The Systems of the Human Body 1

Skeletal Muscular Circulatory Nervous Respiratory Digestive Excretory Review of the 10 Human Body Systems Skeletal Muscular Circulatory Nervous Respiratory Digestive Excretory Endocrine Reproductive Lymphatic (Immune) 2

Homeostasis from Greek: hómoios, "similar"; and stásis, "standing still“ The ability or tendency of an organism or cell to maintain internal equilibrium by adjusting its physiological processes.

You have more than 600 muscles in your body!! Muscular System You have more than 600 muscles in your body!!

Objectives Identify functions of the muscular system Identify types and important muscles Describe how muscles work with bones to create movement Describe how muscles work like levers Recall Muscle Diseases & problems

Functions of the Muscular System Provides stability and posture Motion (walking, swimming, facial expressions..etc.) Heat Production (shivering) Aids in circulation & digestion

Major Muscles

Tendons Skeletal muscles are attached to bone by thick bands of tissue called tendons

Microscopic Muscle Muscles are made of small muscle fibers

Types of muscle Voluntary Involuntary Muscles you can control Muscles you can’t control Cardiac & Smooth Muscle Ex. Heart, muscles that help digest food Voluntary Muscles you can control Striated Muscle Ex. Bicep, Quadriceps

How do muscles work with bones? *Contraction & Relaxation *Muscles Work in Pairs *p. 160

Muscles are the body’s Simple Machines Muscles work like levers 3 Types: 1st Class, 2nd Class & 3rd Class

1st Class In a first class lever, the weight and force are on opposite sides of the fulcrum: Examples of this lever include scissors, crowbars, and teeter-totters. An example of a first-class lever is the joint between the skull and the atlas vertebrae of the spine: the spine is the fulcrum across which muscles lift the head.

2nd Class In the second class lever, the load is between the fulcrum and the force: An example of this lever is a wheelbarrow. An example in the human body of a second-class lever is the Achilles tendon, pushing or pulling across the heel of the foot.

3rd Class In the third class lever, the force is between the fulcrum and the load  Examples of this lever class include: a pair of finger-nail clippers or tweezers. An example of a third-class lever in the human body is the elbow joint: when lifting a book, the elbow joint is the fulcrum across which the biceps muscle performs the work.