Muscle Tissue Flashcards
1
Q
How many nuclei do Skeletal, Cardiac, and Smooth muscle have?
A
- Skeletal - multi
- Cardiac - 1-2
- Smooth - 1
2
Q
What type of muscle exhibits structural branching?
A
Cardiac
3
Q
What is a syncytium? How do skeletal muscle cells exhibit this characteristic?
A
- Many muscle cells acting as 1 unit
- All the muscle fibers contract at once…causes the whole muscles to contract.
4
Q
T/F
Cardiac muscle is regenerative
A
FALSE
Cardiac muscle is not regenerative…skeletal muscle is regenerative.
5
Q
What are the 3 layers of CT surrounding muscle?
A
Epimysium
Perimysium
Endomysium
6
Q
[] is the outer most layer of CT around the entire muscle.
What type of CT is this?
A
- Epimysium
- Densre Irregular CT
7
Q
What type of CT fibers would you find in the epimysium?
A
Collage, elastic, Reticular
8
Q
[] divides the muscle into smaller functional units called fascicles
A
Perimysium
9
Q
What layer of CT surrounds each individual muscle fiber?
What type of CT fibers would you find in this layer?
A
- Endomysium
- Collagen & Reticular Fibers
10
Q
What are the 3 types of muscle fibers?
A
Type I - Slow Oxidative Fibers
Type IIa - Fast Oxidative, Glycolytic Fibers
Type IIb - Fast, Glycolytic Fibers
11
Q
Type I - [] Oxidative Fibers
- [] twitch muscles
- [] myoglobin
- [] mitochondira
- Speed of Myosin ATPase = []
- Found in muscles for running, or []
A
Type I - Slow Oxidative Fiber
- Slow twitch
- Large amounts of myoglobin
- Many mitochondria
- Slowest ATPase
- Posture
12
Q
Type IIa - [] [], Glycolytic Fibers
- [] twitch muscles
- In vivo color - []
- [] amounts of myoglobin
- [] mitochondira
- [] Glycogen
- Speed of Myosin ATPase = []
- [] resistance due to the the ability to use [] respiration and []
A
Type IIa - Fast Oxidative, Glycolytic Fibers
- Fast twitch muscles
- In vivo color - pink
- Large amounts of myoglobin
- Many mitochondira
- Alot of Glycogen
- Speed of Myosin ATPase = moderately fast I guess
- Fatigue resistance due to the the ability to use Cellular Respiration and Glycolysis
13
Q
Type IIb - [] Fibers
- [] twitch muscles
- Size of Fiber -
- In vivo color - []
- [] myoglobin and mitochondria
- [] Glycogen content and [] activity
- Speed of Myosin ATPase = []
- [] prone
- Adapted for [] contractions and precise movements
A
Type IIb - Glycolytic Fibers
- Fast twitch muscles
- Size of Fiber - Large
- In vivo color - white, light pink
- Less myoglobin and mitochondria
- High Glycogen content and anaerobic activity
- Speed of Myosin ATPase = Fastest!
- fatigue prone
- Adapted for rapid contractions and precise movements
14
Q
- The functional/contractile apparti of skeletal muscle and cardiac muscle is the []…
- The structural and functional subunit of the myofiber is the…[]
A
- Sarcomere
- Myofibril
15
Q
Which specific myosin is the “thin filament” in a sarcomere?
A
Psyche!
Myosin is not the thin filament…you should know that.
Myosin II is the thick filament.
16
Q
What 4 things can you find on the head of a Myosin II?
A
2 Light chains (regulatory and ATPase regulating)
1 ATPase
1 actin binding site
17
Q
Where is titin found in the sarcomere? What does it do?
A
- It is found in the Z-line
- It anchors myosin to the Z-lines.
18
Q
What protein anchors actin to the Z-line?
A
Alpha-actinin
19
Q
- What type of protein is Nebulin?
- Where does it lie in the sarcomere?
A
- inelastic protein
- lies parallel to actin and assist in stabilizing alpha-actinin/actin interaction at the Z-line
20
Q
[] is associated with the free end of actin, and “caps” actin to regulate its length
A
Tropomodulin
21
Q
What 2 proteins are myosin binding proteins and hold myosing filaments “in register” at the M line?
A
Myomesin
C-protein
22
Q
What are the 3 Extra Sarcomeric Accessory Proteins and what do they do?
A
- Costamere - sub-membrane Z-line associated protein structure that connects the sarcomere of the muscle to the cell membrane
- Dystrophin - links actin to laminin in the basal lamina
- Desmin - surrounds sarcomere at the Z-line attaching them to the sarcolemm
23
Q
T-tubules align at the [] - [] junction perpendicular to fibrils
A
A-I Junction
So it helps to place the Ca2+ right at the myosin/actin junction for contraction.
24
Q
T/F
Each muscle fiber has only one motor end-plate?
A
True!
25
Muscle Spindle
1. Basically sense []
2. Contains both [] and [] nerves
3. Stretch Reflex - what is it?
4. Loacated within the []
1. basically it senses **stretching**
2. Contains both **afferent** and **efferent** fibers
3. Stretch Reflex - **Stretch on the muscl ecauses a reflex contraction**
4. Located within the **muscle**
26
Golgi Tendon Organ (GTO)
1. Monitors [] developed in muscle
2. Consists of [] fibers only
3. Prevents damage during [] for generation
1. How?
1. Tension
2. Afferent
3. Excessive
1. Stimulation of the GTO results in reflex **relaxation** of muscle via interneuronal inhibition of alpha-motoneurons
27
Regular muscle cells outside of a muscle spindle are called what?
Extrafusal muscle fibers
(INtrafusal muscle fibers are within the spindle
28
What are the 2 types of intrafusal fibers?
1. Nuclear chain fiber
1. connect to efferent nerves
2. Nuclear bag fiber - found within the center of a muscle spindle
1. Connect to afferent nerves
29
What are the 2 types of nerve endings found on a muscle spindle?
1. **Annulospiral endings** - respond to the rate of stretching)
2. **Flower Spray Endings** - respond to the duration of stretching
30
What type of cell does skeletal muscle originate from?
What regulatory protein negatively controls muscle growth and differentiation?
Myoblast
Myostatin
31
Inhibition of [] causes excess muscle growth
myostatin
32
How do myoblasts differentiate from the embryo and end up as muscle cells? (Step-by-Step)
1. Mesodermal progenitor Cells --\>
2. Myoblasts --\>
3. Multinucleate Myotube --\>
4. Muscle Fiber --\>
33
What are the 2 mechanisms for cell repair? What are the cell types used for repair in each?
1. Injury but External Lamina is Intact
1. **satellite cells** become activated after injury and divide and differentiate into **myoblasts.** Then, myoblasts fuse within external lamina and become **myotubes**
2. Injury by External Lamina is not intact
1. **Fibroblast** repairs injury and it becomes scar tissue
34
T/F
Nebulin causes satellite cells to activate and repair skeletal muscle?
FALSE
* Yes, satellite cells repair, only, skeletal muscle....but **cytokins** cause the satellite cells to activate.
35
The sarcoplasm of cardiac muscles contain more [], [], and [] than skeletal muscle becuase its always contraction.
Glycogen, lipid, mitochondria
36
[] [] joins cardiac muscles and provides mechanical and electrical coupling...
intercalated discs
37
What is the sarcoplasmic cone in cardio myocytes?
* area around the nucleus in cardiac cells that is especially enriched with mitochondria and glycogen granules.
* It shows up as a "white cone" around the nucleus in staining.
38
What are the 2 _transverse_ portions of the intercalated discs?
1. Fasciae Adherentes
1. analogous to *zonulae adherens* of epithelia to which actin filaments attach
2. anchors thin filaments in sarcomeres
2. Maculae Adherentes
1. **Desmosomes**
2. Bind cells to prevent separation during contraction
39
What are the 2 portions of an intercalated disc?
1. Transverse Portion
1. Fasciae Adherentes
2. Maculae Adherentes
2. Lateral Portion = **gap junction**
40
Which is stronger in the intercalated disc...
Transverse Portion
Lateral Portion (Gap Junction)
**Transverse** portion cuz it has desmosomes.
41
T/F
Cardiac muscle has SMALLER T-tubules than those in skeletal muscle and are lined with an internal lamina?
FALSE
* Cardiac muscles t-tubules are **LARGER**
* They are lined with an **external lamina**
42
T/F
In cardiac muscle, the T-tubes and SR form a dyad that lines up at the A-I junction, like in skeletal muscle
FALSE
* Cardiacs muscles do form a dyad, instead of a triad.
* However, these are located at the **Z-lines**, not AI-junction.
43
Atrial Granules:
1. Found in muscle cells of the []
2. What 2 polypeptide hormones are found in these granules?
1. What doe these hormones function as? and what is their purpose?
1. Atrium
2. **Atrial Natriuretic Factor (ANF) and Brain Natriuretic Factor (BNF)**
1. These detect too much blood volume and signal the kidney to urinate more to reduce our blood volume!
44
Purkinje Fibers:
1. modified [] muscle cells located in the [] [] of []
2. [] than ordinary cardiac muscle cells
3. lower content of [] & higher content of []
1. modified **cardiac** muscle cells located in the **atrioventricular bundle** of **His**
2. **Larger** than ordinary cardiac muscle cells
3. lower content of **myofibrils** & higher content of **glycogen**
45
How do smooth muscles connect to each other electrically?
Gap Junctions
46
T/F
Smooth muscle secrete a ground substance matrix?
False
Smooth muscle can secrete a CT matrix of collagen.
47
What anchors thin filaments in smooth muscle?
Dense Bodies or Dense Plaques
48
T/F
In smooth muscles, most of the cytoplasmic organelles are mainly confined to conical regions a the ends of the centrally locted nucleus?
True!
49
Thin filament in Smooth Muscle:
1. contains [] - the primary substance
2. Also contains troponin just like skeletal muscle...
3. Contains [] and [] that bind to actin and block the [] binding site on actin
1. Actin
2. FALSE! - smooth muscle does not contain troponin. It has **tropomyosin though.**
3. **Caldesmon** and **Calponin;** block **myosin** binding site on actin
50
Dense bodies in smooth muscle are functionally comparable to skeletal muscle [] - []
Z-Discs
51
What filaments attaches to the dense plaques in smooth muscle?
* Thin filament - actin
* Intermediate Filaments
* **Vimentin**
* **Desmin**
52
53
What are the 2 contractile non-muscle cells?
Myoepithelial Cells
Myofibroblasts
54
Myoepithelial Cells
1. [] to assist in the expression of glandular material
2. Located between the epithelium and [] lamina of certain types of glands
3. In mammary glands - contraction is initiated by []
4. In lacrimal glands - contraction is initiated by []
1. Contract
2. basal lamina
3. oxytocin
4. acetylcholine
55
T/F
Myoepithelium cells may contribute to wound healing contracting to decrease size of defect....
False
Myofibroblasts may do this.
