The Nervous System
By: Ben Redenti
Matt Brandt
Zach Tabak
Frankie Scarano
May 14th 2013
Anatomy L3 B4
What is the Nervous System?
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System body that coordinates the voluntary and
involuntary actions of the animal and transmits signals
between different parts of its body.
The nervous system is divided into two major
categories the Central Nervous System (CNS) and the
Peripheral Nervous System (PNS).
The CNS includes the brain and spinal cord. (Located
along the vertical midline of the body)
The PNS is comprised of all the nerves that lie outside
of, or peripheral to the CNS.
Brain
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An organ of soft nervous tissue contained in
the skull of vertebrates, functioning as the
coordinating center of sensation and
intellect.
All neurons, however, relay information to
each other through a complex
electrochemical process, making
connections that affect the way we think,
learn, move, and behave.
Intelligence, learning, and memory.
http://kidshealth.org/parent/interactive/brain_it.html
The Central Nervous System (CNS)
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The brain is the control center of the body.
It consists of three main components:
o the forebrain
o the brainstem
o the hindbrain
Forebrain: responsible for a variety of functions
including receiving and processing sensory information,
thinking, perceiving, producing and understanding
language, and controlling motor function. The forebrain
contains structures such as the thalamus and
hypothalamus It also contains the largest part of the
brain, the cerebrum.
CNS (cont.)
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Midbrain: the portion of the brain stem that connects
the hindbrain and the forebrain
o The midbrain and the hindbrain together make up the
brainstem.
Hindbrain: extends from the spinal cord and contains
structures such as the pons and cerebellum. The
hindbrain also contains the medulla oblongata
The Senses
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None of your senses would be useful without the
processing that occurs in the brain.
Sight: Sight probably tells us more about the world than
any other sense. Light entering the eye forms an upsidedown image on the retina. The retina transforms the
light into nerve signals for the brain. The brain then
turns the image right-side up and tells us what we are
seeing.
Hearing: Every sound we hear is the result of sound
waves entering our ears and causing our eardrums to
vibrate. These vibrations are then transferred along the
tiny bones of the middle ear and converted into nerve
signals.
The Senses (cont.)
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Taste: The tongue contains taste buds that react to
chemicals in foods. Taste buds react to sweet, sour,
salty, and bitter. Messages are sent from the taste buds
to the areas in the cortex responsible for processing
taste.
Smell: Olfactory cells in the mucous membranes lining
each nostril react to chemicals we breathe in and send
messages along specific nerves to the brain— which,
according to experts, can distinguish between more than
10,000 different smells.
The Senses (cont.)
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Touch: The skin contains more than 4 million sensory
receptors, mostly concentrated in the fingers, tongue,
and lips, that gather information related to touch,
pressure, temperature, and pain and send it to the brain
for processing and reaction.
Contrary to what many people think, humans do not have
only five senses. We humans have over a dozen senses
including sense of hunger, thirst, fullness, and pain.
Peripheral Nervous System (PNS)
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The main function of the PNS is to connect the central
nervous system (CNS) to the limbs and organs.
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The PNS is not protected by the bone of spine and
skull, or by the blood–brain barrier, leaving it exposed to
toxins and mechanical injuries.
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Divided into two smaller systems:
o Somatic System: Control system, functions below
the level of consciousness
o Autonomic System: Voluntary control of body
movements
Somatic System
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Controls all voluntary muscle systems in the
body. (exception reflex arc)
Sending nerve signals through a basic route:
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Motor neurons
Corticospinal tract via axons
Stimuli conveyed from motor neurons to spinal cord through ventral horn.
Received by sensory receptors of motor neurons of the brain stem.
Act. released from axon terminal which relays stimuli
Act. released from the axon terminal knobs of motor neurons and received by
postsynaptic receptors
This relays stimuli to contract muscle fibers.
Somatic (cnt.)
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There are forty three segments of nerves in our body and with each
segment there is a pair of sensory and motor nerves. In the body, thirty
one segments of nerves are in the spinal cord and twelve are in the brain
stem.
3 parts of Somatic System:
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b.
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Spinal Nerves: They are peripheral nerves that carry sensory information into the spinal
cord and motor commands.
Cranial Nerves: They are the nerve fibers which carry information into and out of the brain
stem. They include smell, vision, eye, eye muscles, mouth, vision,. Taste, ear, neck,
shoulders and tongue.
Association Nerves: These nerves integrate sensory input and motor output numbering
thousands.
Autonomic System
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Located in medulla oblongata (lower brainstem).
Controls all visceral functions:
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Heart Rate
Digestion
Respiratory Rate
Perspiration
Sexual Arousal
Most are involuntary functions, though some may be acted upon
through some level of consciousness. An example would be sexual
arousal as voluntary, and digestion as involuntary.
Again split into two systems:
 Sympathetic System
 Parasympathetic System
Sympathetic vs. Parasympathetic
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Sympathetic:
o Responsible for up- and down-regulating many homeostatic
mechanisms in living organisms.
o Most notably for the sympatho-adrenal response of the body, or the
fight-or-flight response.
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Parasympathetic:
o Generally works to promote maintenance of the body at rest.
o It occurs unconsciously and is responsible for the regulation of the
internal organs and glands.
Neurotransmitters
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Biochemicals that carry out synaptic transmission
Synaptic Transmission: messages being transferred
across synaptic clefts (gaps between neurons)
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There are about 50 known types of neurotransmitters
Types of Neurotransmitters
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Acetylcholine
Monoamines
Amino Acids
Neuropeptides
Acetylcholine (ACh)
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Stimulates muscle contraction
Diffuses across synaptic cleft
Binds to specific protein molecules in the
muscle fiber
This begins a chain reaction that contracts
the muscle, as long as ACh is released
Monoamines
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Formed from modified amino acids
Thought to trigger emotional feelings
Dopamine: Creates a sense of pleasure
Serotonin: Causes sleepiness; inhibitory
Amino Acids
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The "building blocks" of proteins
Glutamic Acid: aids in learning and
memorization
Gamma-aminobutyric Acid (GABA): relieves
anxiety
Neuropeptides
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Short chains of amino acids
Substance P: pain perception
Endorphins: reduces pain; antagonist of SP
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In a healthy nervous system, there is an
endless cycle of neurotransmitters
o Some neurotransmitters are decomposed
and rebuilt (Acetylcholine)
o Others are transported back to the
synaptic knob that released them or into
nearby neurons
Nervous System Diseases
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Alzheimer's Disease
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Cerebral Palsy
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Multiple Sclerosis
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Parkinson's Disease
Alzheimer's Disease:
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Most common form of dementia, accounting
for 50-80% of all cases
Greatest risk factor is increasing age; 95%
of sufferers are 65 y/o +
Caused from massive degeneration of
neurons and disruption of neurotransmission
Symptoms: Progressive loss of memory and
thinking ability, mood swings, personality
changes, etc.
Cholinesterase inhibitors & Memantine are
the only two drugs approved to help in the
Cerebral Palsy
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Disorder of muscle movement, tone, and
posture
Caused from abnormalities prior to, during,
or up to two years after birth
Symptoms: Spastic paralysis, fixed
abnormalities of limbs, deficiencies in
posture, balance, intelligence, and speech,
etc.
Treatments include a variety of specialists
to help the sufferer adapt to life with CP
Multiple Sclerosis
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Autoimmune disease (Body attacks itself)
Can affect people of any age; Most common symptoms
reported ages 20-40; Women are twice as likely to be
affected by MS
Immune system attacks the neurons, gradually
disintegrating or causes swelling of the myelin sheath
around the axons -> Inhibits/slows neurotransmission
within body
Symptoms: Poor balance, vision, motor skills. Inability
to control muscle movements, loss of strength,
fatigue, etc.
Immunosuppressive and Anti-inflammatory drugs can
help with treatment
Multiple Sclerosis (cont.)
Parkinson's Disease
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Progressive disorder that affects movement
Developed ages 50-65; Men are 1.5 times more likely
to be affected; Genetic predisposition makes
developing Parkinson's twice as likely
Neurons in the substantia nigra become impaired or
damaged -> cannot produce dopamine (neurochemical
associated with movement) -> neurotransmission
becomes harder between muscle and brain
Early Symptoms: Slight tremor in one hand, little or no
facial expressions, slight limp, etc.
Progressive Symptoms: Slower movements, loss of fine
motor control, tremors in one/both hands,
slurred/impaired speech, stiffness in muscles
Parkinson's Disease (cont.)
Drug Treatments: Levodopa, MOA-B Inhibitors
Work Cited
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Shier, D., Butler, J., & Lewis, R. (2009). Hole's Essentials of Human
Anatomy & Physiology (Tenth Edition ed.). New York: McGraw-Hill Higher
Education.
A, s., SS, K., ME, C., & J., S. (n.d.). Neurobiology of substance P and the
NK1 re... [J Clin Psychiatry. 2002] - PubMed - NCBI. National Center for
Biotechnology Information. Retrieved May 8, 2013, from
http://www.ncbi.nlm.nih.gov/pubmed/12562137
"Left Brain/Right Brain | Scholastic.com." Scholastic, Helping Children
Around the World to Read and Learn | Scholastic.com. N.p., n.d. Web.
10 May 2013. <http://www.scholastic.com/teachers/article/leftbrainright-brain>.
"Nervous System." Dictionary.com. Dictionary.com, n.d. Web. 13 May
2013.
"KidsHealth." Brain and Nervous System. N.p., n.d. Web. 13 May 2013.
"Central Nervous System." About.com Biology. N.p., n.d. Web. 13 May
2013.
"Brain Structures and Their Functions." Brain Structures and Their
Work Cited (cont.)
Alzheimer's Disease & Dementia | Alzheimer's Association. (n.d.).
Alzheimer's Disease and Dementia | Alzheimer's Association. Retrieved
May 14, 2013,
http://www.alz.org/alzheimers_disease_what_is_alzheimers.asp
Alzheimer's disease - National Library of Medicine - PubMed Health. (n.d.).
National Center for Biotechnology Information. Retrieved May 14, 2013,
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001767/#adam_0007
60
Alzheimer's: the chemistry behind the disease. (n.d.). Royal Society of
Chemistry | Advancing the Chemical Sciences. Retrieved May 14, 2013,
http://www.rsc.org/Publishing/Journals/cb/Volume/2009/9/Alzheimers
_facts.asp
Cause of Cerebral Palsy | Brain Damage | Cerebralpalsy.Org. (n.d.).
CerebralPalsy.Org | The ULTIMATE Resource EVERYTHING Cerebral Palsy.
Retrieved May 14, 2013, http://www.cerebralpalsy.org/about-cerebralpalsy/cause/
Works Cited (cont.)
Cerebral palsy - MayoClinic.com. (n.d.). Mayo Clinic. Retrieved May 14, 2013,
from http://www.mayoclinic.com/health/cerebral-palsy/DS00302
Cerebral palsy - National Library of Medicine - PubMed Health. (n.d.).
National Center for Biotechnology Information. Retrieved May 14, 2013,
from
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001734/#adam_00071
6.disease.causes
Diseases and Disorders of the Nervous System. (n.d.). IvyRose Holistic :
Holistic Health, Alternative Medicine, Human Biology, Anatomy &
Physiology and Chemistry Study Pages. Retrieved May 14, 2013, from
http://www.ivy-rose.co.uk/HumanBody/Nerves/Nervous_Disorders.php
Multiple sclerosis - MayoClinic.com. (n.d.). Mayo Clinic. Retrieved May 14,
2013, from http://www.mayoclinic.com/health/multiplesclerosis/DS00188
Multiple sclerosis — Diagnosis and treatment at Mayo Clinic. (n.d.). Mayo
Clinic. Retrieved May 14, 2013, from
http://www.mayoclinic.org/multiplesclerosis/?mc_id=comlinkpilot&placement=bottom
Works Cited (cont.)
Parkinson disease - Genetics Home Reference. (n.d.). Genetics Home
Reference - Your guide to understanding genetic conditions. Retrieved
May 14, 2013, from http://ghr.nlm.nih.gov/condition/parkinson-disease
Parkinson's disease: Treatments and drugs/ - MayoClinic.com. (n.d.). Mayo
Clinic. Retrieved May 14, 2013, from
http://www.mayoclinic.com/health/parkinsonsdisease/DS00295/DSECTION=treatments-and-drugs/
Parkinson’s disease - National Library of Medicine - PubMed Health. (n.d.).
National Center for Biotechnology Information. Retrieved May 14, 2013,
from
http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001762/#adam_00075
5.disease.causes