnitude of the resting membrane.
- Permeability of the cell membrane to ions
- Differences in ion concentrations between the intracellular and extracellular fluids
What is action potential
The all-or-none electrical event in the neuron or muscle cells where the polarity of the cell membrane is reversed and reestablished
Explain the structure of the CNS and PNS.
- CNS: consists of the brain and spinal cord
- PNS: consists of nerves and ganglia
Explain the functions of the CNS and PNS
- Sensory Nervous System:
– Somatic sensors: input consciously perceived from receptors (eyes, ears)
– Visceral sensors: input unconsciously perceived (heart)
-Motor Nervous System:
– Somatic motor: output consciously or voluntarily controlled (biceps)
– Autonomic motor: motor output that is involuntary (digestion)
Role of acetylcholine in neurotransmissions
Binds to receptors on the postsynaptic membrane and opens channels that allow sodium to enter
Role of the Golgi Tendon Organs (GTO)
- Serves as a “tension monitor” or as a protective muscle device. It prevents excessive force during muscle contraction.
- GTO sends a signal to the spinal cord which excites inhibitory neurons that prevent force production.
Explain Motor Unit Recruitment and the Size Principle
Motor unit recruitment is how the body activates more muscle fibers to produce more force. The process follows the size principle, which means the smaller units are used first (easier to activate), then the large ones.
What are the types of fibers in Motor Unit Recruiment
Type I: slow; small units that are endurance-focused muscle fibers
Type IIA: fast; medium-sized motor untits
Type IIX: fast, largest motor unit used for powerful but quickly fatigued muscle fibers
Define innervation ratio
The number of muscle fibers innervated by a single motor neuron
