Skeletal System Video

The Skeleton is the name given to the collection off bones in the body and the tissues that connect them.

The skeleton has 5 major functions. 1- It protects our vital organs such as the brain,, the heart, and the lungs.. 2- It gives us structure. Without it we would just be a blob of blood and tissue on the floor. 3-It allows us to move. Because our muscles are attached to our bones, when our muscles move, they move the bones. 4- It stores calcium. Which keeps bones and teeth hard. 5- It makes Red and White blood cells. Mainly red blood cells. White blood cells are also produced in your lymph nodes.

Skeleton Facts • When you were born, your skeleton had close to 350 bones. • By the time you become an adult, you will only have around 206 bones. • This is because, as you grow, some of the bones fuse together to form one bone such as the skull.

…Skeleton Facts • The smallest bones in the body are found in the ear. (3mm) • The longest bone in the body is the femur. • Over half the body's bones are in the hands and feet. • As your bones grow, you get taller. Girls usually stop growing around age 16, and 18 for boys. • Our bones are 5 times stronger than steel if they are the same weight.

Organization of the Human Skeleton • Your skeleton is made up of two parts; the axial skeleton and the appendicular skeleton. Green = Axial Purple = Appendicular

The Axial Skeleton • Skull 29 • vertebral column 24 • ribs (12 pairs) 24 • Sternum 1 • Sacrum 1 • Coccyx 1 • Total 80 Green Area

The Appendicular Skeleton • pectoral girdles (2 x 2) 4 • Arms (3 x 2) 6 • Wrists (x 2) 16 • hands (19 x 2) 38 • pelvis 2 • legs (4 x 2) 8 • ankles (7 x 2) 14 • feet (19 x 2) 38 • total 126 Purple Area

There are Four Main types of bone Flat: like those found in the skull; provide protection for soft tissues and points for muscle attachment Long: found in the arms and legs; provide strength and support Short: found in the wrists and ankles; not much longer than they are wide; provide flexibility Irregular: backbone, middle ear; have shapes related to a specialized function (ex: vertebra have small extensions for muscle attachments and an opening for the spinal cord)

Flat Long Irregular Short

Bones • Bones get their strength and rigidity from hard deposits of minerals such as calcium and phosphate. • Bones are strong but light because they are hollow and filled with a substance called Bone Marrow.

Bone Marrow • Bone marrow is found in the hollow interior of bones and is a spongy, fatty tissue that houses stem cells. These cells can transform themselves into platelets, white or red blood cells that are needed for immunity and circulation. • Red marrow is found in some flat bones (hip, skull, vertebrae and rib bones) and yellow marrow is a fat tissue storage site in the middle of some longer bones.

Joints • The place where bones meet. • Most joints allow our bones to move (the skull bones are an exception.) • There are several types of body joints including: • Hinge (elbow) • Ball-and-socket (Hip and shoulder) • Pivot (head on spine) • Saddle (interlocking bones in the thumb) • Gliding (bones slide past each other)

Types of Joints Hinge Joint • A hinge joint allows extension and flexion of an appendage. • Note: your knee is a modified hinge joint.

Types of Joints Ball & Socket Joint • A ball and socket joint allows for radial movement in almost any direction. They are found in the hips and shoulders.

Types of Joints Pivot Joint • Pivot joints allow rotation around an axis. The neck and forearms have pivot joints. In the neck the occipital bone spins over the top of the axis. In the forearms the radius twists as it turns over the ulna.

Types of Joints Saddle Joint • A saddle joint allows movement back and forth and up and down, but does not allow for pivoting like a ball and socket joint.

Types of Joints Gliding Joint • In a gliding or plane joint bones slide past each other. Midcarpal and midtarsal joints are gliding joints

Cranium and Facial Bones Nasal Bones The cranial bones include the flat bones that make up the vault for your brain. Their main function is to protect the brain from trauma.

The Vertebral Column The spine Made up of 26 irregularly shaped bones Each vertebra has one round drum shaped body with 3 wing-like projections The vertebrae are held together by bands of ligaments There is a hole in the middle of each vertebra for the spinal cord The way our spine is made, it limits how much we can bend forward/backward Some people are more flexible than others

-Supports the head and neck, holding the head erect. Cervical Region: C1-C7 (7bones) -Supports the head and neck, holding the head erect. Thoracic Region: T1-T12 (12 bones) -rigid group of bones which support the 24 ribs Lumbar Region : L1-L5 (5bones) -largest bones in the vertebral column, carrying a large share of the body mass. Quite mobile bones. Sacrum -transfer body weight to pelvis Coccyx- no significant function

The Sternum and Ribs 12 pairs of ribs that are flat, curved bone. Main function is protection and support. First 7 pairs are attached by cartilage to the sternum (breast bone).These are True Ribs. Next 3 pairs lie below the sternum; each pair is attached by cartilage to the pair of ribs above. These are False Ribs The last 2 pairs are called Floating Ribs because they do not complete the circle and are not attached in front (these ribs are easily broken)

The Upper Limbs Scapula: is loosely held in place by ligaments and muscles, so the arm has great freedom of movement in almost any direction. Humerus: is a long bone in the arm or forelimb that runs from the shoulder to the elbow,has many attachment sites for muscles.

Ulna: is one of the two long bones in the forearm, with the palms facing forward the ulna is placed at the medial side of the forearm closest to the body Radius: is the bone of the forearm that extends from the lateral side of the elbow to the thumb side of the wrist. The radius is situated on the lateral side of the ulna.

Wrist: is made up of 8 small bones (carpals) which are joined to the 5 metacarpals that form the hand The bones that make the fingers and thumb are called phalanges (there are 3 in each finger and 2 in each thumb)

Pelvis Female Male

Functions of the Pelvis The pelvic girdle is a basin-shaped ring of bones connecting the vertebral column to the femurs (upper leg bones) Main function is to hold up the upper body and allow an attachment point for the legs Secondary function is to protect the lower organs of the urinary system and reproductive system.

The Lower Limbs Femur: longest and strongest bone; its round, smooth head fits into a socket formed in the pelvis Patella: flat, disc-shaped bone just in front of the joint for protection. Loosely attached to allow movement

Tibia: shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee, and connects the knee with the ankle bones. Fibula: is a bone located on the lateral side of the tibia, it is the smaller of the two bones.

Tarsal bones: 7 of these bones make up the ankle; these provide a sliding joint which allows the foot to be extended and flexed. The calcaneus is the largest tarsal bone also known as the heel bone. Metatarsals are the 5 bones in the foot. Phalanges are the bones in the toes. Each toe has 3 bones except for the ‘big’ toe.(the most medial digit of the foot)