the senses. sensory inputs become sensations and perceptions in the brain – sensation an awareness...
Post on 01-Jan-2016
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THE SENSES
THE SENSES
• SENSORY INPUTS BECOME SENSATIONS AND PERCEPTIONS IN THE BRAIN– SENSATION• AN AWARENESS OF SENSORY STIMULI
– PERCEPTION• A MEANINGFUL INTERPRETATION OR CONCIOUS
UNDERSTANDING OF SENSORY DATA
THE SENSES
• SENSORY RECEPTOR CELLS CONVERT STIMULI INTO ELECTRICAL ENERGY– SENSORY TRANSDUCTION
• CELL CONVERTS A STIMULUS INTO AN ELECTRICAL SIGNAL
– RECEPTOR POTENTIAL• GRADED CHANGE IN MEMBRANE POTENTIAL
– SENSORY ADAPTATION• THE TENDENCY OF SENSORY RECEPTOR CELLS TO
BECOME LESS SENSITIVE WHEN THEY ARE STIMULATED REPEATEDLY
THE SENSES
• SPECIALIZED SENSORY RECEPTORS DETECT FIVE CATEGORIES OF STIMULI– FIVE RECEPTORS• PAIN RECEPTORS
– RESPOND TO EXCESS HEAT, PRESSURE, DANGEROUS CHEMICALS
• THERMORECEPTORS– DETECT HOT OR COLD
THE SENSES
• SPECIALIZED SENSORY RECEPTORS DETECT FIVE CATEGORIES OF STIMULI– FIVE RECEPTORS• MECHANORECEPTORS
– DETECT TOUCH, PRESSURE, STRETCHING, MOTION AND SOUND
THE SENSES
• SPECIALIZED SENSORY RECEPTORS DETECT FIVE CATEGORIES OF STIMULI– FIVE RECEPTORS• CHEMORECEPTORS
– ATTUNED TO CHEMICALS
THE SENSES
• SPECIALIZED SENSORY RECEPTORS DETECT FIVE CATEGORIES OF STIMULI– FIVE RECEPTORS• ELECTROMAGNETIC RECEPTORS
– SENSITIVE TO ENERGY OF VARIOUS WAVELENGTHS
– EX. PHOTORECEPTORS
THE SENSES
• THREE DIFFERENT TYPES OF EYES HAVE EVOLVED AMONG INVERTEBRATES– 3 TYPES• EYE CUP• COMPOUND EYE
– MANY TINY LIGHT-DETECTING UNITS
• SINGLE-LENS EYE– SIMILAR TO CAMERA
THE SENSES
• VERTEBRATES HAVE SINGLE-LENS EYES
THE SENSES
• VERTEBRATES HAVE SINGLE-LENS EYES– SCLERA– CORNEA– CHOROID
• IRIS
– PUPIL– LENS– RETINA– VITREOUS HUMOR and AQUEOUS HUMOR– CONJUCTIVA
THE SENSES
• TO FOCUS, A LENS CHANGES POSITION OR SHAPE– MUSCLES ATTACHED TO THE CHOROIDS CHANGE
THE SHAPE OF THE LENS; FOCUSING LIGHT APPROPRIATELY
THE SENSES
THE SENSES
• ARTIFICIAL LENSES OR SURGERY CAN CORRECT FOCUSING PROBLEMS– 3 COMMON PROBLEMS• NEARSIGHTEDNESS (MYOPIA)
– EYEBALL TOO LONG
• FARSIGHTEDNESS (HYPEROPIA)– EYEBALL TOO SHORT
• ASTIGMATISM– MISSHAPEN LENS OR CORNEA
THE SENSES
• OUR PHOTORECEPTOR CELLS ARE RODS AND CONES– CONES• STIMULATED BY BRIGHT LIGTH AND CAN DISTINGUISH
COLOR; DO NOT FUNCTION AT NIGHT• PHOTOPSINS
– VISUAL PIGMENTS THAT ABSORB BRIGHT, COLORED LIGHT
THE SENSES
• OUR PHOTORECEPTOR CELLS ARE RODS AND CONES– RODS• EXTREMELY SENSITIVE TO LIGHT AND ENABLE US TO
SEE IN DIM LIGHT AT NIGHT, THOUGH ONLY IN SHADES OF GRAY• RHODOPSINS
– VISUAL PIGMENT THATCAN ABSORB DIM LIGHT
THE SENSES
• THE EAR CONVERTS AIR PRESSURE WAVES INTO ACTION POTENTIALS THAT ARE PERCEIVED AS SOUND
THE SENSES
• THE EAR CONVERTS AIR PRESSURE WAVES INTO ACTION POTENTIALS THAT ARE PERCEIVED AS SOUND– OUTER EAR COLLECTS SOUNDWAVES TO EAR DRUM
• PINNA “EAR”; FLAP-LIKE STRUCTURE• AUDITORY CANAL
– EARDRUM SHEET OF TISSUE THAT SEPARATES OUTER EAR FROM MIDDLE EAR
– MIDDLE EAR• EARDRUM; HAMMER, ANVIL, STIRRUP, OVAL WINDOW
THE SENSES
• THE EAR CONVERTS AIR PRESSURE WAVES INTO ACTION POTENTIALS THAT ARE PERCEIVED AS SOUND– INNER EAR• CONTAINS COCHLEA
– THE ACTUAL HEARING ORGAN
THE SENSES
• THE INNER EAR HOUSES OUR ORGANS OF BALANCE– SEMICIRCULAR CANAL
• DETECT CHANGES IN THE HEAD’S RATE OF ROTATION OR ANGULAR MOVEMENT
– UTRICLE AND SACCULE HAIR CELLS THAT DETECT THE POSITIONOF THE HEADWITH RESPECTTO GRAVITY
THE SENSES
• WHAT CAUSES MOTION SICKNESS?– CONFLICTING SIGNALS FROM THE EYES AND
INNER EAR’S BALANCE MECHANISM– SPIN AROUND OVER AND OVER, THEN SUDDENLY
STOP…WHAT HAPPENS?!?!?!?
THE SENSES
• ODOR AND TASTE RECEPTORS DETECT CATEGORIES OF CHEMICALS
THE SENSES
• REVIEW: THE CENTRAL NERVOUS SYSTEM COUPLES STIMULUS WITH RESPONSE– NERVOUS SYSTEM LINKS STIMULUS RECEPTION
WITH RESPONSE• STIMULI RECEPTORS SENSORY NEURONS CNS
INTEGRATION MOTO NEURON EFFECTOR RESPONSE
– REFLEX ARC
THE SENSES
• WHAT ABOUT OUR MUSCLES??• SKA-DOOSH!!
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