The Skeletal System: Bones, An Overview

Warm-Up 1. Name as many parts of the skeleton as you can think of. 2. Have you broken a bone or know someone who has? If so which one/s - any gnarly bone breaks you had or know of? 3. Explain what is happening in the video

The Skeletal System Parts of the skeletal system Bones (skeleton) Joints Cartilages Ligaments Divided into two divisions Axial skeleton Appendicular skeleton Slide 5.1 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Axial Skeleton: The head and trunk Shade in the axial Skeleton on your notes

Appendicular Skeleton: makes motion possible Shade in the appendicular Skeleton with your pencil/pen

Quick Quiz 1 of 7 Where is the Axial Skeleton Located? What is the function of the Appendicular Skeleton? Name the 4 parts of the skeleton

Functions of Bones Support of the body Protection of soft organs Movement due to attached skeletal muscles Storage of minerals and fats Blood cell formation Slide 5.2 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Bones of the Human Body The skeleton has 206 bones Two basic types of bone tissue Compact bone Homogeneous Spongy bone Small needle-like pieces of bone Many open spaces Figure 5.2b Slide 5.3 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Classification of Bones Long bones Typically longer than wide Have a shaft with heads at both ends Contain mostly compact bone Ex: Femur, humerus Slide 5.4a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Quiz 2 of 7 1. 2 functions of the skeletal system are - 2. Give an example of a long bone and a short bone.

Classification of Bones Short bones Generally cube-shape Contain mostly spongy bone Ex: Carpals, tarsals Slide 5.4b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Classification of Bones Flat bones Thin and flattened Usually curved Thin layers of compact bone around a layer of spongy bone Ex: Skull, ribs, sternum Slide 5.5a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Classification of Bones Irregular bones Irregular shape Do not fit into other bone classification categories Ex: Vertebrae and hip Slide 5.5b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Quick Quiz 3 of 7 What kind of bone can be found in the skull? Name an irregular bone.

Classification of Bones on the Basis of Shape Figure 5.1 Slide 5.5c Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Gross Anatomy of a Long Bone Diaphysis Shaft Composed of compact bone Epiphysis Ends of the bone Composed mostly of spongy bone Figure 5.2a Slide 5.6 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Structures of a Long Bone Periosteum Outside covering of the diaphysis Fibrous connective tissue membrane Sharpey’s fibers Secure periosteum to underlying bone Arteries Supply bone cells with nutrients Figure 5.2c Slide 5.7 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Quiz 4 of 7 1. Epi means ‘on top of’. How does that relate to the definition of epiphysis? 2. Since bone is a living tissue it needs nutrients. How does it get them?

Structures of a Long Bone Articular cartilage Covers the external surface of the epiphyses Made of hyaline cartilage Decreases friction at joint surfaces Figure 5.2a Slide 5.8a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Structures of a Long Bone Medullary cavity Cavity of the shaft Contains yellow marrow (mostly fat) in adults Contains red marrow (for blood cell formation) in infants Figure 5.2a Slide 5.8b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Bone Markings Surface features of bones Sites of attachments for muscles, tendons, and ligaments Passages for nerves and blood vessels Categories of bone markings Projections and processes – grow out from the bone surface Depressions or cavities – indentations Slide 5.9 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Quiz 5 of 7 1. Why is it that when people get older they start having knee and joint pain? 2. identify some structures that need to attach to bones.

Microscopic Anatomy of Bone Figure 5.3 Slide 5.10b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Microscopic Anatomy of Bone Lacunae Cavities containing bone cells (osteocytes) Arranged in concentric rings Lamellae Rings around the central canal Sites of lacunae Figure 5.3 Slide 5.11a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Changes in the Human Skeleton In embryos, the skeleton is primarily hyaline cartilage During development, much of this cartilage is replaced by bone Cartilage remains in isolated areas Bridge of the nose Parts of ribs Joints Slide 5.12 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Quiz 6 of 7 1. Notice the arteries that run through bone. Why do we see bruises when we break a bone? 2. Finish this sentence I still have cartilage in my _________________________________________________

Bone Growth Bones are remodeled and lengthened until growth stops Bones change shape somewhat Bones grow in width Slide 5.13b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Long Bone Formation and Growth Figure 5.4b Slide 5.14b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Types of Bone Cells Osteocytes Osteoblasts Osteoclasts Mature bone cells Osteoblasts Bone-forming cells Osteoclasts Bone-destroying cells Break down bone matrix for remodeling and release of calcium Bone remodeling is a process by both osteoblasts and osteoclasts Slide 5.15 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Quick Quiz 7 of 7 1. What is an Osteoblast? 2. As women get older they some have an imbalance of osteoblast function and osteoclast function. What can result and why is that bad?

Questions for Verbal Skeleton Quiz You will need to be able to identify… Names of bones Divisions of the skeletal system- Axial vs Appendicular Types of bones- flat, long, short, irregular Example question: Point to and identify an irregular bone