Perception of stimuli

By Martin SamajIB study guide: 133

Perception and Stimulus• Perception – the act of apprehending by

means of the senses of the mind• Stimulus – something causing or regarded as

causing a response • Humans have a large variety of sensory

receptors which enable us to perceive a wide range of stimuli

Examples of receptorsType Stimulus Example

Mechanoreceptors Mechanical energy in the form of sound waves

Hair cells in the cochleaPressure receptor cells in

the skinChemoreceptors Chemical substances

dissolved in water (tongue)Chemical substances as

vapor (nose)

Receptor cells in the tongue and nerve endings

in the nose

Thermoreceptors Temperature Nerve endings in the skin detecting warm or cold

conditionsPhotoreceptors Electromagnetic radiation

usually in the form of lightRod and cone cells in the

eye

Structure of the human ear

Hearing• Hearing is one of the 5 major senses (hearing,

touch, smell, sight, taste) that allows us sound perception

• Because of how our auditory systems are constructed a typical human being is able to perceive sounds in the frequency range from 20 – 20 000 hertz.

Perception of sound• Eardrum

– Sound waves cause the ear drum to vibrate. The role of the eardrum is to pick up sound vibrations from the air and send them to the middle ear

• Bones of the middle ear– There is a series of small bones in the middle ear called ossicles. All are in

contact with each other. They transmit vibrations from the eardrum to the oval window

• Oval window– A membranous structure that transmits the sound waves to the fluid filling

the inside of cochlea

• Hair cells in the cochlea– Hair cells enable the transmission of messages across synapses and into

the brain through the auditory nerve

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