Z 342 lab final Flashcards
outer and middle ear function in
hearing only
inner ear function in
hearing and equilibrium
auricle/pinna
elastic cartilage; funnels sound waves into external auditroy meatus; helix = rim; lobule = earlobe
external auditory meatus
transmits sound to eardrum; temporal bone
tympanic membrane
eardrum; connective tissue, vibrates and transfers sound energy to tiny bones of middle ear
middle ear
tympanic cavity; small air-filled musosa lined cavity in temporal bone; malleus, incus, stapesl; opening to auditory tube
inner ear
bony labyrinth: perylymph; 3 regions: vestibule, semicircular canals, cochlea; membranous labyrinth: endolymph
vestibulo….
balance
cochlear
hearing
physiology of hearing
- sounds waves vibrate tympanic membrane 2. auditory ossicles vibrat, pressure amplified 3. pressure waves by stapes push on oval window, move through fluuid in scala vestibuli 4. sounds with frequencies below hearing level do not excite har cells 5. sounds in hearing range go through cochlear duct, vicration basilar membrane and deflecting hairs on inner hair cells
auditory pathway
ascending; auditory info from cochlear receptors (inner hair cells) to cerebral cortex
vestibular apparatus
sends signals to brain that initiate reflexes needed to make changes in position
vestibule
sense of static equilibrium (gravity) - key role in maintaining posture; maculae in vestibule wall
semicircular canals
sense of dynamic equilibrium (rotation), receptors for rotational head movement; cristae at base of each canal
maculae hair cells
monitor position of head in space, key role in controlling posture
otoliths
ear stones increase membrane’s weigth over hair cells and resistance to changes in motion; hairs verticle when head upright; hair cells synapse with fibers of vestibular nerve
cristae hair cells
cristae is receptor for roational acceleration in semicircular canals; rotational movement - endolympth moves capula in opposite direction
differences between nervous and endocrine
endocrine: slower, long term effects, affect target cells (specific or most of body)
similarites between nervous and endocrine
communication and coordination of responses, some organs shared, stimulated by sensory input by neurons, hypothalamic control of both (endocrine and autonomic NS)
exocrine glands
produce non hormonal substances
endocrine glands
produce hormones (single or many), variable stimuli elicit hormone secretion
master regulator of endocrine system
hypothalamus
9 pituitary hormones
ACTH, TSH, GH, PRL, FSH, LH, MSH, ADH
posterior pituitary hormones
oxytocin and ADH
amino acid based hormones
water soluble, free in blood, acts on cell membrane receptors, shorter half life
steroid based hormones
fat soluble, via carrier proteins in blood, acts on receptors inside cell, longer half life, snythesized from choleserol, only gonadal and adrenocortical hormone are steroids
humoral stimulus
ion concentration in blood
neural stimulus
stress, preganglionic, sypathetic nerve fibers
hormonal stimulus
hormones secreted by hypothalamus
negative feedback
production of end product inhibits production of intermediary product