Ch 35 Sensors AP Lecture

Sensory Receptor Cells Sensors or receptors that convert sensory stimuli into change in membrane potential. This causes an action potential which conveys sensory information to the CNS for processing and interpretation. Specific stimuli – Chemoreceptors- chemical signals

– Olfaction- sense of smell, olfactory sensors – Gustation- sense of taste, taste buds work with olfactory receptors – Mechanoreceptors- detect physical force Skin Hair cells

Sensory Transduction Starts with a receptor protein that opens or closes ion channels in response to a stimuli Receptor potential is the change in membrane potential of the receptor cell in response to a stimuli. If the signal needs to travel a long distance then the receptor must cause an action potential.

Auditory Outer ear – Ear tissue collects sound and channels it into the auditory canal – Ear drum, tympanic membrane, covers the end of the canal and vibrates in response to sound waves.

Middle ear – Air filled cavity – Contains three delicate bones, ossicles – Bones amplify vibrations from ear drum to oval window Hammer Avil Stirrup

Middle ear connects to the throat through the eustachian tube, allowing equilibrium of air pressure in and out ear.

Inner ear – Two sets of fluid filled canals – Vestibular system, organ of balance – cochlea Snail shell shaped Organ of hearing Has hair cells that release neurotransmitters into sensory organs which causes an action potential to the brain

Visual Photosensitivity – Rod cells Capture light Stack of discs in plasma membrane packed with pigment, rhodopsin Located in the retina

Photoreceptors – Cone cells Color vision In retina

Image forming eyes – Lens that focuses images on an internal surface that is sensitive to light

Eye is a fluid filled structure bound by a tough connective tissue, sclera Cornea, transparent layer allows light to enter the eye Iris is the muscle that operates the size of the pupil Lens adjusts the focus of the image Retina receives and process visual information and sends visual signal to the brain