Group 8/23/19 Flashcards
(130 cards)
1
Q
Learning issues
A
- anatomy of joints (Moore)
- physiology of somatic sensation (Guyton and Hall ch 48 and 49)
- physiology of types of sensory receptors (Guyton Hall ch 47)
2
Q
mechanoreceptors
A
detect mechanical compression or stretching of the receptor or of tissues adjacent to the receptor
3
Q
thermoreceptors
A
detect changes in temperature
4
Q
nociceptors
A
pain receptors; detect physical or chemical damage occurring in the tissues
5
Q
electromagnetic receptors
A
detect light on the retina of the eye, e.g. rods and cones for vision
6
Q
chemoreceptors
A
detect taste in the mouth, smell in the nose, oxygen level in the arterial blood, osmolality of body fluids, carbon dioxide concentration, and other factors that make up the chemistry of the human body
7
Q
modality of a sensation
A
a principal type of sensation that we experience, like pain, touch, sight, sound, etc.
8
Q
labeled line principle
A
nerve fibers are specific and transmit only one mode of sensation
9
Q
what is the relationship between stimulus intensity and receptor potential?
A
with stronger stimulus intensity, amplitude of the receptor potential increases rapidly at first and then gets progressively less rapid at high stimulus strength
with greater frequency of action potentials, receptor potential increases proportionately
10
Q
adaptation of receptors definition
A
sensory receptors adapt partially or completely with constant stimulus after time
receptor responds at high impulse rate initially, then at a progressively slower rate until few action potentials firing
11
Q
mechanisms of adaptation
A
- when the receptor becomes deformed, a fluid within the corpuscle quickly brings shape back and receptor potential no longer elicited
- accommodation: nerve fiber tip becomes accommodated, inactivated sodium channels prevent depolarization
12
Q
tonic receptors
A
these slowly adapting receptors will continue to transmit impulses to the brain as long as the stimulus is present; lets the brain know continuously about stimulus strength
13
Q
rate/movement/phasic receptors
A
these receptors adapt rapidly and can’t be used to transmit a continuous signal. They are stimulated only when stimulus strength changes. Can be used to predict future changes.
14
Q
what are the main differences between type A and type C nerve fibers?*
A
type A- large, medium sized myelinated fibers of spinal nerves
type C- small, unmyelinated nerve fibers, low velocity of impulses
15
Q
spatial summation
A
increasing signal strength is transmitted using progressively greater numbers of fibers
16
Q
temporal summation
A
transmits signals of increasing strength by increasing the frequency of nerve impulses in each fiber
17
Q
excitatory/subthreshold stimulus
A
a stimulus that is above the threshold required for excitation, might have more than enough terminals to cause the neuron to discharge
18
Q
subthreshold/facilitated stimulus
A
when fibers contribute terminals, but not enough to cause excitation. However, makes it so that the neurons are more likely to be excited by additional incoming nerve fibers
19
Q
facilitated vs discharge vs inhibitory zone in neuronal pool
A
discharge- in central portion, all fibers are stimulated by incoming fiber, reaches excitation threshold
subthreshold- on the peripheral portions, the neurons are facilitated not excited
inhibitory- incoming fibers that inhibit the neurons congregate here
20
Q
amplifying type of divergence
A
an input signal spreads to an increasing number of neurons as it passes through successive orders of neurons in the path
21
Q
divergence into multiple tracts
A
signal transmitted into two different directions from the pool
22
Q
convergence of signals
A
signals from multiple units unite to excite a single neuron, or signals can come from multiple sources, to create a summated effect
23
Q
reciprocal inhibition circuit
A
incoming signal to a neuronal pool may cause one output excitatory signal in one direction and an inhibitory signal going in another direction
responsible for antagonisitic muscle pairs
24
Q
afterdischarge
A
a signal entering a pool can cause a prolonged output discharge, that lasts after the signal is over
can happen in synapses to continue exciting a neuron so it produces a continuous train of impulses
25
reverberatory/oscillatory circuit
circuits that have a positive feedback mechanism so it will re-excite the input of the same circuit. Once stimulated, the circuit may discharge repetitively for a long time.
26
inhibitory circuits as a mechanism for stabilizing nervous system function
inhibitory circuits can help prevent the excessive spread of signals in the brain
some inhibitory feedback networks go from the termini of one network back to the initial excitatory neurons
there are neuronal pools that have inhibitory control over widespread areas of the brain
27
synaptic fatigue as a means of stabilizing the nervous system
synaptic transmission becomes progressively weaker the more prolonged and intense the period of excitation
overused pathways become fatigued and sensitivity decreases; underused ones are rested and sensitivities increase
long-term changes in synaptic sensitivity can be caused by down- or up-regulation of the synaptic receptors
28
what are the 3 physiological types of somatic senses?
1. mechanoreceptive somatic senses, include tactile and position senses
2. thermoreceptive senses, detect heat and cold
3. pain sense
29
what are the tactile vs position senses?
tactile- touch, pressure, vibration, tickle
| position- static position and rate of movement
30
although touch, pressure and vibration are detected by the same tactile receptors, what makes them individually triggered?
touch- stimulation of tactile receptors at skin or tissues immediately beneath
pressure- deformation of deeper tissues
vibration- rapidly repetitive sensory signals
31
Meissner's corpuscle: fiber type, location, senses*
fiber type- large, myelinated fibers that adapt quickly
location- glabrous (hairless) skin
senses- dynamic, fine/light touch, position
32
expanded tip tactile receptors
feature of some touch receptors, such as those in fingertips. Transmit signals that are initially strong but partially adapting signal, then it becomes a weak signal that adapts slowly, to allow determination of continuous touch. Example is a Merkel disc.
33
iggo dome receptor
a receptor organ where Merkel discs group together, innervated by one large myelinated fiber. Protrudes through the epithelium of the skin and creates very sensitive receptor. Locate touch sensations and feel textures.
34
hair end-organ
type of touch receptor that adapts readily. Detects movement of objects on surface of body or initial contact with body.
35
Ruffini's endings: fiber type, location, senses*
fiber- dendritic endings with capsule, adapt slowly
location- finger tips, joints
senses- pressure (esp continuous), slippage of objects along surface of skin, joint angle change
36
Pacinian corpuscles: fiber type, location, senses*
fiber type- large, myelinated fibers that adapt quickly
location- deep skin layers, ligaments, joints
senses- vibration, pressure
37
what transmits tickle and itch sensations?
there are very sensitive, rapidly adapting mechanoreceptive free nerve endings, usually in superficial areas of skin, slowly transmitted.
38
almost all sensory information from the somatic segments of the body enter the spinal cord through the ?
dorsal roots of spinal cord
39
what are the two alternative sensory pathways that sensory signals can be carried through once they enter the spinal cord? where do these systems come back together?
1. dorsal column- medial lemniscal system
2. anterolateral system (aka spinothalamic tract)
They come back together partially at the thalamus.
40
what kind of signals are carried in the dorsal column-medial lemniscal system?
Has large, myelinated fibers with high velocity transmission. Mainly carries sensory information that must be transmitted rapidly with temporal and spatial fidelity.
41
what kind of signals are carried through the anterolateral system?
Composed of small, myelinated fibers with slow velocity transmission. Less critical signals that don't require highly discrete localization or discrimination of fine gradations of intensity. Examples are pain, hot/cold, itch/tickle, sexual sensations
42
Brodmann's areas
human cerebral cortex is divided into 50 distinct areas with histological structural differences
43
central fissure/sulcus
fold that extends horizontally across the brain. Sensory signals terminate immediately posteriorly to this.
44
where do visual and auditory signals terminate in brain?
visual- occipital lobe
| auditory- temporal lobe
45
motor cortex
region of cerebral cortex anterior to the central fissure
| controls muscle contractions and movements
46
which lobes are the somatosensory cortices located in?
anterior parietal lobe
47
main differences between somatosensory areas I and II
I- more extensive and important, high degree of localization for different parts of the body, immediately behind central fissure
II- poor localization, mainly has leg, arm, and face, behind area 1
48
what are some functions that would be lost without somatosensory area 1?
localizing sensations precisely on the body, judging degrees of pressure, judging weights of objects, judging shapes or forms of objects, judging textures of materials
49
astereognosis
person is unable to judge the shape or forms of objects
50
somatosensory association areas
located behind somatosensory area 1. Important for deciphering deeper meanings of the sensory information in the somatosensory areas, by combining information arriving from multiple points.
51
amorphosynthesis
happens when the somatosensory association area is removed. Person loses ability to recognize complex objects and feel forms on opposite side of body to loss. The person forgets about their opposite side of the body and forgets about the other side of objects.
52
two-point discrimination
a test for tactile discrimination where two points pressed on the skin, and the person determines where one or two points were felt. Ability to discriminate the two points depends on lateral inhibition. Greater space for less sensitive areas.
53
what is the effect of lateral inhibition?
sensory pathways get excited, and simultaneously produce lateral inhibitory signals to adjacent neurons
blocks lateral spread of excitatory signals; increases degree of contrast in sensory pattern perceived in cerebral cortex
54
Weber-Fechner principle
gradations of stimulus strength are discriminated approximately in proportion to the logarithm of stimulus strength
55
power law
when plotted as logarithmic coordinates, there's a linear relationship between stimulus strength and interpreted stimulus strength
56
what is another name for position senses?
proprioceptive senses
57
what role does the thalamus play in somatic sensation?
thalamus and lower centers has the slight ability to discriminate tactile sensation, even though its main ability is to relay this information
58
what is the role of corticofugal signals?
these are transmitted to the lower relay stations, and they control the intensity of sensitivity of the sensory input. Usually these are inhibitory signals.
59
dermatome
segmental field of the skin which each spinal nerve innervates
60
free nerve endings: fiber type, location and senses*
fiber type- C slow, unmyelinated fibers, and Adelta, fAst, myelinated fibers
location- all skin, epidermis, some viscera
senses- pain, temperature
61
merkel disc: fiber type, location and senses*
fiber type- large myelinated fibers that adapt slowly
location- finger tips, superficial skin
senses- pressure, deep static touch (eg shapes, edges), position sense
62
homunculus*
topographic representation of the motor and sensory areas in the cerebral cortex. Distorted appearance due to certain body regions being more richly innervated and thus having cortical representation
63
which spinal tract is responsible for pressure, vibration, fine touch, and proprioception?*
dorsal column, which is an ascending spinal tract
64
what is the first order neuron of the dorsal column?*
sensory nerve ending bypasses the pseudounipolar cell body in the dorsal root ganglion, enters the spinal cord, ascends ipsilaterally (same side) in dorsal columns
65
what is the first synapse of the dorsal column?*
nucleus gracilis, nucleus cuneatus (ipsilateral medulla)
66
what is the second order neuron of the dorsal column?*
decussates (intersects) in medulla, then ascends contralaterally as the medial lemniscus
67
what is the second synapse of the dorsal column, what does it project to?*
VPL (ventral posterolateral nucleus) of the thalamus, to the sensory cortex
68
which spinal tract is responsible for pain, temperature, crude touch and pressure, which side responsible for what?*
spinothalamic tract- lateral side receives pain and temperature, anterior side receives crude touch and pressure
69
what is the first order neuron of the spinothalamic tract?*
sensory nerve endings (Adelta and C fibers) bypass pseudounipolar cell body in dorsal root ganglion, enters the spinal cord
70
what is the first synapse of the spinothalamic tract?*
ipsilateral gray matter (spinal cord)
71
what is the second order neuron of the spinothalamic tract?*
decussates (crosses) in spinal cord as the anterior white commissure, then ascends contralaterally
72
what is the second synapse of the spinothalamic tract, what does it project to?*
VPL (ventral posterolateral nucleus) of the thalamus, to the sensory cortex
73
C2 dermatome*
posterior half of skull
74
C3 dermatome*
high turtle neck shirt, spans the body horizontal
diaphragm and gallbladder pain referred to the right shoulder via phrenic nerve
"c3, 4, 5 keeps the diaphram alive"
75
C4 dermatome*
low-collar shirt, spans the body horizontal
76
C6 dermatome*
includes thumb "thumbs up sign on left hand looks like a 6"
77
T4 dermatome*
at the nipple "T4 at the teat pore", spans the body horizontal
78
T7 dermatome*
at the xiphoid process, spans the body horizontal
79
T10 dermatome*
at the umbilicus (bellybutTEN); important point of referred pain in appendicitis, spans the body horizontal
80
L1 dermatome*
at the Inguinal Ligament (around the ASIS), spans the body horizontal
81
L4 dermatome*
includes the knee caps, "down on aLL 4's"
82
S2, S3, and S4 dermatome*
sensation of penile and anal zones, "s2, 3, 4, keep the penis off the floor"
83
joints definition
unions or junctions between two or more bones or rigid parts of the skeleton
84
what are the 3 classes of joints?
synovial joint, fibrous joint, cartilaginous joint
85
structure of synovial joints
- articulating bones are united by a joint (articular) capsule, lined by synovial membrane
- joint cavity is a space that has some lubricating synovial fluid
- articulating surfaces covered by articular cartilage
- provide free movement between articulating bones and locomotion
86
what is the general structure of fibrous joints?
articulating bones united by fibrous tissue
87
syndesmosis
type of fibrous joint that unites the bones with a sheet of fibrous tissue, either a ligament or fibrous membrane. Partially moveable. Example is interosseous membrane in forearm.
88
dento-alveolar syndesmosis (gomphosis)
a fibrous joint in which a peg-like process fits into a socket, forms articulation between tooth root and alveolar process of jaw. Movement would indicate pathology, example is root of tooth and alveolar process of jaw
89
general structure of cartilaginous joints
articulating structures of these joints are united by hyaline cartilage or fibrocartilage
90
primary cartilaginous joints/ synchondroses
bones are united by hyaline cartilage. Usually temporary unions, like those involved in long bone development, and play a role in growth in length of bone.
91
secondary cartilaginous joints/ symphyses
strong, slightly movable joints united by fibrocartilage. Provide strength, shock absorption and flexibility; example is intervertebral discs
92
accessory ligaments
these usually reinforce synovial joints. Extrinsic ones are separate, and intrinsic ones are thickening of a portion of the joint capsule
93
plane joints
- permit gliding or sliding movements in a plane of the articular surface
- opposed surfaces are flat or almost fat
- example is acromioclavicular joint between acromion of scapula and clavicle
94
hinge joints
- permit flexion and extension only, in one plane around single axis (uniaxial)
- joined by strong, laterally placed collateral ligaments
- example is elbow joint
95
saddle joints
- permit abduction/adduction and flexion/extension, involving two axes (sagittal and frontal; biaxial), also in sequence for cirumduction
- opposing articular surfaces shaped like a saddle (reciprocally concave and convex)
- example is carpometacarpal joint at base of 1st digit (thumb)
96
condyloid joints
- permit flexion/extension and adduction/abduction; biaxial, with one plane having better motion, and more restricted circumduction
- example is metacarpophalangeal joints (knuckle joints)
97
ball and socket joints
- allow movement in multiple planes and axes (multiaxial); flexion/extension, abduction/adduction, medial/lateral rotation, circumduction
- have spheroidal surface moving within socket of another
- example is hip joint
98
pivot joints
- permit rotation around a central axis (uniaxial)
- rounded process of a bone rotates within a sleeve or ring
- example is median atlanto-axial joint, where atlas C1 vertebrae rotates around the dens of the axis of the C2 vertebrae
99
where do joints receive blood from?
articular arteries, some anastomose (communicate) and form networks (peri-articular arterial anastomoses); articular veins
100
Hilton law
the nerves supplying a joint also supply the muscles moving the joint and the skin covering the distal attachments
101
which sense do joints provide mainly?
proprioception- an awareness of movement and position of the parts of the body; given by the articular nerves
102
degenerative joint disease
heavy use over years can cause degenerative changes of synovial joints, esp in hip, knee, vertebral column, hands. Activities can wear away articular cartilage, so it's less effective at absorbing shock and less lubricated surface.
also called osteoarthritis, symptoms are stiffness, discomfort, pain
103
sternoclavicular joint: type, bones involved, and movements
- type: saddle synovial joint
- bones: manubrium, sternal end of clavicle
- movement: anterior/posterior and superior/inferior movement of clavicle
104
acromioclavicular joint: type, bones involved, and movements
- type: plane synovial joint
- bones: acromion of scapula and acromial end of clavicle
- movement: small movements
105
glenohumeral joint: type, bones involved, and movements
- type: ball and socket synovial joint
- bones: glenoid cavity of scapula, head of humerus
- movement: flexion/extension, adduction/abduction, circumduction
106
elbow joint: type, bones involved, and movements
- type: hinge synovial joint
- bones: head of radius, trochlear notch of ulna, trochlea of humerus, capitulum of humerus
- movement: flexion/extension
107
what are the two types of pain?
fast pain and slow pain
108
what is the difference between fast and slow pain?
fast pain- felt fraction of a second after stimulus applied. Includes sharp, prickling, acute, and electric pain.
slow pain- felt after a second or more, increases slowly. Includes slow burning, aching, throbbing, nausea, and chronic pain. Usually associated with tissue destruction.
109
what are pain receptors actually?
free nerve endings
110
what are the 3 types of stimuli that excite pain receptors, what kind of pain do they trigger?
mechanical, thermal, chemical
| fast pain triggered by mechanical and thermal; slow pain triggered by all three types
111
hyperalgesia
pain receptors adapt very little or not at all. Sometimes they increase their sensitivity, and excitation of pain fibers is greater.
112
tissue ischemia
blood flow to the tissue is blocked, and tissue becomes very painful within a few minutes.
113
muscle spasms
a muscle spasm can stimulate mechanosensitive pain receptors, and pain can come indirectly from compressed blood vessels and ischemia.
114
what are the two pathways for transmitting pain signals into CNS?
fast-sharp pain pathway (neospinothalamic) and slow-chronic pain pathway (paleospinothalamic)
115
which neurotransmitter is secreted for the type adelta fibers in fast pain pathways?
glutamate, an excitatory, fast transmitter in CNS
116
which neurotransmitter is secreted for the type C fibers in slow pain pathways?
substance P, released slowly and builds up; and glutamate, quick and short-lasting
117
which kind of fibers are in neospinothalamic tract?
transmitted by Adelta fibers
118
which kind of fibers are in the paleospinothalamic tract?
transmitted by type C fibers
119
how does localization of pain signals differ in neospinothalamic vs paleospinothalamic tract?
highly localized in neospinothalamic, sometimes dorsal column-medial lemniscal pathway triggered at same time to help this
imprecise localization in paleospinothalamic tract
120
analgesia system
the brain uses a pain control system to suppress input of pain signals to the nervous system
121
which brain structures are involved in the analgesia system?
mesencephalon, pons, medulla, pain inhibitory complex is dorsal horns of spinal cord
122
which neurotransmitters are involved in the analgesia system, where are they located?
enkephalins (brain stem, spinal cord, and analgesic system), endorphins (hypothalamus, pituitary glands), serotonin (dorsal horns)
123
inhibition of pain transmission by simultaneous tactile sensory signals
stimulation of large type Adelta fibers from peripheral tactile receptors can depress transmission of pain signals from same body area. Probably due to local lateral inhibition. Rubbing skin near painful areas helps relieve pain.
124
mechanism of referred pain
visceral pain fibers synapse in the spinal cord on same second-order neurons that receive pain signals from the skin
125
differences between visceral and surface pain
highly localized damage to viscera rarely cause severe pain, like you can sever an organ without causing pain
126
what kind of damage can cause sharp pain?
disease or injury spreading to parietal structures, like parietal peritoneum, pleura, or pericardium, or skin. Has extensive pain innervation.
127
what is the difference between visceral and parietal pain transmission pathways?
true visceral pain is transmitted via autonomic nerves, which gives sensations referred to surfaces of body that are usually far from painful organ
parietal sensations are conducted directly onto local spinal nerves, and give sensations localized directly over painful area
128
hyperalgesia
hypersensitivity to pain. Primary caused by excessive sensitivity to pain receptors, secondary caused by facilitation of sensory transmission.
129
what do thermal receptors do and where are they located?
thermal gradients are detected by cold, warm, and pain receptors. Cold and warmth receptors located directly under skin at discrete separated spots
130
what are the stimulatory effects of thermal receptors?
thermal senses respond markedly to changes in temperature, and then it adapts to a great extent
works best when a large skin area is stimulated, spatial summation occurs
