Anatomy and Physiology: Chapter 5-The Muscular System, Lesson 1-Muscle Tissue Categories and Functions (5.1)
Muscle Tissue 🏋♀️
Muscle tissue is one of the four types of tissue in the body, and it is unique in its ability to cause movement through contraction.
Characteristics of Muscle Tissue
Allows for movement through contraction
Enables the body to move and function
Found in various parts of the body, including the esophagus, stomach, intestines, heart, and bones
Types of Muscle Fibers 🧬
There are three major categories of muscle fibers:
Type Description | |
Skeletal | Attached to bones, voluntary, and striated |
Smooth | Found in the walls of hollow organs, involuntary, and non-striated |
Cardiac | Found in the heart, involuntary, and striated |
Skeletal Muscle Fibers 💪
Also known as striated muscle fibers
Have multiple nuclei
Voluntary, meaning they can be controlled consciously
Attached to bones and cause movement when contracted
"Voluntary" means that the muscle can be controlled consciously, allowing for intentional movement.
Characteristics of Skeletal Muscle Fibers
CharacteristicDescription | |
Striated | Has visible stripes or striations under a microscope |
Voluntary | Can be controlled consciously |
Multiple Nuclei | Each muscle fiber has more than one nucleus |
Structure of Skeletal Muscle Fibers 📦
A skeletal muscle fiber is composed of:
Sarcolemma: The cell membrane that surrounds the muscle fiber
Cytoplasm: The jelly-like substance inside the cell membrane
Organelles: Small structures within the cell that perform specific functions
Endomysium: A fine, protective sheath of connective tissue that surrounds each muscle fiber
Bundles of Muscle Fibers 📈
A group of muscle fibers is called a fascicle
Fascicles are organized into bundles, which make up the skeletal muscle tissue
Analogy: Skeletal Muscle Fiber Structure 🥤
A skeletal muscle fiber can be compared to a straw:
The straw represents the muscle fiber
The plastic wrapping around the straw represents the sarcolemma
The paper wrapping around the straw represents the endomysium
The bundles of straws represent the fascicles## 🏋♀️ Skeletal Muscle Structure
Muscle Bundles and Connective Tissue
A muscle is composed of multiple bundles of muscle fibers, each wrapped in a layer of connective tissue.
Fascicle: a bundle of muscle fibers wrapped in a layer of connective tissue called paramycin.
Paramycin: a strong, fibrous membrane that wraps around each fascicle.
Epomycin: a thick, tough connective tissue that encloses all the fascicles in a muscle.
Muscle Fibers and Cell Membrane
Muscle Fiber: a single muscle cell.
Sarcolemma: the cell membrane of a muscle fiber.
Connective Tissue Layers
LayerDescription | |
Endomysium | a thin layer of connective tissue that wraps around each individual muscle fiber |
Paramycin | a layer of connective tissue that wraps around each fascicle |
Epomycin | a thick, tough layer of connective tissue that encloses all the fascicles in a muscle |
Tendons and Aponeurosis
Tendon: a cord-like structure that connects muscle to bone.
Aponeurosis: a flat, sheet-like structure that serves the same function as a tendon, but is flat rather than cord-like.
"Tendons connect muscle to bone, whereas ligaments connect bone to bone."
Key Terms
Fascicle: a bundle of muscle fibers wrapped in a layer of connective tissue called paramycin.
Paramycin: a strong, fibrous membrane that wraps around each fascicle.
Epomycin: a thick, tough connective tissue that encloses all the fascicles in a muscle.
Sarcolemma: the cell membrane of a muscle fiber.
Tendon: a cord-like structure that connects muscle to bone.
Aponeurosis: a flat, sheet-like structure that serves the same function as a tendon, but is flat rather than cord-like.