Choroid Overview

Flashcards covering key vocabulary terms and concepts related to the anatomy and physiology of the choroid and the eye.

Choroid

The middle layer of the globe of the eye, located between the outer sclera and inner retina.

Four layers of the choroid

Suprachoroid, Stroma, Choriocapillaris, Bruch's membrane.

Suprachoroid

The outer boundary of the choroid, composed of loose connective tissue and collagen fibers.

Stroma

A layer of blood vessels in the choroid, consisting of Haller's layer (large vessels) and Sattler's layer (smaller vessels).

Choriocapillaris

The layer of capillaries in the choroid that supplies nutrients to the outer retina.

Bruch's membrane

A very thin layer of connective tissue that separates the choroid from the retina.

Collagen fibers in Bruch's membrane

Secreted by fibroblasts in the choriocapillaris and retinal pigment epithelium.

Function of the choroid

To supply blood and nutrients to the outer layers of the retina.

Blood supply of the eye

Provided by the ophthalmic artery, which branches into the anterior and posterior ciliary arteries.

Posterior ciliary artery

Divided into short and long arteries that supply blood to the choroid and iris.

Anterior ciliary artery

Merges with the long posterior ciliary artery to supply the iris, ciliary body, and anterior choroid.

Melanocytes in the choroid

Cells that contain melanin, contributing to the eye's capacity to absorb stray light.

Drusen

Accumulated debris (proteins and lipids) that can push photoreceptors away from the choriocapillaris.

Role of Bruch's membrane

To regulate the transfer of nutrients from the choriocapillaris to the retina.

Choriocapillaris specialisation

Capillaries in the choriocapillaris have large fenestrations, allowing high permeability.

Hydraulic conductivity

The ease with which fluid can flow, which decreases in Bruch's membrane with age.

Age-related melanin accumulation

Contributes to decreased nutrients supplied to the retina due to thicker Bruch's membrane.

Retinal pigment epithelium (RPE)

The apex of the retina that interfaces with Bruch's membrane.

Ciliary body

Contains ciliary muscles and processes, important for accommodation and aqueous humor secretion.

Iris

The colored part of the eye, containing muscles that control the size of the pupil.