Lecture 13: Muscle Tissues Structure Flashcards
How to distinguish skeletal muscle histologically?
- Striated
- Wide muscle fibers
- Nuclei immediately below sarcolemma
- Multinucleated
- Elongated nucleus
- No branching
How to distinguish cardiac muscle histologically?
- Striated
- Not as wide as skeletal muscle
- Centrally positioned cigar-shaped nuclei
- One or two nuclei
- Fibres branch together
- Intercalated discs
How to distinguish smooth muscle histologically?
- Not striated
- Elongated nucleus
What is the ultra structural appearance of striated muscle?
- Cross-striated myofibrils made of myofilaments
- 2 types of myofilaments: thick and thin
Which band contains actin?
Thin myofilaments in I band
Which bands contain both actin and myosin?
Thick myofilaments (myosin) and thin myofilaments (actin) in A band
What are the components of a typical skeletal muscle?
- Muscle fibers are surrounded by endometrium
- Fibers are arranged in fascicles which are surrounded by perimysium
- Bundles of fascicles are surrounded by epimysium
What are the differences between fast and slow striated muscle fibers?
Capillary supply: rich (slow) and poor (fast)
Used in condition: Aerobic (slow) and anaerobic (fast)
Myoglobin levels: high (slow) and low (fast)
Mitochondria: many (slow) and few (fast)
Cytochromes: many (slow) and few (fast)
Color: red (slow) and white (fast)
Fatigue resistance: fatigue resistant (slow) and rapidly fatigued (fast)
Is mature muscle repair possible for skeletal muscles?
- Can’t divide
- Can regenerate by mitotic activity of satellite cells
- Can fuse with existing muscle cells to increase mass
Is mature muscle repair possible for cardiac muscle?
Incapable of regeneration, fibroblasts will invade and lay down scar tissue
Is mature muscle repair possible for smooth muscle cells?
Retain mitotic activity and can form new smooth muscle cells
Where is skeletal muscle located?
Tongue
What are some examples of smooth muscle?
Uterus
