Ciliary body, structure

Uveitis An inflammation of the uvea in the eye. Uveal structures include the iris, the ciliary body, and the choroid. 

Structures of the anterior chamber of the eye. Tissues with significant autonomic functions and the associated ANS receptors are shown in this schematic diagram. Aqueous humor is secreted by the epithelium of the ciliary body, flows into the space in front of the iris, flows through the trabecular meshwork, and exits via the canal of Schlemm arrow). Blockade of the 13 adrenoceptors associated with the ciliary epithelium causes decreased secretion of aqueous. Blood vessels (not shown) in the sclera are also under autonomic control and influence aqueous drainage. 

The ciliary body is a triangular structure at the periphery of the border between the anterior and the posterior segments of the eye (Figure 24.1). Its uveal portion consists of comparatively... 

The eye globe is a hollow structure filled anteriorly by the aqueous humor and posteriorly by the vitreous. The aqueous humor (Figure 24.1) is continuously formed by the ciliary body. It is secreted into the posterior chamber from which it passes through the pupil into the anterior chamber and is drained at the anterior chamber periphery. Due to the blood aqueous barrier formed by zonulae occludentes of the nonpigmentary ciliary epithelium, macromolecules such as proteins can pass to the aqueous in very small quantities, regardless of their plasma concentrations. In humans, the aqueous humor protein level is around 20 mg/100 mL, less than 0.5% of the normal plasma total protein levels (Table 24.1) [22]. In the human eye, the rate of aqueous formation is around 2.5 pL/min, whereas in the case of rabbit eye it is... 

The sclera is an opaque vascular structure continuous with the cornea at the limbus.The loose connective tissue overlying the sclera—the conjunctiva—is also vascularized. The conjunctiva and sclera, as routes of drug penetration, are responsible for less than one-fifth of all drug absorption to the iris and ciliary body. This limited absorption is due to the extensive vascularization of these tissues, which results in removal of most dmgs. However, in recent years, the conjunctiva has been studied as a route of possible drug delivery because it contains a larger surface area than the cornea and possesses key transport processes that may allow fc>r penetration into intraocular tissues (Figure 2-4). 

Uveitis, by definition, describes an inflammatory state affecting the uveal tissues of the eye these include the iris, ciliary body, and choroid. Any or all of these structures may be involved in uveitis, a potentially blinding disorder that has great potential impact from both a medical and socioeconomic standpoint. This chapter reviews the classification, pathophysiology, epidemiology, diagnostic considerations, and medical management of uveitis. 

Expected Gonioscopic Findings. From anterior to posterior, the following structures are present in the angle Schwalbe s line (representing the posterior border of Descemet s membrane), the anterior trabecular mesh-woik (often less pigmented than the posterior trabecular meshwork), the canal of Schlemm within the botmdaries of and deep to the trabecular meshwork (typically only visible if filled with venous blood), the posterior trabecular meshwork, the scleral spur (to which the ciliary muscle is attached), and the ciliary body band. 

The cornea serves as the front part of the AC of the eye. Its exterior is covered by the precorneal tear film, which lubricates, nourishes and protects the corneal surface. The iris and the pupil represent the posterior border of the AC. The AC angle is an important structure which is comprised of Schwalbe s line, Schlemm s canal and trabecular mesh-work, scleral spur, anterior border of the ciliary body and the iris (Figure 5.2). Aqueous humor that fills the AC is produced by the ciliary epithelium located in the posterior chamber. The fluid flows through the pupil and is drained by the trabecular meshwork into Schlemm s canal and subsequently into the episcleral vessels. This passage is named the conventional pathway. Aqueous humor is also drained by a uveoscleral pathway across the ciliary body into the supraciliary space. 

Figure 5.2. Drawing of the structures of the angle of the AC and ciliary body. SL, Schwalbe s line SS, scleral spur IP, iris process TM, trabecular mashwork C, cornea I, iris SC, Schlemm s canal S, sclera CB, ciliary body Z, zonular fibers. (Illustration from Ocular Anatomy, Embryology and Teratology 1982, used with permission from Williams and Wilkins, Philadelphia, PA.)...

FIGURE 63-4 A. Anatomy of the eye. B. Enlargement of the anterior segment revealing the corneoy angle structures, lens, and ciliary body. 

The eye is a spherical structure with a wall made up of three layers the outer part sclera, the middle parts choroid layer, ciliary body and iris, and the iimer section nervous tissue layer retina. The sclera is a tough fibrous coating that protects the inner tissues of the eye, which is white except for the transparent area at the front, and the cornea allows light to enter into the eye. ... 

There are two main structures involved in the formation of the BAB the ciliary body and the iris (Figure 51.2). 

Lens The lens is the transparent biconvex structure situated behind the iris and in front of the vitreous. It plays an important role in the visual function of the eye and also enables accommodation together with the ciliary muscle. The lens is made up of slightly more than 30% protein (water-soluble crystallins) and therefore has the highest protein content of all tissues in the body [20], The lens receives its nutrients from the aqueous humor and its transparency depends on the geometry of the lens fibres. 

In general, cilia are widespread finger-like cell appendages. The structure of a proto-typic motile cilium is characterized as follows the ciliary shaft originates from a basal body complex in the apical cytoplasm beneath the plasma membrane (Figure 2A). 

All cells produce movement internally, and many are capable of motility or of changing shape. In some, movement is related to the function of individual cells, as in the migratory and engulfing movements of phagocytic cells or the swimming movements of sperm cells. In other cases, cells generate movement as one aspect of tissue function, as in the ciliary transport of mucus by the bronchial epithelium. Cells specialized for changing the dimensions or shape of anatomical structures or for movement of body parts with respect to each other are called muscle cells. 

A rudimentary ciliary structure, consisting of a very short roodet, a basal body, an accessory centriole and a short cilium appears in the upper third of the epidermal cell (Fig. 6.2B). As in articulate brachiopod larvae, this rudimentary cilium extends into a small space left by the epidermal cell between its membrane and the embryonic setal surface. The microtubule pattern of the cilium could not be observed and its function remains unclear. 

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