Transcript Nerve cells (Neurons)

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.
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.
When the action potential reaches the end of the axon,
______________________________________________________.
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.
The CNS is constantly kept aware of muscle condition through
stimuli produced from sensory receptors located in the muscles,
_____________, _______________ and _______________.
Sensory (afferent) neurons
transfer messages to the
central nervous system
where they are analyzed
and responded to by motor
(efferent) neurons.
When 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: _______________________


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
__________________.
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 simplest spinal reflex.
It depends only on the
single connection
between ___________
___________ and ______
______________ of the
same ___________.
The reflex arc is
______________ and
______________.
It does not involve the
________ or any
__________________.
 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 _______________________.
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.
The performance capacity of muscles is determined by several ___________
and ______________ factors.
The trainable factors include:
 ______________________________
 ______________________________
 ______________________________
 ______________________________
 ______________________________
 ______________________________
 ______________________________
The non-trainable factors include:
 ______________________________
 ______________________________