Why don’t skeletons play music in church? They have no organs
What does a skeleton order at a restaurant? Spare ribs
The Muscular System – 32.3
Essential Questions What are the three types of muscle tissue? What are the events involved in muscle contraction at the cellular and molecular levels? What are the differences between slow-twitch and fast-twitch muscle fibers? Copyright © McGraw-Hill Education The Muscular System
The Muscular System The ability to move is an essential activity of the human body ½ our body weight comes from muscles Consists of over 600 individual muscles. 3 purposes: Body movement Body shape Body heat (maintain temp.)
The Muscular System Body movements are determined by three types of muscles Smooth (involuntary) – cannot be controlled by will. Cardiac – control the contractions of the heart. Skeletal (Voluntary) – can be controlled by will.
Three Types of Muscle Muscles are classified according to their structure and function. Copyright © McGraw-Hill Education The Muscular System
Three Types of Muscle Smooth Muscle involuntary muscle Not striated Not under conscious control Not striated Many hollow internal organs such as the stomach, blood vessels, intestines, bladder, and uterus are lined with smooth muscle. Copyright © McGraw-Hill Education The Muscular System
Three Types of Muscle Cardiac Muscle Involuntary muscle. Striated Fibers are arranged in a network that allows the heart muscle to contract efficiently and rhythmically. Walls of heart Copyright © McGraw-Hill Education The Muscular System
Three Types of Muscle Skeletal Muscle tough band connective tissue voluntary muscles that cause movement. striated attached to bones by tendons. tough band connective tissue when tightened they contract, they cause movement. muscles connected to bones Copyright © McGraw-Hill Education The Muscular System
skeletal
Cardiac
Smooth
How Do Muscles Move the Body Muscle Movement and Types Copyright © McGraw-Hill Education The Muscular System
Skeletal Muscle Contraction Skeletal muscle is arranged into fibers consisting of smaller units called Myofibrils. Myofibrils c consist of even smaller units: Myosin Actin Arranged in sections called sacromere Copyright © McGraw-Hill Education The Muscular System
Copyright © McGraw-Hill Education The Muscular System
Skeletal Muscle Contraction Sliding Filament Theory Once a nerve signal reaches a muscle, the actin filaments slide toward one another, causing the muscle to contract. Copyright © McGraw-Hill Education The Muscular System
Copyright © McGraw-Hill Education The Muscular System
Skeletal Muscle Contraction Most skeletal muscles are arranged in opposing, or antagonistic pairs. Flexion Extension Copyright © McGraw-Hill Education The Muscular System
Types of Muscular Contractions eccentric – lengthening contraction concentric – shortening contraction isometric – muscle contracts but does not change length (Demonstration) 9-24
They contain myoglobin Skeletal Muscle Strength Slow-twitch muscles Slow-twitch muscle fibers have more endurance than fast-twitch muscle fibers. They contain myoglobin respiratory molecule that stores oxygen and serves as an oxygen reserve. Copyright © McGraw-Hill Education The Muscular System
Skeletal Muscle Strength Fast-Twitch Muscles fatigue easily provide great strength for rapid, short movements. rely on anaerobic metabolism, which causes a buildup of lactic acid. Copyright © McGraw-Hill Education The Muscular System
Textbook page 950 Data Analysis Lab 1
Muscle Review Basics
Identify Muscles Holes Anatomy Book pages 195-208