Microscopic Anatomy Of The Striated Muscle Tissue

The striated muscle fiber is a syncytium (para 5-3b).

a. The fiber, as a whole, is surrounded by a membrane known as the sarcolemma. The sarcolemma has specialized invaginations that enter the interior of the fiber at right angles to the sarcolemma. These are called transverse tubules (T-tubules). The T-tubules connect with the extracellular space and allow interstitial fluid to flow in and through the striated muscle fiber.

b. The fiber is filled with a type of intracellular fluid called sarcoplasm.

SARCO = flesh c. Within the sarcoplasm is a tubular system called the sarcoplasmic reticulum that stores calcium, which is necessary for the muscle activation and contraction.

d. Myofilaments are found in the sarcoplasm.

MYO = muscle

FIL = thread

Myofilaments are long complexes of protein molecules, either actin or myosin. Thus, there are two main types of myofilaments: actin and myosin. The myosin filaments are thicker and have appendages known as myosin "bridges." The myosin filaments are surrounded by the thinner actin filaments.

e. Great numbers of well-developed mitochondria (the "powerhouse" elements of cells) are found in striated muscle fibers.

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Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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