Lecture 4- Muscular Tissue Flashcards Preview

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Flashcards in Lecture 4- Muscular Tissue Deck (34)
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1
Q
What are the three types of muscle tissue?
A
1. Skeletal- striated, voluntary, attached to skeleton
2. Cardiac- striated, involuntary, heart
3. Smooth- smooth, involuntary, bladder, organs, blood vessels
2
Q
What does the term "muscle" mean?
A
Many muscles fibers (cells) surrounded by connective tissue
3
Q
What is the endomysium?
A
Surrounding of the muscle fiber or cell
4
Q
What is the perimysium?
A
Surrounds the muscle fascicle
5
Q
What is the epimysium?
A
Surrounding of the entire muscle
6
Q
Why is there more than one nucleus per muscle fiber?
A
The nucleus divided and the cell did not divide or myoblasts fused during development to form muscle fibers.
7
Q
What are myofibrils and why is skeletal muscle striated?
A
Myofibrils are composed of Actin (thin) and Myosin (thick) filaments and are striated because of the orientation of these fibers
8
Q
What is the Z-Disc made of?
A
A spider web of thin filaments including:
1. Alpha-Actinin
9
Q
What is the role of titin?
A
Titin connects the thick filaments to the Z disk
10
Q
What are the boundaries of the sarcomere?
A
Z-line to Z-line
11
Q
What are the boundaries of the H Zone?
A
The central region between Z-lines containing the M line in the absolute center.
12
Q
What is the I band (isotropic)?
A
The band containing the Z line, stained light
13
Q
What is the A band (anisotropic)?
A
The band containing the thick filaments housing the H zone and the M line.
14
Q
Do skeletal muscle fibers also have other organelles?
A
Yes, lots of mitochondria.
15
Q
What is the main role of the sarcoplasmic (SR)?
A
Store calcium to release during contractions
16
Q
How does Ca get released from the SR to cause contraction?
A
Excitation-contraction (E-C) coupling
17
Q
What controls contraction of the skeletal muscle?
A
Somatic Nervous System
18
Q
What is the neuropathway of contraction (E-C coupling)?
A
1. Neurotransmitter (ACh) released from the neuron
2. ACh binds to its receptor on the sarcolemma or muscle cell membrane
3. Initiates a muscle or electrical impulse to spread along the sarcolemma
4. Impulse travels down into the muscle cell via t-tubules
5. triggers the release of Ca++ from the SR
19
Q
What does the Ca++ do?
A
1. Calcium binds to troponin C
2. Initiates contraction
20
Q
What happens to the Z line, I band, A band, and sarcomere during contraction?
A
1. Z lines narrow
2. I band narrows
3. Sarcomere shortens
4. A band stays the same
21
Q
What are the different types of muscle fibers?
A
1. Slow twitch
2. Intermediate twitch
3. Fast twitch
22
Q
What is the difference between cardiac muscle and skeletal muscle?
A
1. Cardiac muscle contain nuclei in the center
2. The cells are branched
3. Cells have intercalated disks
23
Q
What is the advantage of cell branching?
A
Branching helps organize the muscle in the heart chamber so it ejects more blood with each contraction.
24
Q
What are the advantages of intercalated disks?
A
Intercalated disks bind cells firmly together. It helps with intercellular communication so the ventricles and atria can contract as one unit.
25
Q
What structures in the intercalated disk helps bind cells firmly together?
A
1. Desmosomes
2. Fascia adherens (resembles zonula adherens)
26
Q
What structure helps the intercalated disk with intercellular communication?
A
Gap Junctions
27
Q
What is the advantage of having the gap junctions?
A
Communication
28
Q
What are the components of thin filaments?
A
1. Actin
2. Tropomyosin
3. Troponin C, I, T
29
Q
What type of organelles are found in cardiac cells?
A
Mitochondria
30
Q
What is the terminal cisternae?
A
The endpoint of the sarcoplasmic reticulum. There is only one so it is a dyad.
31
Q
How can you describe smooth muscle?
A
- few mitochondria
-no T tubules
- Actin & Myosin not organized in sarcomeres
- no striations
- cells are small and squished together
32
Q
What is the function of dense bodies in smooth muscles?
A
They function as Z-discs as the attachment for:
-alpha actinin
- intermediate filaments
- thin filaments
33
Q
What causes the corkscrew configuration in smooth muscle?
A
The configuration of smooth muscle during contraction.
34
Q
Does smooth muscle contain desmosomes or gap junctions?
A
No, they don't contain desmosomes, but they do contain gap junctions.