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Reflexes
How Reflexes Were Found
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Sir Charles Sherrington (1857-1952) was the first to
introduce the word 'reflex', taking the view that sensory
information going into the cord was reflected out again
along the motor nerve fibres
He said that the reflection of sensory information was the
equivalent to a beam of light being reflected off of a
mirror.
Sherrington referred to the combination of a receptor,
conductor and effector as a reflex arc.
How reflexes work
Reflexes work when sensory neurons become
interneurons in the gray
matter. Afterwards the interneuron become
motor neurons.
Knee jerk Reflex
Examples of Reflexes
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Blinking when something flies toward your
face.
Raising your arm when something is thrown
at you.
Coughing and sneezing
Shivering
Quick Videos
http://www.youtube.com/watch?v=wLrhYzdb
bpE
reflex test:
http://www.youtube.com/watch?v=eCrY0m5TFU
Process of a Reflex
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First a stimulus causes
the receptor to stimulate
the afferent neuron in the PNS.
The afferent neuron then transmits an
impulse to the spinal cord.
The impulse will transmit through the
ganglion then to the gray matter in the
spinal cord. (Ganglion is a structure
containing a number of nerve cell bodies).
Process of Reflexes continued
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Two interneurons in the spinal cord will
integrate information. One efferent neuron
stimulates the flexor muscle to contract,
and then the other efferent neuron sends
inhibitory signals that keep the extensor
muscles from contracting.
Types of Reflexes
Cranial Reflex-A cranial reflex is a fast,
involuntary response to a stimulus. It uses
the brain stem as an integrating center.
Spinal Reflex- A spinal reflex is a reflexive
action mediated by cells in the spinal cord,
bypassing the brain altogether.
Types of Reflexes (cont)
Somatic Reflexes- Somatic reflexes involve a
response that involves a skeletal muscle
contraction in response to a stimuli.
Autonomic Reflexes- An autonomic reflex is
one that involves the response of an organ,
such as the peristaltic contraction of the
smooth muscle of the intestines, that is not
controlled consciously.
What can go wrong!?!?!?!?!
1. Methylglutaconic Aciduria: Genetic Disorder
2. Acroosteolysis Neurogenic: Total loss
3. STNR: Symmetrical Tonic Neck Reflex
4. Moto Reflex: should disappear within 2-4 months
5. Reflex Sympathetic Dystrophy: Pain disorder
Bib
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http://www.rightdiagnosis.com/symbol/3_methylglutaconic_aciduria_ty
pe_4/intro.htm
http://www.encyclopedia.com/topic/reflex.aspx#1-1O128:reflexes-full
http://faculty.stcc.edu/AandP/AP/AP1pages/nervssys/unit12/reflexes.h
tm
http://kidshealth.org/kid/talk/qa/reflexes.html
http://www.wisegeek.org/what-is-a-spinal-reflex.htm
http://moveplaythrive.com/Reflexes/
http://www.medicinenet.com/reflex_sympathetic_dystrophy_syndrome/
article.htm