accessory structures
structures that support the eyeball in some way
conjunctiva
membrane that lines the eyelid and the outer surface of the eyeball
extrinsic eye
structures outside the eyeball
lacrimal apparatus
consists of all the structures involved with moving tears
sclera
cutaneous membrane covering the eyeball
lacrimal gland
continuously releases tears
eyelashes
hair protecting the border of eyelids
palpebral fissure
gap between eyelids when they are open
lysozyme
enzyme that destroys bacteria in tears
lateral commissure
where the two eyelids meet laterally
medial commissure
where the two eyelids meet medially
tarsal gland
produce oily secretions to lubricate the eye
eyebrow
redirects sweat away from the eyeball
lacrimal cannaliculus
moves tears from the eyeball to the nasolacrimal duct
nasolacrimal duct
moves tears into the nasal cavity
excretory ducts
releases tears onto the eyeball from the lacrimal gland
eyelids, conjunctiva, lacrimal apparatus, and extrinsic eye muscles
list the four main extrinsic eye accessory structures
fibrous layer
most superficial,, or outer, wall of the eyeball
visceral layer
intermediate wall of the eyeball
sensory layer
deepest, or most internal, wall of the eyeball
fibrous layer
this layer is composed of the sclera and cornea
visceral layer
this layer is composed of the choroid and smooth mucsles
sensory layer
this layer is composed of the retina
retina
this is composed of a pigmented layer and a neural layer
sclera
thick, white connective tissue
vitreous humor
portion behind the lens
choroid
blood rich tunic that has dark pigments
ciliary body
smooth muscle that changes the shape of a lens
iris
smooth muscle that changes the size of a pupil
ciliary zonule
ligament that is attached to the lens
pupil
opening to the eye
iris
colored smooth muscle
circular muscle
type of muscle that contracts to make the pupils smaller
aqueous humor
portion in front of the lens
radial muscle
type of muscle that contracts to make the pupils bigger
vitreous humor
fluid that functions to prevent the eyeball from collapsing
retina
responsible for detecting photons
pigmented layer
composed of pigmented cells to absorb light
neural layer
transparent layer that contains photoreceptors
photoreceptors
sensory receptors that are stimulated by light
rods
type of photoreceptor that detects gray light and aids in peripheral vision
optic nerve
cranial nerve that transmits visual information to the brain
cones
type of photopreceptor that detects colored light
posterior segment
portion of the retina where no light can be detected
aqueous humor
fluid that fills the anterior segment
lens
flexible structure that functions to focus the light entering the eyeball
cornea
clear portion of the fibrous layer that is at the anterior portion of the eyeball
virteous humor
fluid that fills the posterior segment
cornea, lens, vitreous humor, aqueous humor
what structures in the eye bend light as it travels through it?
the cornea and humors
which structures provide a constant refraction of light?
the lens by changing its shape
which structure functions primarily in focusing light on the retina? how does it do this?
real image
image focused on the retina that is upside down and reversed
optic nerve
functions to carry impulses from the retina to the brain
optic chiasma
where the optic nerves from each eye cross to the opposite sides of the brain
optic tract
the bundle of neurons that are transmitting the visual information in the CNS
optic radiation
term given to spreading of axons after the nerve impulse has traveled through the thalamus
occipital lobe
where visual information is interpreted
photopupillary reflex
sudden exposure to bright light causing the pupils to constrict
accomodation pupillary reflex
pupils constrict when viewing close objects
fixation point
point outside the body that the eyes are focusing on
chemoreceptors are sensitive to chemicals, mechanoreceptors are sensitive to physical force, and photoreceptors are sensitive to light
what is the difference between chemoreceptors, mechanoreceptors, and photoreceptors?
they are considered to be chemical senses since they both use the detection of chemicals to determine what is being smelt / tasted
why are smelling and taste both using chemoreceptors?
olfactory receptors
receptors for the sense of smell
taste buds
receptors for the sense of taste, composed gustatory/basal/support cells
gustatory cells
specific cells that respond to chemicals dissolved in the saliva
gustatory hairs
long projections that are stimulated by chemicals dissolved in saliva
olfactory hairs
long projections that detect chemicals dissolved in mucus
mucus
dissolves chemicals to be interpreted as smell
saliva
dissolves chemicals to be interpreted as taste
taste buds
located on the cheeks, soft palate, and pharynx
olfactory bulb
located at the roof of the nasal cavity
olfactory filaments
cells with olfactory hairs
olfactory tract
nerve that transmits the impulse of smell to the olfactory cortex
glossopharyngeal nerve and facial nerve
nerves that transmit impulses of taste to the gustatory cortex
circumvallate papillae
small peg projections, located on the dorsal part of the tongue
fungiform papillae
more numerous type of papillae
fungiform papillae
type of papillae that is located on the anterior portion of the tongue
fungiform papillae
taste buds are found on top of this type of papillae
circumvallate papillae
taste buds are found on the sides of this type of papillae
taste pore
pore that gustatory hairs protrude from
sweet receptors
taste receptors that respond to sugars
sour receptors
taste receptors that respond to the acidity of the solution
bitter receptors
taste receptors that respond to alkaloids
salty receptors
taste receptors that respond to metal ions in solution
umani
taste receptors that respond to the amino acid glutamate (BEEF)
olfactory filaments
transmit the impulses from the olfactory hairs to the olfactory bulb
olfactory bulb
transmits the impulses from the olfactory filaments to the olfactory tract
olfactory tract
transmits the impulses from the olfactory bulb to the olfactory cortex
olfactory cortex
interprets the sense of smell
gustatory cortex
interprets the sense of taste
1) light enters eye through pupil
2) lens
3) retina
4) photons hit light receptors
5) stimuli of light is converted to electrical signal
vision pathway 1-5
6) optic nerve
7) optic chiasma
8) optic tract
9) thalamus
10) optic radiation
11) visual cortex
vision pathway 6-11
1) chemicals dissolved into mucus
2) solution comes in contact with olfactory hairs
3) impulse carried along olfactory filaments to olfactory nerve
4) olfactory nerve carries impulse to olfactory bulb
5) olfactory bulb transmits the impulse to olfactory t
smell pathway
1) chemicals dissolved in saliva
2) solution comes in contact with gustatory hairs on papillae
3) impulse sent through gustatory cells to the glosspharyngeal of facial nerve
4) impulse sent to gustatory cortex
taste pathway