ANS VS PNS
Melanie Pacheco
Signey Mojica
Karina Benitez
Valeria Valdez
Nervous System
Peripheral
Nervous System
(PNS)
Somatic Nervous
System
Central Nervous
System (CNS)
Automatic
Nervous System
(ANS)
Sympathetic
Nervous System
Parasympathetic
Nervous System
CENTRAL NERVOUS SYSTEM
•
Organs divided into two major groups:

Brain and Spinal Cord
Responsible for sending and
receiving information
•
PERIPHERAL NERVOUS SYSTEM

Includes:
1) Cranial nerves that come from the Brain
2)Spinal Nerves that come from the Spinal cord

Subdivided into:
1)
2)
Somatic Nervous System
Autonomic Nervous System
SOMATIC NERVOUS SYSTEM

Voluntary Muscle Movements

Muscular movements and sensation

Contains two major types of Neurons:
1) Sensory Neurons(Afferent)
2) Motor Neurons(Efferent)

The neurons of SNS project from the CNS into
the muscles and sensory organs. It is a direct
path with synapses to connect nearby neurons.
AUTOMATIC NERVOUS SYSTEM
Controlled and part of PNS
 Involuntary Muscle Movements
 Regulates glands, cardiac, and smooth muscle by
returning them back to homeostasis; just like the
reflex arc


Divided Into:
1) Sympathetic Nervous System: “Fight or Flight”
2) Parasympathetic Nervous System: “Rest and Digest”
AUTONOMIC V.S SOMATIC
REFLEX ARC

Stimulus: a change in the environment

Response: react to the change in the environment

Receptors: cells specialized to react to a specific
stimulus
CONT.

Reflexes Help Maintain Homeostasis By
Controlling:
Heart Rate
 Breathing Rate
 Blood Pressure
 Digestion

SYMPATHETIC DIVISIONS
o
o
o
Location: thoratic and lumbar spinal cord
Helps the body when it is in need of energy,
under stress, and in emergency situation
Does this by:
increases blood pressure
o decrease digestion
o Increase heart beat
o
o
o
(fight or flight process)
Structure used:
o
o
o
o
Adrenal gland
Gray rami
Sympathetic trunks
Sympathetic chain ganglia
SYMPATHETIC GANGLIA CHAIN
Deliver information to
the body
 Located in the spinal
cord and extend
from the upper neck down
to the coccyx.

PREGANGLIONIC FIBERS


Nerve fibers that connect the central nervous
system to ganglia
Sympathetic preganglionic fibers tend to be
shorter than parasympathetic fibers and
sympathetic fibers tend to form more synapses
than parasympathetic fibers.
POSTGANGLIONIC FIBERS
In the autonomic nervous system, fibers from the
ganglion to the effector organ are called
postganglionic fibers.
 Postganglionic fibers in the sympathetic division are
adrenergic and use norepinephrine as a
neurotransmitter.
 Postganglionic fibers in the parasympathetic
division are cholinergic and use acetylcholine as a
neurotransmitter.

PARASYMPATHETIC DIVISION
Location: in sacral region of the spinal cord
 Allows the body to go back to the resting state
 Counterbalances sympathetic division
 Returns to homeostasis


Structures used:
Parathyroid gland
 Submandibular gland
 Sublingual gland

Neurotransmitters
 Receptors

REGULATION
Reflex centers receive sensory impulses from the
viscera, and use autonomic nervous pathways to
stimulate a motor response from the muscles or
gland.
 The hypothalamus helps regulate the body
temperature, hunger, and electrolyte pathways.
 The limbic system and cerebral cortex controls
the autonomic nervous system during emotional
stress.

TERMINATION
Acetyl Cholinesterase decomposes the
acetylcholine and the acetylcholine affects the
post synaptic membrane
 Then norepinephrine is released from cholinergic
fibers that go back to the presynaptic neurons.

Works Cited
"Central Nervous System and Peripheral Nervous System: MedlinePlus Medical Encyclopedia Image." U.S National Library of
Medicine. U.S. National Library of Medicine, n.d. Web. 17 Mar. 2014.
<http://www.nlm.nih.gov/medlineplus/ency/imagepages/8679.htm>.
"Example: Somatic Reflex Arc." Example: Somatic Reflex Arc. N.p., n.d. Web. 19 Mar. 2014.
<http://www.vetmed.vt.edu/education/curriculum/vm8054/Labs/Lab9/Examples/exsomarc.htm>.
"Grey and White Matter." Difference Between Grey and White Matter | Difference Between | Grey vs White Matter. N.p., n.d. Web. 17
Mar. 2014. <http://www.differencebetween.net/science/health/difference-between-grey-and-white-matter/>.
"Human Anatomy." Human Anatomy. N.p., n.d. Web. 19 Mar. 2014.
<http://ect.downstate.edu/courseware/haonline/labs/L21/150202.htm>.
"Nervous." Dictionary.com. Dictionary.com, n.d. Web. 19 Mar. 2014. <http://dictionary.reference.com/browse/nervous>.
"Neurology - Divisions of the Nervous System." YouTube. YouTube, 14 Oct. 2013. Web. 19 Mar. 2014.
<http://www.youtube.com/watch?v=zeo19WVQ47w&app=desktop>.
"Neuroscience For Kids." - Autonomic Nervous System. N.p., n.d. Web. 19 Mar. 2014.
<http://faculty.washington.edu/chudler/auto.html>.
"Organization of the Nervous System." The Peripheral Nervous System. N.p., n.d. Web. 19 Mar. 2014.
<http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/PNS.html>.
"Peripheral Nervous System Anatomy ." Peripheral Nervous System Anatomy. N.p., n.d. Web. 18 Mar. 2014.
<http://emedicine.medscape.com/article/1948687-overview>.
"Reflex Arc." Reflex Arc. N.p., n.d. Web. 19 Mar. 2014. <http://en.wikivet.net/Reflex_Arcs_-_Anatomy_%2526_Physiology>.