Muscular System Chapter 13.3

Introduction to the Muscular System The muscles in the body make all movement possible. Muscles move body parts, allowing for proper functioning such as heartbeat, breathing, digestion of food, and the movement of the body from place to place

Muscle Functions Skeletal muscles comprise about 40% of the mass of the average human body Muscles are the engine that your body uses to propel itself turning energy into motion Muscles are made up of elastic fibers These fibers are like rubber bands that lengthen and shorten Thick and thin filaments do the actual work of a muscle

Thick filaments are made of a protein called myosin and thin filaments are made up of a protein called actin A muscle contraction occurs when these fibers generate tension through the action of actin and myosin cross-bridging Muscles cannot push; they can only pull. Main functions are produce heat, produce movement, and maintain posture

Types of muscles Voluntary: you contract when you want to move (skeletal muscles. You control these muscles; the movement is not automatic Involuntary: contract automatically (stomach, intestine, heart) The heart pumps automatically The stomach digests food automatically You cannot tell the heart or stomach to start or stop

Tendons Tendons connect muscle to bone When the muscle moves, it moves the tendon and the bone The longest tendon is the Achilles tendon This tendon attaches the calf muscle to the heel bone

Types of muscle tissue Muscle tissue is classified into three categories: Skeletal- voluntary muscles Visceral (smooth muscles) form the walls of the internal organs Cardiac muscles form the wall of the heart

Basic movements of the skeletal muscle Adduct- moving a body part toward the midline Abduct- moving a body part away from the midline Extend- increases the angle of the muscle Flex- decreases the angle of the muscle Rotate- turning a body part on its axis

Diseases of the Muscular System

Medical Terminology

Jobs and Professions Myologist Physical Therapist Sports Medicine Assistant Tenotomist

Questions 1. What position is your leg in when you are sitting normally in a chair? 2. Describe the three types of muscle tissue and what they do. 3. What are the three functions of muscles? 4. What does contract mean? 5. What is a tendon?

Sources Badasch, S. A., & Chesebro, D. S. (2011). Asepsis and Standard Precautions. In Health Science Fundamentals: Exploring Career Pathways (1st ed., Revised , pp. 342-348). Upper Saddle River, NJ: Pearson.