Block 4: Nervous System Flashcards
1
Q
Two branches of the nervous system and their function
A
Central nervous system (cns)
Peripheral nervous system (pns)
Function: regulate homeostasis
2
Q
Divisions of CNS
A
Brain and spinal cord
3
Q
Divisions of PNS
A
Sensory → visceral and somatic
Motor → visceral ( → sympathetic and parasympathetic) and somatic
4
Q
Reflex arc pathways
A
1) sensory (afferent) → spinal → motor (efferent)
2) sensory (afferent) → conscious thought/decision making → motor (efferent)
5
Q
3 neuron structures and their neuron types
A
- Unipolar: soma branched off axon → afferent
- Bipolar: soma within axon → afferent
- Multipolar: axon hillock on soma → efferent and interneuron
6
Q
Neuroglia
A
Cells that support, protect, and provide nutrients to neurons
7
Q
Astrocytes
A
Neuroglia of CNS
Star-shaped
Maintains environment around neurons, forms BBB
8
Q
Oligodendrocyte
A
Neuroglia of CNS
Forms myelin sheaths around axons in the CNS with its processes
9
Q
Microglia
A
Neuroglia of CNS
Engulfs microbes, debris, and dead tissue
10
Q
Ependymal cell
A
Neuroglia of CNS
Forms and circulates CSF
Lines 4 ventricles of the brain and central canal
11
Q
Satellite cell
A
Neuroglia of PNS
Regulate chemical environment
Cover sensory neuron cell body
12
Q
Schwann cell
A
Neuroglia of PNS
Forms myelin sheath on axons in PNS
Each cell is individually around the axon
13
Q
Benefit of myelinated axons
A
More myelinated = faster neural transmission
14
Q
White matter
A
Inside brain, outside spinal cord
Primarily myelinated axons
White because of lipids in the myelin sheath
15
Q
Gray matter
A
Outside brain, inside spinal cord
Nervous tissue with little to no myelination
16
Q
Principal Brain regions*
A
Brainstem
Cerebellum
Diencephalon
Cerebrum
*All can be divide further into specific regions
17
Q
Specific regions of the brainstem
A
Medulla oblongata
Pons
Midbrain
18
Q
Medulla oblongata
A
Location: brainstem
Function: respiratory and cardio control; reflexes - coughing, sneezing, vomiting
19
Q
Pons
A
Location: brainstem
Function: respiratory center assists medulla oblongata; relays information to the diencephalon and cerebrum
20
Q
Midbrain*
A
Location: brainstem
Function: associated with vision, hearing, temperature regulation, sleep, alertness, and motor control
Structures: corpora quadrigemina - superior and inferior colliculi
*contains sensory and motor tracts
21
Q
Corpora quadrigemina
A
Location: midbrain
Structures: superior colliculus and inferior colliculus
22
Q
Superior colliculus
A
Location: midbrain
Function: reflex centers involved with visual stimuli
Sensory tract: eye, head, and neck movements
23
Q
Inferior colliculus
A
Location: midbrain
Function: reflex centers involved in auditory stimuli
Motor tract: head and trunk movements
24
Q
Specific structures and functions of the cerebellum
A
Structures: vermis, folia, arbor vitae
Function: coordinates skeletal muscle contraction; regulates posture and balance
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Vermis
Location: cerebellum
Function: joins two cerebellar hemispheres
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Folia
Location: cerebellum
Function: gray matter in a series of folds within the cerebellar cortex
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Arbor vitae
Location: cerebellum
Function: tracts of white matter
28
Specific structures of the diencephalon
Epithalamus
Thalamus
Hypothalamus
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Thalamus
Location: Diencephalon
Structures: intermediate mass
Functions: maintenance of consciousness, memory, learning, and emotions; motor functions; relays almost all sensory input to cerebral cortex
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Intermediate Mass
Location: thalamus
Function: connection of the thalamus between the two hemispheres
31
Hypothalamus
Location: Diencephalon
Structures: mammillary bodies, optic chiasm, infundibulum, and pituitary gland
Functions: controls and integrates activities of the autonomic nervous system; produces hormones, emotional and behavioral patterns; regulates body temperature eating, drinking, and circadian rhythms
32
Mammillary bodies
Location: hypothalamus
Function: smell and taste reflexes
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Optic chiasm
Location: hypothalamus
34
Infundibulum
Location: hypothalamus
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Pituitary Gland
Location: hypothalamus
36
Epithalamus
Location: diencephalon
Structures: pineal gland
Functions: none specific to the epithalamus
37
Pineal gland
Location: epithalamus
Function: secretes melatonin
38
Structures and functions of the cerebrum
Regions: cerebral cortex, white matter, basal ganglia
Structures: corpus callous, fornix, chornoid plexus
Function: association areas for memory, personality, and intelligence; perception of sensory information; voluntary movements
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Cerebral cortex
Location: cerebrum
Function: grey matter of the brain
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White matter
Location: cerebrum
Function: white matter of the brain
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Basal ganglia*
Location: cerebrum
Function: initiate, suppress, and terminate movements; regulate muscle tone
*Ganglia (nuclei): cluster of neurons in the CNS responsible for similar functions
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Corpus callous
Location: cerebrum
Function: connect right and left hemispheres
43
Fornix*
Location: cerebrum
Function: transmits information from the hippocampus to the maxillary bodies and thalamus
*c-shaped bundle of nerve fibers
44
Choroid plexus*
Location: cerebrum
Function: converts blood plasma into CSF via ependymal cells
*network of capillaries
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Structures and functions of the cymbal system
Structures: amygdala, hippocampus, thalamus, hypothalamus, basal ganglia, cingulate gurus
Functions: promotes range of emotions - pleasure, pain, affection, fear, anger
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Cerebrum surface features
Posterior group: postcentral gyrus, parietal lobe, parieto-occipital sulcus, occipital lobe, transverse fissure
Anterior-superior group: central sulcus, precentral gurus, frontal lobe
Anterior-inferior group: lateral cerebral sulcus, temporal lobe
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Functional areas
Found within structural areas of the brain
Types: motor (initiate impulses to skeletal muscle) and sensory (receive and interpret impulses from sensory receptors)
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Association areas
Location: in between functional areas
Function: complex integration of brain functions
49
Functional areas of the cerebrum
Sensory cortices and association areas:
- primary somatosensory cortex
- somatosensory association area
- primary motor cortex
- motor association area
- primary auditory cortex
- auditory association area
- primary visual cortex
- visual association area
Language areas:
- broca's area
- wernicke's area
50
Primary somatosensory cortex
Function: receives sensory information from the body
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Somatosensory association area
Function: allows you to recognize objects by touch
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Primary motor cortex
Function: initiates voluntary movement of your skeletal muscles
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Motor association area
Function: coordination of complex movement
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Primary auditory cortex
Function: detects sound
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Auditory association area
Function: processes auditory information
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Primary visual cortex
Function: involved in the detection of simple visual stimuli
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Visual association area
Function: processes visual information
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Broca's area
Function: motor speech area that helps in movements required to produce speech
Broca's aphasia "broken speech" - a patient can understand speech but can't speak themselves
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Wernicke's area
Function: sensory area that helps understand speech and using correct words to express our thoughts
Wernicke's aphasia "word salad" - patient can produce speech but not understand the speech of others
60
3 significant lines of defense for the brain
Cranial bones
The meninges
CSF
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Meninges functions
Connective tissue layers that surround the brain
Protect the brain
Keep the brain anchored to the skull
Reabsorb CSF
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CSF flow location
Subarachnoid space
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Superior sagittal sinus
Function: carries waste and fluid away from the brain and back into the bloodstream
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Meninges layers
Dura mater: periosteal layer, meningeal layer, subdural space
Arachnoid mater: arachnoid villi, subarachnoid space
Mia mater
65
Head layers superior to inferior
Scalp
Periosteum
Skull
Superior sagittal sinus
Dura mater: periosteal layer, meningeal layer, subdural space
Arachnoid mater: arachnoid villi, subarachnoid space
Pia mater
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Ventricles of the Brain
2 lateral ventricles
3rd ventricle
4th ventricle
Other structures:
Interventricular foramen
Cerebral aqueduct
Central canal of spinal cord
Lateral aperture
Medial aperture
67
CSF structures and functions
Structures: choroid plexus and ependymal cells
Functions: filtered blood plasma that provides nutrients to the brain and spinal cord
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Choroid plexus
Location: walls of ventricles
Function: network of blood capillaries that filter blood plasma into ependymal cells
69
Ependymal cells
Location: between capillaries and ventricles
70
CSF flow
1) CSF is secreted by choroid plexus in each lateral ventricle
2) CSF flows through interventricular foramina into 3rd ventricle
3) Choroid plexus in 3rd ventricle adds more CSF
4) CSF flows down cerebral aqueduct to 4th ventricle
5) Choroid plexus in 4th ventricle adds more CSF
6) CSF flows out 2 lateral apertures and 1 medial aperture
7) CSF fills subarachnoid space and coats external surfaces of the brain and spinal cord
8) CSF is reabsorbed into venous blood of rural venous sinuses at arachnoid villi
71
Olfactory I
Location: cranial nerve 1
General Function: sensory
Specific Function: smell
72
Optic ll
Location: cranial nerve 2
General Function: sensory
Specific Function: vision
73
Oculomotor lll
Location: cranial nerve 3
General Function: motor
Specific Function: movement of eyelid and eyeball, accommodation of lens, and constriction of pupil
74
Trochlear lV
Location: cranial nerve 4
General Function: motor
Specific Function: movement of eyeball
75
Trigeminal V
Location: cranial nerve 5
General Function: sensory and motor
Specific Function: sensory → touch, pain, thermal sensations from ophthalmic, maxillary, and mandibular areas; motor → chewing and middle ear muscle control
76
Abducens VI
Location: cranial nerve 6
General Function: motor
Specific Function: abduction of the eyeball
77
Facial Vll
Location: cranial nerve 7
General Function: sensory and motor
Specific Function: sensory → taste; motor → facial expression, tears, salivation
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Vestibulocochlear Vlll
Location: cranial nerve 8
General Function: sensory
Specific Function: equilibrium and hearing
79
Glossopharyngeal lX
Location: cranial nerve 9
General Function: sensory and motor
Specific Function: sensory → taste; motor → swallowing, speech, saliva secretion, motors O2, CO2, and blood pressure
80
Vagus X
Location: cranial nerve 10
General Function: sensory and motor
Specific Function: sensory → taste, somatic sensation from pharynx and epiglottis; motor → swallowing, coughing, voice projection; smooth muscle contraction and secretion of GI tract; slows heart rate; constriction of respiratory pathways
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Accessory Xl
Location: cranial nerve 11
General Function: motor
Specific Function: movement of head and pectoral girdle
82
Hypoglossal Xll
Location: cranial nerve 12
General Function: motor
Specific Function:speech, manipulation of food, swallowing
83
Connective tissue nerve coverings
Epineurium
Perineurium
Endoneurium
84
Epineurium
Location: covering that surrounds whole nerve
85
Perineurium
Location: covering that surrounds each fascicle
86
Endoneurium
Location: covering that surrounds myelinated and unmyelinated axons
87
Superfacial to deep organizational structure of nerves
Epineurium
Perineurium
Endoneurium
88
Spinal nerves
Location: 31 pairs of spinal nerves, one emerging from each side of the spinal cord
Functions: sends information from peripheral sensory receptors to the spinal cord and information from the spinal cord to effectors; mediates spinal reflexes
89
Spinal plexuses
Plexus: where spinal nerves form a braided network
Each plexus is named after the anatomical region it extends from
90
Nerves from cervical plexus
Spinal nerve: phrenic nerve
- roots from C3-C5
91
Phrenic nerve
Location: cervical plexus
Muscle innovated: diaphragm
92
Nerves from brachial plexus
Spinal nerves:
- axillary nerve
- musculocutaneous nerve
- radial nerve
- median nerve
- ulnar nerve
93
Axillary nerve
Location: brachial plexus
Muscles innervated:
- deltoid
- teres minor
94
Musculocutaneous nerve
Location: brachial plexus
Muscles innervated:
- brachialis
- biceps brachii
95
Radial nerve
Location: brachial plexus
Muscles innervated:
- triceps brachii
- brachioradialis
96
Median nerve
Location: brachial plexus
Muscles innervated:
- pronator teres
- palmaris longus
97
Ulnar nerve
Location: brachial plexus
Muscles innervated:
- flexor carpi ulnaris
- medial half of flexor digitorum profundus
98
Nerves from lumbar plexus
Spinal nerves:
- femoral nerve
- obturator nerve
99
Femoral nerve
Location: lumbar plexus
Muscles innervated:
- iliacus
- sartorius
100
Obturator nerve
Location: lumbar plexus
Muscles innervated:
- adductor longus
- adductor brevis
101
Nerves from sacral plexus
Spinal nerves:
- sciatic nerve
- tibial nerve
- common fibular nerve
102
Sciatic nerve
Location: sacral plexus
Muscles innervated:
- semimembranosus
- semitendinosus
103
Tibial nerve
Location: sacral plexus
Muscles innervated:
- gastrocnemius
- soleus
104
Common fibular nerve
Location: sacral plexus
Muscles innervated:
- fibularis longus
- tibialis anterior
105
Reflex
Rapid, involuntary motor responses to environmental stimuli detected by sensory receptors
Protective and fast circuits which cerebral decision making is not required for initiation
If we are aware, the reflex is likely autonomic
106
4 ways to classify reflexes
1) site of integration
2) effector(s) involved
3) number of synapses
4) site of stimulus vs. effector
107
Site of integration
Cranial reflex vs. Spinal reflex:
- cranial reflexes are integrated at the brain
- spinal reflexes are integrated at the spinal cord
108
Involved effector
Somatic motor innervation vs. Autonomic efferent motor innovation:
- somatic is voluntary movements
- autonomic can be sympathetic or parasympathetic but are both involuntary
109
Number of synapses
Monosynaptic reflex us. Polysynaptic reflex:
- monosynaptic have direct communication between sensory and motor neuron
- polysynaptic have facilitated communication through interneurons
110
How to test reflex integrity
Cranial nerve tests assess integrity of cranial nerve involvement
Spinal nerve tests assess integrity of spinal nerve involvement
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Corneal reflex
Cranial reflex
Afferent nerve is cn5 and efferent nerve is cn7
Stimulation of cornea
Response is contraction of eye muscles
Somatic, bilateral, and polysynaptic
112
Pupillary light reflex
Cranial reflex
Afferent nerve is cn2 and efferent nerve is cn3
Light stimulus
Response is pupillary constriction on same side
Autonomic, ipsilateral, polysynaptic
113
Consensual light reflex
Cranial reflex
Afferent nerve is cn2 and efferent nerve is cn3
Light stimulus
Response is pupillary constriction of opposite side
Autonomic, contralateral, polysynaptic
114
Salivary reflex
Cranial reflex
Afferent nerve is cn7 and efferent nerve is cn9
Stimulus is thinking about food or tongue stimulation
Response is secretion of saliva
Autonomic, bilateral, polysynaptic
115
Gag reflex
Cranial reflex
Afferent nerve is cn9 and efferent nerve is cn10
Stimulation of soft palate
Response is constriction of pharynx
Autonomic, bilateral, polysynaptic
116
Patellar reflex
Spinal reflex
Sensory receptor is muscle spindle fibers in quadriceps and effector is femoral nerve
Stimulation of striking patellar tendon
Response is extension of the leg
Somatic, ipsilateral, monosynaptic
117
Achilles reflex
Spinal reflex
Sensory receptor is muscle spindle fibers in gastrocnemius and effector is tibial nerve
Stimulation is striking achieves tendon
Response is contraction of gastrocnemius muscle
Somatic, ipsilateral, monosynaptic
118
Plantar reflex
Spinal reflex
Sensory receptor is skin receptors in the sole of foot and effector is the tibial nerve
Stimulation is rubbing foot from lateral sole up to medial toe
Response is flexion of the digits in foot
Somatic, ipsilateral, polysynaptic
119
Flexor reflex
Spinal reflex
Sensory receptor is nociceptors in sole of foot and effector is sciatic nerve
Stimulation is stepping on something
Response is flexion of the leg on the same side as stimulus
Somatic, ipsilateral, polysynaptic
120
Crossed extensor reflex
Spinal reflex
Sensory receptor is nociceptors in sole of foot and effector is femoral nerve
Stimulation is stepping on something
Response is flexion of the leg on the opposite side as stimulus
Somatic, contralateral polysynaptic
121
Cranial reflexes
Corneal reflex
Pupillary light reflex
Consensual light reflex
Salivary reflex
Gag reflex
122
Spinal reflex
Patellar reflex
Achilles reflex
Plantar reflex
Flexor reflex
Crossed extensor reflex
123
Visual tests
Blind spot test
Visual acuity
Astigmatism test
Color blindness test
124
Visual acuity test
Snellen eye chart: 20/50
Top number is now far you are standing away
Bottom number is the distance at which someone with normal eyesight can read the smallest line you see clearly
125
Refractive errors
When eye cannot focus light on the retina, usually causing blurry vision
Most common refractive errors are myopia and hyperopia
126
Myopia
Type of refractive error
When eyeball is too long causing nearsightedness
Fixed with a concave lens
127
Hyperopia
Type of refractive error
When eyeball is too short causing fearsightedness
Fixed with a convex lens
128
Emmetropia
Type of refractive error
When eyeball can see normally
129
Blind spot test
Type of vision test
Section of the retina that does not contain sensory receptors (where the optic ll enters the eye)
130
Astigmatism test*
Type of vision test
Oval shaped cornea causing multiple focal points
*astigmatism is a refractive error
131
Colorblindness test
Type of vision test
Determines if someone is colorblind
132
Sensation vs. Perception
Sensation: input from the physical world obtained by sensory receptors
Perception: organization, interpretation, and conscious experience of sensations that primarily occurs in the cerebral cortex
133
Two types of senses
General senses
Special senses
134
General senses
Sensation provided by somatic and visceral receptors
- found in skin, skeletal muscle, visceral/internal organs
135
Special senses
Sensation provided by receptors related to special sense organs
- ex: eyes, inner ear, nasal mucosal taste buds
136
Somatic senses
Type of general sense
- ex tactile, thermal, pain, proprioception
137
Visceral senses
Type of general sense
- ex: information about conditions within internal organs (interoception)
138
Receptor classifications
Microscopic structure
Location of receptor and origin of activating stimuli
Type of stimulus
139
Microscopic structure
Type of receptor classification
Free or encapsulated nerve endings; separate cells that synapse with neurons
- ex: free nerve endings, tactile disc, hair receptor
140
Location of receptor and origin of activating stimuli
Type of receptor classification
Exteroceptors, interceptors, proprioceptors
- ex: tactile corpuscle, end bulb, bulbous corpuscle
141
Type of stimulus
Type of receptor classification
Mechanoreceptors, thermoreceptors, nociceptors, chemoreceptors, osmoreceptors
- ex: lamellar corpuscle, muscle spindle, tendon organ
142
Skin sensory receptors
Nociceptor
Merkel discs
Meissner's corpuscle
Ruffini's corpuscle
Hair root plexus
Pacinian corpuscle
Thermoreceptors
143
Tactile receptors
Skin sensory receptors
Merkel discs, messier corpuscle, hair root plexus, pacinian corpuscle
144
Merkel discs
Type of tactile receptor
Location: stratum basale
Function: free nerve endings that detect light touch and pressure
145
Messier corpuscle
Type of tactile receptor
Location: dermal papillae of hairless skin
Function: encapsulated nerve endings that detect light touch and pressure in the papillary layer; allows you to distinguish between textures by low-frequency libra tons
146
Hair root plexus
Type of tactile receptor
Location: hair bulb
Function: nerve endings that detect hair movement
147
Pacinian corpuscle
Type of tactile receptor
Location: subcutaneous, submucosal tissue, joints, tendons, muscle
Function: encapsulated nerve endings that detects deep pressure through high-frequency vibrations
148
Adaptation of touch receptors
Adapt to constant stimulus decreasing the number of action potentials they send over time
149
Two- point discrimination
Areas with smaller receptive fields have greater receptor density and are able to discriminate between two points
- primarily in the somatosensory cortex
150
Ruffini corpuscle
Type of proprioceptor
Location: dermis, ligaments, tendons
Function: encapsulated nerve endings that stretched digits and limbs
151
Tactile localization
Being able to match the same spot to test sensory and motor components
- receptive field/ receptor density is the same concept as the two-point discrimination
152
Adaptation of temperature receptors
Adapt to a constant stimulus by decreasing the number of action potentials they send over time
- only adapt if temperature is not extreme
153
Nociceptors
Type of pain receptor
Location: ends of stratum basale
Function: free nerve endings that detect painful stimuli
154
General pain versus Referred pain
General pain: visceral organ and area in pain are innervated by the same segment of the spinal cord
Referred pain: arises due to convergence of synaptic inputs in the pain pathway
155
Regions of ear
External (outer) ear
Middle ear
Inner ear
156
External (outer) ear
Region of ear
Structures: auricle, external auditory canal, tympanic membrane
157
Middle ear
Region of the ear
Structures: auditory ossicles, oval window, auditory tube
158
Inner ear
Region of the ear
Structures: bony labyrinth → cochlea, vestibule, 3 semi-circular canals
159
Auricle
Structure of external ear
Function: collect sound waves
160
External auditory canal
Structure of external ear
Function: directs sound waves to tympanic membrane
161
Tympanic membrane
Structure of external ear
Function: sound waves cause vibrations, which causes malleus to vibrate
162
Auditory ossicles
Structure of middle ear
Structures: stapes, incus, malleus
Function: transmit and amplify vibrations to oval window
163
Oval window
Structure of mida ear
Function: small opening for stapes footplate
164
Auditory tube
Structure of middle ear
Function: equalizes air pressure
165
Semi-circular canals
Structure of inner ear
Function: detect head movement in any direction
166
Vestibule
Structure of inner ear
Function: detects linear movement of the head
167
Cochlea
Structure of inner ear
Structures: cochlear duct
Function: tilled with perilymph that moves in response to vibrations
168
Cochlear duct
Structure of cochlea
Function: transforms auditory vibrations into electrical impulses that are sent to the brain
169
Cochlear branch of cn8
Structure of inner ear
Function: carries sound signals to the brain
170
Vestibular branch of cn8
Structure of inner ear
Function: carries equilibrium/balance signals to the brain
171
Types of deafness
Conduction deafness
Sensorineural deafness
172
Conduction deafness
Type of deafness
Decreased ability to conduct energy of sound waves to hearing receptors
Causes: infection, earwax buildup, punctured eardrum, fluid in middle ear, damage to ossicles
173
Sensorineural deafness
Type of deafness
Damage to hearing receptors, cochlear branch of vestibulocochlear nerve, or neural pathways to auditory cortex
Causes: auditory nerve damage, inner ear hair cell damage, aging
174
Types of hearing deafness
Weber test
Rinne test
175
Weber test
Type of hearing test
Used to determine unilateral deafness
176
Rinne test
Type of hearing test
Used to determine conduction dearness based on Weber test results
177
Weber test results: equal loudness in both ears
Normal hearing
Equal hearing loss in both ears
178
Weber test results: sound louder in R ear
Conduction deafness in R ear
Sensorineural deafness in L ear
179
Weber test results: sound louder in L ear
Conduction deafness in L ear
Sensorineural dearness in R ear
180
Layers of the eye
Fibrous tunic
Vascular tunic
Sensory tunic
181
Fibrous tunic
Layer of the eye
Structures: cornea, sclera
182
Vascular tunic
Layer of the eye
Structures: iris, ciliary body, choroid
183
Sensory tunic
Layer of the eye
AKA retina
184
Eye cavities
Anterior cavity
Vitreous cavity
185
Anterior cavity
Cavity of the eye
Contains aqueous humor
Two chambers: anterior chamber and posterior chamber
186
Vitreous chamber
Cavity of the eye
Contains vitreous humor
187
Macula lutea
Small pigmented area in the retina that contains cones
Function: straight, central, share, and detailed vision
188
Fovea central
Pit located in the center of the macula lutea and has the densest amount of cones
Function: sharp and detailed vision for reading, driving, or any visual activity
