The human body has four types of tissues what part of the eye uses muscle tissue for opening and closing movements
A. Retina
B. Sclera
C. Cornea
D. Iris
D. Iris
The part of the eye that uses muscle tissue for opening and closing movements is the iris.
To determine which part of the eye uses muscle tissue for opening and closing movements, we need to understand the function of each part mentioned:
A. Retina: The retina is the innermost layer of the eye that contains photoreceptor cells responsible for detecting light.
B. Sclera: The sclera is the tough, white outer layer of the eye that provides structural support and protection.
C. Cornea: The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. It helps focus light onto the retina.
D. Iris: The iris is the colored part of the eye surrounding the pupil. It controls the size of the pupil and regulates the amount of light entering the eye.
Among the options provided, the iris is the only part of the eye that uses muscle tissue for opening and closing movements. The muscles within the iris contract to constrict the pupil (making it smaller) in bright light conditions to reduce the amount of light entering the eye. Conversely, the muscles relax to dilate the pupil (making it larger) in low light conditions to allow more light into the eye.
Therefore, the answer is D. Iris.