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Third Grade Science 4th Quarter

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Presentation on theme: "Third Grade Science 4th Quarter"— Presentation transcript:

1 Third Grade Science 4th Quarter
Your Skeletal System Third Grade Science 4th Quarter

2 Bones Your bones are part of your skeleton.
Your bones give your body support. Without your bones you could not sit or stand, walk or run, skate, or swim. Your bones protect the important organs in your body.

3 Bones Your bones protect the important organs in your body.
The skull protects the brain. It is like a hard hat. Your ribs protect the heart, lungs, and stomach.

4 Interesting Facts You were born with 300 bones. By the time you graduate from high school you will have 206 bones. How many more bones did you have when you were born than you will have when you graduate?

5 Speedy Bone Facts The femur is the thigh bone. It is the largest bone in the body. The shortest bone is in your middle ear. It is called the stirrup, or stapes. More than half the bones in your body are in your hands and feet. Humans have the same number of neck bones as giraffes and mice.

6 Bones Bones are made of cells.
Bones are living parts of your body that grow and change just as you do. You began your life with 300 bones. As you grow your bones fuse together. How many bones will you have when you graduate?

7 A Closer Look at Bones The outside of the bone is hard. It is made up of living bone cells that form rings around tiny canals through which blood vessels pass. The inside is a honeycomb of bone cells with spaces between them. This is called spongy bone. Minerals are stored inside the bone.

8 A Closer Look at Bones The hollow centers of many bones are filled with jellylike red and yellow marrow. Yellow marrow stores fat and releases it when it is needed elsewhere in the body. Red marrow is a tissue that makes red and white blood cells and platelets.

9 A Closer Look at Bones Red bone marrow makes up to five thousand million red bloods cells and thousands upon thousands of white blood cells and platelets each day.

10 A Closer Look at Bones Red blood cells are the cells that carry oxygen throughout the body.

11 A Closer Look at Bones White blood cells are the cells that fight disease and infection.

12 A Closer Look Inside The platelets help the blood to clot after injury.


14 Bone Connection Bones are connected together by ligaments at the joints. Cartilage is another kind of connective tissue found in joints and at the ends of bones. Bones are moved by muscles that are attached to them

15 What is a skeleton? The skeleton is a column of interlinked bones, with two legs attached at the bottom and two arms and a skull attached at the top.

16 The Skull The skull is a bony case that supports and protects the brain and some of the body’s sense organs, such as the eyes and ears. There are twenty-nine different bones in the skull. The part of the skull that surrounds the brain is called the cranium.

17 The SKull Fourteen facial bones form the framework for the eyes, nose, cheekbones, and upper and lower jaw. Upper jaw is called the maxilla. Lower jaw is called the mandible. The lower jaw can move from side to side and up and down.

18 Backbone Your backbone, or spine is a flexible column of bones that runs sown the middle of your body. It is made up of thirty-three small bones called vertebrae

19 Rib Cage Your rib cage forms a protective shell for some of your most important organs, including your heart, lungs, stomach, and liver.

20 Collarbone and Shoulder Bone

21 Hands The hand has twenty-seven bones in three groups: the phalanges in the fingers and thumbs, the carpals in the wrist, and the metacarpal in the palm.

22 Hands There are fourteen finger bones – three in each finger and two in each thumb. The joints in the fingers are called knuckles. The wrist is made up of eight small bones arranged in two rows and held tightly with ligaments. Five long bones make up the palm.

23 Names of Bones Femur – thigh bone Pelvis - hip bone Cranium – skull
Ulna-Radius– lower arm bones Humerus – upper arm bone

24 Closing Read the book Bones Our Skeletal System to learn more interesting facts about the skeletal system. Write down five facts that you have learned about your bones.

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