Despite its peripheral location, the retina or neural portion of the eye, is actually part of the central nervous system. During development, the retina forms as an outpocketing of the diencephalon, called the optic vesicle, which undergoes invagination to form the optic cup (Figure 11.3; see also Chapter 22).
What system are eyes part of?
Anatomy of the eye
The eye is the main organ of the visual system, it gets images seen by the person and turns them into an electric signal which is carried along the optic nerve to the brain.
Why is the eye part of the central nervous system?
During embryonic development, the retina and optic nerve extend from the diencephalon, and are thus considered part of the CNS. The retina is composed of layers of specialized neurons that are interconnected through synapses.
Are eyes organs or tissues?
The human eye is an organ that detects light and sends signals along the optic nerve to the brain. Perhaps one of the most complex organs of the body, the eye is made up of several parts—and each individual part contributes to your ability to see.
Where is the ocular nerve?
The optic nerve begins at the optic disk, a structure that is 1.5 mm (0.06 inch) in diameter and is located at the back of the eye. The optic disk forms from the convergence of ganglion cell output fibres (called axons) as they pass out of the eye.
How is the eye connected to the nervous system?
Optic nerve: The optic nerve connects the eye to the brain. The optic nerve carries the impulses formed by the retina, the nerve layer that lines the back of the eye and senses light and creates impulses. These impulses are dispatched through the optic nerve to the brain, which interprets them as images.
Is eye controlled by autonomic nervous system?
The eye has multiple autonomic functions controlled by several autonomic receptors. Among these are the intrinsic muscles of the eye (those controlling the size of the pupil and the shape of the lens) and the secretory epithelium (produces aqueous humor) of the ciliary body.
How many nerves are in the eye?
Six cranial nerves innervate motor, sensory, and autonomic structures in the eyes. The six cranial nerves are the optic nerve (CN II), oculomotor nerve (CN III), trochlear nerve (CN IV), trigeminal nerve (CN V), abducens nerve (CN VI), and facial nerve (CN VII).
Is eye a muscle?
There are six muscles that attach to the eye to move it. These muscles originate in the eye socket (orbit) and work to move the eye up, down, side to side, and rotate the eye. The superior rectus is an extraocular muscle that attaches to the top of the eye. It moves the eye upward.
How many parts are in an eye?
The eye itself is made of 10 general components that all work together to keep us seeing well every day.
Is an eye a tissue?
The eye is a fluid-filled sphere enclosed by three layers of tissue (Figure 11.1). Most of the outer layer is composed of a tough white fibrous tissue, the sclera.
Is the optic nerve part of the central nervous system?
The optic nerve is a CNS structure arising from the diencephalon. As a CNS structure, the optic nerve is myelinated by oligodendrocytes and is ensheathed in the three meningeal layers. The myelination process begins centrally, and as discussed earlier, terminates at the lamina cribrosa.
Does each eye have an optic nerve?
Visual Pathways and the Consequences of Damage
Nerve signals travel along the optic nerve from each eye. The two optic nerves meet at the optic chiasm. There, the optic nerve from each eye divides, and half of the nerve fibers from each side cross to the other side.