Summary
chapter 23 summary Junqueira's Basic Histology
- Course
- Institution
- Book
chapter 23 summary Junqueira's Basic Histology
[Show more]
Connected book
Book Title:
Author(s):
- Edition:
- ISBN:
- Edition:
More summaries for
-
Summary endocrinology (NWI-BB048B)
-
chapter 14 histology Junqueira's Basic Histology
-
chapter 15 GI system Junqueira's Basic Histology
Seller
Follow
OGN
Reviews received
Content preview
EYE DEVELOPMENT The first indication of the eyes is the optic grooves in the neural folds at the cranial end of the embryo.
The grooves form at the beginning of the fourth week and deepen to form hollow optic vesicles that
project from the forebrain.
he optic vesicles contact the surface ectoderm and induce development of the lens placodes.
As the lens placode thickens to form a lens pit and lens vesicle, the optic vesicle invaginates to form the
optic cup. The retina forms from the two layers of the optic cup.
he retina, optic nerve fibers, muscles of the iris, and epithelium of the iris and ciliary body are derived
from the neuroectoderm of the forebrain. The sphincter and dilator muscles of the iris develop from
the ectoderm at the rim of the optic cup.
The surface ectoderm gives rise to the lens and the epithelium of the lacrimal glands, eyelids,
conjunctiva, and cornea. The mesenchyme gives rise to the eye muscles, except those of the iris, and to
all connective and vascular tissues of the cornea, iris, ciliary body, choroid, and sclera.
The eyes are sensitive to the teratogenic effects of infectious agents (e.g., cytomegalovirus). Defects of
sight may result from infection of tissues and organs by certain microorganisms during the fetal period
(e.g.,rubella virus, Treponema pallidum [causes syphilis]).
Most ocular defects are caused by defective closure of the retinal fissure during the sixth week (e.g.,
coloboma of the iris).
Congenital cataract and glaucoma may result from intrauterine infections, but most congenital
cataracts are inherited.
EAR DEVELOPMENT
The otic vesicle develops from the surface ectoderm during the fourth week. The vesicle develops in to
the membranous labyrinth of the internal ear.
The otic vesicle divides into a dorsal utricular part, which gives rise to the utricle, semicircular ducts,
and endolymphatic duct, and a ventral saccular part, which gives rise to the saccule and cochlear duct.
The cochlear duct gives rise to the spiral organ.
The bony labyrinth develops from the mesenchyme adjacent to the membranous labyrinth. The
epithelium lining the tympanic cavity, mastoid antrum, and pharyngotympanic tube is derived from
the endoderm of the tubotympanic recess, which develops from the first pharyngeal pouch.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller OGN. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $7.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
76462 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now