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the sensory system
exam 3
148
Anatomy
Undergraduate 2
10/29/2013

Additional Anatomy Flashcards

 


 

Cards

Term
General senses
Definition
  • touch 
  • pressure
  • pain
  • tempurature
  • itch
Term
special senses
Definition
  • smell
  • taste
  • sight
  • hearing
  • balance
Term

general sense

somatic

Definition
  • provides info about body and environment
Term

general sense

visceral

Definition
  • provides information about interrnal organs, pain pressure
Term
mechanoreceptors
Definition
detect movement, touch, pressure, vibration
Term
chemoreceptors
Definition
detect chemicals-odors
Term
photoreceptors
Definition
detect light
Term
thermoreceptors
Definition
detect temperature changes
Term
nociceptors
Definition
detect pain
Term
Free nerve endings in skin
Definition

Respond to painful stimuli, temp, itch, or movement 

 

in epidermis

Term
Merkel's disks in skin
Definition

Detect light tough and superficial pressure

 

in epidermis and dermis

Term
Hair follicle receptor in skin
Definition

Detects light touch 

 

in dermis 

Term
Meissner's corpuscles in skin
Definition

Involved in fine, descrimive touch 

 

in dermis 

Term
Ruffini's end organs of the skin
Definition

Detects continuous touch or pressure

( holding hands )

 

in dermis

Term
Pacinian corpuscles in skin
Definition

Detects deep pressure, vibration, and position

 

in deep dermis

Term
Gate control theory
Definition
Theory that we can block pain by utilizing mental or physical activity (distract ourselves)
Term
Referred pain
Definition
  • Deep tissue neurons coverage with ascending neurons of superficial areas 
  • Brain can't distinguish signals 
Term
Where are sensory receptors for olfaction located and what type are they?
Definition
Hard palate and are chemoreceptors
Term

How does olfaction work? 

Process

Definition
  • Odorants dissolve in mucus 
  • Cilia on dendrites of olfactory neurons pick up on odor
  • Depolarize 
  • AP to axon in olfactory bulb (cranial nerve 1) 
  • Synapse with interneurons 
  • Olfactory cortex
Term
How does taste work?
Definition
  1. Taste hairs of taste cells
  2. Sensory neurons 
  3. Cerebral cortex

Neurons: facial (7), glossopharyngeal (9), vagus (10)

Term
Types of taste?
Definition
  • Sweet
  • Sour
  • Salty 
  • Bitter
  • Umami 
Term
Conjunctiva
Definition
Mucosa covering inner surface of eyelid
Term
Extrinsic eye muscles
Definition

Help move eyeball

 

4 rectus (long) and 2 oblique (around)

Term
Lacrimal apparatus
Definition

Produces tears

 

gland at top of eye

Term
Lacrimal canaliculi
Definition
Channel from the eye to the lacrimal sac, which transports tears....drains to nasolacrimal duct this is why we can sometimes taste eye drops
Term
tunics of the eye
Definition
  1. Retina nervous tunic... deep
  2. choroid vascular tunic ... mid
  3. sclera fibrous tunic ...superficial
Term
vitreous chamber of the eye
Definition

filled with vitreous humor (jelly like substance)

 

behind the lens

helps maintain pressure, holds lens and retinal in place, refracts light

Term
anterior and posterior chambers of eye
Definition

filled with aqueous humor (water like)

separated by the iris

between cornea and lens

helps maintain pressure, refracts light, and provides nutrients to inner surface of eye

produced by the ciliary body, reabsorbed by venous ring in cornea and blockage causes glaucoma

Term
suspensory ligamens of eye
Definition
ciliary body of vascular tunic
Term
sclera
Definition

firm white outer part of eye

helps maintain eye shape, provides attachment sites, protects internal structures

 

fibrous tunic (superficial)

Term
Cornea
Definition

transparent structure that covers iris and pupil

allows light to enter and focuses light

 

fibrous tunic (superficial)

Term
choroid
Definition

black part (melanin) prevents reflection

delievers O2 and nutrients to retina

 

vascular tunic (mid)

Term
ciliary body
Definition

helps hold lens in place via ciliary muscles and suspensory ligaments

 

vascular tunic (mid)

Term
Iris
Definition

colored part

surrounds and regulates pupil

 

 

vascular tunic (mid)

Term
radial smooth muscles of the iris
Definition

functional in low light and are part of the sympathetic system

 

dilate the pupil

Term
circular smooth muscles of the iris
Definition

functional in hight light

constrict the pupil

Term
retina
Definition

pigmented: outer layer; prevents light from reflecting back into the eye

sensory: contains photoreceptors (rods and cones) and interneurons

 

nervous tunic (deep)

Term
rods
Definition

photoreceptor sensitive to light

can function in dim light

no color vision

Term
cones
Definition

photoreceptor provide color vision

3 types: blue, green, red

needs lots of light

Term
rhodopsin
Definition

composed of opsin (colorless protein)  and retinal (requires vit A and is yellow pigment)

 

works in the disc of a photoreceptor

Term
how vision occures
Definition
  1. retinal attaches inside opsin making rhodopsin
  2. light activates rhodopsin by causing retinal to change shape, opsin thus changes shape
  3. activated rhodopsin stimulates cell changes that result in vision
  4. following rhodopsin activation, retinal detaches from opsin
  5. energy from ATP is required to bring retinal back to its original form
  6. retinal attaches to opsin to from rhodopsin
Term
Action potential propogation (movement)
Definition
  1. light
  2. rods and cones
  3. bipolar cells and horizontal cells of sensory retina (these are interneurons)
  4. ganglion cells
  5. Ganglion cell's axons coverge to form optic nerve
  6. connect outside cranial cavity to optic chasm
Term
optic disk
Definition

blood vessels enter eye and spread over retinal

axons exit as optic nerve

no photoreceptors so called blind spot

Term
distant vision
Definition
  • cilliary muscles in the cillary body are relaxed
  • tension in suspensory ligaments is high
  • Lens flattened
Term
near vision
Definition
  • cilliary muscles in the cillary body contract, moving cilliary body toward lens
  • tension in suspensory ligaments is low
  • Lens thickened
Term
Central nervous system
Definition
brain and spinal cord
Term
PNS
Definition

nerves to face

ganglia

nerves to upper limb

nerves to lower limb

Term
sensroy or afferent divisions of the nervous system
Definition
conduct signals from PNS to CNS
Term
motor or efferent division
Definition
conducts signals from CNS to effector organs
Term
somatic nervous system
Definition
transmits action potential from the CNS to the skeletal muscles
Term
autonomic nervous system
Definition

unconscious control

transmits action potential from the CNS to

cardiac muscles

smooth muscles (digestion)

glands

 goes through an autonomic ganglion outside the CNS

divides pre and post ganglionic nerves


 exception: preganglionic neuron that extends to the adreanal gland...postganglionic neurons are the hormone secreting glands in this case


two parts sympathetic and parasympathetic divisions

Term
what are the functions of neurons?
Definition

they recieve signals in the dendrites and conduct AP through thier axons

 

sensory neurons to CNS to motor neurons

 

transmit signals

Term
multipolar neuron
Definition

motor neurons

 

multiple dendrites

Term
bipolar neurons
Definition

nasal cavity 

 

one dendrite

Term
pseudo-unipolar neuron
Definition

sensory neurons

 

no dendrites

Term
neuroglia
Definition

nonneuronal cells of the CNS and PNS

more numerous than neurons

retain the ability to divide (neurons can't)

 

5 types: astrocyte, ependymal cells, microglia cells, oligodendrocyte, and schwann cells

Term
astrocyte (neuroglia)
Definition

highly branched

 

provieds support

regulates neuronal signaling

contriute to blood-brain barrier

help with neural repair

Term
blood-brain barrier
Definition
a permeability barrier between the blood and the CNS
Term
Ependymal cells (neuroglia)
Definition

epithelial-like

 

line ventricles of brain and central canal of the spinal cord

circulate cerebrospinal fluid (cilia)

some form choroid plexuses

which produce CSF

Term
microglia (neuroglia)
Definition

small, mobile cells

 

protect CNS from infection (immune cells of CNS)

become phagocytic in response to inflammation

Term
oligodendrocytes
Definition

cells with processes that can souround several axons

 

cell processes form myelin sheaths around axons or enclose unmyelinated axons in the CNS

Term
schwann cells
Definition

single cells surrounding axons

 

form myelin sheaths around axons or enclose unmyelinated axons in the PNS

Term
nodes of ranvier
Definition

gaps in the myelin sheaths that occur about every millimeter between oligodendryocyte segments or between individual schwann cells

 

allows ion movement across

Term
myelination helps with what?
Definition

increases the speed and efficienty of an action potential generated along the axon

 

prevents ion movement which then must only occure at the nodes of Ranvier

Term
gray matter
Definition

groups of neuron cell bodies and their dendrites, very little myelin

 

Cerebral cortex: grey matter on the ouside

Spinal cord: grey matter on the inside shaped like an H and has horns (anterior, posterior and lateral)

Term
white matter
Definition

bundles of parallel axons with myelin sheaths (white color) forms nerve tracts which propagate action potentials from one area of the CNS to another

 

cerebral cortex: inside cortex on neurons

brainstem: outside cortex on neurons

Term
charge of cell membranes
Definition

inside is negative compared to the outside creating polarized membrane.

 

Term
resting membrane potential
Definition

higher concentration of K+ immediately inside the cell membrane

higher concentration of Na+ immediatlely outside the cell membrane

greater permeability of cell membrane to K+ than to Na+

 

permeability depends on number of open ion channels

Term
leak channels
Definition

are alway open... ions leak down thier concentration gradient

 

many more K leak channels so K have a greater contribution to the resting membrane potential

 

 

Term
Gated channels
Definition

closed until opened by specific signals

 

chemically gated (neurotransmiters or other chemicals open) and voltage gated (change in membrane potential opens)

 

when open voltage gated channels change the membrane potential and thus are responsible for AP

Term
stronger stimuli on the nervous system...
Definition
produce  a greater frequency of action potentials but do not increase the size of each action potential
Term
sodium-potassium pump
Definition

maintains greater Na+ concentration outside the cell and greater K+ inside

 

uses alot of energy

Term
continuous conduction (unmyelinated axons)
Definition

AP conducted slow

AP in one part of cell membrane stimulates local currrents in adjacent parts of cell membrane that then produce an AP

 

AP conducted along entire axon

Term
saltatory conduction (myelinated axons)
Definition

AP at one node of ranvier causes a local current to flow throught the surrounding extracellular fluid and through the cytoplasm of the axon to the next node stimulating the AP at the node of Ranvier

 

AP "jump" along length of axon = faster

Term
synapse
Definition

junction where the axon of one neuron interacts with another neuron or with cells of effector organs

binding of neurotranmitters from the postsynaptic membrane to the postsynaptic membrane can either inhibit (K+ or Cl- channels open the inside of the postsynaptic cell tends to become more negative or hyperpolarized) or stimulate (Na+ channels open the postsynaptic cell becomes depolarized) the action potential.

Term

local current

 

(muscle and nerve cells)

Definition

movement of Na+

 

when a stimulus is applied to a muscle/nerve cell following the resulting neurotransmitter activation of chemically gated channals, Na+ channels open briefly allowing Na+ to difuse into the cell 

inside of cell becomes positive (depolarization) resulting in local potential

Term

action potentials occur in all or nothing fashion but what determins if the AP is all or nothing?

 

(muscle and nerve cells)

Definition

after a stimulus has caused chemically gated channals to allow Na+ to move in (local current) and depolarize the membrane (+) resulting in a local potential

 

the local potential can either continue or stop depending on if the depolarization was strong enough or not

if depolarization is strong enough the local potential will reach a threshold causing Na+ gated channels to open (axon of hillock, near cell body) causing 600-fold increase in permeability to Na+ (K+ also opens), reversal in charge occures (inside +)...channels reverse Repolarization and hyperpolarization occures briefly

Term
action potentials are...
Definition
repolarization and depolarization
Term
process of neurotranmitter release across the synaptic cleft
Definition
AP enters presynaptic terminal, voltage gated Ca+2 channels release into cells, this influx of Ca+2 causes neurotransmitters to be released by exocytosis from synaptic vesicles in the presynaptic terminal and diffuse across the synaptic cleft that will bind to specific receptors on the postsynaptic membrane which will cause chemically gated channels (Na+, K+, or cl-) to open or close either stimulating or inhibing an AP
Term

acetylcholine (ACh)

neurotransmitter

Definition

released from CNS synapses, ANS synapses and neuromuscular junctions

 

effect: excitatory or inhibitory

 

autonomic neurotransmitter

Term
Norepinephrine (NE)
Definition

released: selected CNS synapses and some ANS synapses

 

Function: excitatory

 

autonomic neurotransmitter

Term
serotonin
Definition

released: CNS synapses

Effect: generally inhibitory

Term
Dopamine
Definition

released: selected CNS synapses and some ANS synapses

Function: inhibitory

Term
Gamma-aminobutyric acid (GABA)
Definition

released: CNS synapses

function: inhibitory

Term
Glycine
Definition

release: CNS synapses

Function: inhibitory

Term
Endorphins
Definition

Released: descending pain pathway

Function: inhibitory

Term
reflex
Definition
an involuntary reaction in response to a stimulus applied to the periphery and transmitted to the CNS
Term
components of the reflex arc
Definition

basic functional unit of the nervous system

 

sensory receptor, sensory neuron, interneurons, motor neuron, and effector organ

 

occur in the spine or brainstem and the simplest dont include interneurons

Term
converging neuronal pathways
Definition
two or more neurons synapse with the same neuron...this way info transmitted in more than one neuronal pathway can converge into a single pathway
Term
Diverging nuronal pathway
Definition
axon from one neuron divides and synapses with more than one other neuron...allows info transmitted in one neuronal pathway to diverge into two or more pathways
Term
summation
Definition

many presynaptic action potentials needed to cause an effect.

 

spatinal summation: local otentials originate from different locations on the postsynaptic neuron (from converging pathways)

Temporal summation: local potentials overlap in time

 

both can either inhibit or stimulate

Term
spinal cord extends from...
Definition

foramen magnum at base of skull to second lumbar vertebra

end by 2nd lumbar vertebra is called the cauda equina (looks like a horse)

Term
Ascending and descending tracts of spinal cord
Definition

Ascending: consists of axons that conduct AP toward brain (prefix spino-) most consist of 2-3 neurons and end in the thalamus (spinothalamic  and dorsal column takes AP from thalaumus to cerebral cortex)

 

Descending: away from brain, named based on origin and termination. Direct extend directly from upper motor neurons in teh cerebral cortex to lower motor neurons in spinal cord (lateral and anterior corticospinal)

indirect no direct connection between cortical and spinal neurons (rubrospinal, reticulospinal, vestibulospinal and tectospinal)

Term
spinal cord anatomy
Definition

grey matter H with posterior, anterior and lateral horns

sensory axons in dorsal root

motor axons in ventral root

somatic and autonomic neurons lay side by side in spinal nerve

Term
spinal nerves
Definition

arise along the spinal cord from the union of the dorsal roots and ventral roots

 

contain axons of both sensory and somatic motor neurons (dubbed mixed nerves)


exit vertebral column between adjacent vertebrae

31 pairs


three plexuses: Cervical (C1-C4), Brachial (C5-T1), and Lumbosacral (L1-S4)

Term
cervical plexus
Definition

spinal nerve

Phrenic

 

(neck and diaphragm)

Term
Brachial Plexus
Definition

 spinal nerves

 

axillary

radial

muscolocutaneous

ulnar

median

Term
Lumbosacral plexus
Definition

spinal nerves

 

obturator

femoral

tibial

common fibular

Term
components of the brainstem
Definition

midbrain 

pons

medulla oblongata

 

contains several nuclei involved in vital body functions (heart rate, blood pressure, breathing)

 

minor damage can cause death

Term
medulla oblongata
Definition

part of brainstem

 

continuous with spinal cord

regulates heart rate, blood vessel diameter, breathing, swallowing, vomiting, hiccupping, coughing, sneezing, balance


anterior surface exist two pyramids (descending nerve tracts)

Term
pons
Definition

part of brainstem

 

above medulla, bridge between cerebrum and cerebellum

breathing, chewing, salivation, swallowing

Term
midbrain
Definition

part of brainstem (smallest part)

 

above pons

coordinate eye movement, pupil diameter, turning head toward noise


dorsal consists of four mounds called colliculi (inferior: major relay centers for auditory nerve pathways in the CNS, superior: visual reflexes and receive touch and auditory output)


substantia nigra (black nuclear mass, regulates general body movement)

Term
Diencephalon components
Definition

thalamus

epithalamus

hypothalamus

Term
thalamus
Definition

largest portion of diencephalon

influences mood and detects pain (unlocalized pain)

 

interthalamic adhesion connects the center of the two lateral parts

Term
epithalamus
Definition

above and behind thalamus

 

emotional and visceral response to odors and pineal gland (function in the onset of puberty)

Term
hypothalamus
Definition

below thalamus

controls pituitary gland and is connected to it by infundibulum

controls homeostasis, body temp, thirst, hunger, fear, rage, and sexual emotions


mammillary bodies: postieror portion envolved in

emotional responses to odors and in memory

 

Term
cerebrum markings
Definition

largest part of brain

fissures: deep indentations or sulci

 

sulci: superficial indentations

 

Gyri: folds on cerebral cortex that increase surface area

Term
right brain people...
Definition
artistic
Term
front, back and sides of the brain
Definition

frontal lobe: front: voluntary motor functions, aggression, moods, smell

top: evaluates sensory input such as touch, taste, and pain

occipital lobe: vision

temporal lobe: hearing,smell, memory

Term
cerebrum component
Definition

cerebral cortex: surface of cerebrum composed of gray matter

controls thinking, communication, remembering, understanding, and initiates involuntary movement

Term
cerebellum
Definition

lower part of brain by brain stem (the comparator-sensing device comparing data fom tow sources, motor cortex and peripheral structures)

 

cortex is composed of gyri, sulci, gray matter

it controls balance, muscle tone, coordination of fine motor movement (closing eyes)


white matter on inside

drinking stops cell firing this is why a drunk person cant find thier nose with thier eyes closed


cerebellar peduncles connect to brainstem and provide communication between cerebellum and other parts of the CNS

Term
what can cause a coma?
Definition
damage to cells of the reticular formation...cells scattered throughout the brainstem that function as the reticular activating system to regulate sleep-wake cycles by mainaining consciousness. suppressed by general anesthetics
Term
where is the 5th lobe?
Definition
where most of the temporal lobe is separated from the rest of the cerebrum by a lateral fissure the insula or 5th lobe is deep within
Term
primary sensory areas
Definition

where ascending tracts project

where sensations are perceived

 in cerebral cortex

 

primary somatic sensory cortex (general sensory area)

Term
association area
Definition
adjacent to primary sensory areas and involved in process of recognition
Term
primary motor cortex
Definition

in the frontal lobe

control voluntary motor movement

 

AP created here will control voluntary movement of skeletal muscles


premotor area-decides which muscles to contract

prefrontal area-motivation and foresight to plan and initiate movements

 

Term
basal nuclei
Definition

corpus striatum: within cerebrum

substantia nigra: midbrain, darkly pigmented cells

 

important in planing, organizing and coordinating moto movement and posture

 

diseases: parkinson, huntington and cerebral palsy

Term
corpus callosum
Definition
commissure connecting the right and left hemispheres of the brain exsising at the base of the longitudinal fissure
Term
types of brain waves
Definition

measured by electroencephalogram (EEG)

alpha: resting but awake

beta: mental activity

theta: child resting or adult during frustration

Delta: deep sleep in infants...signals epilepsy in adults

Term
menings
Definition

three connective tissue membranes surrounding and protecting the brain and spinal cord

 

epidural space (epidural anethesia) in spine only

dura mater (superficial and thick)

subdural space (spinal block and spinal tap-small amount serous fluid)

arachnoid mater (thin)

subarachnoid space (CSF and blood vessels)

pia mater (lightly bound to brain and spinal cord

 

Term
dura mater
Definition

thickest and most superficial layer of the menings

 

two layers-dural folds and dural venous sinuses

folds: extend into longitudianl fissures between the cerebrum and cerebellum, hold brain in place within the skull

sinuses collect blood from small veins of brain and empty into the internal jugular veins to exit the skull

Term
ventricles
Definition

fluid filled cavities of the CNS

 

lateral: large in each hemishpere

third: smaller midline cavity in center of diencephalon between thalamus halves and connectef by foramina to the lateral ventricles

fourth: base of cerebellum and connected to third by narrow canal (cerebral aqueduct) and also the subarachnoid space of the spinal cord

central canal: fourth continuous with it

Term
Cerebrospinal Fluid (CSF)
Definition

bathes brain and spinal cord, providing a protective cushion around CNS

 

produced by choroid plexus in the ventricles

from lateral ventricles to 3rd ventricle through cerebral aqueduct to 4th ventricle then enters the subarachnoid space and also some into the central canal of the spinal cord. Finally it flows from the subarachnoid space to the arachnoid granulations in the superior sagittal sinus, where it enters teh venous circulation

Term
hydrocephalus
Definition
condition where a blockage of the fourth ventricle or cerebral aqueduct causes CSF to accumulate in the ventricles
Term
olfactory nerve (I)
Definition
smell
Term
optic nerve (II)
Definition
vision
Term
oculomotor (III)
Definition
motor to four of six estrinsic eye muscles and upper eyelid; paraympathetic constricts pupil, thickens lens
Term
trochlear (IV)
Definition
motor to one extrinsic eye muslce
Term
trigeminal V
Definition
sensory: taste; motor to muscles of facial expression, parasympathetic to salvary and tear gland
Term
abducens (VI)
Definition
motor to one extrinsic eye muscle
Term
facial (VII)
Definition
sensory taste, motor to muslces of facial expression; parasympathetic to salivary and tear glands
Term
vestibulocochlear (VIII)
Definition
hearing and balance
Term
glossopharyngeal (IX)
Definition
sensory taste and touh to back of toungue; motor to pharyngeal muscles; parasympathetic to salivary glands
Term
vagus (X)
Definition
sensroy to pharynx, larynx, and viscera; motor to palate, pharynx and larynx, parasympathetic to viscera of thorax and abdomen
Term
accessory (XI)
Definition
motor to two neck and upper back muscles
Term
hypoglossal (XII)
Definition
motor to toungue muscles
Term
sympathetic division of the autonomic nervous system
Definition

preganglion are in lateral horn of spinal cord gray matter located between T1-L2 vertebre and exit through the ventral roots and into either sympathetic chain ganglia or collateral ganglia


postganglionic cell bodies in sympathetic chain ganglia or collateral ganglia

fight or fligh function: prepares body for physical activity



Term
Parasypathetic division of the autonomic nervous system
Definition

located in cranial nerves III, VII, IX, X and S2-S4 spinal nerves

 

postganglionic cell bodies in terminal ganglia or near or embedded in the walls of target organs

 

stimulates involuntary activities of the body at rest

Term

sypathetic chain ganglia

 

(autonomic nervous system)

Definition
connected together and form chains along both sides of the spinal cord
Term

Collateral ganglia

 

(autonomic nervous system)

Definition
located nearer target organs and consist of the celiac, superior mesenteric and inferior mesenteric ganglia
Term

splanchnic nerves

(autonomic nervous system)

Definition
sympathetic nerves extending to collateral ganglia in the abdominl and pelvic region
Term
enteric nervous system
Definition

consists of plexuses within the wall of the digestive tract which include

sensory neurons that connect the digestive tract to the CNS

sypathetic and parasympathetic neurons that connect the CNS to the digestive tract

enteric neurons located entirely withing the enteric plexuses

 

capable of independently monertering/controlling digestiong tract however the two generally work together

Term
"taste buds"
Definition

epithelium

papilla: enlargments on the surface of the tongue

taste bud

supporting cell

taste cell

taste hair: where molecules or ions bind to receptors to initiate AP

taste pore


AP to insula of cerebral cortex

influenced by olfaction

Term
path of sound waves
Definition

auricle

external auditory canal

tympanic membrane (vibrates)

malleus strokes incus that moves foot plate of the stapes (which vibrates in the oval window)

inner ear; perilymph in scala vestibuli vibrates causing vestibular membrane to vibrate and thus

endolymph of cochlear duct which displaces the basilar membrane

cilia of hair cells (of spiral organ) detects movement of (hairs attached to) basilar membrane

AP in cochlear nere

auditory cortex

Term
external ear
Definition

auricle


external auditory canal


ceruminous gland (produces cerumen or earwax)


tympanic membrane (eardrum, separating external ear from middle ear) thin layer of connective tissue sandwiched between two epithelial layers

Term
middle ear
Definition

oval window and round window connect middle ear with inner ear


three ossicles: malleus (hammer-attached to medial surface of tympanic membrane), incus (anvil-connects), stapes (stirrup-base set in oval window surrounded by flexable ligament) amplifiction center

these bones transmit vibrations from tympanic membrane to oval window


muscles attaced to malleus and staples dampen sound to protect inner ear structures

two unblocked openings one to the mastoid process of temporal other auditory tube, opens to pharyns and enables air pressure to be equalized between outside and middle ear cavity (unbalance = hard to hear)

 

Term
Inner ear
Definition

interconnecting tunnels and chambers in the temporal bone-bony labyrinth

three sections:

cochlea-shaped like a snail shell contains a bony core shaped like a screw with threads called spiral lamina which has three parts:

scala vestibuli:extends from the oval window to the apex of cochlea

scala tympani-extends parallel to scala vestibuli from apex back to round window

cochlear duct: space between vestibular membrane and basilar membrane (endolymph)

vestibular membrane- balance

semicirular canals- dynamic equilibrium/balance

membranous labyrinth is the smaller membranous tunnels inside the bony labyrinth (filled with clear fluid-endolymph)

perilymph fills space between bony labryinth and membranous labyrinth




Term
balance
Definition

static equalibrium-associated with vestibule (evaluating position of head relative to gravity)

Dynamic equilibrium-associated with semicirular canals and involved in evaluating changes in direction and rate of head movement

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