Skeletal Muscle Tissue: Structure, Properties, and Functions - Chapter 10

Skeletal Muscle Tissue

Introduction to Muscle Tissue

Muscle tissue is a primary tissue type in the human body, essential for movement, stability, and various physiological functions. The term muscle is derived from the Latin word for "little mouse." Muscle tissue is found in the heart (cardiac muscle tissue), the walls of hollow organs (smooth muscle tissue), and as skeletal muscle attached to bones, making up nearly half of the body's mass.

Properties of Muscle Tissue

Key Properties

• Contractility: The ability of muscle cells to shorten forcefully. This is due to myofilaments composed of actin and myosin proteins.

• Excitability: Muscle cells respond to nerve signals, generating electrical impulses that travel along the cell's plasma membrane.

• Extensibility: Muscle tissue can be stretched. For example, contraction of a skeletal muscle stretches the opposing muscle, and smooth muscle is stretched by substances within hollow organs (e.g., food in the stomach, urine in the bladder).

• Elasticity: Muscle tissue recoils after being stretched, returning to its original length.

Terminology Specific to Muscle Tissue

• "Myo-" and "mys-": Prefixes meaning "muscle" (e.g., myofibril).

• "Sarco-": Prefix meaning "flesh" (e.g., sarcoplasm).

• Sarcolemma: The plasma membrane of muscle cells.

• Sarcoplasm: The cytoplasm of muscle cells.

Functions of Muscle Tissue

Major Functions

• Produce Movement:

  • Skeletal muscle: Attached to the skeleton; moves the body by moving bones.

  • Smooth muscle: Squeezes fluids and other substances through hollow organs.

• Open and Close Body Passageways:

  • Sphincter muscles act as valves, opening to allow passage of substances and contracting to close passageways.

• Maintain Posture and Stabilize Joints:

  • Muscle tone enables the body to remain sitting or standing and helps stabilize many synovial joints.

• Heat Generation:

  • Muscle contractions produce heat, which helps maintain normal body temperature.

Example: Sphincter Muscles

Sphincter muscles, such as those found in the digestive tract, regulate the passage of food and waste by opening and closing passageways as needed.

Additional info:

• Muscle tissue is critical in patient care for functions such as movement, posture, and thermoregulation. Disorders affecting muscle tissue can significantly impact quality of life and require clinical attention.