Senses Flashcards
Name the traditional “five senses”. Why is this list oversimplified?
Vision (sight)
Audition (hearing)
Olfaction (smell)
Gustation (taste)
Somatosensation (touch)
There is still scientific debate on how to define a sense.
Briefly describe the three structural types of sensory receptors and give examples
Free nerve endings are neurons with their dendrites embedded in tissue that would receive a sensation. (hot, cold, cut)
Encapsulated nerve endings are neurons with their dendrites wrapped in connective tissue to make them more sensitive. This helps with your sense of touch
Specialized receptor cells are neurons with very fancy cells attached to them. Some examples of these “fancy” cells are found in your taste buds, the “hair cells” used in hearing and balance, and the “rods and cones” in the retina
Briefly describe the three locations and five functional types of sensory receptors.
An exteroceptor senses the external environment, such as the touch receptors in the skin.
An interoceptor senses internal organs and tissues, such as the receptors that sense the stretching of the bladder as it fills with urine.
The proprioceptors are found in muscles, tendons and joints, and help sense your position and movement. These receptors let you touch your finger to your nose - even with your eyes closed!
Chemoreceptors sense chemical stimuli, which is used in taste and smell, but also in your blood where they detect how much oxygen and CO2 are present.
Nociceptors are pain receptors, and they are found in most tissues throughout the body, although not the brain! Interesting.
Mechanoreceptors sense physical stimuli, such as pressure, vibration, and the pull of gravity.
Thermoreceptors sense change in temperature.
Photoreceptors are used in vision.
Explain general senses versus special senses. Give an example of each.
Explain sensory adaptation and be able to give a real-life example.
What is referred pain? Why does it happen?
Use anatomical terms to explain why tears run out of your nose when you cry a lot.
Tears slowly leave the eye area via canaliculi (“little canals”); you can see the openings of the canaliculi in the corner of your eye if you look closely! Finally, tears drain into the nasolacrimal duct.
What is the conjunctiva and what does it have to do with “pink eye”?
The conjunctiva is a thin, transparent membrane lining the inside surface of your palpebrae and covering the white of the eye. Pink eye is a common infection of the Conjunctiva called Conjunctivitis.
Compare and contrast the extrinsic and intrinsic eye muscles. Make sure you thoroughly explain the functions of the extrinsic muscles and both intrinsic muscles.
Extrinsic (external) muscles are 6 muscles found within the eye and used to move them. They are skeletal muscles that we consciously control.
Intrinsic (internal) muscles include the ciliary body and the iris. They are smooth muscle that move outside of our control.
The ciliary body is inside the eye and attached the the lens. When this muscle contracts and relaxes, it changes the shape of (bends) the lens. This allows you to switch your focus from nearby objects to faraway objects and back.
The iris is the colored part of the eye. The iris constricts the pupil in response to bright light and dilates the pupil in response to dim light.
List the major layers and structures of the eye and explain their functions.
Outer layer:
Sclera- White of the eye. The tough layer that protects the eye.
Cornea- A transparent layer that covers the anterior tip of the eye and allows light to enter.
Middle layer:
Iris- The colored part of the eye that constricts and dilates the eye in response to light.
Ciliary body- Bends the lens and allows to switch focus on close or far objects
Choroid- A layer of blood vessels that supply blood to the eyes.
Inner layer:
Retina- Contains the nervous tissue responsible for photoreception
Name the two types of fluid in our eye, and explain the function of each type.
The anterior portion of the eye is filled with aqueous humor (literally, “watery fluid”), which helps the eye keep its shape, but also nourishes the eye, especially the front of the eye.
The posterior part of the eye is filled with a more viscous fluid called the vitreous humor (literally, “glassy fluid” but it is the consistency of slimy gelatin). This fluid helps keep a bit of pressure on the retina
Explain “floaters” and the “blind spot”. Why aren’t we aware of any blind spot?
Blind spots-There are no photoreceptors at the very back of our eyes where the optic nerve begins. We rarely notice because our brain fills in missing information.
Floaters- The vitreous humor also has immune cells that help keep things clean, although, you will still get a buildup of debris in your vitreous humor as you age, which often causes “floaters”: small shadows that dance across your vision, especially when looking at a bright sky or computer screen.
Summarize what happens during cataracts surgery and LASIK surgery.
Creating a hole in the eye and replacing their lens with a plastic one.
What is the anatomical term for taste? How would you classify this type of receptor?
Gustation. This type of receptor is a chemoreceptor.
Explain the functions of papillae, taste buds, and gustatory receptors.
Papillae are raised bumps that hold taste buds and saliva to keep our tongues moist.
Taste buds are sensory organs.
Gustatory receptors gather information from the microvilli.
