Histoglogic COMPONENTS of the OLFACTORY EPITHELIUM
Olfactory Hair Cells Basal Cells Support Cells Cribriform Plate Olfactory Bulb
Odorants must first ______ in order to reach the Olfactory Receptors (on olfactory hairs)
be disosolved in fluid (mucus)
When odorant binds to its receptor, a ____ is activated, As a result, _____ opens
G protein (is activated) Na+ and Ca2+ Channels (open)
7 primary odors
- Camphoraceous (moth balls)
- Musky
- Floral
- Peppermint
- Ethereal
- Pungent
- Putrid
Olfactory NEURONS and EPITHELIUM die/replenished by _____ every 2 months
Basal cells
Once an odorant binds to its receptor, the receptor accomodates and does not respond to another odorant for some time
Olfactory neurons form CNI - They synapse with interneurons to form the __ __
Olfactory Tracts (in olfactory bulb)
Olfactory Tracts terminate in __ and __
- Olfactory CORTEX
2. AMYGDALA (in temporal lobe)
Olfaction: Feedback loops inhibit transmission - leading to adaptation with prolonged exposure
Taste associated with Na+
salty
Taste associated with CARBOHYDRATES, SUGAR, PROTEINS
sweet
Taste associated with GLUTAMATE
umami
Taste associated with ACID
sour
Taste associated with BASES
bitter
3 specialized epithelial cells of each TASTE BUD
- Taste cells (sensory) - with taste hairs & pore
- Basal cells (nonsensory)
- Supporting cells (nonsensory)
__ dissolve in saliva to enter the taste pores
Tastants
Tastants bind to G protein receptors - causing taste cells to __
depolarize (Na+ / H+ Channels open)
Taste from the Anterior 2/3 of the tongue is carried by CN __
CN VII - Facial (Chorda Tympani)
Taste from the Posterior 1/3 of the tongue and superior pharynx is carried by CN __
CN IX - Glossopharyngeal
Taste sensation from the Epiglottis is carried by CN __
CN X - Vagus
Taste: CNVII, CNIX, and CNX extend from the Taste Buds to nuclei in the __ __. Fibers cross and extend to the __.
Cranial Nerves from Taste Buds >
Medulla Oblongata >
Thalamus
Taste: Neurons from the Thalamus project to the __ and __
Insula
Frontal Cortex
Cells of taste buds have normal life span of ___
10 days
Accessory Structure: Prevents perspiration and helps shade eyes from direct sunlight
eyebrows
Eyelids: Five layers of tissue
- Skin
- Loose CT
- Orbicularis Oculi ad Levator Palpebrae (muscle)
- Tarsal Plate (Dense CT)
- Conjunctiva
Eyelids/Eyelashes: Blink Reflex (functions)
- Protects from foreign objects
- Helps lubrication
- Regulate amount of light entering
Modified sweat glands that open into hair follicles to keep eyelashes lubricated
Ciliary glands
When a Ciliary Gland becomes inflamed, it is called a __
sty
Glands near inner margins of the eyelids that produce sebum (sebaceous)
Tarsal glands
Infection of blockage of a Tarsal Gland is called ___
chalazion / meibomian cyst
Accessory Structure:
- Thin, transparent mucous membrane
- Covers inner surface of eyelids and anterior white surface of eye
- Reduces friction
- Barrier to entry of microorganisms
Conjunctiva
Eye muscle(s) that is/are innervated by CN III
CN III (Oculomotor): Superior Rectus Inferior Rectus Medial Rectus Inferior Oblique
Eye muscle(s) that is/are innervated by CN IV
CN IV (Trochlear): Superior Oblique
Eye muscle(s) that is/are innervated by CN VI
CN VI (Abducent): Lateral Rectus
CN that dilates and constricts the PUPIL
CN III, Oculomotor
Extrinsic Eye Muscle:
DEPRESSES and MEDIALLY deviates gaze
Inferior Rectus (CN III)
Extrinsic Eye Muscle:
MEDIALLY deviates gaze
Medial Rectus (CN III)
Extrinsic Eye Muscle:
ELEVATES and MEDIALLY deviates gaze
Superior Rectus (CN III)
Extrinsic Eye Muscle:
LATERALLY deviates gaze
Lateral Rectus (CN IV)
Extrinsic Eye Muscle:
ELEVATES and LATERALLY deviates gaze
Inferior Oblique (CN III)
Extrinsic Eye Muscle:
DEPRESSES and LATERALLY deviates gaze
Superior Oblique (CN IV)
Cranial Nerve that OPENS EYELID
CN III, Oculomotor
Cranial Nerve that CLOSES EYELID
CN VII, Facial
Structures located in the FIBEROUS Layer of the eyeball
- Sclera (posterior 5/6th)
2. Cornea (anterior 1/6th)
Structures located in the VASCULAR Layer of the eyeball
- Choroid (posterior)
- Ciliary Body (anterior)
- Iris (colored)
Helps maintain shape of eyeball
Protects internal structures
Provides attachment point for eye muscles
Sclera
Avascular
Transparent, permits light to enter eye
Repsonsible for most of the refraction of light
Cornea
Posterior Vascular Layer
Associated with Sclera
Consist of MELANIN-CONTAINING PIGMENT CELLS
Choroid
Ciliary Body consists of __ and __
Ciliary Ring (outer) CiliarY Processes (inner)
___ __ attach the Ciliary Ring and Ciliary Processes to the LENS of the eye
Suspensory Ligments
Contraction of ciliary muscles can change the shape of __
the LENS (“accomodation”)
Contractile structure
Mainly smooth muscle
Regulates amount of light by controlling size of the Pupil
Iris
3 Intrinsic Eye Muscles
- Ciliary muscles
- Sphincter pupillae
- Dilator pupillae
- INNER LAYER of the eye
- 126 million photoreceptor cells
- ACTION POTENTIALS are generated/conducted as response to light
Retina
Near center of Posterior Retina
Small, Yellow spot (4mm)
Macula
- Small pit in the center of the Macula
- Highest concentration of PHOTORECEPTOR CELLS in the Retina (most sensitive to light)
Fovea Centralis
White spot Medial to Macula Central Retinal Artery enters Central Retinal Vein exits Where axons converge to form CN II
Optic Disc
Does NOT contain Photoreceptor cells - does not respond to light - called the “blind spot”
Optic Disc
3 Chambers of the eye
- Anterior
- Posterior
- Vitreous
The __ separates the Anterior and Posterior Chambers
Iris
The larger chamber that is posterior to the Lens
Vitreous
The Anterior and Posterior Chamber are located between the __
Cornea
Lens
Fluid that fills the Anterior and Posterior Chambers
Aqueous Humor
Transparent, jellylike substance that fills the Vitreous Chamber
Vitreous Humor
Helps maintain intraocular pressure (inflates, shapes)
REFRACTS light
Provides NUTRITION for Cornea
Aqueous Humor
Abnormal increase in intraocular pressure that results when the rate of production of aqueous humor exceeds its rate of removal
Glaucoma
Holds Lens and Retina in place
Inflates eye
Refraction of light
Slow turnover/production
Vitreous Humor
Avascular, Transparent, Biconvex Disc
Located behind Pupil
Changes shape to focus light
Lens
Light passing through the LENS is focused on the __
Retina
Lens: Cells on the Anterior Surface
Cuboidal Epithelial
Lens: Cells on the Posterior Surface
Columnar Epithelial (Lens Fibers)
Focusing SYSTEM of the eye
- CORNEA
- Aqueous Humor
- LENS
- Vitreous Humor
Light passing through the Focusing System is refracted, producing a __
Focal Point (FP)
In the normal eye, the focused image falls on the __
Retina
The image is __ and ___ because the light rays cross at the FP
Inverted
Reversed, right to left
NEAR VISION: Ciliary muscles \_\_ Lens \_\_ Pupil \_\_ Medial Rectus \_\_
NEAR VISION: Ciliary muscles CONTRACT Lens THICKENS Pupil CONSTRICTS Medial Rectus CONTRACTS
DISTANCE VISION:
Ciliary muscles __
Lens __
Pupil __
DISTANCE VISION:
Ciliary muscles RELAX
Lens FLATTENED
Pupil DILATED
Nearsightedness
Correction: Concave/Convex Lens
Myopia
Correction: Concave Lens
Farsightedness
Correction: Concave/Convex Lens
Hyperopia
Correction: Convex Lens
Images are focused IN FRONT of the Retiba
Myopia
Images are focused behind the Retina when looking at a close object
Hyperopia
- Degeneration of the ACCOMODATION power of the eye
- Lens: Hard and less flexible
Presbyopia
Cornea and Lens is not uniformly curved
Image is not sharply focused
Astigmatism
Result from weak eye muscles
Diplopia
Lack of paralelism of light paths through the eye
Strabismus
Results from loss of Rod function or Retinal degeneration, Vitamin A deficiency.
Night Blindness
Structures of OUTER Ear
- Auricle
- Exteral Acoustic Meatus (passageway)
- Tympanic Membrane
Structures of MIDDLE Ear
- Ossicles (Malleus, Incus, Stapes)
- Oval and Round Windows
- Tensor Tympani and Stapedius
- Eustachian Tube
- Chorda Tympani (nerve)
Structures of the INNER Ear
- Cochlea - Hearing
- Vestibule -Static Balance
- Semicircular canals - Dynamic Balance
INNER EAR: The bony labyrinth is lined with __
Endosteum
INNER EAR: Inside the bony labyrinth - is a similarly shaped but smaller set of tunnels and chambers called __
membranous labyrinth
The membranous labyrinth is filled with __
Endolymph, clear
high K+, low Na+
The space between the bony and membranous labyrinths is flled with __
perilymph
similar to CSF