sensory system Flashcards
What are the functions of the skin?
To be a protective layer
Excrete water
Regulate body temperature (sweat)
Is a sensory organ
What are the 3 layers of skin?
Epidermis ( outer skin layer)
Dermis (middle skin layer)
Subcutaneous/ Hypodermis
Define the Subcutaneous/ Hypodermis skin layer
made of connective and adipose tissue and attaches dermis to underlying muscle
Define the dermis skin layer
Middle layer of skin
most vascular and nervous layer
connective tissues of collagen strength for elastic and flexibility
Contains hair follicles and sweat glands
Define the epidermis skin layer
outer layer of skin which is composed of layers of epithelial cells
top layer is stratum corneum (visible dead cells)
inner layer is stratum germinativum ( where live cells are generated)
Describe the Sudoriferous gland
located in the dermis
coiled gland that secrete sweating ducts of the skin pours
excrete 600cc per day
Describe the sebaceous gland
located in the dermis
secrete oil (sebum) into hair follicles to lubricate the skin
Describe tactile sensations
Nerve endings respond to different sensations
Krause (cold)
Ruffini ( heat)
Merkel (light touch)
Pacini (pressure)
Melanin is…
the chief pigment produced by stratum germinativum of the epidermis
creates darkness of hair and skin
Carotene is…
a minor pigment produced in the epidermis
provides a yellowish orange color which gives the skin and hair light tones
Keratin is…..
not a pigment
but a protein for hair and nails
‘water-proofs” the skin
What are the 3 parts of the ear
The external ear
Middle ear
Internal ear
What structures are in the external ear
Auricle or pinna ( top of ear)
Tragus (ear flap)
EAM (external auditory meatus)
EAC (external auditory canal)
What structures are in the middle ear
tympanic membrane ( eardrum )
Tympanic Cavity ( houses the ossicles )
Eustachian tube (duct that connects ear to throat)
Auditory ossicles ( malleus, incus, stapes)
What are the structures ion the internal ear
contains structures of hearing and balance
membranous labyrinth ( actual organs of hearing and balance)
vestibule ( connects the cochlea, semi circular canals and ossicles)
Oval window ( receives vibrations from stapes)
Round window (ends closed system)
Cochlea (snail portion that converts sound waves)
Semi circular canals (posterior, lateral, superior/ organs of equilibrium)
Define the conjunctiva
thin, transparent outer covering of the eye and inner eyelid for protection (can be flipped inside out)
Define the sclera
White portion of eyeball
Define the cornea
Transparent continuation of sclera over pupil
Define the pupil
Opening into eyeball for light transmission
Define the iris
Muscle which controls the pupil size depending on amount of available light
Define the lens
Transparent , refractive tissue being the pupil which inverts and focuses the light toward the back of the eye
Define the choroid
vascular layer between sclera and retina
Define aqueous humor
Fluid surrounding the pupil and iris
Define vitreous humor
Jelly like fluid filling the eyeball proper posterior to lens
Define the retina
inner layer of eyeball
define fovea centralis
back of the eye in a direct line from the lens
Define optic disc
“blind spot” where the optic nerve attaches to back of the eye
Define photosensitive cells
are located in the fovea centralis and responds to light
What are the 2 types of photosensitive cells
Cones and rods
Define cones
Used for daylight (photopic) vision
perception of color
less sensitive to light
Define Rods
Used for night (scotopic) vision
bland and white perception
more sensitive to light
How many muscles attach to the eye
6 and only 1 muscle controls the eyelid
