Crossword clues for choroid
The Collaborative International Dictionary
Choroid \Cho"roid\, a. [gr. ?; ? chorion + e'i^dos form.] (Anat.) resembling the chorion; as, the choroid plexuses of the ventricles of the brain, and the choroid coat of the eyeball. -- n. The choroid coat of the eye. See Eye.
Choroid plexus (Anat.), one of the delicate fringelike processes, consisting almost entirely of blood vessels, which project into the ventricles of the brain.
Douglas Harper's Etymology Dictionary
1680s, from Latinized form of Greek khoroeides, a corruption of khorioeides, from khorion (see chorion) + eidos "resemblance" (see -oid).
Wiktionary
n. (context anatomy English) The vascular layer of the eye lying between the retina and the sclera.
WordNet
n. a highly vascular membrane in the eye between the retina and the sclera [syn: choroid coat]
Wikipedia
The choroid, also known as the choroidea or choroid coat, is the vascular layer of the eye, containing connective tissue, and lying between the retina and the sclera. The human choroid is thickest at the far extreme rear of the eye (at 0.2 mm), while in the outlying areas it narrows to 0.1 mm. The choroid provides oxygen and nourishment to the outer layers of the retina. Along with the ciliary body and iris, the choroid forms the uveal tract.
The structure of the choroid is generally divided into four layers (classified in order of furthest away from the retina to closest):
- Haller's layer - outermost layer of the choroid consisting of larger diameter blood vessels;
- Sattler's layer - layer of medium diameter blood vessels;
- Choriocapillaris - layer of capillaries; and
- Bruch's membrane (synonyms: Lamina basalis, Complexus basalis, Lamina vitra) - innermost layer of the choroid.
Usage examples of "choroid".
This includes difficulties in memory, speech, and coordination, due to brain oxygen starvation in the orbital gyri of both frontal lobes, as well as the cerebral choroid plexus.
In these cases the lesions have consisted of detachment of the retina, optic atrophy, cataract, hemorrhages into the retina, and rupture of the choroid, paralysis of the oculomotor muscles, and paralysis of the optic nerve.
All around its rim is a ringlike suspensory ligament, which joins it to a portion of the choroid layer immediately behind the iris.
It may even be several minutes before the field of vision really appears black, that is, before the activity of the inner light in the choroid has so far died away that equilibrium prevails between the non-stimulated nerves and the non-stimulated blood.
Just as the nerve processes arising in the retina are continued to the optic centre in the cerebrum, so must we look for the origin of the corresponding blood process not in the choroid itself, but in the lower regions of the organism.
What we call 'seeing' is far more the result of an interplay between the retina carrying the nerves, and the choroid carrying the blood-vessels.