Illinois CTE Curriculum Revitalization Initiative Health Science and Technology Understand the Components of the Muscular System Lesson G1-2

IL CTE- Health Science & Technology There are 3 types of muscle tissue Smooth muscle Cardiac muscle Skeletal muscle

IL CTE- Health Science & Technology Smooth Muscle has no striations, (visible bands) that help the muscle move.  The walls of the hollow body organs and those of the blood vessels and respiratory passageways are composed of smooth muscle.  It moves involuntarily, which means it works on its own without the person having to control it.  The urinary bladder and the intestines are examples of smooth muscle.

IL CTE- Health Science & Technology Cardiac Muscle is striated (visible bands)  It works involuntarily.  Membranes between the cells allow electrical impulses to travel rapidly through them so that contractions can be better coordinated.

IL CTE- Health Science & Technology Skeletal Muscle is heavily striated.  The nervous system stimulates this muscle to contract; it is voluntary muscle and does not move without conscious control.  It is attached to bones and produces movement of the joints.  It constitutes the largest amount of the body’s muscle tissue.  There are more than 600 individual skeletal muscles.

Question: Where can you find smooth muscle?  A. Voluntary muscles that move the body  B. In the heart  C. In hollow body organs (intestines, stomach) IL CTE- Health Science & Technology

Question: Where can you find cardiac muscle?  A. Voluntary muscles that move the body  B. In the heart  C. In hollow body organs (intestines, stomach) IL CTE- Health Science & Technology

Question: Where can you find skeletal muscle?  A. Voluntary muscles that move the body  B. In the heart  C. In hollow body organs (intestines, stomach) IL CTE- Health Science & Technology

Functions of the muscular system Movement of the skeleton Maintenance of posture Generation of heat

IL CTE- Health Science & Technology Movement of the Skeleton Muscles are attached to bones and contract to change the position of the bones at the joint.

IL CTE- Health Science & Technology Maintenance of Posture A steady partial contraction of the muscle keeps the body in position.  a. The thighs, back, neck, shoulders, and abdominal muscles help maintain posture. images.jupiterimages.com

IL CTE- Health Science & Technology Generation of Heat Muscles generate most of the heat needed to keep the body at 37 degrees Celsius (98.6 degrees Fahrenheit). Thermogenesis is the production of body heat. Heat is a natural byproduct of muscle cell metabolism. When we are cold, the muscles boost their heat output by using rapid small contractions known as shivering.

Question The functions of the muscular system include: movement, maintenance of posture, generation of heat, and visual interpretation. TRUE or FALSE IL CTE- Health Science & Technology

Skeletal Muscle Structure Muscle fibers are highly specialized skeletal muscle cells. Fascicles are groups of skeletal muscle fibers that are bound together by a connective tissue envelope. The muscle and its connective tissue covering are firmly attached to the fibrous structures that attach muscles to bone, which allows them to pull the structure during contraction (lengthening or shortening of the muscle fibers).

IL CTE- Health Science & Technology Size, Shape, and Fiber Arrangement of Muscles Skeletal muscles are organs that include skeletal muscle tissue, connective tissue, and nerve tissue. Muscles vary in size, shape, and arrangement of fibers. Arrangement of fibers varies in different muscles. The direction of the fibers is in direct relationship to a muscle’s function.

Question: What are highly specialized skeletal muscle cells called?  A. Fascicles  B. Muscle fibers  C. Periosteum IL CTE- Health Science & Technology

Attachment of Muscles Most muscles cover one joint and attach to two bones. When the muscle contracts, one bone moves while the other remains still. The origin is the point of attachment that does not move. Insertion is the area of attachment that moves when the muscle contracts.

Question: The origin and insertion refer to where muscles attach to bones. TRUE or FALSE IL CTE- Health Science & Technology

How are muscles named? Location refers to where they can be found in the body. Function refers to their action. Shape refers to the physical description. The direction of fibers appears in names like “rectus abdominus.”  For example, rectus means straight. The rectus abdominus muscle runs straight up and down, and the fibers are parallel to each other. The number of heads or divisions reveals information.  For example, “cep” means head. If “bi” means two, then the bicep muscle has two heads. Points of attachment refer to the origin and insertion points of the muscle. The size of the muscle may influence the name, especially if there are other muscles nearby to which it can be compared.  For example: gluteus maximus, which is the largest muscle in the buttock region. It shares space with the gluteus minimus and the gluteus medius.

Question: Which of the following is NOT a way in which muscles can be named?  A. Location  B. Function  C. Shape  D. Strength  E. Direction of fibers  F. Points of Attachment IL CTE- Health Science & Technology

Major Skeletal Muscles One deltoid is located in each shoulder One pectoralis major can be found on each side of the chest. The rectus abdominus helps to flex (bend) the trunk of the body and is the muscle that body builders proudly display: “six-pack abs.” The muscle in your upper arms is your biceps muscle. Quadriceps muscles are located in the front of the thigh. Gastrocnemius is located in the back of the calf. gary2idaho.files.wordpress.com

IL CTE- Health Science & Technology