Nerves & Reflexes!

1. Nerves & Reflexes!

2. Review From Yesterday… PNS: Somatic Nervous System • __________ or _________ nerves which transmit impulses from the periphery or environment to the spinal cord or brain. They carry impulses for the sensations. • __________ or _________ nerves which extend from the spinal column to muscle fibers. They transmit impulses from the brain or spinal column to the muscles or other structures that respond to stimuli.

3. Nerve cells (Neurons) A neuron is composed of a _____________, _____________ and an __________ The _____________ receives the neural impulse which are then carried to the cell body The _________ carries the nerve impulses on to the __________________ in the _________________ The axons of one nerve cell ___________ touch the dendrites of another neuron. There is a tiny gap between the nerve cells called a ______________. Messages must cross this gap if they are to move on.

4. When the action potential reaches the end of the axon, ______________________________________________________. Activity at the Synapse The impulse moves chemically across the gap between the _________ of one cell and the ___________ of another. The chemical then continues as an _____________________ along the next neuron until the next synapse. This electro-chemical process is ____________ until the message reaches its destination.

5. The CNS is constantly kept aware of muscle condition through stimuli produced from sensory receptors located in the muscles, _____________, _______________ and _______________. The Nerve Impulse Sensory (afferent) neurons transfer messages to the central nervous system where they are analyzed and responded to by motor (efferent) neurons.

6. A group of fibers activated by the same nerve is a ________________. • A muscle may be composed of a different number of motor units and each motor units may in turn consist of a different number of fibers. • All fibers of a specific motor unit always have the same ____________ (___ or ____ fibers) • Remember: _______________________ The Motor Unit When a motor unit contracts it will contract _________________ or __________________.

7. Reflex Time!

8. The Reflex Arc • The reflex arc represents the ___________ act that the nervous system can perform. • The reflex arc begins when a ___________ is detected in the ______________ at the end of a __________________.

9. The Five Parts of the Reflex Arc • The______________ receives the _____________________ • The ______________ carries the impulse to the ____________ or ____________ • The______________ interprets the signal and issues an _____________ • The ______________ carries the response message from the ______________ to the ___________ or __________ • The ______________ organ (i.e. ________________ ) carries out the response.

10. The Stretch Reflex The simplest spinal reflex. It depends only on the single connection between ___________ ___________ and ______ ______________ of the same ___________.

11. The Withdrawal Reflex When a body part touches something which stimulates the touch receptors it is immediately withdrawn. The reflex arc is ______________ and ______________. It does not involve the ________ or any __________________.

12. Any physical movement which requires considerable effort by the muscles or muscle groups is dependent on ____________ __________________________. • The ability to apply motor units simultaneously is known as ________________________. • The ________ the participation of muscles and muscle groups, the _________ the importance of inter-muscle coordination for _______________________. Muscle Coordination

13. Muscle Training To coordinate muscle movement and efficiency athletes must train ____________________________. While it is ___________ to have all of the motor units work ________________ , trained athletes (rowers, weightlifter, and shot putters) are able to activate up to _______ of their available muscle fibers simultaneously. (An untrained individual will activate about____ ) High level inter-muscle coordination greatly improves strength performance and enhances the flow, rhythm and precision of movement.

14. Muscle Training Continued… The performance capacity of muscles is determined by several ___________ and ______________ factors. The trainable factors include: • ______________________________ • ______________________________ • ______________________________ • ______________________________ • ______________________________ • ______________________________ • ______________________________ The non-trainable factors include: • ______________________________ • ______________________________