Skeletal Muscle Unit Notes How many bones does

Skeletal & Muscle Unit

Notes

How many bones does the human skeleton contain?

206

Functions of the skeletal system n n n Give shape & support Protect internal organs Moves muscles Form blood cells Store calcium and phosphorous

Bone Cross Section Periosteum: soft, thin, covers and protects the bone Compact Bone: Hard, outer surface. Can heal itself when broken Spongy Bone: Porous, contains blood vessels, nerves Marrow: manufactures red blood cells

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http: //www. bmb. psu. edu/courses/bisci 004 a/bone. htm

Skeletal System is divided into two parts

Axial Skeleton n Skull (protects the brain). Ribs ( protect lungs, and heart). Spinal column (houses and protects the spinal cord).

Appendicular Skeleton Legs n Pelvis n Arms n Shoulders n

Types of Joints n Immovable n n n Skull Pelvis Movable n n Pivot Ball & socket Hinge Gliding

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Ball & Socket: Shoulders and Hips n n Allows arms and hips to move in any direction Can move in a full 360 degrees

Pivot Joints: First two neck vertebrae & joint beneath elbow n Moves in a semicircle motion by twisting against each other

Hinged: Elbows & Knees n n n Move like hinges on a door Limited movement Can only swing back and forth

Gliding Joints: Spine, Wrists, Ankles n n Slide against each other in a gliding motion Gives your wrists and ankles lots of freedom

Immoveable joints are located in the:

How many muscles do we have? n Over 600 muscles

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http: //www. bio. psu. edu/

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http: //www. bio. psu. edu/

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http: //www. sirinet. net/~jgjohnso/ muscle. html

Inside a Muscle Fiber Muscle Myofibril

Vocabulary

Appendicular n The part of your skeleton made up of your arms, legs, pelvis and shoulders.

Axial n Part of your skeleton that includes skull, ribs, and spinal column.

Vertebrae n Irregular bones that make up the spinal column

Cartilage n Smooth tissue that acts as a buffer between bones.

Ligaments Tissues that fasten your bones together

Calcium n The mineral found in bones

Periosteum n The outer covering of bones.

Ball and Socket n These joints are found in hips and shoulders.

Gliding n These joints are found in fingers and the spine.

Immoveable n This type of joint is found in the skull and is fixed.

Pivot n These types of joints are found in the head and arms.

Voluntary n These muscles can be controlled consciously

Involuntary n These muscles can be controlled unconsciously

Skeletal n Muscle tissue that is attached to bones and causes movement.

Smooth n This type of tissue lines the walls of many organs and are involuntary.

Cardiac n Muscle tissue found in the heart.

Tendons n These tough bands of connective tissue connect bones to skeletal muscles.

Strain n An injury caused when a muscle is over stretched.

Cramp n This can be painful and is sometimes caused by too much exercise and not warming up properly.

Hinge n These joints are found in elbows and knees.

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