The document summarizes key information from an anatomy and physiology weekly newsletter, including: 1. It describes the organization of the nervous system into the central and peripheral nervous systems. 2. It provides two articles summarizing nerve impulses and the synapse. 3. It lists the main cell types in the nervous system that help send out impulses to move the human body. 4. It describes a student lab that measured the speed of voluntary kicks versus reflexes using an EKG sensor. The students were able to answer questions about their findings.

1. ANATOMY &
PHYSIOLOGY
WEEKLY
Anatomy and
Physiology Weekly
Volume 1, Issue 1 (Informational Section) 10.17.2012
Inside this issue:
Organization of the Nervous System!! Written by— Agron
Organization of 1 The nervous system is a com- CNS to the rest of the body,
the Nervous plex system that is mainly divid- send motor information to ef-
System ed into two sections the Cen- fectors. Somatic motor volun-
tral Nervous System (CNS) tary nervous system: innervates
which is the brain and spinal skeletal muscle
cord and the Peripheral Nerv-
Nerve Impulses 1 Autonomic motor involun-
ous System (PNS) which con-
Part 1 tary nervous system innervates
sists of the cranial nerves (1). cardiac muscle, smooth muscle,
The nervous system glands .
can be broken down into other
Nerve Impulses 2 divisions and sub divisions. Sen-
Part 2 sory (afferent) division transmits
information from periphery to
CNS, contains receptors.
The Synapse 2
Somatic receives sensory
information from skin, fascia,
joints, skeletal, muscles, special Picture is ©
senses. Visceral receives senso- Get ready to learn all about
Cells of the 3
ry information from viscera. the nervous system in this
Nervous System Motor (efferent) division trans- new issue of Anatomy and
mits information from body Physiology Weekly!
Reflex Arc 4
Nerve Impulses Part 1 Written by—Kamiera
Membrane potential is acid chains snake back and potential exits only across the
when a neuron is adequately forth across the membrane.
stimulated , an electrical im- Some channels , leakage or no membrane. (2)
pulse is generated and conduct- leakage channels , are always
ed along the length of its axon. open. Channels include :
This is response , called the Chemically gate, Ligand-gated,
action potential or nerve im- Voltage-gated, and Mechani-
pulse , is always the same re- cally gated . (2)
gardless of the source or type
There is also Resting
of stimulus , and it underlies
Membrane Potential, which is
virtually all functional activities
The potential difference in a
of the nervous system. (2) resting neuron and the mem-
brane is said to be polarized.
The value of the resting mem-
Membrane channels brane potential varies from -
are large proteins , often with 40mV to -90mV in different
several subunits , whose amino types of neurons. The resting
1

2. Page 2 Anatomy and Physiology Weekly
Nerve Impulses Part 2 Written by —Colton
Membrane Potential: difference in electrical
charge across their plasma membranes. 3. As more Na+ enters the cell through
Resting Membrane Potential: the mem- voltage-gated Na+ channels, the membrane
brane potential maintained by a noncon- depolarized even further.
ducting neuron’s plasma membrane. 4. The magnitude of the action potential
Local Potential: A slight shift away from the peaks (at +30 mV) when voltage-gated Na+
RMP in a specific region of the plasma mem- channels close.
brane. 5. Repolarization begins when voltage-gated
© Action Potential: is, as the term suggests, K+ channels open, allowing outward diffu-
the membrane potential of an active neu- sion of K+.
rons, that is, one that is conducting an im-
6. After a brief period of Hyperpolarization,
pulse. An example of this is shown below. the resting potential is restored by the sodi-
1. A stimulus triggers stimulus-gated Na+ um-potassium pump and the return of ion
channels to open and allow inward Na+ channels to their resting state.
diffusion. This causes the membrane to de-
polarize.
2. As the threshold potential is reached,
voltage-gated Na+ channel open.
The Synapse Written by—Jasmine
Synapse: Functional membrane to mem- Neurotransmitters: chemicals that allow
brane contacts of a nerve cell with an- the transmission of signals from one
© other nerve cell, muscle cell, gland, cell neuron to the next across synapses.
or sensory receptor; functions in the They are found at the axon endings of
transmission of action potenitals from motor neurons, where they stimulate
one cell to another. the muscle fibers. They and their close
relatives are produced by some glands
“Summation is a Summation: Phenomena in which the
such as the pituitary and the adrenal
phenomena in
degree of changing in membrane poten-
tial directly correlates with stimulation glands . (1)
which… degree of
frequently.
changing membrane
potential directly
correlates with
stimulation”
2

3. Volume 1, Issue 1 (Informational Section) Page 3
Cells of the Nervous System Written by—Ashley B.
The nervous system is Non-neural cells are also within the central nerv-
a complex structure called glial cells. Neurons ous system, Ependymal
that is composed of receive stimuli and con- –found lining the canals
many different types of duct action potentials. of the spinal cord and “Help send out
cells. These all help Glial cells support and brain, Oligodendrocyte
send out impulses and protect neurons and – found around nerve impulses… in
the appropriate mes- perform other functions. fibers in the CNS, order for the
sages in order for the There are five kinds of Schwann – found
human body to move. glial cells; Astrocyte- around nerve fibers in human body to
found on the surfaces of the PNS, and Satellite –
The nervous system is move.”
neurons and blood ves- found around the neu-
made up of neurons
sels, Microglia – found ron cell body. (1)
and non-neural cells.
Bipolar neuron – two nerve
fibers
Unipolar neuron – one nerve
fiber
Multipolar neuron – multiple
nerve fibers
Neurons carry nerve impulses
from body parts to the brain
and spinal
cord
(Picture left
is a neuron
©)
Satelite ©
Ependymal ©
Oligodendrocyte (below)
Astrocyte ©
©
Microglia © Schwann © 3

4. Reflex Arc Lab
ANATOMY AND Some of our writers got the chance to go to a local high school and watched as
PHYSIOLOGY they did a lab on neuromuscular reflexes. They used an EKG sensor to compare
WEEKLY the speed of voluntary vs a reflex muscle action and to measure the speed of the
impulse. Here is the information that they collected!
Table 1
An special Kick 1 Kick 2 Kick 3 Kick 4 Kick 5 Average
collaboration with Time of 1.7 4.17 6.66 9.12 22.62 8.856
muscle
students from NISD contraction
(s)
Time of 1.29 3.77 6.39 8.82 22.11 8.476
stimulus (s)
Change of T 0.41 0.4 0.27 0.30 0.51 8. 666
(s)
How much do Table 2
Reflex 1 Reflex 2 Reflex 3 Reflex 4 Reflex 5 Average
you know about Time of 6.06 9.67 16.87 20.69 25.84 15.83
muscle con-
Reflexes? traction (s)
Time of 5.59 9.32 16.67 20.08 25.38 15.43
stimulus (s)
Change of T 0.47 0.35 0.20 0.61 0.46 15.63
(s)
Reflex without reinforcement Reflex with reinforcement
Table 3
Reflex re- Max (Mv) Min (mV) Change of Max (mV) Min (mV) Change of
sponse mV Mv
1 1.632 0.834 0.798 2.478 0.594 1.884
2 1.982 0.748 1.234 2.660 0.481 2.179
3 1.565 0.838 0.727 1.430 0.852 0.578
4 1.572 0.801 0.771 1.231 0.890 0.341
5 1.836 0.583 1.253 2.533 0.641 1.892
Average 1.718 0.761 0.957 2.066 0.691 1.375
After the lab was completed the students were able to answer some questions, here are
their answers! 1.) The contraction wasn’t as high in the voluntary activation as in the in-
voluntary activation because you were voluntarily contracting your muscle. 2.) 0.097 m/s
Put together is the speed at which the stimulus traveled in Agron’s leg. 3.) What could account for the
differences is the measurements of the person, having the electrodes not directly on the
by—Ashley B. nerves and the force of the hit from the hammer could differ. 4.) The speed of a nerve
impulse is a lot slower than the speed of electricity because it has many things to go
through within the body while electricity in a copper wire just goes straight from end to
end with no interruptions. 5.) The size of a person can effect the time it takes for the
nerve pulses to get to the brain.
4