19 D Special Senses Flashcards
Is the receptor for dynamic equilibrium
Is located in the ampulla of each semicircular canal
Responds to angular movements
crista ampullaris (or crista)
Each crista has support cells and hair cells that extend into a gel-like mass called the
cupula
Three canals that each define two-thirds of a circle and lie in the three planes of space
Membranous semicircular ducts line each canal and communicate with the utricle
The ampulla is the swollen end of each canal and it houses equilibrium receptors in a region called the crista ampullaris
These receptors respond to angular movements of the head
The Semicircular Canals
jellylike mass studded with tiny CaCO3 stones called otoliths
Otolithic membrane
The central egg-shaped cavity of the bony labyrinth
Suspended in its perilymph are two sacs: the saccule and utricle
1. Saccule extends into the cochlea
2. Utricle extends into the semicircular canals
These sacs:
House equilibrium receptors called maculae
Respond to gravity and changes in the position of the head
The Vestibule
A spiral, conical, bony chamber that:
Extends from the anterior vestibule
Coils around a bony pillar called the modiolus
Contains the organ of Corti (hearing receptor)
The Cochlea
The cochlea is divided into three chambers
- Scala vestibuli
- Scala media (cochlear duct)-contains the Organ of Corti
- Scala tympani
Series of membranous sacs within the bony labyrinth
Filled with a potassium-rich fluid
Membranous labyrinth
Tortuous channels worming their way through the temporal bone
Contains:
Cochlea-hearing
Vestibule- head tilt and acceleration motion
Semicircular Canals-rotational and acceleration motion
Filled with perilymph
Bony labyrinth
The tympanic cavity contains three small bones
Malleus
Incus
Stapes
Loud sounds are dampened by two muscle
tensor tympani and stapedius muscles
Thin connective tissue membrane that vibrates in response to sound
Transfers sound energy to the middle ear ossicles
Boundary between outer and middle ears
Tympanic membrane (eardrum)
Short, curved tube filled with ceruminous glands
External auditory canal
The auricle (pinna) is composed of:
The helix (rim)
The lobule (earlobe)
Respond only in bright light
Have high-acuity color vision
Are found in the macula lutea
Are concentrated in the fovea centralis
Cones: (blue, red, green)
Respond best in dim light
Are used for peripheral vision
Allow us to see black/white
Rods:
contains:
Photoreceptors
a. Rods- allow you to see black/white and in dim light.
b. Cones- allow you to see color when you have bright light.( only works when plenty of light)
Neural layer
the outer layer that absorbs light and prevents its scattering
Pigmented layer
The colored part of the eye
Pupil – central opening of the iris
Regulates the amount of light entering the eye during:
Close vision and bright light – pupils constrict
Distant vision and dim light – pupils dilate
Changes in emotional state – pupils dilate when the subject matter is appealing or requires problem-solving skills (sympathetic stimulation)
Iris