Senses Flashcards
Free nerve endings
Senses pain, touch, temperature, and pressure
Meissner’s corpuscles
Encapsulated nerve endings found in hairless skin to detect light touch
Merkel’s disk
Direct light touch and pressure within epidermis
Hair follicle receptors
Detect movement of hair
Ruffinis corpuscles
Detect deep pressure and stretching of skin
Pacinian corpuscles
Encapsulated nerve endings that detect deep pressure and vibrations
External anatomy of the eye
- covered with an eyelid
- corners are lateral and medial
- lined with lashes
- conjunctiva (thin membrane) covers the surface of eye and inside of eyelid. secretes mucus to lubricate the eye
- lacrimal apparatus
Lacrimal apparatus
lubricate the eye as tears move from lacrimal gland, across eye and towards the nasal cavity
Sclera
white of the eye
- fibrous connective tissue
-protects and shapes the eye
Choroid
pigmented, vascular membrane (iris and pupil)
Retina
contains photoreceptors that turn light into impulses
Aqueous humor
nourishes cornea (in front of lens)
Vitreous humor
- jelly like, refracts light (behind lens)
Fovea centralis
tiny pit that only contains cones. point of sharpest image
Rods
- all over retina
- vision in low light
- extremely sensitive
- more off to the sides of retina
Cones
- concentrated in the center of retina
- detects colors
- less sensitive
Myopia
- eye is too long, light converges in front of the retina (near sighted)
- glasses can help to refract light so it converges on the correct spot
Hyperopia
- eye is too short. light converges behind the retina (farsighted)
Optic nerve
carries impulses to the brain, creates blindspot where it meets retina
How do you taste flavors?
Smell & taste combined
Where are chemoreceptors found?
On the tounge, in the papillae
What do chemoreceptors do?
(Gustatory cell) respond to molecules dissolved in saliva, then depolarize sending signals to the brain through 3 facial nerves
What do olfactory receptors do?
In the olfactory epithelium - distinguish different molecules
- sniffing brings those molecules into contact with the olfactory receptors
- accomodation = constant contact with a substance causes accomodation (insensitivity)
What is the process of hearing (steps)
1 - sound waves enter outer ear and travel down ear canal
2 - the tympanic membrane vibrates and sends the vibrations to the middle ear bones (ossicles)
3 - the ossicles amplify the vibrations and send then to the inner ear
4 - within the cochlean, the organ of corti is filled with stereocilia that transmit the mechanical electrical impulses
5 - the electrical impulse travels through the auditory nerve towards the brain which interprets the impulse
Semicircular canals
- signal to the brain via vestibular nerve
- static equilibrium - head upright at rest
Tympanic membrane
- aka eardrum
- passes vibrations from outer ear to ossicles
Cochlea
- contains fluid in organ of corti
- the fluid vibrates basilar membrane, receptor cells vibrate tectorial membrane, action potential begins
Auditory nerve
- vibrations are recieved by mechanoreceptors and passed to the brain
Stapes (stirrup)
transmits vibrations to the inner ear
Incus (anvil)
continues to amplify sound waves and vibrates stapes
Malleus (hammer)
vibrates against eardrum and passes vibrations to incus
Mechanoreceptors
- detect movement, tension, and pressure
Photoreceptors
detect variations in light
Chemoreceptors
detect chemicals (taste, smell, blood, CO2)
Thermoreceptors
detects heat
Pain receptors
respond to tissue damage
