Muscle Fiber Types

Flashcards covering the types of muscle fibers and their characteristics.

Type I Muscle Fibers

Slow twitch fibers characterized by low myosin content, oxidative catabolism, high mitochondria, and fatigue resistance.

Type II X Muscle Fibers

Fast twitch fibers with high myosin content, primarily glycolytic metabolism, fewer mitochondria, and rapid fatigue.

Myoglobin

A protein that binds oxygen in muscle cells, contributing to the red color of Type I fibers.

Oxidative Catabolism

A metabolic process that uses oxygen to convert substrates into energy, predominant in Type I fibers.

Glycolytic Metabolism

A metabolic pathway that converts glucose into energy without the use of oxygen, predominant in Type II X fibers.

Mitochondria

Cellular organelles that generate energy through aerobic respiration, abundant in Type I fibers.

Fatigue Resistance

The ability of a muscle to sustain prolonged activity without tiring, characteristic of Type I fibers.

ATPase

An enzyme that catalyzes the hydrolysis of ATP, playing a crucial role in muscle contraction.

Myofibrils

Long, thread-like structures in muscle fibers that are involved in contraction.

Blood Supply

The availability of blood flow to muscle tissues, better in Type I fibers compared to Type II X.

Fast Twitch vs Slow Twitch

Fast twitch fibers (Type II) are adapted for quick bursts of activity, while slow twitch fibers (Type I) are suited for endurance.