Special Sense Organs Part 1 Flashcards
T/F: The special sense organ of vision, the eye, is derived from both the ectoderm and the mesoderm.
True
What are the fibrous coats of the eyes derived from?
mesoderm
What parts of the eye are derived from the ectoderm?>
lens, retina, cornea, and pigmented layers
What 3 coats make up the eye?
Fibrous tunic (outermost), vascular tunic, and the nervous tunic (retina)
Which coat of the eye is made up of the sclera and cornea?
fibrous tunic
What is the term for the thick, dense, firm, opaque, white part of the eye?
sclera
What structure maintains the shape of the eye if internal pressure is increased?
sclera
What kind of structures pass through the many openings of the sclera?
blood vessels and neurons
T/F: extraocular muscles attach to the sclera.
True
T/F: posteriorly, the sclera transitions to the cornea at the limbus and is lined with conjunctiva.
False; this occurs anteriorly
What structure is the sclera continuous with posteriorly?
fibrous sheath that covers CN II
What is the anterior part of the fibrous tunic?.
cornea
T/F:The cornea is transparent, concave to the anterior, and is the primary refractory part of the eyeball.
False; should say convex to the anterior
What are the 5 layers of the cornea from anterior to posterior?
Corneal epithelium, Anterior limiting lamina, Substantia propria, Posterior limiting lamina, and Endothelium (CASPE)
Which layer of the cornea is continuous with the conjunctiva?
Corneal epithelium
What layer of the cornea covers the inside surface of the cornea and lines the iridocorneal layer?
Endothelium
What is the largest part of the cornea?
Substantia propria
What are the 3 parts of the Vascular Tunic?
choroid, ciliary body, and iris
T/F: the choroid is thin with a poor blood supply.
False; thin with a rich blood supply
T/F: the blood vessels of the choroid are heavily supplied by autonomic, vasomotor fibers and may have a cooling effect.
True
The choroid is loosely attached to the sclera except for where?
choroid is firmly attached to the sclera where the optic nerve pierces it
What purpose does the dark pigmentation of the choroid serve?
helps limit the passage of light both through the sclera to the retina and through the retina to the sclera
What is the ciliary body continuous to the anterior? to the posterior?
iris;
choroid
T/F: the ciliary body serves to suspend the lens and produce aqueous fluid found in the anterior segment of the eye?
True
T/F: the ciliary body may produce some glycosaminoglycans of the vitrous body.
True
Where is the ciliary muscle contained?
ciliary body
What is the function of the ciliary muscle?
contraction allows the lens to become more convex, allowing for near vision
What is the colored part of the eye which ranges from light blue to dark brown?
Iris
What divides the anterior segment of the eye into anterior and posterior chambers?
Iris
What muscles does the Iris consist of?
sphincter pupillae and dilator pupillae
What muscle contains fibers arranged circumferentially that constrict the pupil?
sphincter pupillae
What muscle will cause the pupil to become larger when it contracts?
dilator pupillae
T/F: the dilator pupillae is innervated by parasympathetic fibers.
False; dilator pupillae is sympathetic, sphincter pupillae is parasympathetic.
