By Jasmine Luck, Brianna Hebert, Nicole Hickman, Molly Spitters, Ashkan Shahbandi Per. 3

Sensation- A feeling that occurs when brain becomes aware of sensory impulse Perception- A person’s view of the stimulus; the way the brain interprets the information Projection- Process in which the brain projects the sensation back to the apparent source Sensory adaptation- ability to ignore unimportant stimulus Chemoreceptors- respond to changes in chemical concentrations Pain receptors- (nociceptors) respond to tissue damage Thermoreceptors- respond to changes in temperature Mechanoreceptors- respond to mechanical forces Photoreceptors- respond to light

General senses: Joint, muscle, skin, visceral senses. Three groups: exteroceptive (body surface senses), visceroreceptive (changes in viscera), and proprioceptive (muscle/tendon changes) Touch and Pressure Senses: Free nerve endings (sense itching), Meissner’s corpuscles (fine touch), and Pacinian corpuscles (heavy pressure and vibrations) Warm recepetors (sensitive above 25⁰C, unresponsive above 45 ⁰C) Cold receptors (sensitive between 10⁰C and 20⁰C) Pain receptors (respond below 10⁰C and above 45⁰C) Visceral Pain is “referred pain” Acute pain fibers (A-delta fibers) Chronic pain fibers (C fibers)

Olfactory System: Pathway: Olfactory nerves -> olfactory bulbs -> olfactory tracts -> limbic system -> olfactory cortex Olfactory code: a hypothesis about how certain odors stimulate a set of receptor cells and its associated receptor cells and proteins.

Sense of Taste Taste Buds: located on papillae of tongue, roof of mouth, linings of cheeks, walls of pharnx Taste receptors: Taste cells (chemoreceptors)+Taste hairs (microvilli that protrude from taste cells) Primary taste sensations: sweet, sour, salty, bitter (spicy activates pain and sour receptors) Cranial nerves=>medulla oblangata=>thalamus=>gustatory cortex

Hearing External ear: auricle, external auditory meatus, tympanic membrane Middle ear: tympanic cavity, auditory ossicles, oval window Auditory tube: eustachian tube connects middle ear to throat (maintain equal pressure on both sides of tymp. membrane) Inner ear: osseous (perilymph)+membranous (endolymph) labyrinth; cochlea, semiciruclar canals, vestibule Cochlea composed of scala vestibuli + tympani, cochlear duct, vestibular membrane, basilar membrane Organ of Corti: hair cells on surface of basilar membrane, different frequencies of vibration move different parts of membrane

Equlibrium Static Equilibrium: Vestibule (utricle, saccule, macula); sense position of head when body is not moving Dynamic Equilibrium: semicircular canals (ampulla, crista ampullaris); sense rotation and movement of head and body

Visual Eyelid: papebra (skin, muscle, connective tissue, conjunctiva), orbicularis oculi (closes), levator palperbrae superioris (opens), conjunctiva (mucous membrane) Lacrimal Apparatus (lacrimal gland => canaliculi => lacrimal sac => nasolacrimal duct) Extrinsic eye muscles (superior rectus rotates up+medially, inferior rectus rotates down+medially, medial rectus rotates medially, lateral rectus rotates laterally, superior oblique rotates down+laterally, inferior oblique rotates up+laterally)

Visual Cont. Outer tunic: cornea (light refraction), sclera (protection) Middle tunic: iris (controls light intensity), ciliary body (holds+moves lens), choroid coat (vascular region) Anterior portion of eye filled with aqueous humor Lens: transparent, biconvex, lies behind iris Accommodation: changing lens shape to view objects Pupil: hole in iris Inner tunic: retina (visual receptors), macula lutea (yellowish spot in retina), fovea centralis (sharpest vision), optic disk (blind spot), vitreous humor in posterior cavity (thick gel holds retina against choroid coat) Vision: cornea=>aqueous humor=>lens=>vitreous humor=>retinal layers=>photoreceptor cells

Visual Cont. Retinal neurons: Receptor cells, bipolar cells, and ganglion cells (provide pathway for impulses) Horizontal cells and amacrine cells (modify impulses) Refraction: bending of light Convex causes convergence (hyperopia), concave causes divergence (myopia) Rods (more sensitive, colorless vision, dark+dim light, blurry), cones (colored vision, sharp) Rods: rhodopsin Cones: erythrolabe (red), chlorolabe (green), cyanolabe (blue) Stereoscopic vision: perception of distance+depth