Ch 46-47 Wrap-up

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Ch 46-47 Wrap-up
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• Urchin Gastrulation
• ( proto or deutero-stome ? )
• Triploblastic (know 3 layers/colors)
• Archenteron, blastocoel

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• Nerve cord? Notochord?
• Primitive streak
• What structure(s) does each layer give rise to?
• Organogenesis (differentiation) happens very early

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Table 47.1 GERM LAYER p. 945 Organs and tissues formed
ECTODERM Skin, cornea and lens of eye, nervous system (neural tube), mouth and rectum
ENDODERM Digestive tract lining, respiratory system lining, many organs
MESODERM Notochord, skeleton, muscles, circulatory systems, reproductive system, excretory system
KNOW THIS!
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Ch. 48

• Nervous Systems

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Nervous system
afferent
interneurons
efferent

• PNS, CNS

Effector cells

• INPUT Sensory Neurons (receptors)
• INTEGRATION CNS(brain spinal cord)
  Interneurons
• OUTPUT Motor Neurons (effectors)

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The Reflex Arc
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The Neuron

• Dendrites receivethe signal, axon delivers the
  signal away to another neuron or to the CNS
• Myelin sheaths (white matter) insulate the axon
  and are made by Schwanns cells or
  oligodendrocytes.
• Schwanns and Oligodendrocytes are both types of
  supporting cells called glia.
• What is saltatory conduction? P.970
• What is a Node of Ranvier?
• What is a synapse?

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Anatomy of a Neuron
Makes myelin - PNS
gtSpeed of Transmission Larger axons Myelin
sheath (Saltatory conduction)
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Outside is always zero Less () inside -
inside and outside
-70 mV is the resting membrane potential
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• What makes a signal travel down the axon ?

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Na into the cell
Action Potential(all or none nerve impulse)
K out of the cell
EPSP
Membrane potential (mV)
-70 -50 0
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Threshold Potential reached -50
Na/K pump restores
resting state restored (-70)
Hyperpolarization from ___ ions
0 1 2 3 4
Time (milliseconds)
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Hyperpolarizationmore negative insideby K
moving outdoes not cause an action potential
Depolarization inside gains more
positive charge by Na rushing in
EXCITATORY ()

• INHIBITORY(-)

-70
What is meant by allornone action potential?
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The steps of an action potential
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Resting State
Na gates closed, K gate closedNa/K pump is
maintaining 70mV
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Depolarizing Phase
Na gate OPENS, (fast gate)K channels are still
closed (slow
gate) Na rushes into the neuron ( )
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RE-polarizing Phase
Na inactivation gate closes, K slow gate
OPENS K rushes out of the neuron
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Undershoot
Na channels closed, K channels still OPEN K
still rushes out of the neuron (Hyperpolarizing
the inside - - - - - -)
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Direction of transmission? Slow closing of the K
channels prevents back-flow One way flow of
Electricity!
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Chemical synapses

• TERMS
• Vesicles
• synaptic cleft
• neurotrans-mitters
• (Ca2)
• receptor
• ion channel
• Pre/post synaptic membrane
• Enzymes to degrade the neurotrans-mitters

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Summation of IPSP EPSPInhibitory(-)
Excitatory() Post-Synaptic Potential
Temporal and Spatial Summation
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PNS
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AUTONOMIC

• Sym-pathetic
• Stress (like a fight or flight response)
• Para-sympa-thetic
• Peace (relaxed, normal functions)

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The real thing . . . . . . . .
Cerebrum
Thalamus Hypothalamus
Cerebellum
Brain stem medulla oblongata, pons, midbrain
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Cerebrum
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Right versus left Cerebrum
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BRAIN STRUCTURES AND FUNCTIONS

• Brain Stem
• Medulla Oblongata Pons (autonomic,
  homeostatic, data conduction)
• Midbrain (receives and integrates sensory
  information)
• Cerebellum Automatic coordination of movements
  and balance
• Thalamusintegration of stimuli coming to the
  brain
• Hypothalamus important homeostatic regulation
  (temperature, hunger, thirst) hormones
• Cerebrum memory, learning , emotions, motor
  movements, sensory cortex areas