Nerves & Reflexes!

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.

Review From Yesterday…

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.

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.

When the action potential reaches the end of the axon, ______________________________________________________.

The Nerve Impulse

Sensory (afferent) neurons transfer messages to the central nervous system where they are analyzed and responded to by motor (efferent) neurons.

The CNS is constantly kept aware of muscle condition through stimuli produced from sensory receptors located in the muscles,

_____________, _______________ and _______________.

The Motor UnitWhen a motor unit contracts it will contract

_________________ or __________________. 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: _______________________

Reflex Time!

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 __________________.

The Five Parts of the Reflex Arc

1. The ______________ receives the _____________________

2. The ______________ carries the impulse to the ____________ or

____________

3. The ______________ interprets the signal and issues an _____________

4. The ______________ carries the response message from the ______________

to the ___________ or __________

5. The ______________ organ (i.e. ________________ ) carries out the response.

The Stretch Reflex

The simplest spinal reflex. It depends only on the

single connection between ___________

___________ and ______ ______________ of the

same ___________.

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

__________________.

Muscle Coordination 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 Training

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.

To coordinate muscle movement and efficiency athletes must train ____________________________.

The performance capacity of muscles is determined by several ___________ and

______________ factors.

The trainable factors include: ______________________________ ______________________________ ______________________________ ______________________________ ______________________________ ______________________________ ______________________________

The non-trainable factors include: ______________________________ ______________________________

Muscle Training Continued…