Chapter 10 Flashcards
(116 cards)
1
Q
Authorythmicity
A
Build in rhythm
Natural pacemaker of heart
2
Q
Functions of muscular tissue
A
Producing movement
Stabilizing body positions
Storing/moving substances in body
Generating heat
3
Q
Thermogenesis
A
Muscle tissue contracts producing heat
4
Q
Electrical excitability
A
Ability to respond to stimuli by producing action potentials
Stimulated by electrical signals (auto rhythmic) or chemical stimuli (neurotransmitter/hormones/pH changes)
5
Q
Muscle fibers also called
A
Myocytes
6
Q
Subcutaneous layer/hypodermis
A
Aereolar/adipose separate in skin from muscle
7
Q
Fascia
A
Dense sheet/broad band or ICT
Lines body wall, supports/surrounds muscles/organs
8
Q
Layer of connective tissue extending from fascia
A
Epimysium
Perimysium
Endomysium
9
Q
Epimysium
A
Outer later around entire muscle
DITC
10
Q
Perimysium
A
DICT
Surrounds 10-100+ muscle fibers separating into fascicles
11
Q
Fasicles
A
Bundles of 10-100+ muscle fibers
Can be seen with naked eye
Meat rips at these
12
Q
Endomysium
A
Penetrates interior of each radicle and separating individual fibers
Mostly reticular fibers
13
Q
Tendon
A
All three connective layers extend rope like from muscle and attach to periosteum
14
Q
Aponeurosis
A
Tendon but Broad flat sheet
15
Q
Neurons that stimulate skeletal muscle
A
Somatic motor neurons
16
Q
Bloody supply of muscles
A
Capillaries
17
Q
Sarcolemma
A
Llamas membrane of muscle cell
18
Q
Transverse tubules
A
Invaginations of sarcolemma
Filled with interstitial fluid
19
Q
How do muscle action potentials travel
A
Along sacrolemma through T tubules throughout muscle fiber
20
Q
Sarcoplasm
A
Cytoplasm of muscle cell
Large amount of glycogen
Myoglobin
21
Q
Myoglobin
A
Red protein only in muscle
Binds o2 and releases it for ATP production
22
Q
Myofibrils
A
Tiny threads in sarcoplasm
Contractile organelles of skeletal muscle
2um diameter
23
Q
Sarcoplasmic reticulum
A
Fluid filled membranous sacs encircling myofibril
Stores Ca2+
24
Q
Terminal cisterns
A
Dilated end sacs of SR
Butt against t tubules
Releases Ca2+
25
Triad
T tubules and 2 terminal cisterns
26
Where are filaments found
In myofibrils
27
Thin filaments
Actin
8nm diameter
Contractile protein
28
Thick filaments
Myosin
16nm diameter
Contractile protein
29
Sarcomeres
Basic functional units of myofibril
Have filaments inside
30
Z disc
Seperate one sarcomere from bect
31
A band
Entire length of thick
32
Zone of overlap
Where thin/thick are
In A band
33
I band
Rest of thin filaments
Z disc in center
34
H zone
Thick not thin in A band
35
M line
Hold thick filaments at center of H zone
36
Contractile proteins
Myosin (thick)
Actin (thin)
37
Binding sites on myosin
Actin binding site
ATP binding site
38
Binding sites on actin
Myosin binding site
39
Regulatory proteins
Tropomyosin: blocks myosin binding sites in actin
Troponin: troponin moves tropomyosin away uncovering binding sites
40
Titan
Structural protein
Third most plentiful protein
Huge (50x larger than normal protein)
Z disc to M line stabilizing thick filament
Very elastic
41
Sliding filament mechanism
Thin slide inwards
I band and H zone narrow then disappear (max contraction)
42
What happens before Contraction cyle
SR release Ca ions into sarcoplams
Ca binds to troponin which moves tropomyosin away from binding sites
43
Contraction cycle steps
1.ATP hydrolysis: myosin head is energized and orientated (90°)
2. Attachment of myosin to actin: cross bridge formed, P group released
3. Power stroke: myosin head picots pulls thin past thick (45°), ADP released
4. Detachment of myosin from actin: myosin binds ATP detaching cross bridge
44
#cross bridges in thick filament
600
Attached/detaches 5/sec
45
Excitation contraction coupling
Sequence of events linking excitation (muscle action potential) to contraction (sliding of filaments)
Occurs at triad
46
Voltage gated Ca2+ channels
In t tubule membrane arrange as tetrads
Voltage sensors triggering opening of ca2+ release channels
47
Ca2+ release channels
Terminal cistern of SR
Prevent ca ions from leaving in relaxed, open during excitation for ca to flow into sarcoplasm and filaments
48
Ca2+ -ATPase pumps
Terminal cisterns of SR
Use ATP to transport ca ions from sarcoplasm to SR
49
Calsequestrin
Protein binds ca ion in SR to store them
50
Length-tension relationship
100 percent max tension occurs when zone of overlap extend from edge of H zone to one end of thick filament
51
When is there no overlap of filaments? What does this cause
170% stretched
No contraction as no cross bridge can be formed
52
Neuromuscular junction
Synapse between somatic motor neuron and skeletal muscle fiber
Muscle action potential arise at NMJ
53
Synapse
Region where communication occurs between two neurons
Between somatic motor neuron and muscle fiber at NMJ
54
Synaptic cleft
Small gap at synapse
55
Neurotransmitter
Chemical messenger from NmJ to muscle fiber
56
Axon terminal
End of motor neuron divided into synaptic end bulbs
57
Synaptic end bulbs
Contain membrane enclose sacs (synaptic vesicles)
58
Synaptic vesicle
Membrane enclosed sacs in shanties end bulbs contains thousand of acetylcholine (ACh) modelcules (neurotransmitter)
59
What is the neurotransmitter and NMJ
Acetylcholine (ACh)
60
Motor end plate
Region of sarcolemma opposite synaptic end bulbs
Has ACh receptors
61
Acetylcholine receptors
Integral membrane proteins that bind ACh at motor end plate
Have functional folds for large SA
Logan gated ion channels
62
Muscle action potential steps
1. Release of ACh: never impulse arrives, Ca ion stimulate synaptic vesicle to undergo Exocytosis of ACh
2. Activation of ACh receptors: 2 ACh bind, opens ion channel for Na+ to flow
3. Production of muscle action potential: inflow of Na tigers muscle action potential that goes along sarcolemma and into t tubules, SR release ca ion=contraction
4. Termination of ACh activity: acetylcholinesterase (AChE) is an enzyme breaking down ACh
63
Curare
Posion used by South American Indians
Causes muscle paralysis by burning and blocking ACh receptors
64
Three ways muscle fibers produce ATP
Creatine phosphate
Anaerobic glycolysis
Aerobic respiration
65
Creatine phosphate
Excess ATP synthesizes creatine phosphate is enzyme creatine kinase (CK) to transfer P group from ATP to creatine
CK transfer P group back to ADP=ATP when contraction begins
Very rapid, 15secs of energy
66
Anaerobic glycolysis
Occurs in cytosol
Muscle glycogen->
glucose (from blood)->
Undergoes glycolysis=2ATP->
Pyruvic acid->
2 lactic acid->
Into blood
Faster than aerobic, 2 minutes of energy
67
Aerobic respiration
Pyruvic acid from glycolysis enter mitochondria
Fatty acids from adipose cells, Pyruvic acid from glycolysis, O2 from hemoglobin/myoglobin, amino acids from protein breakdown all enter Krebs cycle and electron transport chain in mitochondrion
Produces heat, Co2, O2, H2O, 30-32ATP
Several minutes to hours of energy
68
Where does muscular tissue get O2 from?
1. Oxygen that diffuses into muscle fibers from blood (hemoglobin)
2. Oxygen release by myoglobin within muscle fibers
69
Muscle fatigue def
Inability of muscle to maintain force of contraction after prolonged activity
70
Central fatigue
Feeling of tiredness/desire to stop
Cause by changes in central nervous system thought to be protective mechanism
71
Oxygen debt
Added oxygen above resting oxygen consumption, taken in after exercise
Recovery period few minutes to several hours
72
How does extra oxygen during oxygen debt restore resting metabolic conditions? (3)
Convert lactic acid back into glycogen stores in liver
Resynthesize creatine phosphate and ATP in muscle fibers
Replace oxygen removed from myoglobin
73
Recovery oxygen uptake
Elevated body temp increase texted it reactions=more ATP needed=more O2 needed
Heart works harder=more ATP
Tissue repair is increased=more ATP
74
Motor unit
Consists of somatic motor neuron plus all skeletal MF it stimulates
Average of 150 MF
75
Twitch contraction
Brief contraction of all MF in a motor unit in response to single action potential in motor neuron
20-200 m sec
76
Myogram
Record of muscle contraction
77
Latent period
Delay of contraction
Muscle action potential sweeps over sarcolemma, ca ion release from SR
2msec
78
Contraction period
Ca ion binds to troponin, tropomysion exposes binding sites, cross bridges form
10-100 msec
79
Relaxation period
Ca ions actively transports back into SR, cross bridges detach
10-100 msec
80
Refractory period
Period of lost excitability
Skeletal: 1msec
Cardiac: 250msec
81
Wave summation
Stimuli arriving at different times cause larger contractions
Infused tetanus
Fused tetanus
82
Infused tetanus
20-30x/sec
Partially relaxes=wavering contraction
83
Fused tetanus
80-100x/sec
Doesn’t relax at all, cant see individual twitches
84
Motor unit recruitment
Process in which number of active motor units increases
Some contract other relaxes=delays muscle fatigue
Weakest recruited first
85
Muscle tone
Small amount of tautness/tension due to weak involuntary contraction of motor units
86
Flaccid
State of limpness in which muscle tone is lost
87
Isotonic contraction
Concentric isotonic contraction: muscle shortens/moves
Eccentric isotonic contraction: muscle lengthens/moves
88
Isometric contraction
Tension generated isn’t large enough to move muscle length doesn’t change
89
Red muscle fibers vs white
High myoglobin, mitochondrion, capillaries
Low myoglobin
90
Slow oxidative fibers
Myoglobin content
Mitochondria
Capillaries
Colour
Large
Many
Many
Red
91
Fast oxidative glycolytic fibers
Myoglobin content
Mitochondria
Capillaries
Colour
Large
Many
Many
Red-pink
92
Fast glycolytic fibers
Myoglobin content
Mitochondria
Capillaries
Colour
Small
Few
Few
White
93
SO Fibers
Capacity ATP generation/method
Rate of ATP hydrolysis
Contraction velocity
Fatigue resistance
Creatine kinase
Glycogen stores
Order of recruitment
Location where abundant
Primary function
High by aerobic respiration
Slow
Slow
High
Lowest
Low
First
Postural muscles
Maintaining posture/endurance
94
Fog Fibers
Capacity ATP generation/method
Rate of ATP hydrolysis
Contraction velocity
Fatigue resistance
Creatine kinase
Glycogen stores
Order of recruitment
Location where abundant
Primary function
Intermediate aerobic and anerobic glycolysis
Fast
Fast
Intermediate
Intermediate
Intermediate
Second
Lower limb
Walking/sprinting
95
FG fibers
Capacity ATP generation/method
Rate of ATP hydrolysis
Contraction velocity
Fatigue resistance
Creatine kinase
Glycogen stores
Order of recruitment
Location where abundant
Primary function
Low anerobic
Fast
Fast
Low
Highest
High
Third
Extraocular muscles
Rapid intense/short duration
96
Microscopic appearance of three muscular tissues
Skeletal: long, peripheral nuclei, unbranched, straited
Cardiac: branch, central nucleus, intercalated discs, striated
Smooth: thick middle tapered ends, central nucleus, not striated
97
Location of three MT
Skeletal: attached to bones by tendons
Cardiac: heart
Smooth: walls of hollow viscera, airways, BV, iris, cilia, arrector pili
98
fiber diameter/length of 3 MT
Skeletal: very large (10-100um)
Very large (100um-30cm)
Cardiac: large (10-20um)
Large(50-100um)
Smooth: small (3-8um)
Intermediate (30-200um)
99
Connective tissue comments of 3 MF
Skeletal: Endomysium Perimysium Epimysium
Cardiac: Endomysium and Perimysium
Smooth: Endomysium
100
Contractile proteins organized in sarcomere of three MT
Skeletal: yes
Cardiac: yes
Smooth: no
101
SR in three MT
Sketela: abundant
Cardiac: some
Smooth: very little
102
T Tubules in three MT
Skeletal: yes A-I band junction
Cardiac: yes with z disc
Smooth: no
103
Junctions between fibers of three MT
Skeletal: none
Cardiac: intercalated discs
Smooth: gap in visceral smooth, none in multi unit smooth
104
Autorhythmicity in three MT
Skeletal: no
Cardiac: yes
Smooth: yes in visceral
105
Source of ca ions for contraction in three Mt
Sketal: SR
Cardiac: SR/ interstitial fluid
Smooth: SE/interstitial fluid
106
Regulatory proteins for contraction I three MT
Skeletal: troponin and tropomyosin
Cardiac: ^
Smooth: calmodulin/myosin light chain kinase
107
Speed of contraction of three MT
Skeletal: Fast
Cardiac:Moderate
Smooth:slow
108
Nervous control of three MT
Skeletal: voluntary (somatic)
Cardiac: involuntary (autonomic)
Smooth: ^
109
Contraction regulation of three MT
Skeletal: ACh released by somatic motor neurons
Cardiac: ACh/norepinephrine released by autonomic motor neurons, hormones
Smooth: ^ as well as local chemical changes, stretching
110
Capacity for regeneration of three MT
Skeletal: limited via satellite cells
Cardiac: limited under certain conditions
Smooth: considerable via pericytes
111
Hypertrophy
Enlargement of existing cells
112
Hyperplasia
Increase in number of fibers
113
Visceral smooth muscle tissue
Skin walls of small arteries/veins/hollow organs
Contract in unison
114
Multi unit smooth muscle tissue
Walls of large arteries/airways/arrector pili/iris/cilia
Only one MF contracts
115
What does smooth have instead of T tubules
Caveolae: small invaginations of plasma membrane
116
Calmodulin
Regularity protein of smooth MT
Binds ca ion, activates myosin light chain kinase=adds P to myosin head
