7.Muscle Tissue Flashcards
(75 cards)
1
Q
What do the prefix my or myo denote to?
A
Muscle
2
Q
Define myalgia
A
Muscle pain
3
Q
Define myasthenia
A
Weakness of the muscles
4
Q
Define myocardium
A
Muscular component of the heart
5
Q
Define myopathy
A
Any disease of he muscles
6
Q
Define myoclonus
A
A sudden spasm of the muscles
7
Q
In the muscle hierarchy what can muscle cell types be split into?
A
- Striated muscle
2. Non striated muscle
8
Q
What can striated muscle be divided into?
A
Skeletal muscle and cardiac muscle
9
Q
What can non striated muscle be divided into?
A
Smooth muscle
10
Q
Give three features of skeletal muscle
A
- Myoglobin present
- voluntary control
- Direct nerve- muscle communication
11
Q
Give three features of cardiac muscle
A
- Myoglobin present
- Involuntary control
- Indirect nerve- muscle communication
12
Q
Give 3 features of smooth muscle
A
- Myoglobin absent
- Involuntary control
- No direct nerve muscle communication
13
Q
What is myoglobin?
A
A red protein that is structurally similar to a single sub unit of haemoglobin. It is an oxygen storing molecule which provides oxygen to working striated muscles.
14
Q
What is the difference between haemoglobin and myoglobin?
A
Haemoglobin has the capacity to carry CO2 whereas myoglobin doesn’t
15
Q
What happens to myoglobin when striated muscle dies(muscle necrosis)
A
Myoglobin is releases into the bloodstream (myoglobinuria)
16
Q
How is myoglobin removed from the blood?
A
By the kidney through the urine - tea coloured urine
17
Q
Define sarcolemma
A
The outer membrane of a muscle cell
18
Q
Define saroplasma
A
The cytoplasm of a muscle cell
19
Q
Define sarcosome
A
The mitochondrion
20
Q
Define sarcomere
A
The contraction unit in striated muscle
21
Q
Define sarcoplasmic reticulum
A
The smooth endoplasmic reticulum of a muscle cell - contains calcium ions needed for contraction
22
Q
What is the function of skeletal muscle?
A
To contract
23
Q
What is movement dependent on?
A
Direction of muscle fibre contraction
24
Q
Regarding direction of movement, where is tension created at?
A
Origin tendon point
25
Regarding direction of movement, where is movement created at?
Insertion tendon point
26
Do thin skeletal muscle fibres needs less or more blood?
Less
27
Do thick skeletal muscle fibres need less or more blood?
More
28
What is a striated muscle called?
Muscle fibre
29
How many myofibrils do each striated muscle cell(fibre) contain?
Numerous
30
Which is the thin filament in the sarcomere?
Actin
31
What is the thick filament in a sarcomere?
Myosin
32
Which band in the sarcomere is the dark band?
A band
33
Which band in the sarcomere is the light band?
I band
34
What type of activities are slow twitch muscle fibres used for?
Endurance type activities
35
What kind of activities are type 2b fast twist fibres used for?
Strength/anaerobic type activities
36
Why are slow twitch muscle fibres red?
Have many mitochondria
37
Why are type 2A fast twitch muscle fibres(intermediate)red to pink?
Have many to intermediate mitochondrial numbers
38
Why are type 2B fast twitch muscle fibres white?
Have few mitochondria
39
Which twitch fibres are aerobic?
Slow twitch and intermediate fast twitch
40
Which twitch fibres are anaerobic/
Type 2B fast twitch fibres
41
Which twitch fibres have a rich capillary supply and which don’t?
Slow twitch fibres and type 2A fast twitch fibres have rich capillary supply.
Yep 2B fast twitch fibres have poor capillary supply
42
Which twitch fibres have high myoglobin levels?
Slow twitch fibres and type 2A
43
Which twitch fibres have low myoglobin levels?
Type 2B fast twitch fibres
44
Which twitch fibres have many cytochromes?
Slow twitch and type 2A
45
What two things do continued muscle contraction depend upon?
1. Calcium ions
| 2. Amount of ATP
46
What is the main storage molecule for type 2B fast twitch fibres?
Glycogen
47
What is the main storage molecule for type 2A fast twitch fibres?
Fatty acids and glycerol
48
What is the main storage molecule for slow twitch fibres?
Fatty acids
49
Give 4 features of cardiac muscle
1. striations
2. centrally positioned nuclei (1 or 2 per cell) 3.intercalated discs
4. branching (arrows)
50
What are 2 similarities between cardiac and skeletal muscle?
1. Both striated muscles
| 2. Contraction mechanisms are similar
51
Give 8 differences between cardiac and skeletal muscle
In cardiac muscle:
1. the muscle fibres are not as wide as those of skeletal muscle.
2. the nuclei are positioned centrally and are cigar-shaped.
3. there are usually only one or two nuclei per cell.
4. the muscle fibres branch and join together (anastomose).
5. Sarcomere not so developed
6. No T-tubules in sarcoplasmic reticulum
7. Only one contractile cell type - cardiomyocyte
8. Cardiomyocytes communicate through gap junctions
- (in intercalated disk)
52
Which naturietic peptide is released by the heart during heart failure which affect the ventricle?
Brain-type naturietic peptide
53
Which naturietic peptide is released by the heart during heart failure which affects the atria?
Atrial natriuretic peptide(ANP)
54
What is hypertrophy?
Enlargement of individual cells
55
What is hyperplasia?
Multiplication of cells
56
Purkinje fibres are large cells with?give 3
1. Abundant glycogen
2. Sparse myofibrils
3. Extensive gap junction sites
57
What is the name when heat is smaller than normal?
Atrophy
58
Why do purkinje fibres have lots of glycogen?
Glycogen is a very good conductor of electricity for electrical transmission
59
Give 6 features of smooth muscle cells
1. Spindle-shaped (fusiform)
2. single central large nucleus
3. Not striated
4. no sarcomeres
5. no T tubules
6. Capable of being stretched substantially
60
How is contraction in smooth muscle different to contraction in skeletal or cardiac muscle?
Contraction in smooth muscle is slower, more sustained and requires less ATP
61
What shape are smooth muscle cells?
Spinel shaped(fusiform)
62
How long can smooth muscle stay contracted for?
Hours or days
63
Describe skeletal muscle including where it is found
Voluntary muscle responsible for the movement of the skeleton and structures such as the eye and tongue
64
Describe cardiac muscle including where it is found
Involuntary muscle found only in the heart
65
Describe smooth muscle including where it is found
Involuntary visceral muscle, found in the uterus/bladder and associated with tube-like structure, e.g.
the gastrointestinal tract, blood vessels, lymphatics and conducting airways of the respiratory tract
66
Muscle fibres (cells) are each surrounded by a loose connective tissue called the ——1——. The cells (fibres) are arranged in bundles called fascicles that are enclosed in a slightly thicker loose connective tissue called the ——2——. Bundles of fascicles constituting the muscle belly are enclosed by an even thicker, denser connective tissue called ——-3——. Collectively, this becomes a muscle.
Fill in the gaps
1. Endomysium
2. Perimysium
3. epimysium
67
Muscle striations are only visible in which kind of section? Longitudinal or transverse?
Longitudinal
68
Describe the structure of skeletal muscle
1. Many myofibrils (that are made from myofilaments that create the striated patterns) make up a muscle cell()fibre.
2. The Multiple muscle fibres come together in a tight arrangement that uses a loose connective tissue arrangement of collagen and reticular fibres which bind the muscle cells (fibres) together to create an even stronger muscle structure (the fascicle)
3. Which in turn joins with a series of other fascicles to generate a complete muscle.
69
Is it possible to repair skeletal muscle?
Skeletal muscle cells cannot divide but can regenerate by mitotic activity of satellite cells, so that hyperplasia follows muscle injury. Satellite cells can also fuse with existing muscle cells to increase mass (skeletal muscle hypertrophy)
70
Is it possible to repair cardia muscle?
Adult cardiac muscle is incapable of regeneration Following damage, fibroblasts invade, divide, and lay down scar tissue
71
Is it possible to repair smooth muscle?
Smooth muscle cells retain their mitotic activity and can form new smooth muscle cells.
72
List 3 differences between cardiac and smooth muscle?
1. Smooth muscles do not contain sarcomeres
2. Electrical conduction- specialised cells/routes in cardiac muscle
3. No troponins in smooth muscle
73
List 4 similarities between cardiac and smooth muscle
1. Nuclei are central not peripheral
2. Only one contractile cell type
3. Acts as a syncytium(wave like function)
4. Myocytes communicate through gap junctions- cardiomyocytes - intercalated disk
74
Which factor of cardiac muscle helps identify the type of muscle in histology pictures?
Intercalated disk
75
Describe cardiac innervation and contraction
* A neurotransmitter is released which acts on the sarcolemma of the myocyte.
* This induces an electrical signal within the cell which acts in the T tubule within the sarcomere which then interacts with a voltage gated calcium channel called the dihydropyridine receptor.
* A conformational change in the protein occurs which results in a conformational change in the adjacent protein in the sarcoplasmic reticulum called the ryanodine receptor
* the conformational change in the ryanodine receptor causes the release of calcium into the sarcoplasm
* the calcium bind to troponin c on actin causing tropomyosin to change shape and expose myosin binding sites.
* Myosin binds to actin and a cross bridge is formed
