Muscular System

Muscular System Functions:Muscle Tissue Can Contract (shorten) and Relax (lengthen).

This causes mobility and provides support.

1. Allow for movement of:• skeleton – muscles are connected to bones• material inside organs (food through digestive

system, blood and materials in blood by pumping of heart)

2. Provide Support• Muscles maintain your posture while sitting and

standing• Muscles stabilize joints• Muscles help prevent dislocation of bones

Muscles can be:

• Voluntary – you can control their movement

• Involuntary- you cannot con control their

movement

Some can be both – diaphragm, eyelids

1. Skeletal muscle – striated (dark/light fibers), voluntary

2. Cardiac muscle – striated (dark/light fibers), involuntary

3. Smooth muscle – no striations (smooth), involuntary

The Three Types of Muscle Tissue:

• Voluntary• Striated (dark and light bands of

tightly packed fibers)• Attaches to bone using tendons• Tendons – connective tissue

that connects muscle to bone• Many work in pairs (as one

contracts, the other relaxes)

http://www.youtube.com/watch?v=VCminz-X52I

Cardiac Muscle• Involuntary

• Striated (dark and light bands of tightly packed fibers)

• Makes up the HEART• Pumps blood throughout the

body• A pacemaker in the heart

controls when the muscle contracts

Heart beat animation

Cardiac Muscle Cells (Cardiac Muscle Tissue)

• Involuntary• NOT striated (smooth)• Found in many internal organs (esophagus, stomach,

intestines, uterus, diaphragm)

Digestion Video

Examples of smooth muscle action:• Esophagus pushing food to the stomach by peristalsis• Stomach churning food• Intestines squeezing food through• Muscles that makes your pupil contract/dilate• Diaphragm• Uterus contracting to go into labor and give birth

Smooth muscle of the intestines

1. Keep skeletal and cardiac muscles strong and working properly

2. Helps prevent disease

http://www.brainpop.com/health/bodysystems/muscles/

Fun MUSCLE Facts:• Contraction of skeletal muscle helps push blood through the

veins• Humans have more than 640 skeletal muscles!!• It takes 17 muscles in the face for us to smile and 43 muscles

to frown.• If muscle strength is regarded as the ability to use force on

something then the jaw muscle (masseter) is the strongest in the body. The tongue has 8 muscles, so is technically not the strongest muscle in the body

• The gluteus maximus is the largest muscle in the human body.• Muscle memory is created by practicing an action over and

over again. Our muscles fine tune themselves, becoming more precise and exact in what they do. So practice is very important when learning a sport!!

• Skeletal muscle can be further divided into two types, slow twitch and fast twitch.

• Slow twitch (Type I) muscle contain proteins that give it a rich red color. This muscle carries more oxygen efficiently and using fats, proteins or carbs as energy, slow twitch muscle fibers contract over a long period of time. Therefore type I muscle fiber works well for aerobic sports such as long distance running and cycling.

• Fast twitch (Type II) muscle is whiter in color as it has less myoglobin (a oxygen carrying protein). Fast twitch fibers contract quickly and powerfully, however they fatigue rapidly. Therefore type II muscle fiber is useful for anaerobic exercise such as sprinting or for strength sports like weightlifting.