What is the difference between a large and a small motor unit?
A small motor unit is an arrangement where a single motor neuron supplies a small number of muscle fibers in a muscle. Small motor units permit very fine motor control of the muscle. A large motor unit is an arrangement where a single motor neuron supplies a large number of muscle fibers in a muscle.
What is a motor unit and what is its role in muscle contraction?
A motor unit is made up of a motor neuron and the skeletal muscle fibers innervated by that motor neuron’s axonal terminals. Groups of motor units often work together to coordinate the contractions of a single muscle; all of the motor units within a muscle are considered a motor pool.
What is a motor unit why motor units are important for skeletal muscle function?
Motor units, defined as a motoneuron and all of its associated muscle fibers, are the basic functional units of skeletal muscle. Their activity represents the final output of the central nervous system, and their role in motor control has been widely studied.
What is the all or nothing principle of muscle contraction?
The all-or-none law is a principle that states that the strength of a response of a nerve cell or muscle fiber is not dependent upon the strength of the stimulus. If a stimulus is above a certain threshold, a nerve or muscle fiber will fire.
What two things determine the strength of a muscle contraction?
Strength
- Physiological strength, which depends on factors such as muscle size, the cross-sectional area of the muscle and responses to training.
- Neurological strength, which looks at how weak or how strong the signal is that tells the muscle to contract.
What are the long term effects of the muscular system?
Long term effects of exercise on the body systems
| Long term effects of exercise | |
|---|---|
| Muscular system | Muscle hypertrophy; increased strength of tendons; increased strength of ligaments |
| Skeletal system | Increase in bone density |
| Fitness | Increase in strength; increase in flexibility; increase in speed; increase in muscular endurance |
How do you explain the force of a muscle contraction?
When a sarcomere contracts, myosin heads attach to actin to form cross-bridges. Then, the thin filaments slide over the thick filaments as the heads pull the actin. This results in sarcomere shortening, creating the tension of the muscle contraction.
What are the factors that affect muscle contraction?
The peak force and power output of a muscle depends upon numerous factors to include: (1) muscle and fiber size and length: (2) architecture, such as the angle and physical properties of the fiber-tendon attachment, and the fiber to muscle length ratio: (3) fiber type: (4) number of cross-bridges in parallel: (5) force …
What are the four factors that influence force of contraction?
Terms in this set (4)
- Recruitment. increasing the number of motor units activated (firing at one time) to increase force.
- Wave Summation. stimuli of motor unit with progressively higher frequencies in action potentials creating gradual increase in force.
- Tetanus.
- Muscle Length-Tension Relationship.