Hearing and Balance Flashcards
3 parts of the outer (external) ear and their functions
Auricle (pinna): helps direct sound
External acoustic meatus: between outside and eardrum, has hairs, sebaceous glands and ceruminous glands to stop things from getting in
Tympanic membrane: forms the boundary between external and middle ear, cone shaped
3 ossicles
Malleus
Incus
Stapes
Tensor tympani and stapedium
2 tiny skeletal muscles in the middle ear cavity
They contract to prevent the bones from moving as much so that if you hear a really loud noise, it wont damage your auditory system
Cranial nerve rule:
1 for cerebrum 1 for diencephalon 2 for midbrain 3 for pons 4 for medulla But thats only 11 - cranial nerve 11 is attached to spinal cord
Cochlea
Spiraling chamber in the bony labyrinth
Coils around a pillar of bone (the modiolus)
Helicotrema is apex
Cochlear nerve runs through core of modiolus
Spiral lamina is a spiral of bone in the modiolus
Inner vs outer hair cells
I: Receptors that transmit vibrations of the basilar membrane, 1 of them
O: actively tune the cochlea and amplify the signal (efferent control from brainstem, can regulate vibration), 3 of them
Superior vs inferior colliculus
S: visual reflexes
I: auditory reflexes
Macula
One in each of the utricle and saccule
Contain receptor cells
Monitor the position of the head when the head is still
Contains columnar supporting cells
Receptor cells are hair cells (embedded in otolith membrane)
What orientation are the utricle and saccule in
U: horizontal
S: verticle
3 semicircular canals and what plane to they lie in
Anterior and posterior: lie in vertical plane at right angle
Lateral: lies in horizontal plane
Membranous ampulla
Located within the bony ampulla of the semicircular canals
Houses crista terminalis
Crista ampullaris
Contain receptor cells of rotational accleration
Epithelium contains supporting cells and receptor hair cells
These are the ampullary cupula
