1. A Presentation by:
Timothy Dominguez
Nathan Maglasang
Jose Mari Mendoza

2. What is the Nervous System?
 A very complex system
 Organ System that contain neurons
 Divided into two parts:
 Central Nervous System (CNS)
 Brain and Spinal Cord
 Peripheral Nervous System (PNS)
 Nerves and Ganglia

3.  The CNS consists of the Brain and the Spinal Cord
 The brain plays a central role in the control of most
bodily functions, that include:
 Awareness • Thoughts
 Movements • Speech
 Sensations • Memory
 Some reflex movements can occur via spinal cord
pathways without the participation of brain structures.

5.  Cerebrum - is the largest part of the brain
and controls voluntary actions, speech, senses, thought, an
d memory.
 Frontal Lobes - located in the front of the brain and are
responsible for voluntary movement and, via their
connections with other lobes, participate in the execution
of sequential tasks; speech output; organizational skills;
and certain aspects of behavior, mood, and memory.
 Parietal Lobes – processes sensory information such as
temperature, pain, taste, and touch.
 Temporal Lobes - processes memory and auditory
(hearing) information and speech and language functions.
 Occipital Lobes - receives and processes visual
information.

6.  The central structures of the brain include the
thalamus, hypothalamus, and pituitary gland.
 Thalamus - integrates and relays sensory
information to the cortex of the parietal, temporal, and
occipital lobes.
 Hypothalamus - located below the thalamus, regulates
automatic functions such as appetite, thirst, and body
temperature.
 Pituitary Gland - regulates the production of many
hormones that have a role in
growth, metabolism, sexual response, fluid and
mineral balance, and the stress response.

7.  Midbrain - located below the hypothalamus. Some
cranial nerves that are also responsible for eye muscle
control exit the midbrain.
 Pons - serves as a bridge between the midbrain and the
medulla oblongata. The pons also contains the nuclei
and fibers of nerves that serve eye muscle
control, facial muscle strength, and other functions.
 Medulla Oblongota - the lowest part of the brainstem
and is interconnected with the cervical spinal cord.
The medulla oblongata also helps control involuntary
actions, including vital processes, such as heart
rate, blood pressure, and respiration, and it carries the
corticospinal (that is, motor function) tract toward the
spinal cord.

8. Amygdala - The amygdala is an almond-shape set of
neurons located deep in the brain's medial temporal
lobe.For processsing of emotions, the amygdala forms
part of the limbic system.For fear responses and
pleasure.
Hippocampus - the part of the brain that is involved in
memory forming, organizing, and storing. forming
new memories and connecting emotions and
senses, such as smell and sound, to memories. acts as a
memory indexer for long-term storage and retrieving
them when necessary.

9. Broca's area – For Language comprehension,action
recognition and production, and speech-associated
gestures
Wernicke's area - It is involved in the understanding of
written and spoken language.

11.  The spinal cord is an extension of the brain and is surrounded by
the vertebral bodies that form the spinal column
Within the spinal cord are 30 segments that belong to 4 sections
(cervical, thoracic, lumbar, sacral), based on their location:
 Eight cervical segments: These transmit signals from or to
areas of the head, neck, shoulders, arms, and hands.
 Twelve thoracic segments: These transmit signals from or to
part of the arms and
the anterior and posterior chest and abdominal areas.
 Five lumbar segments: These transmit signals from or to the
legs and feet and some pelvic organs.
 Five sacral segments: These transmit signals from or to the
lower back and buttocks, pelvic organs and genital areas, and
some areas in the legs and feet.
 A coccygeal remnant is located at the bottom of the spinal
cord.

12.  Peripheral Nervous System Divisions
The peripheral nervous system is divided into the following sections:
Peripheral Nervous System
 Sensory Nervous System - sends information to the CNS from internal organs or from external
stimuli.
 Motor Nervous System - carries information from the CNS to organs, muscles, and glands.
 Somatic Nervous System - controls skeletal muscle as well as external sensory organs.
 Autonomic Nervous System - controls involuntary muscles, such as smooth and cardiac muscle.
 Sympathetic - controls activities that increase energy expenditures.
 Parasympathetic - controls activities that conserve energy expenditures.

13.  Peripheral Nervous System Connections
 Peripheral nervous system connections with various
organs and structures of the body are established
through cranial nerves and spinal nerves. There are 12
pairs of cranial nerves in the brain that establish
connections in the head and upper body, while 31 pairs
of spinal nerves do the same for the rest of the body.

14.  Sources:
 http://biology.about.com/od/organsystems/a/aa06180
4a.htm
 http://www.emedicinehealth.com/anatomy_of_the_ce
ntral_nervous_system/
 http://library.thinkquest.org/5777/ner1.htm
 http://en.wikipedia.org/wiki/Nervous_system

15.  Neurons are nerve cells that transmit nerve signals to and
from the brain
DIFFERENT TYPES OF NEURONS
 Sensory neurons or Bipolar neurons carry messages
from the body's sense receptors (eyes, ears, etc.) to the
CNS.
 Motoneurons or Multipolar neurons carry signals from
the CNS to the muscles and glands.
 Interneurons or Pseudopolare (Spelling) cells form all
the neural wiring within the CNS. These have two axons
(instead of an axon and a dendrite). One axon
communicates with the spinal cord; one with either the
skin or muscle.

16.  Neurotransmitters are the chemicals which allow the
transmission of signals from one neuron to the next
across synapses.
Acetylcholine: Associated with memory, muscle
contractions, and learning.
Endorphins: Associated with emotions and pain
perception. The body releases endorphins in response
to fear or trauma
Dopamine: Associated with thought and pleasurable
feelings.

17.  Glial cells make up 90 percent of the brain's cells. Glial
cells are nerve cells that don't carry nerve impulses.
 The various glial cells perform many important
functions, including: digestion of parts of dead
neurons, manufacturing myelin for neurons, providing
physical and nutritional support for neurons, and
more.

18.  Microglia are special immune cells found only in the brain
that can detect damaged or unhealthy neurons.
 Astrocytes are star-shaped glia that hold neurons in
place, get nutrients to them, and digest parts of dead
neurons.
 Oligodendrocytes are cells that coat axons in the central
nervous system with their cell membrane forming a
specialized membrane differentiation
called myelin, producing the so-called myelin sheath.
 Schwann cells are involved in many important aspects of
peripheral nerve biology - the conduction of nervous
impulses along axons, nerve development
and regeneration, trophic support for neurons, production
of the nerve extracellular matrix,and modulation of
neuromuscular synaptic activity

19.  STEPS:
a.) In order to transmit a signal between two
neurons, an electrical impulse must be communicated
over a synapse.
b.) When an action potential begins in a neuron, it
travels down the axon.

20. c.) When the action potential reaches the axon
terminal, calcium channels open, and calcium ions
rush into neurons.
d.) The neuron makes and stores neurotransmitter in
ventricles.
e.) When calcium bind to ventricles, the vesicles carry
transmitter toward the presynaptic membrane.

21. f.) When the vesicles contact the axon terminal
membrane, the neurotransmitter is released into the
synaptic cleft.
g.) Neurotransmitter diffuses across the synaptic cleft
and binds to receptors on the postsynaptic neuron.
h.) The postsynaptic neuron receptors are activated. In
this case, these receptors allow Sodium in the neuron
by facilitated diffusion, causing an action potential to
start in the postsynaptic membrane.

22. i.) Neurotransmitters are released from receptors and
diffuse back into the synaptic cleft.
j.) Vesicles recycle some neurotransmitter to prepare
the neuron for its next action potential.

23.  Calcium Ions – a factor in the clotting of blood.
 Presynaptic membrane - The part of the cell
membrane of an axon terminal that faces the cell
membrane of the neuron or muscle fiber with which
the axon terminal establishes a synapse.
 Postsynaptic membrane - The part of the cell
membrane of a neuron or muscle fiber with which an
axon terminal forms a synapse.

24.  Synaptic cleft - a narrow extracellular cleft between the
presynaptic and postsynaptic membranes.
 Axon - a process of a neuron that conducts impulses
away from the cell body. Axons are usually long and
straight.

25.  During a thunderstorm, Luigi Galvani touched a frog’s
leg with a metal instrument and noticed the muscles
twitching.
 His conclusion was nerves do transmit impulses from
one part of the body to another, but in a different way
than in an ordinary conductor.
 The electrical properties are different in neural
conduction because it is slower and does not vary in
strength

26.  There is an excess of negative ions inside the cell
membrane and an excess of positive ions outside
 Potassium(K+) , sodium ions(Na+), chloride
(Cl--)
 Nerve cells use both passive diffusion and active
transport to maintain these differentials across their
cell membranes.
 Specialized proteins embedded in the nerve cell
membrane function as voltage-dependant
channels, passing through Na+ and K+ during nerve
impulse transmission.

27.  If a physical or chemical stimulus is strong enough to
cause depolarization from the resting potential of 70
mV to around 50 mV, the voltage-dependant
Na+ transmembrane channels open.
 The influx of Na+ causes a local reversal of electric
polarity of the membrane, changing the electric
potential to about +40 mV

28.  The sodium ions(Na+) channels then close again.
 The movement of K+ ions and slower action of the Na+-
K+ pump soon restore concentration differentials and
electric gradient to the resting state.
 The transient change in the electric potential across
the membrane is the action potential. After
depolarization, for a brief period (milliseconds), the
Na+ channels cannot be stimulated. This is called
the refractory period.

29.  The local depolarization at the site of the original
stimulus causes passive diffusion of ions into areas
adjacent to the site of the stimulus.
 Because of the refractory period, the nerve impulse
can only be propagated in one direction, away from the
nerve cell body towards the terminal branches, to
release neurotransmitter substances.
 The myelin sheath is a good insulator, so ions cannot
flow through it.

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