A&P Mini Practical 8 - General and Special Senses

Photoreceptors

Stimulated by light. Special sense (vision)

Thermoreceptors

Stimulated by temperature. General sense (temperature)

Proprioceptors

Stimulated by mechanical stretch or tension in muscles, tendons, and joints. General sense (proprioception)

Nociceptors

Stimulated by pain. General sense (pain)

Mechanoreceptors

Stimulated by pressure or stretch. General sense (touch, pressure, vibration, proprioception)

Free Nerve Ending

• Stimulated by temperature, pain, light touch

• Warm receptors, cold receptors, nociceptors (pain)

• General sense

Meissner corpuscles

Stimulated by light touch, texture perception, 2-point discrimination. General sense (fine touch)

Merkel discs

Stimulated by light touch and pressure. General sense (fine touch)

Pacinian corpuscles

Stimulated by deep pressure, stretch, tickle, and vibration (texture). General sense (pressure, vibration)

Baroreceptors

Stimulated by stretch (of blood vessels). General sense (blood pressure regulation)

Chemoreceptors

Stimulated by chemicals (oxygen, CO₂, pH, smell, taste). Special sense (smell, taste) and general sense (blood chemistry)

Taste bud

Taste pore

Taste cell

Supporting cell

Gustatory hair

Olfactory tract

Olfactory bulb

Olfactory nerve

Ethmoid bone

Cribriform plate

Superior rectus

CN III (oculomotor nerve), moves gaze up

Inferior rectus

CN III (oculomotor nerve), moves gaze down

Medial rectus

CN VI (abducens nerve), moves gaze medially

Lateral rectus

CN III (oculomotor nerve), moves gaze laterally

Superior oblique

CN IV (trochlear nerve), internally rotates the eye

Inferior oblique

CN III (oculomotor nerve), externally rotates the eye

Conjunctiva

Palpebrae

Eyelids - palpebral fissure, eyelashes

Lacrimal gland

Lacrimal canal

Cornea

Sclera

Anterior chamber

Posterior chamber

Aqueous humor

• Posterior chamber - from lens to iris

• Anterior chamber - from iris to cornea

• Blue arrows

Iris

Pupil

Lens

Suspensory ligaments

Ciliary body

Vitreous chamber

Behind lens, in vitreous humor

Vitreous humor

Contains vitreous chamber

Choroid

Retina

• Lines posterior two-thirds of eye, photoreception

• Entire nervous tunic

• Contains photoreceptors (rods and cones), converts light into electrical signals

Macula Lutea

• Central patch for detailed vision

• Center of retina, sharp central vision

• High concentration of cones

Fovea Centralis

• Pit in center of macula

• Highest concentration of cones, no rods

• Spot of sharpest visual acuity

Optic disc

• Blind spot without photoreceptors

• Where the optic nerve exits retina

Rods

• Night vision, monochromatic

• Rhodopsin - pigment

• Maximizes light absorption

Cones

• Day vision, trichromatic

• Color vision

• Photopsins - three different pigments

  • Red, green, blue

  • Respond to different wavelengths

Auricle

Ear lobule

External auditory canal

Tympanic membrane

Malleus

Incus

Stapes

Eustacian (Auditory) Tube

Oval window

Round window

Cochlea

Vestibule

Semicircular canals

Spiral organ

Basilar membrane

Vestibular membrane

Hair cell

Stereocilia

Utricle

Saccule

Crista ampullaris

Cupula