Chapter 6 the skeletal system

Chapter 6: The Skeletal System

© 2013 John Wiley & Sons, Inc. All rights reserved.


The Skeletal System Functions of bone and the skeletal system Types of bones Bone formation Exercise and bone tissue Divisions of the skeletal system Skull and hyoid bone Vertebral column Thorax Pectoral (shoulder) girdle Upper limb Pelvic (hip) girdle Lower limb Comparison of female and male skeletons Aging and the skeletal system


Functions of Bone and the Skeletal System

Support Provides a structural framework for the body

Protection Protects many internal organs from injury

Assistance in movement Provides skeletal muscle attachments


Functions of Bone and the Skeletal System Mineral homeostasis

Bone tissue stores several minerals, especially calcium and phosphorus

Blood cell production Within certain bones a connective tissue called

red bone marrow produces red blood cells Triglyceride storage

Yellow bone marrow consists mainly of adipose cells, which store triglycerides

Types of Bones Long bones have greater length than width and consist of a shaft and a

variable number of ends. They are usually somewhat curved for strength. Long bones include those in the thigh (femur), leg (tibia and fibula), arm (humerus), forearm (ulna and radius), and fingers and toes (phalanges).

Short bones are somewhat cube-shaped and nearly equal in length and width. Examples of short bones include most wrist and ankle bones.

Flat bones are generally thin, afford considerable protection, and provide extensive surfaces for muscle attachment. Bones classified as flat bones include the cranial bones, which protect the brain; the sternum (breastbone) and ribs, which protect organs in the thorax; and the scapulae (shoulder blades).

Irregular bones have complex shapes and cannot be grouped into any of the previous categories. Such bones include the vertebrae and some facial bones.



Structureof Bones


Structure of Bones


Anatomy Overview:

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• Bone Structure and Tissues


Animation:


• Bone Growth and Remodeling


Bone Formation


Animation:


• Bone Formation


Bone Formation – Fractures

A fracture (FRAK-choor) is any break in a bone. Types of fractures include the following: Partial: an incomplete break across the bone, such as

a crack. Complete: a complete break across the bone; that is,

the bone is broken into two or more pieces. Closed (simple): the fractured bone does not break

through the skin. Open (compound): the broken ends of the bone

protrude through the skin.


Bone Formation – Fractures Repair of a fracture involves several steps

First, phagocytes begin to remove any dead bone tissue

Then, chondroblasts form fibrocartilage at the fracture site that bridges the broken ends of the bone

Next, the fibrocartilage is converted to spongy bone tissue by osteoblasts

Finally, bone remodeling occurs, in which dead portions of bone are absorbed by osteoclasts and spongy bone is converted to compact bone


Bone Formation

Bone’s role in calcium homeostasis


Animation:


• Regulation of Bone Growth & Blood Calcium


Exercise and Bone Tissue Within limits, bone tissue has the ability to alter its

strength in response to mechanical stress When placed under stress, bone tissue becomes

stronger through increased deposition of mineral salts and production of collagen fibers

Without mechanical stress, bone does not remodel normally because resorption outpaces bone formation

The absence of mechanical stress weakens bone through decreased numbers of collagen fibers and demineralization, loss of bone minerals


Exercise and Bone Tissue


Animation:


• Bone Dynamics and Tissue


Divisions of the Skeletal System


Anatomy Overview:


• The Skeletal System


Skull and Hyoid Bone


Vertebral Column


Vertebral Column Cervical

vertebrae


Thoracic Vertebrae


Lumbar Vertebrae


Sacrum and Coccyx


Vertebral Column Identify the vertebrae


Thorax


Pectoral (Shoulder) Girdle


UpperLimb


Pelvic (Hip) Girdle


Lower Limb


LowerLimb


Lower Limb


Comparison of Female and Male Skeletons


Aging and the Skeletal System

End of Chapter 6

Copyright 2013 John Wiley & Sons, Inc. All rights reserved. Reproduction or translation of this work beyond that permitted in section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permission Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publishers assumes no responsibility for errors, omissions, or damages caused by the use of these programs or from the use of the information herein.


Chapter 6 the skeletal system

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Transcript of Chapter 6 the skeletal system