Muscular Tissue Flashcards
(85 cards)
1
Q
What are the 3 types of muscle tissue?
A
Skeletal
Cardiac
Smooth
2
Q
what is the location of skeletal muscle?
A
On the bones
3
Q
What is the function of skeletal tissue?
A
Move Bones
4
Q
what is the appearance of muscular tissue?
A
Multi-nucleated and striated
5
Q
what is the control of skeletal muscle?
A
voluntary
6
Q
what is the location of cardiac muscle?
A
Heart
7
Q
what is the function of cardiac tissue?
A
pump blood
8
Q
What is the appearance of cardiac tissue
A
one nucleus striated and intercalated discs
9
Q
what is the control of cardiac tissue
A
involuntary
10
Q
what is the location of (visceral) Smooth muscle tissue?
A
various organs, GI tract
11
Q
what is the function of smooth tissue?
A
various, peristalsis
12
Q
what is the appearance of smooth tissue?
A
one nucleus and no striations
13
Q
what is the control of smooth tissue?
A
involuntary
14
Q
what is the overall function of muscular tissue?
A
producing body movements
stabilizing body positions
storing and mobilizing substance within the body
generating heat
15
Q
what are the properties of muscular tissue?
A
Electrical excitability
contractility
extensibility
elasticity
16
Q
how are muscles formed?
A
the fusion of myoblasts into skeletal muscle fibre
17
Q
what are the components of a Sarcomere?
A
Z discs
A band
I band
H zone
M line
18
Q
describe the Z discs
A
Narrow plate-shaped regions of dense material that separate one sarcomere from the next
19
Q
describe A band
A
dark middle part of sarcomere that extends entire length of thick filaments and includes those parts of thin filaments that overlap thick filaments
20
Q
describe I band
A
Lighter less dense area of sarcomere that contains remainder of thin filament but no thick filaments , A Z disc passes through centre of each I band
21
Q
describe H zone
A
narrow region in centre of each A band that contains thick filaments but not thin filaments
22
Q
describe M line
A
region in centre if H zone that contains proteins that hold thick filaments together at centre of sacromere
23
Q
what are the contractile muscle proteins?
A
Myosin
Actin
24
Q
what are the regulatory muscle proteins?
A
Troponin
Tropomyosin
25
what are the structural muscle proteins?
Titin
Nebulin
Alpha-Actin
Myomesin
Dystrophin
26
what do the contractile proteins do?
Generate force during muscle contractions
27
describe Myosin
Contractile protein that makes up thick filament, consist of a tail and 2 myosin heads
28
describe Actin
Contractile protein that is the main component of thin filament, each actin molecule has a myosin binding site where myosin head of thick filament binds during muscle contraction
29
what do Regulatory Proteins do?
Proteins that help switch muscle contraction on and off
30
describe Tropomyosin
reg protein that is a component of thin filament, when skeletal muscle fibre is relaxed, tropomyosin covers myosin binding sites on actin molecules, thereby preventing myosin from binding to actin
31
describe Troponin
Reg protein that is a component of thin filament, when calcium ions bind to troponin, it changes shape, this moves tropomyosin away from myosin binding sites on actin molecules, and muscle contraction subsequently begins as myosin binds to actin
32
What do Structural Proteins do?
Proteins that keep thick and thin filaments of myofibrils in proper alignment, give myofibrils elasticity and extensibility and link myofibrils to sarcolemma and extracellular matrix
33
describe Titin
Structural protein that connects Z disc to M line of sarcomere, thereby helping to stabilize thick filament positions, can stretch and then spring back unharmed, and thus accounts for much of the elasticity and extensibility of myofibrils.
34
Describe Alpha-Actinin
Structural Protein of Z discs that attaches to actin molecules of thin filaments and to titan molecules
35
Describe Myomesin
Structural Protein that forms M line of sarcomere, binds to titan molecules and connects adjacent thick filaments to one another
36
Describe Dystrophin
Structural protein that links thin filament of sarcomere to integral membrane proteins in sarcolemma, which are attached in turn to proteins in connective tissue matrix that surrounds muscle fibers, thought to help reinforce sarcolemma and help transit tension generated by sarcomeres to tendons
37
what are thin filaments?
Actin
38
What are thick filaments?
Myosin
39
what are the levels of organization of skeletal muscle? (Outside-Inside)
Skeletal Muscle
Fascicle
Muscle Fiber
Myofibril
Filament
40
Describe Skeletal Muscle
organ made up of fascicles that contain muscle fibres, blood vessels and nerves, wrapped in epimysium
41
Describe Fascicle
Bundle of muscle fibres wrapped in perimysium
42
Describe Muscle Fiber
Long cylindrical cell covered by endomysium and scarolemma, contains sarcoplasm myofibrils, many peripherally located nuclei, mitochondria, transverse tubules, SR and terminal cisterns, the fibre has a striated appearance
43
describe Myofibril
Threadlike contractile elements within Sarcoplasm of muscle fiber that extends entire length of fibre, composed of filaments
44
Describe Filaments
contractile proteins within myofibrils that are of 2 types, thick filaments composed of myosin and thin filaments composed of actin, tropomyosin and troponin, sliding of thin filaments past thick filaments produces muscle shortening
45
what produces muscle shortening?
Sliding of thin filaments past thick filaments
46
what is the length tension relationship?
The force of a muscle contraction depends on the length of the sarcomeres in a muscle prior to contraction
47
How do muscles derive the ATP necessary to power the contraction cycle?
Creatine phospate
Anaerobic glycolysis
Cellular Respiration
48
describe Creatine Phosphate
creatine kinase catalyzes the transfer of a phosphate group from CP to ADP to rapidly yield ATP
49
describe Anaerobic Glycolysis`
When CP stores are depleted, glucose is converted into pyretic acid to generate ATP
50
describe cellular respiration
under aerobic conditions, pyretic acid can enter the mitochondria and undergo a series of O2 requiring reactions to generate large amounts of ATP
51
how long does the energy from CP last?
15 seconds
52
how long does energy last from Anaerobic Glycolysis
2 minutes
53
how long does energy last from cellular respiration?
several minutes to hours
54
what is muscle fatigue?
is the inability to maintain force of contraction after prolonged activity
55
what causes the onset of muscle fatigue?
Inadequate release of Ca2+ from SR
Depletion of CP, O2 and nutrients
Build up of lactic acid and ADP
Insufficiant release of ACh at NMJ
56
what is central fatigue?
occurs due to changes in the central nervous system and generally results in cessation of exercise
57
what does extra O2 go to after exercise?
Replenishing CP stores
Converting lactic acid to pyruvate
Reloading O2 onto myoglobin
58
what does the strength of a muscle contraction depend on?
how many motor units are activated
59
what does a motor unit consist of?
a somatic motor neuron and the muscle fibres it innervates
60
what is motor unit recruitment?
is the process in which the number of active motor units increases
61
what is a twitch contraction
The brief contraction of all muscle fibres in a motor unit response to a single action potential.
62
what are the steps of the twitch contraction?
latent period
contraction period
relaxation period
refractory period
63
what is isotonic contractions?
tension is constant while muscle length changes (moves)
concentric
eccentric
64
what is isometric contractions?
muscle contracts but does not change length (Doesn't Move)
65
what are intercalated discs?
part of cardiac muscle, the contain desmosomes and gap junctions that allow muscle action potentials to spread from one muscle fibre to another
66
what does cardiac muscle have more of than skeletal muscle?
Mitochondria, their contractions last up to 10-15 times longer than skeletal.
67
68
Describe Electrical Exciteablility
The ability to respond to certain stimuli by producing electrical signals called action potentials
69
Describe Contractility
Ability of muscular tissue to contract forcefully which stimulated by nerve impulses
70
Describe extensibility
Ability of muscular tissue to stretch within limits without being damaged
71
What limits the muscles range of stretch?
Connective tissue
72
Describe elasticity
Ability of muscular tissue to return to its original length and shape after contraction
73
What is the hypodermic composed of?
Areolar connective tissue and adipose tissue
74
What does the hypodermis provide?
Pathway for nerves blood vessels and lymph vessels to enter and exit muscles
75
What does the adipose tissue store
Tryglycerides
76
What does the adipose tissue serve as?
Insulating layer, reduces heat loss and protects muscles from physical trauma
77
What is fascia
Dense sheet of connective tissue that lines the body wall and limbs and supposed and surrounds muscles and other organs
78
What is the epimysium
Outer layer encircling the entire muscle, consists of dense irregular connective tissue
79
What is the perimysium
Layer of dense irregular connective tissue, surrounds groups of 10-100 muscle fibers, making bundles called muscle fascicles
80
What is the endomysium
Penetrates the interior of each muscle fascicle and separates individual muscle fibers from one another
81
What neurons stimulate skeletal muscle to contract
Somatic motor neurons
82
Which proteins connect into Z disc?
Titian and nebulin
83
Which proteins are present in the A band?
Myosin
84
What protein is present in I Band
Actin
85
What happens to the I band and the H zone as muscles contract
They get shorter
