senses
Somatic and Special Senses
Introduction
Sensory Receptors - detect environmental changes and trigger nerve impules
- somatic senses (touch, pressure, temp, pain)
- special senses (smell, taste, vision, equilibrium, hearing)
Receptors and Sensations
1. Chemoreceptors = _____________________________
2. Pain receptors = _______________________________
3. Thermoreceptors = _____________________________
4. Mechanoreceptors = ____________________________
5. Photoreceptors = ______________________________
Sensation = feeling that occurs when a brain interprets a sensory impulse
Projection = process where the cerebral cortex causes a feeling to stem from a source (eyes, ears)
Sensory adaptation = sensory receptors stop sending signals when they are repeatedly stimulated
Somatic Senses
1. Sensory Nerve Fibers - epithelial tissue, pain and pressure2. Meissner's corpuscles - hairless areas of skin (lips, fingertips)3. Pacinian corpuscles - deep pressure (tendons, joints)Temperature Senses (warm and cold receptors)Sense of Pain - pain receptors do not adapt, prompts a person to take action to avoid stimulusVisceral Pain - occurs in visceral tissues such as heart, lungs, intestineReferred pain - feels as though it is coming from a different part (heart pain may be felt as pain in arm or shoulder)Acute Pain - originates from skin, usually stops when stimulus stops (needle prick)Chronic Pain - dull aching sensationRegulation of Pain impulsesInhibitors of Pain (natural brain chemicals can be mimicked by drugs such as morphine)Enkephalins / Serotonin / EndorphinsSpecial Senses
Smell (olfactory organs); Taste (taste buds); Hearing & Equilibrium (ears); Sight (eyes)Sense of Smell
Olfactory organs contain olfactory receptorsOdor Molecule --> olfactory receptor cell -->olfactory bulb --> olfactory tract --> limbic systemSense of Taste
Taste buds = PapillaeSweet / Sour / Salty / BitterTaste Receptors --> cranial nerves --> medulla oblongata --> Thalamus --> Parietal Lobe of Cerebrum
Steps in Hearing
1. Sound waves enter external ______________________________________
2. __________________________ vibrates
3. Auditory ______________________(malleus, incus, stapes) amplify vibrations
4. Stapes hits oval window and transmits vibrations to _______________________
5. _________________ contain receptor cells (hair cells) that deform from vibrations
6. Impulses sent to the _____________________________ nerve
7. Auditory cortex of the ________________lobe interprets sensory impulses
8. _____________________ dissipates vibrations within the cochlea
Sense of Hearing
External Ear
Auricle (pinna) - outer ear
External Auditory Meatus
Middle Ear (tympanic cavity)
Eardrum
Auditory Ossicles - malleus, incus, stapes - transmit vibrations and amplify the signal
Auditory Tube (eustachian tube) - connects the middle ear to the throat - helps maintain air pressure
Inner Ear
Labyrinth - communicating chambers and tubes
Osseous Labyrinth and Membranous Labyrinth
Perilymph and Endolymph (fluids within the labyrinth)
Semicircular Canals - sense of equilibrium
Cochlea - sense or hearing
Organ of Corti - contains hearing receptors,hair cells detect vibrations
Sense of Equilibrium
Static Equilibrium - sense the position of the head, maintain stability and posture
Dynamic Equilibrium (semicircular canals) - balance the head during sudden movement
Cerebellum - interprets impulses from the semicircular canals and maintains overall balance and stability
Sense of Sight
All About Vision -- How the Eye Works
The Anatomy of the Eye at LensShopper
Focusing and Pupil Dilation - How lenses work
Fill out the Chart as you review the slides.
Description/Function
Visual Accessory Organs Eyelid
Conjunctiva
Lacrimal Gland
Extrinsic Muscles
Outer Tunic Cornea
Sclera
Optic Nerve
Middle Tunic Choroid Coat
Ciliary Body
Lens
Iris
Aqueous Humor
Pupil
Inner Tunic Retina
Fovea centralis
Optic disc
Vitreous Humor
Light Refraction - the bending of light around an object
Images viewed by the eye are upside-down, our brains interpret it properly
Accommodation - the lens changes shape to focus on objects (ciliary muscles, suspensory ligaments)
Visual Receptors
Rods and Cones - located within the retina, rods for light/dark; cones for color
Retinal neurons --> form optic nerves --> optic chiasma --> thalamus --> visual cortex of the occipital lobe
EYE PROBLEMS: Glaucoma, cataracts, nearsightedness, farsightedness, eye floaters
