Neural Control

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Neural Control

• How Neurons work
• Supporting Cast
• Information Flow
• Vertebrate
• Human Brain

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Evolution of Nervous System

• First animals in the sea with simple nervous
  systems
• Nerve net
• An asymmetric mesh of sensory motor neurons
  that control simple movements

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Who needs a head?

• Nerves
• A sheath-like, cord-like communication line that
  holds bundles of sensory and/or motor neurons
• Ganglion
• A cluster of nerve cell bodies that function as a
  local integrating center

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Cephalization

• The formation of a head
• Cephalopods
• Brainiest of all invertebrates
• Complex brain sensory organs
• Vertebrates
• Nervous tissue thickened at base of nerve cord
• Adaptation to land
• Sensory load

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Vertebrate Nervous System

• Central Nervous System (CNS)
• Brain spinal cord
• Peripheral Nervous System (PNS)
• Nerves extending through the rest of the body
• Afferent
• Deliver signals to CNS
• Efferent
• Carry signals out of CNS

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Neurons

• Sensory neurons
• Detects a stimulus at one or more site then
  relays info to other neurons
• Motor neurons
• Delivers commands from neurons to muscles or
  glands
• Interneurons
• Intermediate from sensory neurons to motor neurons

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Neurons

• Dendrites
• Input zones, short slender extension from cell
  body
• Axons
• Signal-conducting zone, long slender process

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Membrane Gradients

• at rest
• No stimulus
• Action potential
• Abrupt reversal in the voltage differences across
  the plasma membrane
• Transport proteins
• K Na

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Sodium-potassium pumps

• Maintain ion gradients
• Also return gradient after they are reversed
  during an action potential
• K Na are pumped against the gradient

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Sending Messages

• Chemical synapse
• A space between neighboring neurons in which
  neurotransmitters diffuse
• Neurotransmitter
• Signaling molecule that is secreted by neurons

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Neuroglial cells

• Framework that holds neurons in place
• As neurons move to final destination, neuroglial
  cells hold into place
• Once neurons move mature
• No longer enter mitotic division

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Nerves

• The long-distance cables between body regions
• Myelin Sheath
• Wrapping around axons if neurons
• Acts as an insulator

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Reflex Arc

• Reflex
• A movement or some other response to a stimulus
  that happens automatically, no though required

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Major Expressways

• Somatic Nervous System
• Nerves that connect the CNS to the skeletal
  muscles
• Autonomic Nervous System
• Nerves that connect the CNS to the smooth
  muscles, cardiac muscles, glands of the viscera

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Major Expressways

• Sympathetic neurons
• A neuron of the autonomic nervous system
• Signals increase in times of stress or heightened
  awareness

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Major Expressways

• Parasympathetic neuron
• Neuron of the autonomic nervous system
• Signals slow activities divert energy to basic
  tasks

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Spinal Cord

• Connects the peripheral nervous system with the
  brain control some reflexes
• Thread through ligament bones of the vertebral
  column, protection
• Meninges
• Protection

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The Brain

• Brain stem
• Most ancient nervous tissue, persists in all
  three regions is continuous with the spinal cord

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Subdivisions

• Medulla oblongata
• Hindbrain
• Controls respiration, circulation other
  essential tasks
• Cerebellum
• Uses inputs from eyes, ears, muscles, forbrain
  to control motor skills

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Subdivisions

• Pons
• Controls the signal flow between cerebellum
  integrating centers of the forbrain

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Subdivisions

• Thalamus
• Forebrain center for sorting sensory input
  relaying to the cerebrum
• Hypothalamus
• Main center for homeostatic control of internal
  environment

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Cerebrum

• Olfactory lobes paired outgrowths from the
  brain stem that are the most complex integrating
  center

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All together