Question

Eyeball is moved in the orbit by
A) four rectus and two oblique muscles
B) Ciliary muscles
C) suspensory ligaments and ciliary muscles
D) three circular and four oblique muscles

Answer 1

The human eyes are a part of the sensory nervous system. They are the organs related to vision and react to the light. The structure of the eye is complex and it is formed by the association of muscles colour lens and photosensitive cells. Two different structures are involved in the movement.

Complete answer:
Eyes in humans are situated in the bony orbits that are present in the skull. The eyes are moved through the extranuclear muscle which remains directly connected to the eyes. They are six in numbers. The front portion of the eye, which is visible, is whitish in colour and it is known as the sclera. In this portion, a coloured iris and the pupil is present. The sclera forms the external layer of the eyes and along with the cornea, it forms the fibrous layer or the fibrous court. The major function of the conjunctiva is to protect the cornea which is a delicate portion of the eye. The cornea is transparent and more curved in structure. The cornea is the anterior portion of the eye and absorbs oxygen present in the air. It is devoid of blood supply. It is linked to the posterior segment. It is composed of the vitreous, retina, choroid and the outer sclera. The uvea is the middle layer and it consists of the choroid, ciliary body, pigmented epithelium and the iris. The orbits of the eye sockets have six muscles, with the help of which, the eye is attached to the orbit and moves in it. These 6 extranuclear muscles control the moments of the eye in up, down, right and left directions. These four muscles are lateral, medial, inferior and superior rectus muscles. These two muscles adjust the movement of the eye accordingly.
Thus, the correct answer is option A.

Note: The structures and functions of the eyes are complex. Each eye constantly adjusts the amount of light it lets in, focuses on objects near and far, and produces continuous images that are instantly transmitted to the brain.