Vascular Tunic of the Eyeball

pupil

is the central foramen of the iris and its diameter is controlled by 2 smooth muscles. the dilator muscle of the pupil consists of smooth muscle fascicles, which originates at the ciliary margin of the iris and insert at the pupillary margin.

iris

is the colored portion of the eye that forms a flat ring-like structure in front of the ciliary body.

choroid

is the portion of the vascular tunic directly adjacent to the sclera. it has 4 histologically recognizable layers: suprachoroid layer- is adjacent to sclera, vascular layer- is the layer with the largest vessels, choriodocapillary layer- is the layer with small vessels deep to the vascular layer, basal layer (basal complex)- is the layer in contact with the pigmented layer of the retina.

ciliary muscle

is the ring of smooth muscle within the ciliary body that controls the thickness of the lens

ciliary body

is the thickened portion of the vascular tunic between the choroid and iris. it consists of ciliary processes and folds superficially and a muscle within the body.

ciliary processes

the approximately 70 small ridges on the free inner surface of the ciliary body. the processes project towards the lens of the eyeball.

ciliary folds

the furrows between the ciliary processes

vascular tunic/coat/layer of the eyeball

this layer sometimes called the uveal tract of the eyeball. it is highly vascularized layer that lies deep to the sclera and consists of three main components: choroid, ciliary body, and iris.