Transcript Perception of stimuli

By Martin Samaj
IB 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 receptors
Type
Stimulus
Example
Mechanoreceptors
Mechanical energy in the
form of sound waves
Hair cells in the cochlea
Pressure receptor cells in
the skin
Chemoreceptors
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
conditions
Photoreceptors
Electromagnetic radiation
usually in the form of light
Rod 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