Special Sense Organs Flashcards
General Senses
Thermoreceptors (temp)
Nociceptors (pain)
Baroreceptor (pressure/stretch)
Proprioreceptors (proprioception)
Special Senses
Chemoreceptors (taste and smell)
Mechanoreceptors (hearing and equilibrium)
Photoreceptors (vision and light)
Sensory innervation of tongue
Anterior 2/3 - special sensory for taste facial n. CN VII, general sensory mandibulaire division of trigeminal nerve 3
Posterior 1/3 - special sensory for taste and general sensory by glosspharyngeal CN IX
Extrinsic muscles of the tongue
Hypoglossal innervation CN XII
Genioglossus protract tongue (genio=chin)
Styloglossum elevate and retract tongue attaches to styloid process
Hyogossus depress tongue attaches to hyoid bone
Smell
CN I olfactory nerve
Olfactory tract and olfactory bulb passes through cribiform plate of ethmoid
Primary olfactory cortex - Located mostly at the medial aspect of the temporal lobe; conscious awareness of odors
Subcortical route to hypothalamus, amygdala, and other regions of limbic system - to elicit emotional and memory; evokes response to odors
Ear
External ear - Auricle, external auditory canal, Tympanic membrane
Middle ear- Ossicles- Malleus, incus, stapes. Pharyngotympanic tube(allows air and pressure equalization, mucus and waste removal)
Inner ear - oval window, cochlea and semicircular canals, round window
Eyeball structure
Three layers/tunics - fibrous(sclera, cornea), vascular(uvea), sensory(retina)
Lens
Internal cavity - Anterior segment(aqueous humor), posterior segment(vitreous humor)
Fibrous tunic
Sclera - whites of eyes, muscles attach
Cornea - clear, light pass through, refract(bend)
Extrinsic muscle of eye
Oculomotor CNIII
Superior rectus - elevation of eyeball
Inferior rectus - depression of eyeball
Medial rectus - adduction of eyeball
Inferior oblique - Elevation and abduction of eyeball
Abducens CNVI
Lateral rectus - abduction
Trochlear CNIV
Superior oblique - Depression and abduction of eyeball
Vascular Tunic
Choroid - Highly vascularized, highly pigmented(absorb light)
Ciliary body
Iris - central opening (pupil) - Colored area, pupil allows light entry
Oculomotor nerve is parasympathetic, affect iris/pupil diameter
Constrict pupil
Sympathetic dilate pupil
Sensory tunic
Optic nerve CNII, axons of the retinal ganglion cells
Retina
Internal cavity -
anterior segment, anterior to lens, filled with aqueous humor (replaced often, clear liquid)
posterior segment, posterior to the lens, filled with vitreous humor(not replaced, gelatinous, shock absorption)
Lacrimal apparatus
Tear
lacrimal gland
Nascolacrimal duct
CNVII facial nerve
Medial eye
Visual pathway
Photoreceptors - ganglion cells(axons for the optic nerve) - optic chasm(partial crossover) - optic tract - thalamus - primary visual cortex
Light converted into electrical signal
Retinal ganglion cell axons leave eye as optic nerve- portion of each visual field information
Fibers from nasal aspect of retina cross over at optic chiasm
Fibers continue via optic tracts - right holds left and left holds right
Fibers synapse with thalamus - project to visual cortex in occipital lobes
