Biology Grade 10: Eye Anatomy and Physiology

Flashcards covering human eye anatomy, eye layers, chambers, fluids, photoreceptors, and visual mechanism based on Biology Class 10 notes.

What is the primary function of the sclera?

The sclera is the outer layer of the eye that provides firmness and protection.

What are the main functions of the choroid layer?

The choroid is the middle layer of the eye that provides oxygen and nutrients to the inner layer of the retina and regulates temperature.

What is the function of the retina?

The retina is the inner layer of the eye that contains photoreceptor cells and is the site where images are formed.

What is the cornea and what is its role?

The cornea is the transparent anterior part of the eye that allows light to enter.

What function do the ciliary muscles serve?

The ciliary muscles adjust the curvature of the eye lens.

What pigment is present in the iris, and what are its functions?

The iris contains melanin, which gives the iris its characteristic colour and absorbs ultraviolet rays.

What type of lens is present in the human eye, and what type of image does it form on the retina?

The eye contains a convex lens that forms a small, real, and inverted image on the retina.

How do rod cells and cone cells differ in function?

Rod cells recognise objects in dim light and in shades of black and white, whereas cone cells provide vision in intense light and help recognise colours.

What is the function of the bipolar cell layer and what types of cells does it contain?

The bipolar cell layer transmits impulses from photoreceptors to ganglion cells and consists of two types of cells: on bipolar cells and off bipolar cells.

What is the function of the ganglion cell layer?

The ganglion cell layer transmits impulses from bipolar cells to the optic nerve.

What is the conjunctiva and what are its functions?

The conjunctiva is the membrane covering the anterior part of the eye, including the eyelids except the cornea. Its functions are to protect the eye, keep it moist and lubricated, and prevent dust, germs, and other particles from entering.

Where are lacrimal glands located, and how do tears protect the eye?

Lacrimal glands are located in the eyelids towards the upper part. They produce tears that keep the surface moist, provide nutrients, eliminate waste materials, and contain the enzyme lysozyme to protect against infections.

Where is the aqueous chamber located, and what is the role of aqueous humor?

The aqueous chamber is located between the cornea and the lens. It contains watery aqueous humor (oozed from blood-like tissue fluid and reabsorbed into blood) which regulates pressure inside the chamber and provides oxygen and nutrients to the lens and cornea.

Where is the vitreous chamber located, and what is the function of vitreous humor?

The vitreous chamber lies between the lens and the retina. It contains transparent jelly-like vitreous humor that maintains the shape of the eyeball.

What is the blind spot of the eye?

The blind spot is the region of the retina where the optic nerve originates. It contains no photoreceptor cells, resulting in no vision.

What is the yellow spot (macula)?

The yellow spot (macula) is located in the middle of the retina where cone cells are abundant.

What is the normal size of the pupil, and how much more light can enter when its size increases?

The normal size of the pupil ranges from $2\text{ to }3\,mm$. When its size increases, it allows $16$ times more light to be directed onto the retina than normal.

How do the muscles of the iris regulate pupil size in intense light versus dim light?

In intense light, circular muscles contract to reduce pupil size and prevent damage to the retina. In dim light, radial muscles contract to increase pupil size and allow clear vision.

What is the correct pathway of light rays through the eye to the retina?

Cornea $\rightarrow$ Aqueous humor $\rightarrow$ Pupil $\rightarrow$ Lens $\rightarrow$ Vitreous humor $\rightarrow$ Retina.

Identify the external protective structures and muscles of the eye shown in this diagram.

The structures depicted are the bony eye socket, eye muscles, eyelid, eye lashes, and lacrimal gland.

Based on this figure of the major parts of the eye, identify the three main layers and the internal structures of the eye.

Layers: Sclera (outer), Choroid (middle), Retina (inner). Parts include the Ciliary muscles, Cornea, Iris, Pupil, Lens, Aqueous chamber, Vitreous chamber, Yellow spot (macula), Blind spot, Optic nerve, and layers of the retina.

Identify the two fluid-filled chambers and fluids illustrated in this diagram.

The diagram illustrates the aqueous chamber containing watery aqueous humor, and the vitreous chamber containing jelly-like vitreous humor.