Musculoskeletal System Bones Muscles Skin

Bones Bones Bones The skeletal system

Interesting Information A fully grown human skeleton has 206 bones. A baby has 275 – How does that happen? The longest bone in your body is your femur. The smallest bone is the stirrup inside your ear. Your hands contains 26 bones each. Your feet contain ¼ of all of the bones in the human body!

5 Functions of the Skeletal System Provides shape and support Enables you to move Protects your internal organs Produces blood cells Stores minerals until your body needs them

Shape and Support Your skeleton supports and shapes your body like a steel frame shapes and supports a building. The vertebral column (back bone) is the center of the skeleton. You have 26 vertebrae. Your backbone is flexible and able to bend – if it could not, you would not be able to bend or twist. Label the skeleton – individual and group Each bone should be a different color. labeled skeleton

Your skeleton allows movement Most bones are associated with muscles – muscles pull on the bones to make the body move. Bones also provide a sort of cage for your vital organs located in your abdomen.

Produces and Stores…. The long bones of your body – legs and arms – are factories that make blood cells. Bones store minerals such as calcium and phosphorus. (these are the minerals that make bones hard) When the body needs these minerals, the bones release small amounts of them into the blood

Bones are ALIVE Bones are strong. They can absorb more force without breaking that concrete or granite. Bones are lightweight. Only 20% of the adult’s body weight. Bone Growth Bones are made up of cells and tissue. As you grow they form new bone tissue. After you are grown, they continue to form new bone tissue to repair tissue from accidents or normal wear and tear.

Structure of Bone (draw picture) Outer Membrane – where blood vessels enter and leave the bone Compact Bone – hard and dense but not solid – small canals run through the compact bone that carry blood vessels and nerves Spongy Bone – like a sponge – this structure spongy bone lightweight but strong Marrow – connective tissue contained in the spaces in the bones center and ends Red marrow – makes red blood cells (ends of your femur, hip bones, sternum) Yellow Marrow – stores fat for energy reserve

How bones form As an infant – much of your skeleton was made of Cartilage ( a connective tissue much more flexible than bone) By the time you stop growing cartilage replacement by bone tissue is mostly complete…. Cartilage remains in your nose ears and knees

Joints of the Skeleton – where 2 bones meet Immovable joints – allow little or no movement (example – bones of the skull or ribs to sternum) Movable Joints – allow a wide range of movement – held together by ligaments Ball and socket joints – allows movement in a circle (arm + shoulder, hip+ femur) Pivot Joint – allows movement from side to side (Neck) Hinge Joint – allows forward and backward movement (knee, elbow) Gliding Joint – bend and flex with limited side to side movement (wrist and ankles)

Bone Health Get plenty of exercise – during exercise your bones support your weight – helps your bones grow denser and stronger Eat a well balanced diet Meats, whole grains, leafy green veggies – phosphorus Dairy products – calcium This helps to prevent OSTEOPOROSIS later in life – a condition in which the bodies bones become weak and break easily

Help with “it all fits together” Periosteum The periosteum is a fibrous sheath that covers bones. It contains the blood vessels and nerves that provide nourishment and sensation to the bone. Tendon Tendons are tissues that connect muscles to bone. When muscles contract, tendons pull on bones. This causes parts of the body (such as a finger) to move.

Label the Skeleton Metacarpals Cranium Clavicle Tarsals Pubis Mandible Humerus Phalanges x 2 Ischium Femur Tibia Sternum Metatarsals Sacrum Radius Carpals Ribs Ilium Ulna Metacarpals Cranium Clavicle Tarsals Pubis Mandible Patella Fibula Scapula

The Muscular System

You have about 600 muscles in your body!! There are 2 types of muscle action: Involuntary Muscles – these are not under your conscious control – responsible for activities like digesting food, breathing, heart beating Voluntary Muscles – muscles that are under your control

Three types of muscles Skeletal Muscle – attached to bone by a tendon (a strong connective tissue that attaches muscle to bone) Skeletal muscles appear banded or striated Voluntary muscles They will tire quickly

Three Types of Muscles Smooth Muscles – Found on the inside of many internal organs (walls of the stomach and blood vessels) Involuntary muscles – work automatically to control movement in your body (example: digestion) Under a microscope – these muscles are not striated but smooth The react slowly and tire slowly compared to skeletal muscles

Three Types of Muscles Cardiac Muscle – has characteristics of both skeletal and smooth muscles Like smooth muscles – cardiac muscles do not get tired – it can contract repeatedly = heartbeats Like skeletal muscles – it appears striated

How do muscles work? Muscle cells contract when they receive a message from the nervous system. Muscles cells can only contract – not extend. Because of this – muscles must work in pairs. While one muscle contracts – the other muscle in the pair returns to its original length

Taking Care of your Skeletal Muscles Exercise is important for maintaining strength and flexibility. Muscle cells grow wider ---> muscle thickens stronger muscle

Skin – Integumentary System If an adult’s skin is stretched flat, it would cover about 1.5 meters – about the size of a twin mattress!

The skin’s 6 major functions… Protects the body by forming a barrier keeping diseases and micro-organisms outside the body. Keeps important substances inside the body.......acts like plastic wrap to keep water in.

The skin’s 6 major functions… Helps the body maintain a steady temperature. Blood vessels run through the skin Too warm? Blood vessels enlarge to increase blood flow – allows heat to move from the body to the outside Sweat glands respond to excess heat by producing perspiration. As perspiration evaporates from your skin, heat escapes.

The skin’s 6 major functions… Because perspiration contains some dissolved waste materials – your skin helps to eliminate waste. Gathers information about the environment – nerves in skin provide information about pressure, pain, temperature Produce Vitamin D in the presence of the sun. Vitamin D – helps cells process calcium for healthy bones

Structure of Skin – 2 main layers Epidermis – outer layer of skin does not contain nerves or blood vessels New epidermal cells form deep in the epidermis  mature and move upward- the cells die and become the surface layer of skin This process provides protection for the skin Some epidermal cells make fingernails Some epidermal produce melanin – gives the skin its color

Structure of Skin – 2 main layers Dermis – lower layer of skin – located between the epidermis and a layer of fat Contains nerves, blood vessels, sweat glands, hairs, and oil glands Sweat glands produce perspiration – which reaches the surface through openings called PORES. Strands of hair grow within the dermis in structures called FOLLICLES

Caring for your skin Four simple habits can help you keep your skin healthy: Eat Properly - replacing cells requires the energy you get from a healthy diet Drinking water – replace the water you lost through perspiration Limit sun exposure – repeated sun exposure can damage skin cells and cause them to become cancerous Keeping skin clean and dry – removes dirt and bacteria … clogged pores – leads to acne…fungus – athletes foot 

Skin Cancer – Do you know the 2 careers where skin cancer is the most prevalent? Athlete’s Foot – fungal infection from walking on contaminated surfaces – very contagious and can grow in your shoes  Dry skin – can cause skin to look prematurely aged