practical 2 Structures of the Eye, Ear, Brain, and Nervous System

Choroid (vascular) layer

Supplies blood to the retina and absorbs excess light.

Cornea

The clear, outermost layer of the eye that helps focus light.

Ciliary zonule (suspensory ligaments)

Connects the ciliary body to the lens, adjusting its shape for focusing.

Iris

The colored part of the eye that controls pupil size.

Pupil

The opening in the iris that regulates the amount of light entering the eye.

Neural (retina) layer

Contains photoreceptor cells that detect light and send signals to the brain.

Sclera

The white, protective outer layer of the eye.

Optic disc

The 'blind spot' where the optic nerve exits the retina.

Lacrimal gland

Produces tears to lubricate and protect the eye.

Lens

Focuses light onto the retina for clear vision.

Scleral venous sinus (canal of Schlemm)

Drains aqueous humor from the eye to maintain intraocular pressure.

Tympanic membrane

The eardrum; vibrates in response to sound waves.

Pharyngotympanic (auditory) tube

Connects the middle ear to the throat, equalizing pressure.

Stapes (stirrup bone)

One of the three ossicles; transmits sound vibrations to the inner ear.

Anvil (incus)

Middle ossicle that transmits vibrations from the malleus to the stapes.

Cochlea

The spiral-shaped organ of hearing in the inner ear.

Semicircular canals

Help with balance and detecting head movements.

Optic chiasma

The crossing point of optic nerves for visual processing.

Corpus callosum

Connects the left and right brain hemispheres.

Corpora quadrigemina (superior and inferior colliculi)

Involved in visual and auditory reflexes.

Pons

A brainstem structure that relays messages between the brain and spinal cord.

Ventral horn of the spinal cord

Contains motor neurons that send signals to muscles.

Temporal lobe

Processes auditory information and memory.

Gyrus

A ridge on the brain's surface that increases surface area.

Hypothalamus

Regulates homeostasis, hunger, and hormone release.

Pituitary gland

The 'master gland' that controls other endocrine glands.

Olfactory nerve (CN #1)

Carries smell information to the brain.

Dorsal root ganglion of spinal cord

Contains sensory neuron cell bodies.

Cerebellum

Controls coordination and balance.

Ventricles of the brain

Cavities filled with cerebrospinal fluid (CSF) that cushion the brain.

Choroid plexus of ventricle

Produces cerebrospinal fluid.

Phrenic nerve

Controls the diaphragm for breathing.

Sciatic nerve

The largest nerve in the body, running down the leg.