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Flashcards in Test 3 Deck (382):
1

Factors that determine effects of muscle contraction:

1. Anatomical arrangement of muscle fibers
2. The way the muscle attaches to bone

2

One can classify muscles by which 3 factors?

1. Shape
2. Action (movement)
3. Size and range of motion

3

Based on the arrangement of a fascicle:

All muscle fibers are parallel in a single fascicle.

4

List the 4 different shapes of muscles:

1. Parallel
2. Pennate
3. Convergent
4. Circular or Sphincter

5

Muscle shape in which the axes of fascicles run parallel to axes of the muscle:

parallel muscles

6

Muscle shape: spindle shaped or strap-like, will have a central body (belly or gaster)

parallel muscles

7

Muscle shape: contraction--gets smaller and larger in diameter, especially at the belly

parallel muscles

8

Give examples of parallel muscles:

biceps and sartorius

9

Muscle shape: feather-like, fascicles are short and oblique attached to a central tendon--produces more tension

pennate muscles

10

List the 3 different types of pennate muscles:

1. Unipennate
2. Bipennate
3. Multipennate

11

Shape: fascicles insert into only one side of the tendon, also give example

Unipennate muscles; ex. extensor digitorum (extends fingers)

12

Muscle shape: fascicles insert on both sides of tendon, also give example

bipennate muscles; ex. rectus femoris (extends knee)

13

Muscle shape: many fascicles are inserted into a tendon that typically branches, also give example

multipennate muscles; ex. deltoid muscle

14

Muscle shape: fan-shaped, force directed to a point (raphe), can pull in different directions since each section can change direction, also give example

convergent muscles; ex. pectoralis major

15

point where tendon, aponeurosis, and collagen fibers converge

raphe

16

Muscle shape: contraction acts to close; fascicles are arranged in a circular pattern, also give example

circular/sphincter muscle; ex. obicularis oris, obicularis oculi

17

immovable end of muscle to bone

origin

18

moveable end of muscle to bone attachment

insertion

19

Movement can be named for what two factors?

Bone involved or joint involved (ex., flexion of forearm, flexion of elbow)

20

What are the 3 functional groups of muscles based on size and range of motion?

1. Agonist
2. Antagonist
3. Synergists

21

prime mover, muscle is chiefly responsible for movement; give example

agonist; ex. prime mover of elbow is biceps brachii--origin is the humerus and the insertion is the radius

22

oppose or reverse a movement--located on opposite side of joint; give example

antagonist; ex. triceps brachii vs. biceps brachii

23

help prime movers; list 3 different functions

synergists; 1. adds extra force to the movement
2. reduces undesirable or unnecessary movement
3. it is a fixator--immobilises a bone of muscle origin

24

Give an example of the synergist function of adding extra force to a movement:

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