Test 3 Flashcards
1
Q
Factors that determine effects of muscle contraction:
A
- Anatomical arrangement of muscle fibers
2. The way the muscle attaches to bone
2
Q
One can classify muscles by which 3 factors?
A
- Shape
- Action (movement)
- Size and range of motion
3
Q
Based on the arrangement of a fascicle:
A
All muscle fibers are parallel in a single fascicle.
4
Q
List the 4 different shapes of muscles:
A
- Parallel
- Pennate
- Convergent
- Circular or Sphincter
5
Q
Muscle shape in which the axes of fascicles run parallel to axes of the muscle:
A
parallel muscles
6
Q
Muscle shape: spindle shaped or strap-like, will have a central body (belly or gaster)
A
parallel muscles
7
Q
Muscle shape: contraction–gets smaller and larger in diameter, especially at the belly
A
parallel muscles
8
Q
Give examples of parallel muscles:
A
biceps and sartorius
9
Q
Muscle shape: feather-like, fascicles are short and oblique attached to a central tendon–produces more tension
A
pennate muscles
10
Q
List the 3 different types of pennate muscles:
A
- Unipennate
- Bipennate
- Multipennate
11
Q
Shape: fascicles insert into only one side of the tendon, also give example
A
Unipennate muscles; ex. extensor digitorum (extends fingers)
12
Q
Muscle shape: fascicles insert on both sides of tendon, also give example
A
bipennate muscles; ex. rectus femoris (extends knee)
13
Q
Muscle shape: many fascicles are inserted into a tendon that typically branches, also give example
A
multipennate muscles; ex. deltoid muscle
14
Q
Muscle shape: fan-shaped, force directed to a point (raphe), can pull in different directions since each section can change direction, also give example
A
convergent muscles; ex. pectoralis major
15
Q
point where tendon, aponeurosis, and collagen fibers converge
A
raphe
16
Q
Muscle shape: contraction acts to close; fascicles are arranged in a circular pattern, also give example
A
circular/sphincter muscle; ex. obicularis oris, obicularis oculi
17
Q
immovable end of muscle to bone
A
origin
18
Q
moveable end of muscle to bone attachment
A
insertion
19
Q
Movement can be named for what two factors?
A
Bone involved or joint involved (ex., flexion of forearm, flexion of elbow)
20
Q
What are the 3 functional groups of muscles based on size and range of motion?
A
- Agonist
- Antagonist
- Synergists
21
Q
prime mover, muscle is chiefly responsible for movement; give example
A
agonist; ex. prime mover of elbow is biceps brachii–origin is the humerus and the insertion is the radius
22
Q
oppose or reverse a movement–located on opposite side of joint; give example
A
antagonist; ex. triceps brachii vs. biceps brachii
23
Q
help prime movers; list 3 different functions
A
synergists; 1. adds extra force to the movement
- reduces undesirable or unnecessary movement
- it is a fixator–immobilises a bone of muscle origin
24
Q
Give an example of the synergist function of adding extra force to a movement:
A
ex. external intercostals aiding with respiration
25
Give an example of the synergist function of reducing undesirable or unncessary movement:
ex. brachioradialis for forearm flexion
26
Give an example of the synergist function of immobilising a bone of muscle origin
ex. scapula to the axial skeleton, muscle maintaining upright posture
27
A muscle may act as a prime mover in one movement, an antagonist in another movement, and a synergist for a third movement: true or false?
true
28
Give an example of a muscle that may act as a prime mover in one movement, an antagonist in another movement, and a synergist in a third movement:
deltoid muscle
29
List the 3 different example functions of a deltoid muscle performing all three muscle functions in three different movements:
1. prime mover of arm abduction when all fibers contract simultaneously
2. antagonist of pectoralis major and latissimus dorsi which adduct the arm
3. synergist of pectoralis major, which is the prime mover of arm flexion
30
Operation of most skeletal muscles involves the use of levers---these can change what?
1. Direction of applied force
2. Distance and speed of movement
3. Effective in strength of applied force
31
rigid bar that moves on a fixed point; give example
lever; ex. bones
32
fixed point; give example
fulcrum; ex. joints
33
effort used to move a resistance; give example
applied force; ex. muscle contraction
34
the load; give example
resistance; ex. bone, tissue, etc.
35
Mechanical advantage---power lever; give example
1. needs less work
2. effort is farther than the load from the fulcrum
3. resistance is close to the fulcrum
4. applied force is applied far from the fulcrum
5. slower, more stable, strength
small effort over long distance moves a large load over small distance; ex. jacking a car
36
Mechanical disadvantage---speed lever; give example
1. more work
2. effort (resistance) is nearer to the load than to the fulcrum
3. applied force is far from the fulcrum
4. the resistance is applied near the fulcrum
5. good speed and range of motion
force exerted by muscle must be greater than the load moved or supported; ex. shoveling
37
List the 3 classes of levers:
1. First class
2. Second class
3. Third class
38
Resistance -- Fulcrum -- Applied Force; which lever is this? Also give example.
first class lever; ex. scissors or seesaws
39
What is a mechanical advantage of a first class lever?
lifting a head off of a chest
40
What is a mechanical disadvantage of a first class lever?
triceps extending the forearm
41
Fulcrum -- Resistance -- Applied Force; which lever is this? Also give an example.
second class lever; ex. wheelbarrow, or standing on toes
42
List the 3 different aspects of second class levers:
1. Lift the greatest weight with the least applied force--moves slowly and covers short distance
2. uncommon in the body
3. sacrifices speed and range of motion
43
Resistance -- Applied Force -- Fulcrum; which lever is this? Also give example.
third class lever; ex. forceps, tweezers biceps
44
List the 4 different aspects of third class levers:
1. speed and distance increase
2. always at mechanical disadvantage
3. most common in the body
4. these muscles tend to be thicker and more powerful
45
What are the 8 factors for naming skeletal muscles?
1. Location of the muscle
2. Shape of the muscle
3. Position
4. Relative size of the muscle
5. Number of origins
6. Location of attachments
7. Direction of muscle fibers/fascicles
8. Action of the muscle
46
location of the muscle ex.
fibularis, tibialis, sternocleidomastoid
47
shape of muscle ex.
deltoid, trapezius
48
position of muscle ex.
extremus or superficialis, interns, extrinsic (stabilise organ), intrinsic (within organ)
49
relative size of muscle ex.
maximus, minimus, longus, brevis
50
number of origins ex.
biceps, triceps, quadriceps
51
location of attachments ex. (origin is listed first and then insertion)
sternocleidomastoid
52
direction of muscle fibers/fascicles ex.
rectus, oblique, transverse
53
action of muscle ex.
flexor, extensor, adductor, abductor, etc.
54
List the 4 different effects of aging on the muscular system:
1. skeletal muscle fibers become smaller in diameter because of a decrease in myofibrils, resulting in decreased function--fatigue rapidly
2. muscles become less elastic as a result of fibrosis (increase of fibrous CT)
3. lower tolerance for exercise resulting in difficulty with fatigue and thermoregulation
4. muscle repair after injury decreases--fewer myoblasts and satellite cells
55
List the 4 disorders of the muscular system:
1. Charley horse
2. Calcaneal tendon rupture
3. Shin splints
4. Hernia
56
tearing of the muscle with bleeding into the tissue; severe, prolonged pain
Charley horse
57
plantar flexion not possible, dorsiflexion is exaggerated
Achilles (calcaneal) tendon rupture
58
irritation of the anterior compartment of the leg caused by irritation of the anterior tibialis muscle; may be used loosely to indicate stress fracture of the tibia, inflammation of fascia or muscle tears
Shin splints
59
organ protrudes through a muscle--more common in obese and elderly
hernia
60
Hernia results more easily in which two types of people?
1. those whose lifestyles result in a lack of the use of the abdominal muscles
2. those whose livelihood requires heavy lifting
61
List the 5 different types of hernias:
1. inguinal hernia
2. femoral hernia
3. umbilical hernia
4. hiatus hernia
5. incisional hernia
62
80% of all hernias are of this type--these individuals have a defect which carries the spermatic cord from the scrotum or the round ligament of the uterus to the labia majora
inguinal hernia
63
this type of hernia occurs when there is an enlargment of the ring that normally passes the blood vessels to and from the thigh
femoral hernia
64
type type of hernia is more common in infants
umbilical hernia
65
in this type of hernia there is a protrusion of the stomach into the thoracic cavity as a reult of a weakness in the opening passing the esophagus through the diaphragm
hiatus hernia
66
this type of hernia is due to surgery--there is a weakness at the cut site and the viscera will protrude---additional surgery will be required
incisional hernia
67
List the 5 functions of neural tissue:
1. Control and communication
2. Control homeostasis
3. Monitor
4. Integration
5. Motor output
68
changes in stimuli and information--sensory input
monitor
69
evaluate sensory input and fashion a response
integration
70
respond to stimuli via an effector organ
motor output
71
What are the two parts of the nervous system?
1. Central nervous system (CNS)
| 2. Peripheral nervous system (PNS)
72
brain & spinal cord
central nervous system
73
List the two aspects of the central nervous system:
1. Responsible for integration
| 2. Responses may be based on reflexes, experience, or current conditions
74
spinal and cranial nerves
peripheral nervous system
75
The peripheral nervous system is responsible for what?
monitoring & motor output
76
What are the two different parts of the peripheral nervous system?
1. Afferent system
| 2. Efferent system
77
sensory information from receptors to the CNS
afferent system
78
motor information from the CNS to effector organs (muscles, glands, etc.)
efferent system
79
What are the two parts of the efferent system?
1. Somatic nervous system
| 2. Autonomic nervous system
80
supplies voluntary information to skin and skeletal muscles, any automatic action like reflexes
somatic nervous system (somatic motor division)
81
supplies involuntary information to smooth muscles, heart, and glands
autonomic nervous system (visceral motor division)
82
List the 2 parts of the autonomic nervous system (ANS):
1. Sympathetic
| 2. Parasympathetic
83
causes changes in response to stress
sympathetic
84
maintains normal functions
parasympathetic
85
structural and functional unit of the nervous system
neuron
86
List the 4 aspects of neurons:
1. extreme longevity--100 years
2. high metabolic rate--high oxygen and glucose usage
3. contains no structures associated with cell division, stem cells still active in the nose (olfactory) and hippocampus (memory storage)
4. mitosis ceases between 6 months and 4 years
87
List the 10 parts of the neuron:
1. dendrites
2. axon
3. neurofibrils
4. nissl bodies
5. myelin sheath
6. nodes of ranvier
7. neurolemma (sheath of Schwann)
8. cell body
9. golgi apparatus
10. plasma membrane
88
branch-like extensions of the cytoplasm each with spines forming 80-90% of neuron total surface
dendrites
89
What are the 3 aspects of dendrites?
1. carry impulses toward the cell body
2. their distal ends form receptors
3. dendrite length will vary from micro to over 3 feet
90
single, long process
axon
91
What are the 4 aspects of axons?
1. carries impulse away from the cell
2. terminates with with branches called teliodendria at the synaptic terminal
3 may have side branches called collaterals
4. axon length will vary from micro to 3 feet
92
cytoplasm of the axon
axoplasm
93
special portion of the axon cell membrane
axolemma
94
provide internal support
neurofibrils
95
List one aspect of neurofibrils:
they spread nutrients and depolarisation waves through the cell
96
most active and well-developed rough endoplasmic reticulum in the body; protein synthesis--gives gray colour to gray matter
nissl bodies
97
a segmented, whitish, phospholipid covering that will act to insulate the fiber and spread the condution of nerve impulses
myelin sheath
98
What is the myelin sheath formed by in the peripheral nervous system (PNS)?
Schwann cell
99
What is the myelin sheath formed by in the central nervous system (CNS)?
oligodendrocytes
100
large areas of axon that are myelinated
internodes
101
unmyelinated gaps in the myelin sheath from which axon collaterals can emerge
nodes of ranvier
102
thin living nucleated membrane around the fiber or its myelin sheath of the PNS
neurolemma (Sheath of Schwann)
103
List the 3 aspects of the neurolemma (Sheath of Schwann):
1. brain and spinal cord do not have a neurolemma
2. essential along with a cell body for regeneration of a nerve fiber
3. is formed by the Schwann cell
104
biosynthetic center
cell body (perikaryon, soma)
105
well developed in the neuron
Golgi apparatus
106
3 structural components of the neuron:
1. dendrite
2. axon
3. axonal terminal
107
receptive or input region of a neuron
dendrite
108
conducting component of a neuron
axon
109
secretory or output component of a neuron
axonal terminal
110
clusters of cell bodies in the CNS are called:
nuclei
111
clusters of cell bodies that lie along the nerves in the PNS are called:
ganglia
112
functional connection between neuron and cell
synapse
113
List 2 aspects of synapses:
1. must have neurotransmitter--acetylcholine, norepinephrine, serotonin, dopamine, etc.
2. if the neurotransmitter substance remains in contact with the postsynaptic neuron, the impulse will continue indefinitely; to stop the impulse an enzyme is necessary
114
neuron conducting impulses toward the synapse; information sender
presynaptic neuron
115
neuron that transmits the electrical signal away from the synapse; information receiver
postsynaptic neuron
116
where neurotransmitters are released
presynaptic membrane
117
these have receptors for the neurotransmitters
postsynaptic membrane
118
Explain neuron functions:
In the body periphery, postsynaptic cells may be either neuron or effector cell (muscle, gland)
119
List 3 aspects of neuron functions:
1. neuromuscular junction
2. neuroglandular junction
3. synaptic knob
120
nerve to muscle junction
neuromuscular junction
121
neuron to gland junction
neuroglandular junction
122
postsynaptic cell is another neuron
synaptic knob
123
movement of materials between synaptic knobs and the cell body
axoplasmic transport
124
movement from cell body to synaptic knobs
anterograde flow
125
movement from synaptic knob to cell body
retrograde flow
126
Give an example of retrograde flow:
rabies enters nerve cells by way of retrograde actions
127
List the 4 structural classifications of neurons:
1. multipolar
2. bipolar
3. unipolar or pseudounipolar
4. anaxonic
128
What are the 3 aspects of multipolar neurons?
1. they consist of one axon and several dendrites
2. they are found in the brain and spinal cord
3. they are the most common type in humans and a major type in the CNS and in skeletal muscle
129
What are the 2 aspects of bipolar neurons?
1. they have one axon, one dendrite, and a cell body between
| 2. they are rare: found in the retina, inner ear, and olfactory area
130
What are the 3 aspects of unipolar neurons?
1. axon and dendrite are continuous, cell body to one side
2. sensory neurons of the PNS
3. some of the longest are from the toes to the spinal cord
131
What are the 2 aspects of anaxonic neurons?
1. small and no anatomical clues to distinguish dendrites from axons
2. located in the brain and special sense organs
132
List the 3 functional classifications of neurons:
1. Sensory (Afferent)
2. Motor (Efferent)
3. Association Neurons (connector, interneurons)
133
What are the 3 aspects of sensory neurons?
1. carry information from receptors to the spinal cord and brain
2. unipolar with processes called afferent fibers
3. cell bodies in the sensory ganglia outside CNS
134
What are the sensory receptor categories?
1. exteroreceptors
2. proprioceptors
3. interoceptors
135
external environment receptors
exteroceptors
136
body position and movement receptors
proprioceptors
137
internal organ system receptors--taste, deep pressure, pain
interoceptors
138
List the 3 aspects of motor neurons:
1. carry impulses from the brain and spinal cord to effector organs
2. multipolar and axons have efferent fibers
3. most cell bodies are in the CNS
139
What are the 4 aspects of association neurons?
1. conduct impulses from sensory to motor neurons
2. most are multipolar, ex. Purkinje & pyramidal cells
3. found only in the brain and spinal cord--memory, learning, and planning
4. outnumber all other types combined
140
small and more numerous than neurons; branching processes and a cell body
neuroglia (glial cells)
141
List the functions of neuroglia:
1. supports the neurons and anchors them to blood vessels
2. protection or defense through phagocytosis
3. plays a part in the formation of the myelin sheath in the CNS
142
What are the neuroglia of the central nervous system?
1. astrocytes
2. microglia
3. oligodendrocytes
4. ependymal cells
143
List the aspects of astrocytes:
1. most abundant and most versatile
2. star shaped cells; many processes
3. provide structural framework for neurons in the CNS
4. can assist in repair of injury by stabilising the tissue and preventing further injury
5. direct neuron development in the embryonic brain
6. astrocyte end feet provide signals that stimulate endothelial cells of the brain capillaries to form tight junctions to maintain the blood-brain barrier
7. controls chemical environment around neurons--absorb and recycle excess neurotransmitters; regulate concentration of Na+, K+, and CO2.
144
List the aspects of microglia:
1. smallest and least numerous
2. migrate through neural tissue, many fine processes
3. move around and carry on phagocytosis--important because cells of the immune system are denied access to the CNS
145
List the aspects of oligodendrocytes:
1. fewer and shorter processes than astrocytes
2. support and connect neurons to blood vessels
3. function in formation of the myelin sheath around axons of neurons of the CNS (white matter because of lipids)
146
List the aspects of ependymal cells:
1. single layer of epithelial cells, may be ciliated
2. form the continuous lining of the ventricles of the brain and central canal of the spinal cord, filled with CSF
3. cilia may contribute to the circulation of CSF
147
What are the neuroglia cells of the peripheral nervous system?
1. Schwann cells
| 2. satellite cells
148
List the aspects of Schwann cells:
1. they are also called neurilemmal cells
2. they form a sheath around every peripheral axon, myelinated or not
3. peripheral nerve fibers regeneration
149
List the aspects of satellite cells:
1. also called amphicytes
2. surround cell bodies in ganglia
3. work like astrocytes
150
If damage is severe or near the cell body of a neuron:
the entire neuron may die and other neurons stimulated by that axon may die
151
if cell body of a neuron remains intact, cut, or compressed:
axons on peripheral nerves can regenerate
152
the greater the distance between the severed nerve ending:
the less likely regeneration will occur
153
List the steps of neural repais in the peripheral nervous system:
1. Wallerian degeneration spreads distally from the site until the axon is fragmented
2. Macrophages move to the injury site and phagocytise debris
3. Neurolemma remains intact within the endoneurium
4. Neuron cell body undergoes changes in response to axonal injury by dispersing genetic material to the cell periphery, where it can direct synthesis of proteins to support regeneration
5. Macrophages release chemicals that cause Schwann cells to proliferate and move to injury site
6. Schwann cells then release growth factor to encourage axon growth forming a regeneration tube; then remyelinating the regeneration tube
154
within a few hours of injury, the axon and myelin sheath distal to the injury start to disintegrate from lack of nutrients
Wallerian degeneration
155
Neural changes are produced by:
1. anything that changes membrane permeability to any type of ion
2. anything that alters ion concentration on the two sides of the membrane
156
Two types of signals are produced by change in membrane potential:
1. graded potentials
| 2. action potentials
157
temporary localised change, decrease in strength over distance
graded potentials
158
signal over long distance and brief reversal of membrane potential: only axons can generate these
action potential
159
electric potential across a nerve fiber membrane resulting from concentration differences of certain ions between the two sides of the membrane (Na+, K+, and protein ions), passive (gradients) and active (sodium-potassium pump) forces act across membrane
transmembrane potential
160
when the membrane is positively charged on the outside and negatively charged on the inside; cell is polarised
resting membrane potential
161
List the 3 aspects of resting membrane potential:
1. Na+ concentration is greater outside the resting fiber than inside
2. K+ concentration is greater inside the resting fiber than outside
3. Sodium-potassium pump transports 3 Na+ out of the cell for every 2 K+ into the cell---ATP driven
162
no energy required to move ions
passive forces
163
concentration gradient; sodium and potassium
chemical gradients
164
results from differences in speed of movement of Na+ and K+ ions and polarity; can reinforce or oppose chemical gradient (positive is attracted to negative so K+ slowly leaves and Na+ wants to come in more)
electrical gradient
165
sum of the chemical and electrical gradients acting on an ion across the cell membrane
electrochemical gradient
166
requires energy
active forces
167
List the 2 aspects of active forces:
1. sodium-potassium pump requires ATP to work
2. DDT and other chlorinated hydrocarbons (pesticides) interfere with the sodium-potassium pump so it can effect nerve impulses, and helps to cause deaths
168
List the 2 membrane channels:
1. (Passive) leak channels
| 2. (Active) gated channels
169
always open but can change permeability from moment to moment
leak channels
170
open and close in response to a stimuli
gated channels
171
changes relative to resting membrane potential--spreads in a wave or nerve impulse or action potential
depolarisation
172
What are the 3 graded potentials?
1. depolarisation
2. repolarisation
3. hyperpolarisation
173
inside of the membrane becomes less negative resulting in a decrease in membrane potential; influx of Na+; local current, can't go very far
depolarisation
174
restoration of resting membrane potential, but not in the original ionic distributions (sodium-potassium pump restores original distribution), starts at the same point in the fiber where depolarisation began
repolarisation
175
inside of membrane becomes more negative resulting in an increase in membrane potential
hyperpolarisation
176
A neuron receives info via graded potential at the dendrites and cell body but is unable to transmit info for long distances so:
an action potential links graded potential to the synaptic terminals which in turn causes a graded potential in the presynaptic membrane which may trigger release of a neurotransmitter
177
changes in the membrane potential that affect an entire excitable membrane
action potentials
178
What is an aspect of action potentials?
Not all local depolarisations produce action potentials. The depolarisation must reach threshold values.
179
minimal stimulus strong enough to decrease the receptor potential and initiate an impulse
threshold stimulus
180
any stimulus not capable of initiating an impulse unless a second or several stimuli are applied quickly to a neuron, at which time these additional stimuli are summed
subthreshold stimulus
181
a stimulus is either strong enough to trigger an action potential or does not produce one at all
all-or-none law
182
Period from opening of activation gates of Na+ channels to the closing of the inactivation gates; membrane can't respond to further stimulus ensuring each action potential is separate; ensures one way propagation of the action potential
absolute refractory period
183
Na+ gates closed and K+ gates open; return to resting state (repolarisation)
relative refractory period
184
What are the 2 aspects of propagation of action potentials?
1. continuous
| 2. saltatory
185
action potential moves across the membrane in small steps; unmyelinated fiber, always away from the site of generation
continuous
186
myelinated fiber; myelin sheath acts as an insulator and the action potential jumps from node to node, faster and takes less energy
saltatory
187
rate of impulse propagation depends on:
1. axon diameter
| 2. degree of myelination
188
List the 3 axon diameters:
1. Type A fibers
2. Type B fibers
3. Type C fibers
189
What are the 5 aspects of Type A fibers?
1. largest
2. all myelinated
3. carry sensory information to the CNS concerning position balance, and fine touch and pressure sensations from the skin surface
4. carry commands from motor neurons to skeletal muscles
5. 300 mph
190
What are the 5 aspects of Type B fibers?
1. mid-sized
2. all myelinated
3. carry less urgent information such as pain, temperature, general touch, and pressure sensations to the CNS
4. carry motor commands to smooth muscle, cardiac muscle, glands, and periphery effectors
5. 40 mph
191
What are the 5 aspects of Type C fibers?
1. smallest in diameter
2. unmyelinated
3. carry less urgent information as type B
4. incapable of saltatory propagation
5. 2 mph
192
List the 3 aspects of degree of myelination:
1. myelin sheath decreases time between reception of stimulus and response
2. myelination is not complete until adolescence
3. myelination improves coordination and control
193
The two types of synapses:
1. electrical
| 2. chemical
194
List the 3 aspects of electrical synapses:
1. rare, in the CNS and PNS
2. presynaptic and postsynaptic membranes held together at gap junctions
3. action potentials move rapidly from cell to cell
195
specialised for release and reception of chemical neurotransmitters
chemical synapses
196
in presynaptic neuron, contains synaptic vesicles containing neurotransmitters
axonal terminal
197
on the membrane of a dendrite or cell body of a postsynaptic neuron that has neurotransmitter receptors
receptor region
198
What are the 2 parts of a chemical synapse and what is between them?
1. axonal terminal
2. receptor region
synaptic cleft
199
these result in depolarisation and propagation of an action potential
excitatory neurotransmitter
200
these result in hyperpolarisation and suppress propagation of action potential
inhibitory neurotransmitter
201
release acetylcholine
cholinergic synapse
202
Other neurotransmitters:
1. norepinephrine
2. dopamine
3. serotonin
4. gammaaminobutyric acid
203
brain and ANS; usually excitatory effects
norepinephrine
204
brain; may be either excitatory or inhibitory; regulates motor function; Parkinson's
dopamine
205
CNS; role in emotional behaviour; low levels may contribute to chronic depression
serotonin
206
generally inhibitory effect; may reduce anxiety
GABA (gammaaminobutyric acid)
207
regulate the rate of neurotransmitter release by the presynaptic neuron or alter the response by the postsynaptic cells to the neurotransmitter; neuropeptides
neuromodulators
208
natural opiates
endorphins
209
neurotransmitter and neuromodulator functions:
1. direct effect
2. indirect effect
3. lipid-soluble gases
210
gated channels; acetylcholine
direct effect
211
G proteins serve as a link between the first messenger and second messenger
indirect effect
212
CO and NO; bind to enzymes on the inside of the cell which then form second messengers that affect cellular activity
lipid-soluble gases
213
graded potentials in postsynaptic membranes in response to a neurotransmitter; may be excitatory (EPSP) or inhibitory (IPSP)
postsynaptic potentials
214
neurotransmitter binding causes graded depolarisation of the postsynaptic membrane which may trigger an action potential at the axon hillock; opening of chemically regulated gates
excitatory postsynaptic potential (EPSP)
215
neurotransmitter binding causes graded hyperpolarisation of the postsynaptic membrane; reduces ability to propagate an action potential
inhibitory postsynaptic potential (IPSP)
216
a single EPSP or TPSP may not initiate an action potential, combining them may initiate the action potential
summation
217
rapidly reoccurring stimuli at a single synapse
temporal summation
218
simultaneous stimuli at multiple synapses
spatial summation
219
a neuron close to reaching threshold; it will be easier for the next stimulus to initiate the action potential
facilitation
220
Give an example of facilitation:
caffeine and other chemicals cause this; it lowers the threshold so you become jumpy because your reflexes are primed
221
6 neural conditions:
1. demyelination
2. rabies
3. tay-sachs disease
4. hyperkalemia
5. tumors
6. neurotoxins
222
progressive destruction of myelin sheaths in both CNS and PNS, result in loss of sensation and motor control, many diseases may cause this
demyelination
223
retrograde flow carries the virus from bitten/infected tissues to the cell bodies, results in cell death and once many are lost animal dies
rabies
224
genetic abnormality involving metabolism of gangliosides, gradual deterioration of neurons because of by-product build up
tay-sachs disease
225
abnormally high extracellular concentration of K+
hyperkalemia
226
result from division of abnormal neuroglia
tumors
227
compound that disrupts normal nerve functions
neurotoxins
228
Example of neurotoxins:
TTX tetrodotoxin, some snake, spider, scorpion, mammale (rare) venoms
229
Peripheral nervous system terms:
1. ganglia
2. nerves
3. spinal nerves
4. cranial nerves
230
collection of neuron cell bodies in the PNS
ganglia
231
bundles of axons, usually myelinated
nerves
232
connected to the spinal cord
spinal nerves
233
connected to the brain
cranial nerves
234
Central nervous system terms:
1. center
2. nucleus
3. neural cortex
4. higher centers
5. tracts
6. columns
7. sensory (ascending) pathway
8. motor pathway
9. horns
10. gray matter
11. white matter
235
collection of neuron cell bodies in the CNS with common function
center
236
collection of neuron cell bodies in the interior of the CNS
nucleus
237
outer surface of the brain composed of gray matter
neural cortex
238
complex centers of the brain
higher centers
239
bundles of axons in the CNS, usually myelinated
tracts
240
large bundles of axons in the spinal cord that are divided into tracts
columns
241
carry information from peripheral receptors to the brain
sensory (ascending) pathway
242
CNS to effectors
motor pathway
243
masses of neuron cell bodies located in the gray matter of the spinal cord
horns
244
mainly neuron cell bodies and dendrites or bundles of unmyelinated axons and neuroglia
gray matter
245
myelinated nerve bundles
white matter
246
Spinal cord continues to grow to enlarge and elongate with the spinal column until:
age 4
247
The quantity of gray matter increases in areas involved with:
sensory and motor control of limbs
248
from C4 to T1 and supplies nerves to the shoulder girdle and upper limbs
cervical enlargement
249
from T9 to T12 and supplies nerves to the pelvis and lower limbs
lumbar enlargement
250
below lumbar enlargement, spinal cord tapers into a conical portion
conus medullaris
251
nerve roots at the inferior end of the vertebral column arising from the conus medullaris
cauda equina
252
fibrous extension of the pia mater that anchors the spinal cord in place
filum terminale
253
deep, wide groove on the anterior surface
anterior median fissure
254
shallower, narrow groove on the posterior surface
posterior median sulcus
255
31 pairs; contain both sensory and motor fibers, mixed nerves
spinal nerves
256
contains cell bodies of sensory neurons
dorsal root ganglia
257
contains axons of sensory neurons
dorsal root
258
axons of motor neurons
ventral root
259
collective term for the 3 membranes that cover the brain and spinal cord
meninges
260
Spinal meninges:
1. pia mater
2. arachnoid mater
3. dura mater
4. epidural space
5. subdural space
6. subarachnoid space
7. denticulate ligaments
261
tender mother, inner vascular, carries blood to brain and spinal cord
pia mater
262
spider form, middle layer, web like and thin enclosing the subarachnoid space
arachnoid mater
263
hard mother, outer, tough layer, major protective layer; anchors spinal cord at the foramen magnum and coccygeal ligament, prevents longitudinal movement of spinal cord
dura mater
264
loose CT, adipose, blood vessels; fuses to periosteum of occipital bone at the foramen magnum and becomes continuous with the cranial dura mater; blends with filum terminale to become coccygeal ligament
epidural space
265
below the dura mater
subdural space
266
filled with CSF
subarachnoid space
267
extends from pia mater through arachnoid mater and attaches at the dura mater; prevent lateral movement of spinal cord
denticulate ligaments
268
unmyelinated nerve fibers, in the inside of the spinal cord
grey matter
269
List the parts of grey matter:
1. posterior gray horn
2. anterior gray horn
3. lateral gray horn
4. gray commissure
270
contain somatic and visceral sensory nuclei
posterior gray horn
271
contain somatic motor nuclei
anterior gray horn
272
contains visceral motor nuclei; located in thoracic and lumbar segments
lateral gray horn
273
contains axons that cross over
gray commissure
274
myelinated nerve fibers, outside of spinal cord
white matter
275
List the parts of white matter:
1. posterior white column
2. anterior white column
3. lateral white column
4. white commissure
5. posterior median sulcus
6. anterior median fissure
276
sensory tracts
ascending tracts
277
motor tracts
descending tracts
278
List the parts of the ascending tracts:
1. lateral spinothalamic tract
2. ventral spinothalamic tract
3. dorsal and ventral spinothalamic tract
4. gracilis and cuneate tracts
279
pain and temperature
lateral spinothalamic tract
280
crude touch
ventral spinothalamic tract
281
unconscious muscle sense for controlling muscle tone and posture
dorsal and ventral spinothalamic tract
282
touch, pressure, two-point discrimination, conscious muscle sense concerned with appreciation of body position. The impulses come from the skin, muscles, tendons, and joints.
gracilis and cuneate tracts
283
List the parts of the descending tracts:
1. lateral and ventral corticospinal tracts
2. rubrospinal tract
3. reticulaspinal tract
4. vestibulospinal tract
284
carry voluntary impulses to the skeletal muscles
lateral and ventral corticospinal tracts
285
carries involuntary impulses to skeletal muscles concerned with tone and posture
rubrospinal tract
286
increases skeletal muscle tone and motor neuron activity
reticulaspinal tract
287
regulates muscle tone to maintain balance and equilibrium
vestibulospinal tract
288
a clear, colourless protective fluid in the subarachnoid space of the brain and spinal cord
cerebrospinal fluid
289
List the aspects of cerebrospinal fluid:
1. the composition is similar to blood plasma--water, proteins, glucose, urea, lactic acid, cations (Na+, K+, Ca+, Mg+), anions (Cl-, HCO3-), and some lymphocytes
2. Volume: 80 to 150 ml
3. pH: 7.35-7.4
290
List the functions of cerebrospinal fluid:
1. Mechanical protection--the fluid serves as a shock-absorbing medium to protect the brain and spinal cord from hitting against the cranial and vertebra cavities
2. Chemical protection--provides an optimal chemical environment for accurate neuronal signaling. Even slight changes in ionic composition of CSF within the brain could disrupt action potentials
3. Circulation--the fluid delivers nutritive substances filtered from the blood to the brain and spinal cord, and removes wastes and toxic substances produced by brain and spinal cells
291
Lumbar puncture or spinal tap:
1. Fluid is removed from between the 3rd and 4th lumbar vertebrae or between the 4th and 5th lumbar vertebrae. A lumbar puncture is made at this point because it is below the spinal cord and thus poses little danger to it. In addition, the subarachnoid space is slightly larger at this point.
2. Lumbar punctures are used to withdraw fluid for diagnostic purposes, to introduce antibiotics and contrast media, or to introduce an anesthetic to create spinal anesthesia, to administer chemotherapy, or to measure CSF pressure
3. A line drawn across the highest points of the iliac crests passes through the spinous process of the 4th lumbar vertebra
292
Spinal nerves terms:
1. epineurium
2. perineurium
3. endoneurium
4. fascicle
293
outer layer, dense CT
epineurium
294
middle layer, encloses a fascicle
perineurium
295
surround an axon
endoneurium
296
bundle of axons, 31 pairs
fascicle
297
How many cervical spinal nerve bundles are there?
8
298
How many thoracic spinal nerve bundles are there?
12
299
How many lumbar spinal nerve bundles are there?
5
300
How many sacral spinal nerve bundles are there?
5
301
How many coccygeal spinal nerve bundles are there?
1
302
Each spinal nerve connects to the spinal cord by two roots:
1. dorsal root
| 2. ventral root
303
sensory or afferent; arise from sensory neurons in the spinal ganglia that conduct impulses from peripherally located receptors
dorsal root
304
motor or efferent; arise from anterior horn motor neurons that extend to the skeletal muscles
ventral root
305
The motor and sensory fibers mingle together in the spinal nerve. The spinal nerves are short because:
almost immediately after leaving the foramen they branch into small dorsal rami or larger ventral rami
306
supply the posterior body trunk
dorsal rami
307
supply the rest of the body trunk and limbs
ventral rami
308
Roots:
lie medial to and form the spinal nerves; each root is strictly motor or sensory
309
Rami:
lie distal to and are lateral branches of the spinal nerve and carry both sensory and motor fibers
310
each region of the skin is served by a single pair of spinal nerves, parts that "fall asleep" have nerves that are pinched or compressed and the nerve loses contact with that area. Except for T2-T12, all ventral rami join one another lateral to the vertebral column in nerve plexuses or groups.
dermatomes
311
What are the aspects of the cervical plexus?
1. Cervical nerves (C1-C5) combine to form the cervical plexus lying in the upper part of the neck under the sternocleidomastoid muscle
2. Nerves from the plexus pass to the muscles and skin of the scalp and neck, and to the diaphragm by way of the phrenic nerve, controls breathing and is the most important nerve here.
3. A broken neck may result in respiratory paralysis through injury to the phrenic nerve.
4. Hiccups result from irritation of this nerve and if severed must be put on mechanical respirator.
5. Contains ventral rami only.
312
What are the aspects of the brachial plexus?
1. The anterior roots of spinal nerves from the lower cervical and upper thoracic (C6-T1) combine to form this plexus, which lies in the anterior base of the neck just superior to the clavicle.
2. It sends nerves to the skin and muscles of the upper appendages.
3. The nerves are superficial at the axilla so injury may result in paralysis.
4. There are five major nerves that exit from this plexus.
313
What are the 5 major nerves that exit the brachial plexus?
1. Axillary nerve
2. Musculocutaneous nerve
3. Median nerve
4. Ulnar nerve
5. Radial nerve
314
supplies shoulder joint and deltoid
axillary nerve
315
supplies structures of the anterior upper arm
musculocutaneous nerve
316
supplies anterior forearm, injury makes it hard to use the pincer grasp; wrist slashing
median nerve
317
supplies anterior forearm, injury prevents ability to make a fist or grip; stimulates the "funny bone"
ulnar nerve
318
supplies the posterior upper arm, forearm, and hand; injury causes wrist drop, may be caused by improper use of crutch
radial nerve
319
What are the aspects of the lumbar plexus?
1. Lumbar nerves (L1-L4) combine to form the lumbar plexus lying within the posterior part of the psoas muscle.
2. Three main nerves exit from the plexus.
320
What are the 3 major nerves that exit the lumbar plexus?
1. Femoral nerve
2. Lateral cutaneous nerve
3. Obturator nerve
321
supplies the skin and muscles of the anterior thigh
femoral nerve
322
supplies the skin and muscle of the upper lateral thigh
lateral cutaneous nerve
323
supplies the skin and muscles of the medial thigh
obturator nerve
324
What are the aspects of the sacral plexus?
1. The lower lumbar and upper sacral (L4-S4) combine to form the sacral plexus lying in the middle portion of the greater (false) pelvis.
2. The major nerve of the sacral plexus is the sciatic nerve. There are 3 important branches of the sciatic nerve.
325
What are the 3 important branches of the sciatic nerve in the sacral plexus?
1. hamstring nerve
2. tibial nerve
3. common peroneal nerve
326
rises from the sciatic nerve in the thigh and supplies the skin and muscles of the posterior thigh. This nerve is a part of the tibial nerve.
hamstring nerve
327
rises from the sciatic nerve just above the knee and supplies the skin and muscles of the knee joint and posterior leg
tibial nerve
328
also rises just above the knee. It continues down the leg, giving branches that supply the skin and muscles of the knee, anterior and lateral leg, and foot
common peroneal nerve
329
What are the aspects of intercostal nerves?
1. Not arranged in plexus.
2. Arise from the thorax (T2-T11) and form the intercostal nerves supplying the intercostal muscles and abdominal muscles
330
Nerve fibers crisscross and redistribute so:
1. each branch contains fibers from different spinal nerves
2. each muscle receives nerve supply from more than one spinal nerve
Damage to one spinal segment or limb cannot paralyse an entire limb
331
functional groups of neurons that integrate incoming information received from other sources and then forward the processed information to other destinations--connection neurons
neuronal pools
332
patterns of synaptic connections in neuronal pools, which determine functional capabilities of the pool
neural circuits
333
What are the 5 aspects of neural circuits?
1. Divergence
2. Convergence
3. Reverberation
4. Serial processing
5. Parallel
334
one incoming fiber triggers responses in ever-increasing numbers of neurons farther and farther along the circuit
divergence
335
What are the 2 aspects of divergence and an example?
1. amplifying circuit
2. common in sensory and motor systems
ex. eye sense--goes to conscious to process, also balance and posture sites
336
a motor neuron can be controlled by both conscious and subconscious, breathing
convergence
337
oscillating circuits; works like positive feedback mechanisms; maintains consciousness, coordination, and normal breathing
reverberation
338
relay system passing on info
serial processing
339
multiple neurons or pools process information at the same time allowing many responses to occur simultaneously; in response to pain--feel it, pull away, make response
parallel
340
Reflex arcs:
1. simplest functional unit of the nervous system
2. reflex--quick involuntary response to a stimulus transmitted over a reflex arc
3. negative feedback
4. ex. respiration, urination, defecation, heart rate, digestion
341
Parts of a reflex arc:
1. receptor
2. sensory (afferent) neuron
3. center
4. motor (efferent) neuron
5. effector
342
to detect a change
receptor
343
to conduct the impulse from stimulation of the receptor to the CNS
sensory (afferent) neuron
344
where a synapse is made between neurons. This will be within the CNS and may contain a connector neuron.
center
345
to conduct an impulse to the organ of the body that will respond
motor (efferent) neuron
346
an organ, either a muscle or gland, that does something to maintain homeostasis
effector
347
Classification of reflexes:
1. Development
2. Processing site
3. Response
4. Complexity of circuit
5. Control
348
Development:
1. Innate
| 2. Acquired
349
Processing site:
1. spinal
| 2. cranial
350
Response:
1. Somatic
| 2. Visceral
351
voluntary control of muscle system, skin, tendons
somatic
352
other systems autonomic reflexes
visceral
353
Complexity of circuit:
1. monsynaptic
| 2. polysynaptic
354
sensory neuron synapses directly on a motor neuron
monsynaptic
355
at least 1 interneuron between the sensory and motor, more delay
polysynaptic
356
Control:
1. ipsilateral
| 2. contralateral
357
same side affected--left hand moves when left is stimulated
ipsilateral
358
opposing sides--right hand moves when left is stimulated
contralateral
359
Monosynaptic reflexes:
Intrafusal muscle fibers; stretch reflex
360
What are the aspects of intrafusal muscle fibers?
1. lack myofilaments
2. noncontractile
3. receptor surface of the spindle
4. primary sensory endings
5. secondary sensory endings
6. innervated by gamma efferent fibers which maintain sensitivity of the spindle at the distal ends of intrafusal fibers
361
stimulated by rate and amount of stretch
primary sensory endings
362
monitor degree of stretch
secondary sensory endings
363
Stretch reflex example:
knee jerk reflex (patellar reflex), some postural reflexes
364
What are the aspects of stretch reflex?
1. external stretch
2. internal stretch
3. stretch --> action potential down afferent --> spinal cord, stimulate interneurons --> afferent pathway down motor neuron to muscle fiber, ESPS, contraction
3. the opposite muscle = interneurons send afferent pathway down motor neurons to antagonistic muscle, causes an ISPS on that muscle to lead to relaxation
4. ipsilateral and monosynaptic (all stretch reflexes single synapse); reflex arcs that inhibit the antagonistic muscles are polysynaptic
5. stretch reflex is necessary for normal muscle tone and activity but never acts alone; accompanied by gamma motor neuron reflex arc
6. as muscle shortens, the spindle's rate of firing declines --> reduces impulse generation by alpha motor neurons
365
lengthening entire muscle--give example
external stretch; ex. carry heavy weight or antagonistic muscle contract
366
stretching the middle of the muscle by activating gamma motor neurons
internal stretch
367
List the polysynaptic reflexes:
1. tendon reflex
2. withdrawal reflex
3. crossed extension reflex
4. superficial reflex
368
What are the aspects of the tendon reflex?
1. has the opposite effect of the stretch reflex, muscle relaxes in response to stretching; protects the muscle from over-stretching and tearing tendons
2. golgi tendon organs ensure smooth onset and termination of muscle contractions
369
What are the aspects of withdrawal reflex?
1. flexor reflex
2. ex. moving hand off hot stove; pricking your finger
3. response to painful stimuli, where stimulus causes automatic withdrawal
4. polysynaptic and ipsilateral
370
What are the aspects of crossed extension reflex?
1. important in maintaining balance
| 2. combination of ipsilateral withdrawal and contralateral (opposite) extensor reflexes
371
What are the aspects of superficial reflex?
1. cutaneous stimulation
2. plantar reflex
3. plantar reflex is replaced by Babinski sign if the primary motor cortex or coricospinal tract is damaged
4. abdominal reflex
372
downward flexion of toes when sole is stroked
plantar reflex
373
found in infants and abnormal in adults; with the same stimulation, the toes flare and move laterally; normal for infants because the nervous system is incompletely myelinated
Babinski's sign
374
light stroking of the abs will cause twitch
abdominal reflex
375
Clinical conditions of the spine:
1. ALS (amyotropic lateral sclerosis)
2. Poliomyelitis
3. Shingles/chicken pox/herpes
4. Meningitis
5. Epidural block
376
Lou Gehrig's Disease; progressive destruction of anterior horn and pyramidal tracts; results in loss of speech, swallowing, and breathing
amyotropic lateral sclerosis
377
destruction of anterior horn motor neurons by virus, produces paralysis
poliomyelitis
378
invades dorsal root of the spinal nerves, forming blister-like lesions on the skin along the dermatome; reactivated virus migrates along sensory nerve associated with the infected dorsal root ganglion
shingles/chicken pox/herpes
379
inflammation of the meninges
meningitis
380
meningitis affecting only the dura mater
pachymeningitis
381
meningitis affecting the arachnoid and pia mater. This form is most common.
leptomeningitis
382
affects the area immediately around the site of injection
epidural block
