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Title: Nervous%20System

Nervous System
  • By Daniel Aleynick

What does it do?
  • Responsibilities
  • Receive signal
  • Interpret signal
  • Send signal to do an action

The Nervous System control most of the actions
your body performs
Organization of Nervous System
  • Nervous System
  • Central Nervous System (CNS) Consists of the
    brain and spinal cord.
  • Peripheral Nervous System (PNS) Are the nerves
    that connect the CNS to the rest of the body

Information Processing
  • A sensor (example eye or skin) picks up a
    signal, which is sends to the brain.
  • The CNS processes the information, and sends
    another signal to a specific effector (example
  • Effector proceeds with an action, such as a

Neuron Structure
  • Composed of
  • Cell Body
  • Dendrites
  • Axon
  • Synaptic terminals

Supporting Cells
  • Supporting cells are known as Glia.
  • Astrocytes provide support for neurons and
    control concentration of ion levels
  • The blood-brain barrier is formed by astrocytes
    creating a very tightly controlled extracelluar
    chemical environment.
  • Radial Glia Form tracks that newly formed
    neurons can travel. Also act as stems cells and
    can generated new neurons.

Surrporting Cells Cont
  • Schwann Cells They make up the myelin sheath
    which covers the axon of neurons. They act as an
    insulator and increase the speed of the action

Resting Potential
  • Membrane potential The electrical difference
    between the inside and outside of a cell.
  • Resting potential The membrane potential when a
    cell is not transmitting a signal.

Membrane Potential
Gated Ion Channels
  • There are three types ion channels
  • Stretch-gated ion channels
  • Ligand-gated ion channels
  • Voltage-gated ion channels

Voltage and Lignad Ion Channels
  • Voltage-gated Ion Channels
  • Are found in axons and open and close when the
    membrane potential changes.
  • Stretch-gated Ion Channels
  • Open and close when the cells sense it is being
    stretch. This occurs when the cell becomes
    mechanically deformed.

Ligand-gated Ion Channels
  • Ligand-gated Ion Channels Are ion channels that
    open and close when a specific molecule binds to
    the channel. This molecule is usually a

Action Potential Useful Terms
  • Hyperpolarization An increase of the magnitude
    of membrane potential by becoming more negative.
    This is caused by K channels to opening up.
  • Depolarization A reducation in the magnitude of
    membrane potential. This occurred when Na
    channels open up.
  • The changes in the membrane potential are called
    graded potentials.

Production of Action Potentials
Action Potentials
  • What is an action potential?
  • An action potential is a stimulus strong enough
    to produce depolarization past the threshold
  • The threshold is the membrane potential limit
    that must be reached for an action to occur. This
    is a all or nothing event so nothing occur unless
    the limit is reached. Once reached, the whole
    action takes place.

Conduction of Action Potentials
  • An action potential starts in the axon hillock.
  • From there a cascade effect takes place
  • As the axon hillock is depolarized, it
    depolarizes a neighboring region of axon
  • This next region than depolarizes another nearby
    region until the action potential reaches the
    synaptic terminals

Conduction Speed
  • The faster the body can send out signals, the
    faster one can react. But how does the body
    increase the speed of conduction?
  • The axon of some neurons is covered by Schwann
    cells. Since these cells are made from lipids,
    they are insulators. This causes the electrical
    signal to jump over the Schwann cells increase
    the speed of the signal. This is known as
    salutatory conduction.

Neuron Communication
  • A neuron pass a signal to another neuron by
    chemical synapses.
  • Synaptic terminals produce a neurotransmitter and
    package then in synaptic vesicles.
  • The neurotransmitter move across the synaptic
    cleft and active the ligand-gated ion channels on
    the nearby neuron.

  • Acetylcholine
  • Is one of the most common neurotransmitters.
  • Functional Class Is an excitatory in vertebrate
    skeletal muscles and an inhibitory at other
  • It is secreted by the CNS, PNS, and neuromuscular

Neurotransmitters Cont
  • The next group of neurotransmitters are the
    Biogenic Amines
  • Norepinephrine Can be an excitatory or
    inhibitory and is produced in the CNS and PNS
  • Dopamine Is both an excitatory and inhibitory
    and is produced in the CNS and PNS
  • Serotonin Is generally a inhibitory and is
    produced by the CNS

Neurotransmitters Cont
  • Amino Acids can also be used as
  • Gamma Aminobutyric Acid Is an inhibitory and is
    made in the CNS and neuromuscular junctions.
  • Glycine It is an inhibitory neurotransmitter and
    is created in the CNS
  • Glutamate Is an excitatory and is produced in
    the CNS and neuromuscular junction.
  • Aspartate An excitatory that is made in the CNS

Neurotransmitters Final
  • The last group of major neurotransmitters are
  • Substance P (not a creative name) is an
    excitatory that is produce in both the CNS and
  • Met-enkephalin Is generally an inhibitory that
    is made in the CNS

Gases as Neurotransmitters
  • Gases can be dissolved in fluids of the body and
    used as neurotransmitters as well.
  • Common examples are
  • NO and CO

Regions of the Nervous System
  • The peripheral nervous system is made up of all
    the nerves connect the brain and spine to the
    rest of the body
  • Cranial nerves extend from the brain and spread
    to organs of the head and upper body
  • Spinal Nerves originate in the spinal cord and
    extend to parts of the body below the head.

  • The PNS can be divided into two functional
  • The Somatic Nervous System (SNS)
  • The Autonomic Nervous System (ANS)
  • The Autonomic Nervous System can then be divided
    further into 3 more division
  • Sympathetic division
  • Parasympathetic division
  • Enteric division

Somatic Nervous System
  • Is considered voluntary because it is subject to
    conscious control.
  • Sends signals to and from the skeletal muscles of
    the body.

ANS Sympathetic
  • The sympathetic division deals with arousal and
    energy generation of the body
  • The Fight or Flight response
  • Digestions stops
  • Energy production increases
  • Adrenaline is released
  • Faster Heart Rate

Adrenaline RUSH
ANS Parasympathetic
  • Self-maintenance functions known as Rest and
  • Digetionenchanced
  • Heart Rated Slowed
  • Glycogen production

Resting and Digesting
ANS Enteric Division
  • Is a network of neurons in the digestive tract,
    pancreas and gallbladder.
  • They control the secretions and smooth muscle
    activities of the body, such as peristalsis, the
    uncontrolled movement of food through the body.

Brain Structure
  • In adults the brain consists of 5 structures
  • Cerebrum
  • Dienceohalon
  • Midbrain
  • Cerebellum
  • Medulla Oblongata

  • Is divided into two different regions
  • The Right Cerebral Hemisphere
  • The Left Cerebral Hemisphere
  • Each Hemisphere has an other cover of gray brain
    matter and an inner region, the cerebral cortex,
    that is white brain matter.
  • Basal Nuclei are groups of neurons in the
    cerebrum that are centers for planning and
    learning movement
  • A think band of axons known as the corpus
    callosum always the right and left hemisphere to

  • Is divided into 3 regions
  • The Epithalamus
  • The Thalamus
  • The Hypothalamus
  • The Epithalamus consists of the pineal gland and
    choroid plexus that produces cerebrospinal fluid.
  • The Thalamus is the sensory center. All incoming
    information from sense is sorted here
  • The Hypothalamus produced vital hormones and is
    the bodys thermostat, control temperature as
    well as hunger, thirst, and other survival

  • Acts as the rely stations for all auditory and
    visual information that brain receives.
  • It also controls the eyes and how they move

  • The cerebellum is important for coordination and
    error checking during motor, perceptual, and
    cognitive functions
  • Is responsible for hand-eye coordination and
  • Good way to remember its function is

Medulla Oblongata
  • Is the control central for some of the most vital
    body processes
  • It controls automatic and homeostatic functions
    such as
  • Breathing
  • Heart Beats
  • Blood Vessel Activity
  • Swallowing
  • Vomiting
  • Digestion

Circadian Rhythms
  • The biological clock of the body controlling
    cycles such as the sleep/wake cycle
  • Uses cues from the environment to change cycles.
  • Examples of cues are light intensity and hunger.
  • Paired up with the hypothalamic structures call
    the Superchiasmatic nuclei, clusters of neurons
    in the CNS.

  • During brain development, different function
    segregate to either the left or the right
    cerebral hemisphere
  • The Left side is more adept to language, math,
    logical operations, etc
  • The Right side is stronger at pattern
    recognition, nonverbal thinking and emotion
  • Left side is factual information while right side
    is creativity.

Memory and Learning
  • The body is constantly making connection between
    what is happening to what has already happen.
  • Short-term Memory is stored in the frontal lobe
    and are memories of what has recently happened.
    When these memories become irrelevant, the brain
    forgets them.
  • Long-term Memory is aided by the hippocampus.
    These are short-term memories that were stored
    for later use. The more a memory is used the
    easier it is to remember, hence practice makes

Disease/Nervous Problems
  • Schizophrenia
  • A mental disturbance where the patient can no
    longer distinguish between reality and
  • Bipolar Disorder
  • Involves swings of mood from high to low and
    affects 1 of the population
  • Alzheimer's Disease
  • Mental deterioration which results in confusion,
    memory loss, and other variable symptoms. Usually
    the results of old age
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