Sensation and Perception

Sensation- awareness or mental process which is aroused due to stimulation of a sense organ. ACQUIRING SENSORY AWARENESS 1 ST CONDITION: Stimulation – anything which rouses a sense organ to activity. 2 types of stimulus 1. physical energy 2. chemical form energy

Receptor Organ – highly specialized part of the body and selecting sensitive to a definite stimulus. - doorway of the body responsible for all the sensation we experience. - “sense organ”

2 nd Condition: Presence of Receptor Cell - the sense organ detect stimuli from the environment and transmit information to the appropriate areas of the brain. 3 rd Condition: Sense Receptor is stimulated by certain “stimulus”.

Stimulus must be transferred into a code of electrochemical impulses which is travel to the brain. Transduction – process of converting physical energy into activity in the nervous system which takes place in the receptor.

QUESTION: When a stimulus is said to be detected? ANSWER: Stimulus to be detected must be strong enough and to produce sensation. 1. Absolute threshold – stimulus is in the inner limit or does not go or reach beyond the threshold. 2. Subliminal threshold – stimuli are way above the threshold. 3. Terminal threshold – stimuli reach an increased intensity it produces pain and individual uncomfortable.

Sensory Adaptation : 1. Sense Receptor – ability to make adaptation to changes/ adjust to a particular stimulus. 2. Sense Organ: a. Distal senses – sensitive to stimuli coming from a distance in the outside environment. b. Proximal senses – bring information when we come direct contact with the objects that stimulates them.

A. DISTAL SENSES 1. Vision - utilize the physical characteristic of light. EYE (receptor organ of Vision). Light Waves ( stimuli for seeing) waves of radiant energy coming from the sun. Eye utilizes 2 basic properties of light: 1. brightness – intensity of light (the amount of radiant energy coming from the sun. 2. color – wave length or frequency

Parts of the Eye: 1. Sclerotic coat (SCLERA) – hard and outer most covering , it protects the eye. 2. Choroid coat – full of bloody tissues, gives nourishment to the eye. 3. Retina – inner most covering of the eye. Photosensitive plate of the eye. Regarded as the true organ of vision. RODS and CONS (receptors cells) embedded on in the coat.

connects light energy to nerve impulse Receptor cells Nerve impulse Optic nerve BRAIN

Receptor cells of the eye: RODS - slender nerve cells ( 100 million) Function: used for twilight vision or low light intensity, enable one to make colorless discrimination, sensitive to tiny amount of lights ( dim light ), color blind (they see the world in black and white). Cones – thicker / cone shape ; interprets color. ( 6 million) Function: Daytime vision , enable one to discriminate brightness , hue or color. See the color of the spectrum ( 3 types of cones) Sensitive to A. red B. green C. blue

3 dimension of colors 1. Hue - name of colors red- longest wave length. violet – shortest wave length. blue , green , yellow – intermediate wave length. 2. Brightness – energy of the source of light coloring range from bright to dim. intensity of the stimulus. 3. Saturation – purity or richness of color. highly saturated color – pure hues ( no tint of gray added) low saturation – close to gray note: Saturation of any color is reduced by mixing it with white.

Visual defects 1. myopia 2.Hyperopia 3.Presbyopia 4. Astigmatism 5. Diplopia 6. Scotoma

Parts of the retina: Fovea – in the central region, the point of clearest and sharpest vision Blind spot – are where all the nerve fibers converge to form optic nerve which carries impulse to the brain. 2 kinds of Blind spot Dichromatic – 2 or 3 primary colors Achromatic – no cones in the retina

2. AUDITION Sound Waves 1. pitch – highness or lowness of a sound. 2. loudness – intensity sound pursue that activates the eardrum. 3. timbre – quality of musical tone .

Mechanism of the hearing 3 major parts: 1. outer / external serves to collect sound waves. 2. middle ear – transmit the sound waves. 3. inner ear – has sensitive receptors for hearing.

How do we hear? Sound waves travel and collected by pinna Funneled by the auditory canal Ear drum

Changes in air pressure Middle ear Tiny bones hammer anvil

Stirrup ( to vibrate) 3 tiny bones conduct the sound impulse inward to the inner ear: Hammer – eardrum- stirrup Oval windows

cochlea Auditory portion of the inner ear ( pressure Changes , fluid displace Receptor cells

Hair cells (receptor cells of organ of corti) Auditory nerve Brain

II. Proximal Distance: 1. Olfaction – sense of smell stimulus substance : gaseous substance( must be dissolved in the air “ vaporous form.

Mechanism of Smell: RECEPTOR – Olfactory receptor – long thread like nerve tissue from Olfactory bulb Nasal cavity

Process: 1. Anything that is sniffed must best dissolved in the air. 2. Receptor cells detect the molecules dissolved in the air that is sucked up in the nasal cavity. 3. Move up to the olfactory bulbs of the brain. 4. Physical Energy is transduced in the olfactory epithelium to be able to reach the brain.

2. Gustation “ Tongue” organ for the sense of taste Stimulus – chemicals – must transform into soluble substance to penetrate into the taste cells. Receptor – taste receptor Papillae – tongue elevation Taste buds – lie between the papillae ( taste receptor) Pore – opening of the taste buds.

Mechanism of taste: The food is transformed into soluble form . Depolarized liquid substance can penetrate into the taste cells: depolarized Will incite the nerve fiber

Give rise to nerve impulse Gustatory nerve Brain

Sensation and Perception

More Related Content

What's hot

Viewers also liked

Similar to Sensation and Perception

More from Mypzi

Recently uploaded

Sensation and Perception