Reflex Arc

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Reflex Arc

• SC.912.L.14.23

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Essential Questions

• What is a reflex?
• Why do doctors make certain your reflexes work?

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What are reflexes

• A reflex is different from a reaction. Reflexes
  are FAST, INVOLUNTARY, sequence of actions that
  occur in response to a particular stimulus.
• It is possible to learn a reflex but only after
  much practice and repetition.

Inborn Reflexes Learned Reflexes
Withdrawal reflex moving your hand off the hot stove Tracking movements of eyes when you read
Patellar Reflex Visual and manual reflexes required to drive a car
Newborn Suckling/Rooting Balancing required to ride a bike
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The Reflex Arc
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What is happening in the body?

• A reflex is special physiologically because the
  body reacts before the brain is consciously
  aware.
• The reflex occurs because the impulses travel the
  reflex arc independent of the impulses that relay
  messages to the brain.
• There are five parts of a reflex arc sensory
  receptor, sensory neuron, integrating center,
  motor neuron, and the effector.

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The Patellar reflex
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Neurological testing

• Doctors check the reflexes because they give
  information about the health of the nervous
  system.
• In children and adults abnormal response to
  reflex testing can be a sign of neurological
  disorder.
• Extrusion Reflex

Normal Newborn pushes tongue outward when tip of tongue is touched with finger or nipple. Abnormal Continuous extrusion of tongue or repetitive tongue thrusting occurs with CND anomalies and seizures.
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More about newborn reflexes

• http//nursingcrib.com/newborn-reflexes/

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Activities that test reflexes

• http//faculty.washington.edu/chudler/chreflex.htm
  l

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Day 4

• Step 1 Place in order
• Stimulus received
• Integrating center responds
• Effector acts
• Sensory neuron carries message
• Motor neuron carries message

• Step2 Write out the action of a reflex of your
  choice be sure to list all five parts.