1. THE SKELETAL AND MUSCULAR SYSTEMS Grade 7 Science

2. VIDEOS BONES: http://kidshealth.org/PageManager.jsp?li c=1&article_set=59294&cat_id=20607 http://kidshealth.org/PageManager.jsp?li c=1&article_set=59294&cat_id=20607 MUSCLES: http://kidshealth.org/PageManager.jsp?li c=1&article_set=59302&cat_id=20607 http://kidshealth.org/PageManager.jsp?li c=1&article_set=59302&cat_id=20607

3. We sure have a lot of bones! A newborn baby has more bones than an adult. A baby is born with 305 bones. An adult only has 206.

4. INTERESTING FACTS… Babies have 305 bones whereas adults have 206 bones. This is because as we grow, some of our bones join together to form one bone. The longest bone in our body is the femur (thigh bone). The smallest bone is the stirrup (bone inside the ear). Our nose and ears are not made of bone - they are made of cartilage, a flexible substance that is not as hard as bone. Differences between males and females : Males and females have slightly different skeletons, including a different elbow angle. Males have slightly thicker and longer legs and arms; females have a wider pelvis and a larger space within the pelvis, through which babies travel when they are born.

5. INTERESTING FACTS… Your hand has 27 bones!

6. INTERESTING FACTS… Babies are born without the patella (knee bone) – it develops between the age of 2 and 5.

7. INTERESTING FACTS… One quarter of your bones are located in your feet!

8. INTERESTING FACTS… There are 14 bones in your face.

9. LOOKING AT THE SKELETON The Skeleton is the name given to the collection of bones that holds our body up. Without the trunk and branches of a tree, were would the leaves be? Without your skeleton, where would you be?

10. TYPES OF SKELETONS Exo-skeleton: - animals that have shells Endo-skeleton: - hard structure inside the animal No skeleton

11. WHAT ARE THE MAIN FUNCTIONS OF THE HUMAN SKELETON? 1.Protect the vital organs 2. Give us shape 3. Allow us to move because our muscles are attached to our bones 4. Storage of nutrients such as calcium and silicon 5. Formation of blood cells

12. 1. Carpals 2. Cranium 3. Femur 4. Innominate 5. Mandible 6. Metacarpals 7. Metatarsals 8. Phalanges 9. Rib 10. Scapula 11. Sacrum 12. Vertebra 1. Clavicle 2. Fibula 3. Humerus 4. Patella 5. Radius 6. Sternum 7. Tarsals 8. Tibia 9. Ulna On your worksheet, label each of the bones

13. X-RAY MACHINE

14. EXAMPLES OF X-RAYS

15. JOINTS OF THE SKELETON A joint is a place in the body where two bones come together Joints allow bones to move in different ways. There are two kinds of joints: – Immovable joints – Moveable joints Immovable joints allow little or no movement, for example the bones of the skull are held together by immovable joints

16. MOVABLE JOINTS Most of the joints in the body are movable joints which allow the body to make a wide range of movements Movable joints are held together by strong connective tissues called ligaments Most joints have a second type of connective tissue called cartilage – Cartilage covers the ends of the bones and keeps them from rubbing against each other Four types of movable joints: – Hinge joint, Ball-and-socket joint, Pivot joint, Gliding joint

17. MOVABLE JOINTS HINGE JOINT: – Allows forward or backward motion BALL-AND-SOCKET JOINT: – Allows the greatest range of motion in a circular motion

18. MOVABLE JOINTS PIVOT JOINT: – Allows one bone to rotate around another GLIDING JOINT: – Allows one bone to slide over another

19. MOVABLE JOINTS Work with a partner to write down as many example of different joints as you can think of… Move around! Can you feel your joints moving inside you??

20. THE MUSCULAR SYSTEM Muscle : A tissue composed of fibers capable of contracting to effect bodily movement Involuntary muscles : muscles not under your conscious control, eg. your heart Voluntary muscles : muscles under your conscious control, eg. leg muscles There are about 600 muscles in your body which have many functions Every person has a unique tongue print Hiccups are spasm of the diaphragm

21. TYPES OF MUSCLE TISSUE Three types of muscle tissue: – Skeletal muscle – Smooth muscle – Cardiac muscle Both skeletal and smooth muscles are found in many parts of the body Cardiac muscle is found only in the heart Each muscle type performs specific functions in the body

22. SKELETAL MUSCLE Every time you walk, you are using your skeletal muscles Skeletal muscles are attached to the bones of your skeleton and provide the force that moves your bones At the end of a skeletal muscle is a tendon Skeletal muscle cells appear banded, or striated Skeletal muscles are voluntary and react very quickly, however they also tire quickly

23. SMOOTH MUSCLE Many internal organs, such as the stomach and blood vessels, contain smooth muscles Smooth muscles are involuntary muscles They work automatically to control certain movements inside your body, such as those involved in digestion Unlike skeletal muscles, smooth muscle cells are not striated, react more slowly and tire more slowly

24. CARDIAC MUSCLE Cardiac muscle is tissue only found in your heart Cardiac muscle has some characteristics in common with both smooth and skeletal muscle Like smooth muscle, cardiac muscle is involuntary Like skeletal muscle, cardiac muscle in striated, however unlike skeletal muscle, cardiac muscle does not get tired – it can contract repeatedly

25. MUSCLES AT WORK Because muscles can only contract, not extend, skeletal muscles must work in pairs: – While one muscle contracts, the other muscle in the pair relaxes to its original length Example: – Muscle action involved in bending the arm at the elbow: First the biceps muscle on the front of the upper arm contracts to bend the elbow, lifting the forearm and hand – As the biceps muscle contracts, the triceps on the back of the upper arm relaxes and returns to its original length Can you think of other examples??

26. BONES – STRONG AND LIVING Bones are complex living structures that undergo growth and development The word “skeleton” comes from a Greek word meaning “a dried body”

27. BONE STRUCTURE Bones consist of four main parts: 1.Membrane 2.Compact bone 3.Spongy bone 4.Marrow

28. BONE STRUCTURE A thin tough membrane covers all of the bone except the ends – Blood vessels and nerves enter and leave the bone through the membrane Beneath the bone’s outer membrane in a layer of compact bone ― Hard and dense, but not solid ― Small canals run through the compact bone that carry blood vessels and nerves from the bone’s surface to the living cells within the bone

29. BONE STRUCTURE Just inside the compact bone is a layer of spongy bone – Many small spaces within it – Lightweight and strong – Found also at the ends of the bone The spaces in many bones contain a soft, connective tissue called marrow – Two types of marrow: red and yellow – Red bone marrow produces some of the body’s blood cells – Yellow blood marrow stores fat that can serve as an energy reserve

30. BONE STRENGTH The structure of bone makes it both strong and lightweight – Bones are so strong they can absorb more force without breaking than can concrete or granite rock – Bones make up about 20% of an average adult’s body weight – Bones are hard because they contain minerals: primarily phosphorus and calcium

31. BONE GROWTH Bones are alive: – They contain cells and tissues, such as blood and nerves – They form new bone tissue as you grow – Even after you are grown, bone tissue continues to form within your bones, eg. when you play sport or if you break a bone

32. TAKING CARE OF YOUR BONES A combination of a balanced diet and regular exercise are important for a lifetime of healthy bones A well-balanced diet includes: – Calcium and phosphorus – Meats, whole grains, leafy green vegetables, dairy products Getting plenty of exercise: – Running, skating, dancing (anything that requires your bones to support your entire weight)

33. OSTEOPOROSIS As people become older, their bones begin to lose some of the minerals they contain Mineral loss can lead to a condition called osteoporosis in which the body’s bones become weak and break easily Osteoporosis is more common in women than in men Regular exercise is proven to help prevent osteoporosis