Skeletal System

2 Types of Skeletons

2 Types of Skeletons Exoskeleton: Outside the body Endoskeleton: Inside the body

Functions of the Skeletal System 1. Provides shape and support. 2. Protects internal organs. 3. Muscles are attached to bones which provide movement. 4. Bone marrow makes blood cells. 5. Minerals stored in bones (calcium and phosphorus)

Are Bones Alive? Yes! Bone is made of cells which do all of the life functions like other cells.

Parts of Bone

Periosteum The covering on the outside of the bone, a tough, tight fitting membrane.

Compact Bone Under the periosteum. A hard, strong layer of bone made of bone cells, blood vessels, protein, calcium and phosphorus.

Spongy Bone Found on the end of long bone. Less dense than compact bone with many holes in it. This decreases the mass while staying strong.

Bone Marrow Located inside long bones. Produces 2 million red blood cells per second. Also makes white blood cells.

Interesting facts When you were born, your skeleton had around 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 join together to form one bone.

Skull and upper jaw 21 bones 3 tiny bones in each ear How Many Bones? Skull and upper jaw 21 bones 3 tiny bones in each ear Lower jaw (mandible) Front neck bone (hyoid) Backbone or spine (26 separate bones or vertebrae) Ribs (12 pairs - same number for men and women) Breastbone Each upper limb has 32 bones: 2 in shoulder, 3 in arm, 8 in wrist, 19 in hand and fingers. Each lower limb has 31 bones: 1 in hip (one side of pelvis), 4 in leg, 7 in ankle, 19 in foot and toes. Total = 206 bones

DO NOW List the functions of the skeletal system What are the four parts of bone? List and describe their function.

1. Cranium 2 Mandible 4. Clavicle 3. Scapula 5. Sternum 6. Humerus 7. Ribs (Costa) 8. Floating Ribs 22. Vertebrae 9. Radius 11. Pelvis 10. Ulna 12. Carpals 13. Metacarpals 14. Phalanges 15. Femur 16. Patella 18. Fibula Fracture 17. Tibia 19. Tarsals 20. Metatarsals 21. Phalanges

Cartilage Soft, flexible tissue which provides a cushion between bones and absorbs shock while allowing some flexibility. Found where two bones meet Found between vertebrae Found where ribs meet the sternum. Found in tip of nose and ears.

Interesting Facts Baby skeletons are made of cartilage, by the age of two cartilage has turned to bone. Cartilage on our ears and nose continue to grow all our lives.

DO NOW What is cartilage? What is the function of cartilage and where do you find it?

Where Bone meets Bone… Joints Types of Joints Same Here! Nice to meet you! Joints Where bone attaches to another bone Described by their movements Types of Joints Immovable (Fixed) Semi-Movable Movable

Joints The bones join together to form joints. Our bones are held together by strong stretchy bands called ligaments.

Five major joints 1. Immovable: Where two bones meet, but there is no movement.

2. Ball and Socket: A ball-like structure on one bone fits into a socket of another bone. Can move 360º

3. Hinge: Can move in only one direction like a hinge on a door.

4. Gliding: One part of a bone slides over another bone 4. Gliding: One part of a bone slides over another bone. They move in a back and forth motion. Wrist, ankle, vertebrae

5. Pivot: One bone rotates while the other stays stationary 5. Pivot: One bone rotates while the other stays stationary. Turning your head. Also found where your radius and ulna meet.

The knee Joint

DO NOW 1. Which joint only bends in one direction? 2. Which joint has the most range of motion? 3. Which joint involves one bone sliding over the other? 4. Give an example of a pivot joint.

BUT WHAT MAKES OUR BONES MOVE?!

Muscles

Functions of Muscles MOVEMENT! Muscles contract and relax to allow movement. They move your bones. They pump blood.

Both lists involve muscles, what is different about them? Heart beating running Peristalsis sitting Blinking turning your head

Voluntary Vs. Involuntary Voluntary Muscle: Muscles you can consciously control. Involuntary Muscle: Muscle you do not consciously control them.

Difference between voluntary and involuntary muscle Striated or smooth cells. Striations make the muscle stronger.

Striated muscle is voluntary and strong. Smooth muscle is involuntary.

3 Types of Muscle 1. Striated (skeletal) Muscle: This muscle moves bone and is striated and voluntary.

2. Smooth Muscle This muscle is smooth and involuntary. Ex: Digestive system Blinking choking

3. Cardiac Muscle Only found in the heart Unique because it is striated and involuntary. Why? This makes the muscle strong and you don’t have to tell your heart to beat.

DO NOW Give an example of voluntary and involuntary muscle. What is the difference between striated and smooth muscle.

Tendons Tendons attach muscle to bone.

How do muscles work? 1. Muscles always pull bones, they never push. 2. Muscles always work in pairs. When one muscle contracts, the other relaxes. Ex: biceps and triceps

Interesting Facts Muscles use oxygen for energy. When oxygen runs out another pathway is used and you buildup of lactic acid which causes cramps. There are a specific number of muscles in your body, exercise makes each muscle cell bigger.