Muscular & Skeletal Systems

Muscular System Muscles are the motors that move body parts. Bones and joints have no power to move on their own. More than 600 muscles in the body –35–40% of body mass is muscle

Muscular System Muscle—organ that contracts and becomes shorter or expands and becomes longer –Result = Body parts move, energy is used, and work is done.

Muscular System Two Groups of Muscles 1.Voluntary—You can control these. these. Arms, legs, hands, face 2. Involuntary—You can’t control these; you don’t have to decide to these; you don’t have to decide to make these muscles work. make these muscles work. Muscles around the heart

Muscular System Three Types of Muscle Tissue 1. Skeletal Muscle 1. Skeletal Muscle Most numerous in body Attached to the bones by tendons –Tendons—thick bands that pull on the bone as the muscle contracts Voluntary

Muscular System Three Types of Muscle Tissue (cont.) 2. Smooth Muscle 2. Smooth MuscleInvoluntary Found in: walls of stomach, intestine, uterus, etc.

Muscular System Three Types of Muscle Tissue (cont.) 3. Cardiac Muscle 3. Cardiac Muscle Only found in heart Involuntary Contracts 70 times per minute (heartbeat)

Muscles at Work Skeletal muscle movements are Skeletal muscle movements are results of pairs of muscles results of pairs of muscles working together. working together. –One muscle contracts while the other muscle relaxes. –Muscles always pull; they never push.

Muscles at Work Results of Muscle Action Results of Muscle Action –Muscles contract This produces thermal energy, and it uses chemical energy. Thermal energy produces heat that helps keep body temperature constant. Chemical energy is from glucose. (When glucose is used up, muscles are tired and need to rest.)

Muscles at Work Results of Muscle action (cont.) –Over time, muscles become larger or smaller, depending on how much work they do.

Skeletal System Made up of all of the bones in your body, it is the framework of the body. –Each bone in your body is a living organ, made of different tissues. Cells in bones take in food and use energy.

Skeletal System Made up of all of the bones in your body, it is the framework of the body. - Four Functions of Skeletal System 1. Framework gives shape & support to the body.

Skeletal System Made up of all of the bones in your body, it is the framework of the body. – Four Functions of Skeletal System 1. Framework gives shape and support to the body. and support to the body. 2. Bones protect the internal organs. internal organs.

Skeletal System Made up of all of the bones in your body, it is the framework of the body. – Four Functions of Skeletal System 1. Framework gives shape & support to the body. 2. Bones protect the internal organs. 3. Major muscles of the body are attached to the are attached to the bones. bones.

Skeletal System Made up of all of the bones in your body, it is the framework of the body. – Four Functions of Skeletal System 1. Framework gives shape & support to the body. 2. Bones protect the internal organs. 3. Major muscles of the body are attached to the bones. attached to the bones. 4. Blood cells are formed in red marrow of some in red marrow of some bones. bones.

Bones The adult skeleton has 206 bones (baby has 270).

Joints Any place where two or more bones meet Ligaments: tough bands of tissue that hold bones together at the joints