The Nervous System

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The Nervous System

• Central Nervous System (CNS)
• Peripheral Nervous System (PNS)

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Do Now

• Get Your Clicker!
• Contract a K-W-L chart on loose-leaf
• List everything you already Know about the
  Nervous System in the K-column
• List everything you Want to know in W-column

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Functions

• Monitors internal and external environments
• Integrates sensory information
• Coordinates voluntary and involuntary responses
  of other organ systems
• 2 subdivisions
• CNS brain and spinal cord
• Intelligence, memory, emotion
• PNS all other neural tissue
• sensory, motor

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Receptors and Effectors

• Receptors receive sensory info
• Afferent division carries info from sensory
  receptors to the CNS
• Efferent division carries info from CNS to PNS
  effectors (muscles, glands, adipose)
• Somatic Nervous System (SNS)
• Controls skeletal muscles (voluntary)
• Autonomic Nervous System (ANS)
• Controls involuntary actions
• Sympathetic Division (increase heart rate)
• Parasympathetic Division (decreases heart rate)

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Classwork

• Construct a flow chart detailing the direction in
  which information flows in the nervous system

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The sensory part of the PNS is...

1. Somatic division
2. Sympathetic division
3. Parasympathetic
4. Afferent division
5. Efferent division
6. Control center

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The fight or flight response is the...

1. Somatic division
2. Sympathetic division
3. Parasympathetic division
4. Afferent division
5. Efferent division
6. Control Center

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A change in ambient temperature would be detected
by

1. Somatic division
2. Sympathetic division
3. Afferent division
4. Efferent division
5. Control Center

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Label Neuron

• Read the functions to determine the structure of
  a typical neuron

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Neurons

• Communicate w/other neurons
• Soma-Cell body
• Dendrites - receive info
• Axon- sends signal to synaptic terminals
  (terminal buds)
• Synapse site of neural communication (gap)
• Myelin fatty insulation
• Node of Ranvier exposed axon between myelin
• 3 structural types
• Multipolar multiple dendrites single axon
  (motor neurons)
• Unipolar continues dendrites axon, cell body
  lies to side (sensory neurons)
• Bipolar one dendrite and one axon w/cell body
  between them (special senses)

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Types of Neurons

• 3 functional types
• Sensory afferent division
• info about surrounding environment
• position/movement skeletal muscles
• digestive, resp, cardiovasc, urinary, reprod,
  taste, and pain
• Motor efferent division (response)
• skeletal muscles
• cardiac and smooth muscle, glands, adipose tissue
• Interneurons
• Brain and spinal cord - memory, planning, and
  learning

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Neuroglia

• Regulate environment around neurons can be
  phagocytes actively divide
• Functions in CNS
• maintains the blood-brain barrier
• create myelin (lipid) to coat axon
• Nodes gaps between myelinated sections
• Internodes areas covered in myelin
• Phagocytic cells
• Secrete cerebrospinal fluid (CSF)

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The most common type of neuron is

1. multipolar
2. bipolar
3. unipolar

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The part of the neuron that has receptor proteins
on its surface is

1. Dendrites
2. soma
3. axon
4. Myelin sheath

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The part of the neuron that increases the speed
of transmission is the

1. Dendrites
2. soma
3. axon
4. Myelin sheath

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Complete Action Potential POGIL

• Remember
• Discuss each question and answer with your group
• Use the information from the models to support
  your responses
• You may use any resources to assist you

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Membrane Potential

• Cells are polarized (measured in volts)
• Resting potential of neuron -70mV
• Remains stable due to Na/K Pumps

Leak channels always open (K diffuses out)
K Proteins- Net - charge
Na Cl-
Gated channels open/closed under specific
circumstance
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Changes in Membrane Potential

• Depolarization
• Stimulus opens Na gated channels
• increase charge of cell towards 0mV
• Action Potentials
• Affects entire surface of cell membrane
• () feedback as nerve impulse continues
• Hyperpolarization
• Stimulus opens K gated channels
• Increases charge (from -70mV to -80mV)
• Restores resting potential

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Action Potential All or Nothing Principal

• Only skeletal muscle fibers and neuron axons have
  excitable membranes
• Graded potential increases pressure until
  sufficient enough to reach action potential
• Resting potential (-70mV)
• Reaches Threshold (-60mV)
• Refractory Period cell cannot respond to
  stimulation
• Depolarization
• Repolarization
• Continuous Propagation
• chain rxn until reaches cell memb
• Unmyleinated 1m/s (2mph)
• Salatory Propagation
• Myelinated (blocks flow of ions except at nodes)
• Action potential jumps from node to node
• 18-40m/s (30-300mph)

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Neural Communication

• Nerve impulse info moving in the form of action
  potentials along axons
• At end of axon the action potential transfers to
  another neuron or effector cell by release of
  neurotransmitters from synaptic terminal (only
  occur in 1 direction)
• Activity of neuron depends on balance between
• Excitatory neurotransmitters - depolorization
• ACh Norepinephrine
• Inhibitory neurotransmitters -hyperpolarization
• Dopamine, Seratonin, GABA

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An excitatory neurotransmitter

1. Increases electrical impulse
2. Causes the release of more neurotransmitters
3. Is released in a synaptic cleft
4. All of the above

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The resting membrane potential inside a neuron is

1. 0mV
2. 30mV
3. -60mV
4. -70mV

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After stimulus, the rush of sodium ions into the
cell is called

1. depolarization
2. repolarization
3. hyperpolarization

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The action potential is propagated by

1. More Na rushing into the cell
2. K leaving the cell
3. Neurotransmitters binding to dendrite
4. Vesicles release neurotransmitters

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The cells charge at the peak depolarization is

1. 0mV
2. 30mV
3. -60mV
4. -70mV

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During repolarization

1. The resting potential is restored
2. K diffuse out of cell
3. The cell membrane becomes negatively charged
   again
4. All of the above

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Once the action potential reaches the axon
terminal, the signal will be carried to the next
neuron by

1. Na ions
2. Neurotransmitters
3. K ions
4. All of the above

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If an excitatory neurotransmitter binds to neuron
number one, how will that affect the number of
neurotransmitter released?

1. more
2. less
3. No effect at all

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If previous neuron releases GABA, an inhibitory
neurotransmitter, how will that affect neuron 2

1. Increase electrical stimulus
2. Decrease electrical stimulus
3. Increase neurotransmitters released
4. decreased neurotransmitters released
5. 13
6. 24

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Reflexes

• Reflex involuntary response to stimulus w/o
  requiring the brain
• Reflex arc- sensory neuron? Interneuron? motor
  neuron (opposes initial stimulus)
• Ex. Knee jerk reflex
• Babinski reflex (infants only)
• Stroke sole of foot ? toes fan out
• Plantar reflex (adults only)
• Stroke sole of foot? toes curl
• Signals sent to brain by interneurons allow for
  control
• Ex. Toilet training, gag, blink

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Testing reflexes activity