Structure, Function, and Diseases The Skeletal System: Structure, Function, and Diseases of the bones and joints

Is this the correct anatomical position?

The Skeletal System Parts of the skeletal system Bones (skeleton) Joints Cartilages Ligaments (bone to bone)(tendon=bone to muscle) Divided into two divisions Axial skeleton- skull, spinal column Appendicular skeleton – limbs and girdle Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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 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 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Bones are classified by their shape: Long- bones are longer than they are wide (femur, humerus) Short- usually square in shape, cube like (carpals, tarsals) Flat- flat, curved (skull, sternum, ribs) Irregular- odd shapes (vertebrae, pelvis)

Classification of Bones on the Basis of Shape Figure 5.1 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 Examples: Femur, humerus Slide 5.4a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Classification of Bones Short bones Generally cube-shape Contain mostly spongy bone Examples: 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 Examples: 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 Example: Vertebrae and hip Slide 5.5b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Gross Anatomy of a Long Bone Diaphysis Shaft Made of compact bone Epiphysis Expanded ends of long bones Covered with dense bone Internal structure is 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 Arteries Supply bone cells with nutrients Figure 5.2c Slide 5.7 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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

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

Repair of Bone Fractures Hematoma (blood clot) is formed Break is splinted by fibrocartilage forms a callus (chondroblasts, other cells, and vessels) Callus is replaced by a bone (osteoblasts) Bony callus is remodeled (osteoclasts) Slide 5.18 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Repair of Bone Fractures Fracture Repair Hematoma formation (A) Callus formation (B) Bone replacement (C ) Bone remodeling (D) A B C D Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Axial skeleton supports and protects organs of head, neck and trunk skull (cranium and facial bones) hyoid bone (anchors tongue and muscles associated with swallowing) vertebral column (vertebrae and disks) bony thorax (ribs and sternum)

Appendicular skeleton includes bones of limbs and bones that anchor them to the axial skeleton shoulder girdle (clavicle, scapula) upper limbs (arms) pelvic girdle (sacrum, coccyx) lower limbs (legs) Articulation- where joints meet, connect, and are formed.

The Axial Skeleton Forms the longitudinal part of the body Divided into three parts Skull Vertebral Column Rib Cage Slide 5.20a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

The Axial Skeleton Slide 5.20b Figure 5.6 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

The Skull 8 sutured bones in cranium Facial bones: 13 sutured bones 1 mandible Cranium encases brain attachments for muscles sinuses

Bones of the Skull Figure 5.11 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Allows for growth

The Vertebral Column Vertebrae separated by intervertebral discs made of cartilage The spine has a normal S curvature Each vertebrae is given a name according to its location Figure 5.14 Slide 5.28 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Thoracic cage ribs thoracic Vertebrae sternum costal cartilages True ribs are directly attached to the sternum (first seven pairs) Three false ribs are joined to the 7th rib Two pairs of floating ribs

Joints A joint, or articulation, is the place where two bones come together. Fibrous- Immovable:connect bones, no movement. (skull and pelvis). Cartilaginous- slightly movable, bones are attached by cartilage, a little movement (spine or ribs). Synovial- freely movable, much more movement than cartilaginous joints. Cavities between bones are filled with synovial fluid. This fluid helps lubricate and protect the bones.

The Synovial Joint Slide 5.51 Figure 5.28 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Types of Synovial Joints Based on Shape Figure 5.29a–c Slide 5.52a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Types of Synovial Joints Based on Shape Figure 5.29d–f Slide 5.52b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Types of synovial joints In ball and socket joints, the rounded end of one bone fits inside a cup-shaped ending on another bone. Ball and socket joints allow movement in all directions and also rotation. The most mobile joints in the body are ball and socket joints. Examples: Shoulders and hips. Hip Describe ball and socket joints at the hip and shoulder. Discuss the movements possible at these joints. How do they help during sport?

Types of synovial joints Pivot joints have a ring of bone that fits over a bone protrusion, around which it can rotate. These joints only allow rotation. Atlas Examples: The joint between the atlas and axis in the neck which allows you to shake your head. Axis

Types of synovial joints In saddle joints, the ends of the two bones fit together in a special way, allowing movement forwards and backwards and left to right, but not rotation. Examples: The thumb is the only one. Hinge joints – as their name suggests – only allow forwards and backwards movement. Examples: The knee and elbow. Elbow

Types of Joints Hinge- 
A hinge joint allows extension and retraction of an appendage. (Elbow, Knee)

Ball and Socket- 
A ball and socket joint allows for radial movement in almost any direction. They are found in the hips and shoulders. (Hip, Shoulder)

Gliding- In a gliding or plane joint bones slide past each other Gliding- 
In a gliding or plane joint bones slide past each other. Mid-carpal and mid-tarsal joints are gliding joints. (Hands, Feet)

Saddle- This type of joint occurs when the touching surfaces of two bones have both concave and convex regions with the shapes of the two bones complementing one other and allowing a wide range of movement. (Thumb)