Exam 4 Flashcards
1
Q
what are the 4 major regions of the brain
A
cerebrum (two hemispheres; five lobes per hemisphere)
diencephalon
brainstem
cerebellum
2
Q
gyri
A
ridges
3
Q
sulci
A
derpessions between ridges
4
Q
fissues
A
deep sulci
5
Q
what matter is the brain and spinal cord composed of
A
gray and white tissue
6
Q
gray matter
A
made of neuron cell bodies, dendrties, and unmyelinated axons
7
Q
white matter
A
consists of myelinated axons
8
Q
cerebral cortex and the cerebral nuclei are
A
grey matter
9
Q
cranial meninges
A
three connective tissue layers
separate and support soft tissue of brain
enclose and protect blood vessels supplying the brain
help contain and circulate cerebrospinal fluid
10
Q
cranial meninges from deep to superficial
A
pia mater
arachnoid mater
dura matter
11
Q
pia matter
A
innermost of the meninges; adheres to brain surface
thin layer of areolar connective tissue
12
Q
arachnoid mater
A
lies external to pia mater
made of a web of collagen and elastic fibers
lies deep to dura mater
-subdural space is a potential space that can fill with blood if a vein is ruptured (subdural hematoma)
13
Q
arachnoid trabeculae
A
extends to pia mater through subarachnoid space
14
Q
subarachnoid space
A
contains cerebrospinal fluid
15
Q
dura mater
A
though outer membrane
made of dense irregular connective tissue in 2 layer
-meningeal layer (deeper layer of dura)
-periosteal layer (more superficial layer of dura)
-layers are usually fused but in some areas they separate to form dural venous sinuses that drain blood from the brain
the epidural space is a potential space between dura and skull
-contains arteries and veins
16
Q
what does the periosteal layer form
A
the periosteum on internal surface of cranial bones
17
Q
ventricles
A
cavities within the brain that are lined with ependymal cells and contain cerebrospinal fluid
connect with each other and with spinal cord’s central canal
18
Q
lateral ventricles
A
large cavities in cerebrum
separated by medial partition, septum pellucidum
19
Q
third ventricle
A
narrow space in middle of diencephalon
connected to each lateral ventricle by an interventricular formen
20
Q
what connects the lateral ventricle to the third ventricle
A
interventricular foramen
21
Q
fourth ventricle
A
sickle-shaped space between pons and cerebellum
connected to third ventricle by cerebral aqueduct
opens to subarachnoid space medially and laterally
narrows before merging with central canal of spinal cord
22
Q
cerebropsinal fluid (CSF)
A
clear, colorless liquid surrounding CNS
circulates in ventricles and subarachnoid space
provides buoyancy; reduces brain’s apparent weight by 95%
protects CNS by providing a liquid cushion
keeps CNS environment stable by transporting nutrients and wastes and protecting against chemical fluctuations
23
Q
what forms CSF
A
choroid plexus
-specialized tissue in each ventricle
-layer of ependymal cells and blood capillaries
24
Q
CSF formation
A
blood plasma is filtered through capillary and modified by ependymal cells
in addition, ependymal cell secretions and interstitial fluid from subarachnoid space help make CSF
25
CSF circulation
CSF is continuously formed and reabsorbed
-formation begins in choroid plexus of ventricles
-CSF flows from lateral ventricles into third ventricle
-From 3rd ventricle into fourth
-after passing through apertures, it flows in subarachnoid space and down into central canal of spinal cord
-excess CSF flows into arachnoid villi and drains into dural venous sinuses
26
cerebrum
two large hemispheres on superior aspect of brain
origin of all complex intellectual functions
center of
-intelligence and reasoning (thought memory judgement)
-voluntary motor control
-special sense interpretation (visual auditory)
27
longitudonal fissure
deep cleft separating left and right hemispheres of cerebrum
28
what connects the cerebrum
white matter tracts
29
corpus collosum
largest white matter tract providing a connection between cerebral hemispheres
30
cerebral hemispheres connection with the brain
left hemisphere recieves sensory signals from right side of body and sends motor signals to right side of body
31
what are the 5 lobes of the cerebrumm
frontal
parietal
temporal
occipital
insular
32
frontal lobe
anterior part of cerebrum
-posterior border is deep central sulcus
-frontal lobe has varied functions
33
precentral gyrus controls
voluntary movement
34
frontal lobe controls
motor control
concentration
verbal communicaiton
decision making
planning
personality
35
parietal lobe
serves general sensory functions
-evaluating shape and texture of objects
36
temporal lobe
located inferior to lateral sulcus
-hearing and smell
37
occipital lobe
functions in vision and visual memories
38
insula
small lobe that can be observed by pulling away temporal lobe
functions in memory and sense of taste
39
primary motor cortex
primary motor cortex located in precentral gyrus
also called somatic motor area
controls skeletal muscle activity on opposite side of body
-project contralaterally (opposite side) wihtin brainstem or spinal cord
hands tongue and face heavily impacted
40
motor speech area
located in inferolateral portion of left frontal lobe
controls movements for vocalization
41
frontal eye field
on superior surafce of middle frontal gyrus
regulates eye movements needed for reading and binocular vision
42
premotor cortex (somatic motor association area)
located anterior to primary motor cortex
coordinates learned, skilled activites
43
what are the motor areas of the cerebrum
primary motor cortex
motor speech area
frontal eye field
premotor cortex
44
what the sensory areas of cerebrum
primary somatosensory cortex
somatosensory association area
primary visual cortex
visual association area
primary auditory cortex
auditory association area
primary olfactory cortex
primary gustatory cortex
45
primary somatosensory cortex
located in postcentral gyrus of parietal lobes
receives somatic sensory information from
-proprioceptors, touch, pressure, pain, temperature receptors
lips fingers and genitals heavily impacted
46
primary somatosensory cortex
located in postcentral gyrus of parietal lobes
receives somatic sensory information from
-proprioceptors, touch, pressure, pain, temperature receptors
lips fingers and genitals heavily impacted
47
motor areas are found in what area of the brain
frontal lobes
48
somatosonsory association area
immediately posterior to postcentral gyrus (in parietal lobe)
integrates touch information allowing us to identify objects by feel
49
primary visual cortex
located within occipital lobe
50
visual association area
surrounds primary visual cortex
integrates color, form, memory to allow us to identify things we see like faces
51
primary auditory cortex
located within temporal lobe
52
auditory association area
located in temporal lobe
interprets sounds; stores and retrieves memories of sounds
53
primary olfactory cortex
located within temporal lobe
provides conscious awareness of smells
54
primary gustatory cortex
located within insula
involved in processing taste infromation
55
what are the function brain regions
prefrontal cortex
wernicke area
gnostic area
all integrate information from multiple association areas
56
prefrontal cortex
located rostral to premotor cortex (in frontal lobe)
complex thought, judgement, personality, planning, deciding
still developing in adolescence
57
wernicke area
typically located in left hemisphere (temporal lobe)
involved in language comprehension
58
gnostic area (common integrative area)
integrates information from variety of sensory association areas
sights, smells, sounds, converge and brain becomes aware of sitaution
(lunchtime)
59
where is white matter and white gives it that color
lies deep to grey cerebral cortex
composed of myelinated axons grouped into tracts
60
association tracts
connect regions of cerebral cortex within same hemisphere
arcuate fibers: short tracts connecting neighboring gyri
longitudinal fasciculi: longer tracts connecting gyri in different lobes
61
commissural tracts
commissures connect regions in different hemispheres
include corpus callosum, anterior and posterior commissure
62
projection tracts
link cerebral cortex to inferior brain regions and spinal cord
-corticospinal tracts carry signal from cerebral cortex to spinal cord
-as this projection tract passes between thalamus and cerebral nuclei it is called the internal capsule
63
hemisphere specialization (cerebral lateralization)
two sides of cerebrum exhibit differences in higher-order functions
categorical hemisphere is usually left hemisphere
-specialized for language abilities, functions in categorization and analysis
-contains wernicke area and motor speech area
representational hemisphere is usually right hemisphere
-concerned with visuospatial relationships, imagination, comparison of senses
two hemispheres communicate through the corpus callosum and other commussures
64
when does lateralization develop
early childhood usually before 5-6 years of age
65
what determines handedness
lateralization
in right handers, left hemisphere is almost always categorical, speech-dominant
left handed individuals may have either hemisphere be categoriacal
66
dienccephalon
includes the epithaalmus, thalamus and hypothalamus
provides relays and switching centers for sensory, motor, visceral pathways
67
epithalamus
forms posterior part of roof of diencephalon, covers third ventricle
pineal gland - endocrine gland secreting melatonin
-helps regulate day-night cycles, circadian rhythm
68
thalamus
oval masses of gray matter on lateral sides of third ventricle
composed of about a dozen talamic nuclei
-axons from a given nucleus project to a particular region of cortex
receives signals from all conscious senses
-relays some signals to appropriate part of cortex and filters out other signals distracting from subject of attention )background noise in crowded room)
69
hypothalamus
anteroinferior region of the diencephalon
infundibulum: stalk of pituitary that extends from hypothalamus
70
functions of the hypothalamus
control of autonomic nervous system
-influences heart rate, blood pressure, digestive activities, respiration
control of endocrine system
-secretes hormones that control activities in anterior pituitary gland
-produces antidiuretic hormone and oxytocin
regulation of body temperature
-neurons in preoptic area detect altered temperature
-signal other hypothalamic nuclei to heat or cool the body
emotional behavior
-part of limbic system; controls emotional responses (pleasure fear rage contentment sex drive)
food intake
-ventromedial nucleus monitors nutrient levels regulates hunger
water intake
-anterior nucleus monitors concentration of dissolved substances in blood regulates thirst
sleep-wake ryhthms
-suprachiasmatic nucleus directs pineal gland to secrete melatonin, regulates circadian rhythms
71
brainstem
connects cerebrum, diencephalon, and cerebellum to spinal cord
contains ascending and descending tracts
contains autonomic nuclei, nuclei of cranial nerves and reflex centers
consists of
-midbrain
-pons
-medulla oblongata
72
midbrain
several tracts and bands of axons carry impulses to an from other portions of CNS
reticular formation - altertness
cerebral aqueduct (aqudeuct of Sylvius)
-connects third and fourth ventricles
houses nuclei of CN III (oculomotor) and IV (trochlear)
tectum
-contains four mounds making a tectal plate (corpora quadrigemmina)
73
cerebral peduncles
motor tracts
74
pair of supperior colliculi
controls visual reflexes and tracking
75
pair of inferior colliculi
control auditory reflexes
76
pons
bulging region on anterior brainstem
-includes sensory and motor tracts connecting brain to spinal cord
-cranial nerve nuclei (sensory and motor)
- nuclei for CN V to CN VIII: trigeminal, abducens, facial, and vestibulocochlear nerves
77
medulla oblongata
inferior portion of brainstem
-continuous with spinal cord inferiorly
-includes sensory and motor tracts connecting brain to spinal cord
78
autonomic nuclei of medulla
cardiac center regulates heart's output
vasomotor center regulates blood vessel diameter
-strong influence on blood pressure (vessel constriction increases pressure)
medullary respiratory center controls respiratory rate
-communicates with pontine respiratory center
79
cranial nerve nuclei of medulla
ncueli for vestibulocochlear, glosssopharnygeal, vagus, accessory, and hypoglossal nerves
80
cerebellum
2nd largest brain area (after cerebrum)
-cerebellar cortex: convoluted surface with folia (folds)
-left and right cerebellar hemispheres
vermis
- narrow band of cortex between left and right lobes
- receives sensory signals regarding torso
position and balance
arbor vitae: internal region of white matter
81
three thick nerve tracts connect cerebellum to brainstem
superior cerebellar peduncles
-connect cerebellum to midbrain
middle cerebellar peduncles
-connect cerebellum to pons
inferior cerebellar peduncles
-connect cerebellum to medulla oblongata
82
cerebellum. coordinates and "fine tunes" movements
ensures muscle acitivity follows correct pattern
adjusts movements initiated by cerebrum, ensuring smoothness
helps maintain equilibrium and posture
-receives proprioceptive information from muscles and joints
83
spinal cord
extends inferiorly from brain's medulla through vertebral canal
ends at L1 vertebra with conus medullaris
two winded regions with greater number of neurons
-cervical enlargement: contains neurons innervating upper limbs
-lumbosacral enlargement: contains neurons innervating lower limbs
84
spinal cord from top to bottom
cervical part
-8pairs of cervical spinal nerves
thoracic part
-12pairs of thoracic spinal nerves
lumbar part
-5pairs of lumbar spinal nerves
sacral part
-5pairs of sacral spinal nerves
coccygeal part
-1 pair of coccygeal spinal nerves
85
rootlets from L2 and below exend inferiorly called
cauda equina
86
filum terminale
thin strand of pia attaching conus medullaris to coccyx
87
spinal cord size and shape
varya long its length but is roughly cylindrical
88
spinal cord meninges
pia mater : delicate layer adhering to spinal cord
-filum terminale: pia anchoring inferior end of spinal cord to coccyx
arachnoid mater: web-like layer, external to pia
-subarachnoid space: area deep to arachnoid through which CSF flows
dura mater: tough, outermost layer
-subdural space is between dura and arachnoid
-epidural space is between dura and vertebra (houses adipose, areolar connective tissue, blood vessels)
89
anterior horns
house cell bodies of somatic motor neurons (gray matter)
90
lateral horns
house cell bodies of autonomic motor neurons
only present in T1-L2
(gray matter)
91
posterior horns
house axons of sensory neurons and cell bodies of interneurons
(gray matter)
92
white matter portions of spinal cord
posterior funiculus
lateral funiculus
white commisure
anterior funiculus
93
gray commissure
horizontal band of gray matter surrounding central canal
contains unmyelinated axons connecting left and right grey matter
94
nuclei
groups of cell bodies
95
sensory nuclei is found
in posterior horn and they contain interneurons
-somatic sensory nuclei: recieve signals from skin, muscle, joints
-visceral sesnory nuclei: receive signals from blood vessels, viscera
96
motor nuclei
in anterior and lateral horns contain motor neurons
-somatic motor nuclei (anterior) innervate skeletal muscle
-autonomic motor nuclei (lateral) innervate smooth muscle, heart, glands
97
cranial nerves are part of the
peripheral nervous system
98
CN I
olfactory nerve
special sensory nerve that conducts smell sensation from the nose to brain
99
CN II
optic nerve
special sensory nerve that conducts visual information from the retina of the eye to the brain
100
CN III
oculomotor nerve
motor nerve that innervates four of the six extrinsic eye muscles, an upper eyelid muscle, and intrinsic eye muscles (smooth muscle within the eye)
101
CN IV
trochlear nerve
motor nerve that innervates on extrinsic eye muscle (superior oblique) that loops through a pulley-shaped ligament called a trochlea
102
CN V
trigeminal nerve
mixed nerve that consists of the three visions: opthalmic (V1), maxillary (V2), and mandibular (V3), recieves sensory nerve signals from face, oral cavity, nasal cavity, meninges, and anterior scalp and innervates muscles of mastication
103
CN VI
abducens nerve
motor nerve that innervates one extrinsic eye muscle (lateral rectus) to move the eye
104
CN VII
facial nerve
mixed nerve that conducts taste sensations from anterior two-thirds of tongue; relays motor output to muscles of facial expression; lacrimal (tear) gland, and most salivary glands
105
CN VIII
vestibulocochlear nerve
sensory nerve with two branches that conducts equilibrium and auditory (hearing) sensations from the inner ear to brain
106
CN IX
glossopharyngeal nerve
mixed nerve that receives taste and touch sensations from posterior one-third of the tongue, innervates one pharynx muscle and the parotid salivary gland
107
CN X
vagus nerve
visceral sensation; parasympathetic nerve to any organs of body
108
CN XI
accessory nerve
motor nerve that innervates trapezius and sternocleidomastoid muscles, also assists CN X to innervate pharynx muscles; formerly called the spinal accessory nerve
109
CN XII
hypoglossal nerve
motor nerve that innervates both intrinsic and extrinsic tongue muscles; name means under the tongue
110
spinal nerve characteristics
31 pairs of spinal nerves (C1 - Co1)
each nerve formed from merger of anterior root and posterior root
-anterior root is many axons of motor neurons whose somas are in anterior and lateral horns
-posterior root is many axons of sensory neurons whose somas are in posterior root ganglion
111
spinal nerves location
cervical nerves exit inervertebral foramina superior to the vertebra of the same number (eg C2 nerve exits between C2 and C1 vertebrae
-exception is nerve C8 - it exits below C7 vertebra
below C8 nerves exit inferior to the vertebra of the same number (eg T2 nreve exits between T2 and T3 vertebrae)
lumbar sacral and coccygeal spinal nerves have long roots that extend inferiorly before exiting vertebrae
-these roots form the cauda equina
112
somatic nervous system
consciously perceived or controlled processes
somatic sensory portion detects signals from special senses (vision, hearing, equilibrium, smell, taste) and from skin and proprioceptors
somatic motor portion sends signals from CNS to skeletal muscles
-voluntary movements involve cerebrum
-reflexive movements involve brainstem and spinal cord
113
somatic nervous system function
somatic sensory neuron detects stimuli and transmits nerve signals from skin, special senses (ie, vision, hearing, equilibrium, smell, taste, and proprioceptors in joints and muscles
this goes to the posterior root ganglion which then stimulates the anterior root
somatic motor neuron transmits nerve signals to skeletal muscle
114
sensory nervous system is composed of
somatic sensory (sensory input consciously perceived from receptors like eyes, ears, skin)
visceral sensory (sensory input not consciously perceived from receptors of blood vessels and internal organs (eg. heart)
115
motor nervous system is composed of
somatic motor (motor output consciously or voluntarily controlled; effector is skeletal muscle)
autonomic motor (motor output not consciously controlled; effectors are cardiac muscle, smooth muscle, and glands)
116
autonomic motor system (ANS)
processes regulated below conscious level
transmits signals from CNS to hear, smooth muscle, glands
response to visceral sensory inputs (eg. from blood vessels)
-those sensory neurons are not considered part of ANS
functions to maintain homeostasis
-keeps conditions inside body within optimal ranges
117
what are the two divisions of the autonomic motor system
parasympathetic (carniosacral division)
sympathetic (thoracolumbar division)
118
parasympathetic division
orginates in preganglionic neurons located in brainstem nuclei and S2-S4 segments of spinal cord (craniosacral)
functions to bring body to homeostasis in conditions of "rest-and-digest"
conserves energy and replenishes nutrient stores
119
sympathetic division
originates in preganglionic neurons located in lateral horns of T1-L2 segments of spinal cord (thoracolumbar)
functions to bring body to homeostasis in conditions of flight or fight
increases alterness and metabolic activities
exercise excitement emergency
120
parasympathetic division axons
closer to or within effector organ wall (terminal ganglia and intramural ganglia
preganglionic neuron is myelinated
has long preganglionic axon and short postganglionic axon because it is already near target
121
sympathetic division axons
autonomic ganglion is close to the vertebral column (sympathetic trunk ganglia and prevertebral ganglia)
has 2 neuronal sequence
has a short branching preganglionic axon
has long postganglionic axon
thoracolumbar in origin
122
sympathetic division summary
sympathetic function : exercise, emergency, excitment
thoracolumbar anatomical origin
ganglia are close to CNS but anatomical pathways are complex
123
sympathetic trunks and ganglia
left and right trunks are just lateral to the vertebral column
trunk resembles a string of pearls
-string is composed of axons
-pearls composed of sympathetic trunk ganglia housing cell bodies
124
sympathetic pathways
adrenal medulla pathway
125
adrenal medulla pathway
for central region of adrenal gland (its medulla)
preganglionic sympathetic axons extend through sympathetic trunk and prevertebral ganglia without synapsing in either
preganglionic cells stimulate adrenal medulla cells to release epinephrine and norpeinephrine into the blood
-these hormones potentiate and prolong the fight-or-flight response
126
ANS neurotransmitters
ANS uses ACH and NE
either transmitter can cause stimulation or inhibition, depending on the postsynaptic receptor
cells that release ACH are cholinergic neurons
127
cholinergic neurons
all ANS preganglionic neurons
all parasympathetic ganglionic neurons
sympathetic ganglionic neurons innervating sweat glands and blood vessels in skeletal muscle
target cells have cholinergic receptors
128
cells that release norepinephrine (NE) are
adrenergic neurons
-most sympathetic ganglionic neurons are adrenergic
-target cells have adrenergic receptors
129
parasypathetic pathway
preganglionic axon releases
ganglionic neuron cell body and dendrites always contain nicotinic receptors for ACH
postganglionic axon releases ACH
target cells contain muscanric receptors to bind ACH
130
sympathetic pathways
1. preganglionic axon releases ACH which binds to nicotinic receptors. postganglionic axon releases ACH to bind to muscarinic receptors on target cell (sweat glands)
2. preganglionic axon releases ACH which binds to nicotinic receptors on ganglionic neuron cell body. postganglionic axon releases NE which binds to adrenergic receptors on target cells (most other body structures)
3. adrenal medulla pathway where there is one neuron that has. a long axon leading from origin to target cell releasing ACh going to nicotinic receptors on adrenal medulla cell
131
cholinergic receptors
nicotinic and muscarinic
132
nicotinic receptors
found on all ganglionic neurons and adrenal medulla cells
-also on skeletal muscle cells at neuromuscular junction
when ACH binds to nicotinic receptor it opens cation channel
-Na+ moves into cell (a lesser amount of K+ moves out of cell)
-cell depolarizes: excitatory postsynaptic potential produced
133
muscarinic receptors
found in all target organs of parasympathetic division and a few of sympathetic division
-sympathetic effectors within muscarinic receptors include sweat glands and blood vessels in skeletal muscle
different subtypes of muscarinic receptors have different effects
-when ACH binds to muscarinic receptors of smooth muscle in GI tract it is stimulated to contract more
-when ACH binds to muscarinic receptors on cardiac muscle the heart rate decreases
134
NE is a
catecholamine which is a chemical subtype of monamines
-norepinephrine and epinephrine are both catecholamines that bind to adrenergic receptors
135
adrenergic receptors
two main type of adrenergic receptors are alpha and beta receptors
-cells with alpha receptors are typically stimulated by NE
-cells with beta receptors may be stimulated or inhibited by NE
136
dual innervation
organ receives input from both the sympathetic and parasympathetic divisions
-two divisions may have antagonistic or cooperative effects
137
antagonistic effects of dual innervation
commonly the two division oppose each other
parasympathetic activity slows heart rate; sympathetic activity increases heart rate
-cardiac cells have both cholinergic and adrenergic receptors
parasympathetic activity increases GI tract motility; sympathetic activity decreases motility
-GI smooth muscle cells have both types of receptors
parasympathetic activity decreases pupil diameter; sympathetic activity dialates pupil
-parasympathetic fibers innervate circular iris muscles; sympathetic fibers innervate radial iris muscles
138
cooperative effects of dual innervation
seen when parasympathetic and sympathetic stimulation have different effects that are part of an overall response
eg. male sexual function
-penis erection due to parasympathetic activity
-ejaculation due to sympathetic activity
139
parasympathetic nervous system summary
originates in the cranial and sacral regions of the CNS
tends to have long preganglionic axons and short postganglionic axons
ganglia lie close to organ or within effector (terminal or intermural)
main effects: pupilconstriction, increases motility of digestive system, storage of fuel molecules in liver, decreases heart rate and causes bronchoconstriction, stimulates secretion of lacrimal (tear), nasal, and digestive system galnds
ACH is released from preganglionic axons and binds to cholinergic receptors (nicotinic) and then postganglionic axons release ACH which binds to muscarinic receptors
140
sympathetic nervous system summary
tends to have shorter preganglionic axons and longer postganglionic axons, preganglionic axon has many branches and extensive divergence
ganglia (sympathetic trunk or prevertebral) lie close to the spinal cord
orginiates in the T1-L2 segements of the spinal cord
main effects: pupil dialation, increases heart rate, force of contraction, and causes bronchodilation, stimulates adrenal medulla to secrete epinpherine and NE to prolong symapthetic effects, decreases activity of digestive system, increases secretion of sweat glands, contraction of arrector pili, vasoconstricts most blood vessels but vasodialates coronary arteries and arteries to skeletal muscle, release of fuel molecules from liver and adipose connective tissue into the blood
ach is released from preganglionic axons and bind cholinergic (nicotinic) receptors, postganglionic axons release either ACH or NE and ACH binds to muscarinic receptors and NE binds to adrenergic receptors
-ACH - muscarinic for sweat glands and blood vessels to muscle
-NE - adrenergic receptors for all other structures
141
sensory receptors
provide information about external and internal environments
respond to stimuli
each type of receptor responds best to a type of stimulus
-light energy for eye receptors; sound energy for ear receptors
transducer - convert stimulus energy into electrical energy
-receptors have a resting membrane potential
-receptor membranes have modality gated channels that respond to their type of stimulus
action potentials are conveyed to CNS for interpretation
142
receptive field
the distribution area of the endsing of a sensory neurons
-smaller receptive fields allow more precise stimulus localization
finger tips have small receptive fields back has larger
143
sensory receptors are classified based on
distribution, stimulus origin, and stimulus modality
144
receptor distribution: general vs specific
general sense receptors
-simple structures distributed throughout the body
-somatic sensory receptors
-visceral sensory receptors
145
somatic sensory receptors
tactile receptors of skin and muscous membranes; proprioceptors of joints, muscles, and tendons (general sense receptor)
146
visceral sensory receptors
found in wall of internal organs they monitor stretch, chemical environment, temperature, pain (general sense receptor)
147
special sense receptors
specialized receptors in complex sense organs of the head
5 special sense: olfaction, gustation, vision, audition, equilibrium
148
stimulus origin categories
exteroceptors
interoceptors
proprioceptors
149
exteroceptors
detect stimuli from external environment
-skin and mucous membranes; special sense receptors
150
interoceptors
detect stimuli from internal organs
-visceral sensory receptors monitoring internal environment
151
proprioceptors
detect body and limb movements
-somatosensory receptors of muscles, tendons, and joints
152
modality of stimulus categories
chemoreceptors
thermoreceptors
photoceptors
mechanoreceptors
nociceptors
153
chemoreceptors
detects chemicals dissolved in fluid
-include receptors for external environment (smell of food) or internal environment (oxygen levels in blood)
154
thermoreceptors
detect changes in temperature
-include receptors in skin, hypothalamus
155
photoreceptors
detect changes in light intensity, color, movment
-in retina of eye
156
mechanoreceptors
detect distortion of cell membrane
-include touch, pressure, vibration, and stretch receptors
-function as baroreceptors, proprioceptors, tactile receptors, and specialized receptors in the inner ear
157
nociceptors
detect painful stimuli
-somatic nociceptors detect chemical, heat, or mechanical damage to the body surface or skeletal muscles
-visceral nociceptors detect internal organ damage
158
classifying receptors in eyes
special sense, exteroceptors, photoreceptors
159
classifying receptors in blood vessel stretch
general sense, interoceptors, mechanoreceptors (baroreceptors)
