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Sense Organs
Term | Definition |
---|---|
Mechanoreceptors | These receptors respond to factors--such as pressure, stretch, or vibration--that change the positive of a receptor. |
Chemoreceptors | These receptors react to various chemicals , including odors and taste, as well as the concentration of various chemicals(such as Glucose or Carbon dioxide) in the body. |
Photoreceptors | Only found in the eyes, these receptors respond to light. |
Papillae | Protrusions on the tongue |
Proprioceptors | Found in muscle, joints and tendons. Provides information about body movement,muscle stretch and general orientation to the body. |
Nociceptors (Pain receptors) | Consist of free nerve endings that carry pain impulses to the brain. |
Olfaction | Sense of smell |
Gustation | Sense of taste. Results when chemicals come in contact with taste buds. |
Middle Ear | Consist of Malleus, incus and the Stapes. |
Eustachian tube | The passageway from the middle ear to the nasopharynx. It's purpose is to equalize pressure on both side of the tympanic membrane. |
Olfaction | Sense of smell |
Cochlea | This snail like structure contains the structures forhearing. |
Middle Ear | Consist of Malleus, incus and the Stapes. |
Eustachian tube | The passageway from the middle ear to the nasopharynx. It's purpose is to equalize pressure on both side of the tympanic membrane. |
Cochlea | This snail like structure contains the structures for hearing. |
Process of balance | The vestibule and semicircular canal of the inner ear play a key role in the process of balance. |
Malleus | Hammer shaped ear bone. |
Conjunctiva | Transparent mucous membrane that lines the inner surface of the eyelid and covers the anterior surface of the eyeball(except the cornea. It secretes a thin mucous film to keep the eyeball moist. |
Semicircular canals | These structures are crucial for the maintenance of equilibrium and balance. |
Vestibule | This structure which marks the entrance to the labyrinths, contains organs necessary for sense of balance. |
Sclera | Formed from dense connective tissue--is the outer most layer of the eye aka the with of the eyes. |
Cornea | The transparent extension of the Sclera in the anterior part of the eye. It sits over the iris and admits light into the eye. |
Iris | A ring of colored muscle; it works to adjust the diameter of the pupil( to control the amount of light entering the eye) |
Retina | The inside contains photoreceptors called rods and cones, that are stimulated by light rays to produce an electrical or chemical signal |
Lens | Is a transparent disc of tissue just behind the pupil between the anterior and posterior cavities. |
Emmetropia | When light rays focus on the retina without the need of corrective lenses. |
Myopia(nearsightedness) | When light rays focus in front of the retina instead of the directly on it, distant objects appear blurry while those up close are clear. |
Hyperopia(farsightedness) | When light rays focus at a point behind the retina, objects up close appear blurry. The eyeball is too short and the cornea is flatter than normal. |
Astigmatism | Result from uneven or asymmetrical curvature the cornea, causing light to be focused unevenly. |
Presbyopia : with age lens losses flexibility | Interfering with its ability to change shape --and focusing muscles in the eye weaken. As a result light focuses behind the retina, creating difficulty focusing on object close up. usually begins between age 40-50 |
What triggers Smell? | Incoming odor molecules bind to cilia, this stimulates an impulse along nerve fibers leaving the nasal cavity through pores in the ethmoid bone. Signals continue on to the primary olfactory cortex in the brain. |
Function of tears. | Tears clean and moisten the eyes surface and also deliver oxygen and nutrients to the conjunctiva. Furthermore tears contain bacterial enzyme called lysozyme that helps prevent infection. |
How do eye work? | Light enters the eye and focus o the retina to produce a tiny upside down image of the object being viewed. The photoreceptors in the retina must convert that image into nerve impulses. The impulses must be transmitted to the brain for interpretation. |