Download - Sensations
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Marian M. Miguel-Lagundino, MA
Instructor
SENSATION
EXTERNAL SENSATION
A process of knowing material, concrete stimuli through
external senses namely: vision, audition, olfaction,
gustation and cutaneous sensation.
If there is no sensation, there is no perception.
CONDITIONS
If one of these elements is absent, there is no sensation.
General conditionsStimulus
Any aspect of the world that influences our behavior
Must be strong enough to elicit a sensation
Threshold stimulus: minimum amount of stimulus that is capable of producing a sensation
A subminimal stimulus can elicit a sensation if applied repeatedly on the same receptor
Receptor
Any structure in the body that is excitable to stimuli
A peripheral termination of sensory fibers
Exteroceptors: found at the external surface of the body
Proprioceptors: found in muscles, joints and tendons
Interoceptors: found in visceral organs
Transmissor
Fiber tracts: Bundles of nerve fibers that convey sensory impulses from one neuron to the next
Transmits the sensory impulses to the brain
Brain Center
Houses the primary sensory area located in different lobes
Also contains secondary and association areas
VISUAL SENSE
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Stimulus: light waves
Receptor: rods and cones
Transmissor: optic nerve
Brain center: primary visual area
http://www.tutorsglobe.com/CMSImages/52_Visual_pathway.jpg
POINTS OF DIFFERENCE CONES RODS
Shape Conical Tubular
Distribution in the retina Center Periphery
Function Daytime vision Nighttime vision
Sensitivity to color Sensitive Not sensitive
FOVEA BLIND SPOT
https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcSXxe6cyqQ0R4OS73YdZYD5CpxLwSGk4jfFdb2BRwW9OWAyvn4gaQ
AUDITORY SENSE
Stimulus: sound waves
Receptor: hair cells
Transmissor: auditory/cochlear nerve
Brain center: primary auditory area
http://www.daviddarling.info/images/organ_of_Corti.jpg
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OLFACTORY AND GUSTATORY SENSES
Stimulus: chemical substances
Receptor: olfactory cells
Transmissor: olfactory nerve
Brain center: primary olfactory
area
http://www.medical-look.com/systems_images/Olfactory_sense.gif
Stimulus: chemical substances
Receptor: taste buds
Transmissor: facial and
glossopharyngeal nerves
Brain center: primary gustatory
area
CUTANEOUS SENSE
Stimulus: mechanical energy
Receptor: somatosensory
receptors
Transmissor: ascending nerve
fibers
Brain center: primary
somatosensory area
http://1.bp.blogspot.com/_kaQ5P19FVgk/SlYj8SW_S7I/AAAAAAAADSo/cVLxJASLnNo/s400/SomaticSensoryCortex1.
JPG
http://www.corpshumain.ca/en/images/SensorielFaisseauxDorsal_en.jpg
Somatosensation Receptor
Touch Merkels disk
Pressure Pacinian Corpuscles
Pain Free nerve endings
Coldness Krauses Corpuscles
Warmth Ruffinis Endings
Kinaesthesia Proprioceptors
http://www.rci.rutgers.edu/~uzwiak/AnatPhys/ChemicalSomaticSenses_files/image020.jpg