Presentation on theme: "7.2 The Skeletal System Key terms: skeleton, vertebrae, joint, ligament, cartilage, compact bone, spongy bone, marrow, osteoporosis Key concepts: What."— Presentation transcript:
1 7.2 The Skeletal SystemKey terms: skeleton, vertebrae, joint, ligament, cartilage, compact bone, spongy bone, marrow, osteoporosisKey concepts: What are the functions of the skeleton? What role do joints play in the body? What are the characteristics of bone, and how can you keep your bones strong and healthy?
2 What the skeletal system does Skeleton – framework of bonesThe number of bones in your body depends on your age. Why?Bones fuse together as you grow. A baby has 275, a fully-grown adult has 206.
3 What the skeletal system does Your skeleton has five major functions:Shape and supportMovementProtects organs (think about your lungs!)Produces blood cells (in the marrow)Stores minerals until your body needs them
4 Shape and supportYour skeleton provides a shape for your body, and points of attachment for your musclesVertebrae – 26 small bones that make up your backbone
5 Movement and protection Your skeleton allows you to move. Muscles pull on the bones to make the body move
6 Production and storage of substances Bones make blood cells and store calcium and phosphorous
7 Joints of the skeletonJoint – a place in the body where two bones come togetherJoints allow bones to move in different waysTwo kinds: immoveable and movable
8 JointsImmovable – these joints connect bones that provide little or no movement. Example: bones in the head are held together by immovable jointsMoveable – mostly 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.
10 Bones – strong and living Bones are complex living structures that undergo growth and developmentFun fact: longest bone in the body is the femur!
11 Bone structureA thin, tough membrane covers all of bones except their endsBlood vessels and nerves enter and leave through the membraneBeneath the membrane is a layer of compact bone (hard and dense but not solid)Inside the compact bone is a layer of spongy bone which has many small spaces within itSpaces in many bones contain a connective tissue called marrow.
14 Marrow Two types – red and yellow Red marrow produces most of the body’s red blood cellsAs a child, most of your bones contained red marrow. As a teen, only the ends of your femurs, skull, hip bones, and sternum contain red marrow.Yellow marrow stores fat
15 Bone strength and growth The structure of bone makes it both long and lightweightBones are alive – they contain cells and tissues. Bone continues to grow even after you are full grown to correspond to use and weight. Heavier people have thicker bones.
16 Bone developmentCartilage from youth is replaced by bone as you get older.Your ears and the tip of your nose are made of cartilageYour skull is made of bone. Feel the difference?
17 Taking care of your bones Balanced diet and regular exerciseGet enough calcium and phosphorous. Soda and caffeine can take calcium out of you, fyi.Exercise – weight-bearing activities help keep your bones healthyOsteoporosis – mineral loss creates weak bones. More common in women than men.