Muscle Tissue
Introduction
Properties
Types
Unique Term of component of muscle cells
- Consist of : Elongated cells call muscle fibers that can use ATP to generate force
- Arrangement: Parallel array - work together effectively
- Function: Body movements, posture maintenance, generates heat & for changes in size and shape of its internal organs
- Characterized by aggregates of specialized cells whose primary role is contraction
Extensibility
- Ability of muscle to stretch w/o being damaged
Elasticity
- Ability of muscle to return to its original length and shape after contraction and extension
Contractibility
- Ability of muscle to contract forcefully when stimulated
Electrical excitability
- Ability to respond to certain stimuli (action potential)
Striated Muscles
Non-striated Muscle/Smooth Muscle
Muscle cells aka muscle fibers
Sarcoplasm= cytoplasm
Sarcoplasmic reticulum = SER
Sarcolemma = Cell membrane
Sarcosomes = Mitochondria
Alternative of light and dark cross-bands
Skeletal Muscle
Cardiac Muscle
Intercalated discs
Histology
- Present only in the heart
- Involuntary & striated
- Shape: branched cylinders with one central nuclei
- Attached to and communicate with each other by intercalated discs and desmosomes
Transverse portion
- Bind cardiac cell together
Lateral portion
- Ionic continuity between cells
- Highly specialized end-to-end junctions
- Junctional complexes at the interface between adjacent cardiac muscle cells
Myogenesis of skeletal muscle
Connective tissue surrounding skeletal muscle
Organization of muscle fibers
Functions
Histology
- Voluntary/ conscious control and striated (visible light and dark banding)
- Shape: Long cylinders with multinucleated peripheral nuclei
- Skeletal movement
- Posture and body position
- Support of soft tissue
- Guarding of entrances and exits
- Maintenance of body temperature
Myoblast
(precursor/pendahulu)
Myotubes
(long multinucleated cells)
Myofibrils
(cytoplasmic & contractile elements)
Myofilaments
(protein responsible for contraction)
Histology
- Location: Walls of hollow organs(blood vessels, GI tract, bladder)
- Lack striations and involuntary (regulated by hormones, ANS &local)
- Shape: Spindle with a single central nuclei, fusiform features
- T tubules-absent
- Bundles of myofilaments crisscross obliquely through the cell
Regeneration of muscle tissue