By: Melissa Montes, Annalise Castner, and Jessica Roesgen

32.1 Skeletal System  The skeleton supports the body, protects internal organs, assists movements, stores minerals, and is a site of blood cell formation.

The Skeleton  There are 206 bones in the adult body. The 2 types of skeleton systems are Axial skeleton: this supports the central axis of the body. It consist of the skull the vertebral column and the rib cage. Appendicular skeleton: The bones of the arms, legs, pelvis, and shoulder area.

Bones Bones are a solid network of living cells and protein fibers are surrounded by deposits of calcium salts.  Structure of bones Nerves and blood vessels run through out compact bone in channels called Haversian canals.

Structure of Bones  Long bones are surrounded by a tough layer of connective tissue called periosteum.  Bones are cavities that contain a soft tissue called bone marrow. Yellow marrow: contains mostly fat Red marrow: produces blood cells

Development of bones  Cartilage: type of connective tissue that is soft, strong, and flexible that supports the body. Ossification: process were cartilage is replaced by bone Osteoblasts: secrete mineral deposits that replace cartilage in developing bones Osteocytes: help maintain the minerals in bone tissue and continue to strengthen the growing bone  Osteoclasts: cells that break down bone minerals

Joints  Joints contain connective tissue that holds bone together. Joints permit bones to move without damaging each other  Types of Joints: Immovable- cranium and sacrum Semi-moveable- vertebrae Freely moveable- ball and socket, pivot, hinge, and saddle.

Structure of Joints  Ligaments: hold bones together in a joint and are attached to the membrane that surround bones. Bones are held together by ligaments

32.2 Muscular system

Muscle Tissue  There are three different types of muscle tissue: Skeletal- attaches to and moves bones; voluntary Smooth- controls breathing, digestive system; involuntary Cardiac- muscles only found in the heart; voluntary

Muscles and Movement  Muscles are joined to bones by connective tissues called tendons  Skeletal muscles generate force and produce movement by pulling on body parts as they contract  Muscles work in pairs, one contracts and the other relaxes Flexor contracts when bone angle is decreased Extensor contracts when angle between bones increases

32. 3 Skin-The Integumentary System  The integumentary system serves as a barrier against infection and injury, helps to regulate body temperature, removes waste from the body, gathers information, and produces Vitamin D

Integumentary System Structures  Skin and its related structures-the hair, nails, and several types of glands-make up the integumentary system.  Epidermis: outer layer of the skin Outer layer is dead skin, inner layer are living cells  Keratin: tough fiber that causes waterproofing  Melanocytes: cells that produce brown pigment called melanin

Dermis  The dermis lies beneath the epidermis and contains the protein collagen, blood vessels, nerve endings, glands, sensory receptors, and hair follicles. Forms finger prints  Sebaceous glands: secrete an oily substance called sebem that is released at the surface of the skin

Skin Problems  Acne: develops when sebem and dead skin cells form plugs in hair follicles  Hives: Allergic reactions to food or medicine often display themselves as red welts.  Skin Cancer: Excessive exposure to ultra violet radiation in sunlight and artificial radiation from tanning beds can produce an abnormal growth of cells in the skin