special senses
cochlea
hearing
nociceptor
pain
fibrous tunic
sclera and cornea
Sclera
white of the eye muscle attachment superficial, protective
retina ganglion cells
- axons form the optic nerve - only cells that can generate action potentials
Layers/tunics of the eyeball
1. fibrous tunic 2. vascular tunic (uvea) 3. Sensory tunic (retina)
lens
focus light on the retina by changing shape
mechanoreceptor
hearing and equalibrium
Optic n
CN II made up of the axons of the retinal ganglion cells
right optic tract
left visual field
genioglossus m
protracts tongue
photoreceptors
rods and cones
iris
central opening = pupil color of eye
Cornea
clear light passes through refract light
anterior segment
contains aqueous humor
extrinsic muscles of the tongue innervated by
hypoglossal n (CN XII)
ciliary body
muscle, changes shape of lens
Lateral rectus muscle
A: abduction of eyeball I: abducens n (CN VI)
Medial rectus muscle
A: adduction of eyeball I: oculomotor n (CN III)
Superior oblique muscle
A: depression & abduction of eyeball I: trochlear n (CN IV)
inferior rectus muscle
A: depression of eyeball I: oculomotor n (CN III)
Inferior oblique muscle
A: elevation & abduction of eyeball I: Oculomotor n (CN III)
superior rectus muscle
A: elevation of eyeball I: Oculomotor n (CN III)
primary olfactory cortex
-located mostly at the medial aspect of the temporal lobe -conscious awareness of odors
two main destinations of smell impulses
1) Primary olfactory cortex 2) Subcortical route to the hypothalamus, amygdala, and other regions of limbic system
Visual pathway order
1. Photoreceptors 2. Ganglion cells (axons for the optic nerve) 3. Optic chiasm (partial crossover) 4. Optic tract 5. Thalamus 6. Primary visual cortex
Structure of the Eyeball
Wall of eyeball contains three layers Fibrous tunic Vascular tunic Sensory tunic Lens Internal cavity - anterior segment - posterior segment
hypoglossus m
depress tongue
styloglossusm
elevate and retract tongue
semicircular canals
equilibrium
posterior segment
filled with vitreous humor
choroid
highly vascularized highly pigmented absorb light
right primary cortex
integrates information from left visual field
left primary cortex
integrates information from right visual field
right primary visual cortex
left visual field
photoreceptors convert
light signals into electrical signals
auditory ossicles
malleus, incus, stapes
general sensory
mandibular division of trigeminal n (CN V3)
Optic chiasm
partial crossover peripheral info
retina (sensory tunic) composed of
photoreceptors
Optic (2) contains
portions of each visual field information
proprioreceptors
position of body in space
oval window
pressure in - stapes
round window
pressure out
baroreceptor
pressure receptor
thalamus
relay station
Mechonoreceptors
semicircular canal, cochlea
structures of the internal ear
semicircular canals cochlea oval window round window
anterior 2/3 of tongue
special sensory for taste innervated with CN VII, facial n
posterior 1/3
special sensory for taste and general sensory glossopharyngeal n (CN IX)
Oculomotor nerve - parasympathetic
stimulation causes circular muscles to contract change pupil diameter
visual pathway 5&6 fibers in the optic tract
synapse with neurons in the thalamus
chemoreceptor
taste and smell
Thermoreceptors
temperature
auditory cortex
temporal lobe
subcortical route to the hypothalamus, amygdala, and other regions of limbic system
to elicit emotional memory; evoked responses to the odors
fibers from thalamus project
to the primary visual cortex in the occipital lobes
structures of the middle ear
auditory ossicles, pharyngotympanic tube
structures of the external ear
auricle, external auditory canal, tympanic membrane
left optic n
carries information from both right and left visual fields
right optic n
carries information from right and left visual fields
Optic information
carry info from 1 eye carry info from L + R visual fields
pupil
central opening light enters
Vascular tunic
choroid, ciliary body, iris
