The Skeletal System Structure Function of the bones

The Skeletal System: Structure & Function of the bones and joints

What is a skeleton? • The skeleton is a column of interlinked bones, with two legs attached at the bottom and two arms and a skull attached at the top.

The picture to the right is referred to as anatomical position.

The Skeletal System · Parts of the skeletal system · Bones (skeleton) · Joints · Cartilages · Ligaments (bone to bone)(tendon=bone to muscle) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Functions of Bones · Support of the body · Protection of soft organs · Movement due to attached skeletal muscles · Storage of minerals and fats · Blood cell formation Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Bones • Your bones protect the important organs in your body. • The skull protects the brain. It is like a hard hat. • Your ribs protect the heart, lungs, and stomach.

Bones of the Human Body You were born with 300 bones. By the time you graduate from high school you will have 206 bones. How many more bones did you have when you were born than you will have when you graduate? Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Bones are classified by their shape: 1. Long- bones are longer than they are wide (arms, legs) 2. Short- usually square in shape, cube like (wrist, ankle) 3. Flat- flat , curved (skull, Sternum) 4. Irregular- odd shapes (vertebrae, pelvis)

Classification of Bones on the Basis of Shape Figure 5. 1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

The Skull • The skull is a bony case that supports and protects the brain and some of the body’s sense organs, such as the eyes and ears. • There are 29 different bones in the skull. • The part of the skull that surrounds the brain is called the cranium.

The Skull • 14 facial bones form the framework for the eyes, nose, cheekbones, and upper and lower jaw. • Upper jaw is called the maxilla. • Lower jaw is called the mandible. • The lower jaw can move from side to side and up and down.

Backbone • Your backbone, or spine is a flexible column of bones that runs down the middle of your body. • It is made up of 33 small bones called vertebrae

Rib Cage • Your rib cage forms a protective shell for some of your most important organs, including your heart, lungs, stomach, and liver.

Collarbone and Shoulder Bone

Hands • The hand has 27 bones in three groups: the phalanges in the fingers and thumbs, the carpals in the wrist, and the metacarpal in the palm.

Names of Bones • • Fibula – Lower leg Tibia - Shin Femur – thigh bone Pelvis - hip bone Spinal Column - Backbone Cranium – skull Ulna & Radius– lower arm bones Humerus – upper arm bone

Bones • Bones are made of cells. • Bones are living parts of your body that grow and change just as you do.

A Closer Look at Bones • The outside of the bone is hard. It is made up of living bone cells that form rings around tiny canals through which blood vessels pass. • The inside is a honeycomb of bone cells with spaces between them. This is called spongy bone. • Minerals are stored inside the bone.

A Closer Look at Bones • The hollow centers of many bones are filled with jellylike red and yellow marrow. • Yellow marrow stores fat and releases it when it is needed elsewhere in the body. • Red marrow is a tissue that makes red and white blood cells and platelets.

A Closer Look at Bones • Red bone marrow makes up to five thousand million red bloods cells and thousands upon thousands of white blood cells and platelets each day.

A Closer Look at Bones • Red blood cells are the cells that carry oxygen throughout the body.

A Closer Look at Bones • White blood cells are the cells that fight disease and infection.

A Closer Look Inside • The platelets help the blood to clot after injury. – Scabs

Speedy Bone Facts • The femur is the thigh bone. It is the largest bone in the body. • The shortest bone is in your middle ear. It is called the stirrup, or stapes. • More than half the bones in your body are in your hands and feet. • Humans have the same number of neck bones as giraffes and mice.

Bone Connection • Bones are connected together by ligaments at the joints. • Cartilage is another kind of connective tissue found in joints and at the ends of bones. • Bones are moved by muscles that are attached to them

Joints A joint is the place where two bones come together.

Types of Joints Hinge- A hinge joint allows extension and retraction of an appendage. (Elbow, Knee)

Ball and Socket- A ball and socket joint allows for radial movement in almost any direction. They are found in the hips and shoulders. (Hip, Shoulder)

Gliding- In a gliding or plane joint bones slide past each other. Mid-carpal and midtarsal joints are gliding joints. (Hands, Feet)

Saddle- This type of joint occurs when the touching surfaces of two bones have both concave and convex regions with the shapes of the two bones complementing one other and allowing a wide range of movement. (Thumb)