Lesson 7: Major Organ Systems MUSCULAR SYSTEM

Muscle Tissue LocationFunctionVoluntary or Involuntary skeletal attached to bones pull bones to make them move voluntary

Muscle Tissue LocationFunctionVoluntary or Involuntary skeletal attached to bones pull bones to make them move voluntary smooth Internal organs they move food through digestive system involuntary

Muscle Tissue LocationFunctionVoluntary or Involuntary skeletal attached to bones pull bones to make them move voluntary smooth Internal organs they move food through digestive system involuntary cardiac heart onlypumps blood through body; controls the contractions of the heart involuntary

Muscular System FunctionsOrgans  Helps to move the body  Helps blood to circulate  Helps food move through digestive system  Muscles (3 types)  Tendons

The Muscular System half of our body weight comes from muscles consists of over 600 individual muscles

The Muscular System 3 purposes: –Body movement –Body shape –Body heat (maintain temp.)

Movement of the Human Body Muscles help make all of your daily movements possible. A muscle is an organ that can relax, contract, and provide the force to move your body parts.

Working Muscles You move because pairs of skeletal muscles work together. Muscles always pull. They never push. When one muscle of a pair contracts, the other muscle relaxes, or returns to its original length.

Working Muscles When the muscles on the back of your upper leg contract, they shorten and pull your lower leg back and up. When you straighten your leg, the back muscles lengthen and relax, and the muscles on the front of your upper leg contract.

The tricep relaxes. The bicep relaxes. animation

contract when a muscle gets shorter

relax when a muscle returns to its original length

Muscle Control Muscles that you are able to control are called voluntary muscles. Your hand, arm, and leg muscles are voluntary. You can choose to move them or not move them.

Muscle Control Involuntary muscles are muscles you can’t control consciously. They go on working all day long, all your life. Blood gets pumped through blood vessels, and food is moved through your digestive system by the action of involuntary muscles.

voluntary muscles muscles that are under your control skeletal muscles

involuntary muscles muscles that are not under your control smooth muscles, cardiac muscles

Classification of Muscle Tissue The three types of muscles are skeletal, smooth, and cardiac. The muscles that move bones are skeletal muscles.

They are more common than other muscle types and are attached to bones by thick bands of tissue called tendons. Classification of Muscle Tissue They tend to contract quickly and tire more easily than involuntary muscles do.

Muscle Tissue LocationFunctionVoluntary or Involuntary skeletal attached to bones pull bones to make them move voluntary

tendons a strong connective tissue that connects muscles to bones

Classification of Muscle Tissue Smooth muscles are found in your intestines, bladder, blood vessels, and other internal organs. They are involuntary muscles that slowly contract and relax. Internal organs are made of one or more layers of smooth muscle.

Muscle Tissue LocationFunctionVoluntary or Involuntary skeletal attached to bones pull bones to make them move voluntary smooth Internal organs they move food through digestive system involuntary

Classification of Muscle Tissue Cardiac muscle is found only in the heart. This type of muscle contracts about 70 times per minute every day of your life.

Muscle Tissue LocationFunctionVoluntary or Involuntary skeletal attached to bones pull bones to make them move voluntary smooth Internal organs they move food through digestive system involuntary cardiac heart onlypumps blood through body; controls the contractions of the heart involuntary

Like skeletal muscle, cardiac muscle is striated. Smooth muscles are called smooth because they do not have striations.

What are the 3 types of muscle tissue? Skeletal muscles Smooth muscles Cardiac muscles

Function of Cardiac muscle Moves blood through the body Found only in the heart Involuntary muscle

Function of Skeletal muscles Attach to bones to provide movement Blinking eyes, talking, breathing, eating, dancing and writing all produced by these muscles Voluntary muscles

Function of Smooth Muscle Moves substances through the body Found in walls of internal organs (intestines, bladder, stomach, blood vessels) Not under conscious control so they are also called involuntary muscles

Muscle Movement a. voluntary – can be controlled by will –skeletal b. involuntary – cannot be controlled by will –smooth, cardiac

Changes in Muscles Over a period of time, muscles can become larger or smaller, depending on whether or not they are used. Some of this change in muscle size is because of an increase in the number of muscle cells. However, most of this change in muscle size is because individual muscle cells become larger.

Changes in Muscles In contrast, if you participate only in non- active pastimes, your muscles will become soft and flabby and will lack strength. Muscles that aren’t exercised become smaller in size. When someone is paralyzed, his or her muscles become smaller due to lack of exercise.

How Muscles Move Your muscles need energy to contract and relax. As the muscle contracts, this released energy changes to mechanical energy (movement) and thermal energy (heat). Your blood carries energy-rich molecules to your muscle cells where the chemical energy stored in these molecules is released.

pairs of skeletal muscles work together

reflex 25. an automatic response that occurs without conscious control