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Special Senses - Anatomy & Physiology

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Terms in this set (32)

  • What are the five special senses?

    Smell, taste, sight, hearing, and equilibrium are the five special senses.

  • What structures are considered special sense receptors?

    Large, complex sensory organs like the eye and ear, and localized clusters of receptors such as taste buds and olfactory epithelium.

  • What percentage of sensory receptors are in the eyes?

    About 70 percent of all sensory receptors are in the eyes.

  • Name the accessory structures of the eye.

    Extrinsic eye muscles, eyelids, conjunctiva, and lacrimal apparatus.

  • What is the function of the tarsal glands in the eyelids?

    They produce an oily secretion that lubricates the eye.

  • What is the conjunctiva and its function?

    A membrane lining the eyelids and eyeball that secretes mucus to lubricate and keep the eye moist.

  • Describe the lacrimal apparatus and its function.

    Includes the lacrimal gland and ducts; produces tears that cleanse, protect, moisten, and lubricate the eye.

  • What are the components of tears?

    Tears contain dilute salt solution, mucus, antibodies, and lysozyme (an enzyme that destroys bacteria).

  • What are the three layers (tunics) of the eyeball wall?

    Fibrous layer (outer), vascular layer (middle), and sensory layer (inner).

  • What structures make up the fibrous layer of the eye?

    Sclera (white connective tissue) and cornea (transparent anterior portion).

  • What is the function of the choroid in the vascular layer?

    It is a blood-rich nutritive layer containing pigment that prevents light scattering inside the eye.

  • What are the two smooth muscle structures derived from the choroid?

    The ciliary body (attached to the lens) and the iris (regulates light entering the eye).

  • What are the two layers of the retina?

    Outer pigmented layer that absorbs light and inner neural layer containing photoreceptors (rods and cones).

  • What is the function of rods in the retina?

    Allow vision in dim light and peripheral vision, perceiving only gray tones.

  • What is the function of cones in the retina?

    Enable detailed color vision and are concentrated in the fovea centralis for sharpest vision.

  • What is the optic disc and why is it called the blind spot?

    It is where the optic nerve leaves the eyeball and contains no photoreceptors, so no image is detected there.

  • What are the two chambers of the eye divided by the lens?

    The anterior (aqueous) segment containing aqueous humor and the posterior (vitreous) segment containing vitreous humor.

  • What is the role of aqueous humor?

    It maintains intraocular pressure, provides nutrients to the lens and cornea, and is reabsorbed through the scleral venous sinus.

  • How does the eye focus light for near vision?

    Through accommodation, the lens changes shape to focus light on the retina for objects less than 20 feet away.

  • What is myopia and its cause?

    Nearsightedness where distant objects appear blurry because the eyeball is too long and light focuses in front of the retina.

  • What is hyperopia and its cause?

    Farsightedness where near objects are blurry because the eyeball is too short or the lens is lazy, focusing light behind the retina.

  • What is the function of the ossicles in the middle ear?

    Transmit and amplify vibrations from the tympanic membrane to the inner ear fluids via the malleus, incus, and stapes.

  • What are the components of the bony labyrinth in the inner ear?

    Cochlea, vestibule, and semicircular canals, filled with perilymph fluid.

  • What is the spiral organ of Corti?

    The receptor organ for hearing located in the cochlear duct, containing hair cells that detect sound vibrations.

  • How are high-pitched and low-pitched sounds detected in the cochlea?

    High-pitched sounds stimulate hair cells near the oval window; low-pitched sounds stimulate hair cells further along the cochlea.

  • What are the two types of equilibrium detected by the vestibular apparatus?

    Static equilibrium (head position) and dynamic equilibrium (angular or rotational movements).

  • What is the role of maculae in static equilibrium?

    Receptors in the vestibule that detect head position and help maintain head erectness by sending signals to the cerebellum.

  • What is the crista ampullaris and its function?

    Receptor in the semicircular canals that detects rotational head movements by hair cells covered with a gelatinous cupula.

  • What causes conduction deafness?

    Hindrance of sound vibration transmission through the external or middle ear.

  • What causes sensorineural deafness?

    Damage to nervous system structures involved in hearing, such as the cochlear nerve or auditory cortex.

  • Where are olfactory receptors located and how do they detect smells?

    In the roof of the nasal cavity; chemicals must dissolve in mucus to stimulate olfactory receptor neurons with cilia called olfactory hairs.

  • What are the five basic taste sensations?

    Sweet, sour, bitter, salty, and umami (savory taste from glutamate).