The Functions of the Skeletal System

The Functions of the Skeletal System The Functions of the Skeletal System Bởi: OpenStaxCollege Bone, or osseous tissue, is a hard, dense connective tissue that forms most of the adult skeleton, the support structure of the body In the areas of the skeleton where bones move (for example, the ribcage and joints), cartilage, a semi-rigid form of connective tissue, provides flexibility and smooth surfaces for movement The skeletal system is the body system composed of bones and cartilage and performs the following critical functions for the human body: • • • • • supports the body facilitates movement protects internal organs produces blood cells stores and releases minerals and fat Support, Movement, and Protection The most apparent functions of the skeletal system are the gross functions—those visible by observation Simply by looking at a person, you can see how the bones support, facilitate movement, and protect the human body Just as the steel beams of a building provide a scaffold to support its weight, the bones and cartilage of your skeletal system compose the scaffold that supports the rest of your body Without the skeletal system, you would be a limp mass of organs, muscle, and skin Bones also facilitate movement by serving as points of attachment for your muscles While some bones only serve as a support for the muscles, others also transmit the forces produced when your muscles contract From a mechanical point of view, bones act as levers and joints serve as fulcrums ([link]) Unless a muscle spans a joint and contracts, a bone is not going to move For information on the interaction of the skeletal and muscular systems, that is, the musculoskeletal system, seek additional content 1/7 The Functions of the Skeletal System Bones Support Movement Bones act as levers when muscles span a joint and contract (credit: Benjamin J DeLong) Bones also protect internal organs from injury by covering or surrounding them For example, your ribs protect your lungs and heart, the bones of your vertebral column (spine) protect your spinal cord, and the bones of your cranium (skull) protect your brain ([link]) 2/7 The Functions of the Skeletal System Bones Protect Brain The cranium completely surrounds and protects the brain from non-traumatic injury Career Connection Orthopedist An orthopedist is a doctor who specializes in diagnosing and treating disorders and injuries related to the musculoskeletal system Some orthopedic problems can be treated with medications, exercises, braces, and other devices, but others may be best treated with surgery ([link]) Arm Brace An orthopedist will sometimes prescribe the use of a brace that reinforces the underlying bone structure it is being used to support (credit: Juhan Sonin) 3/7 The Functions of the Skeletal System While the origin of the word “orthopedics” (ortho- = “straight”; paed- = “child”), literally means “straightening of the child,” orthopedists can have patients who range from pediatric to geriatric In recent years, orthopedists have even performed prenatal surgery to correct spina bifida, a congenital defect in which the neural canal in the spine of the fetus fails to close completely during embryologic development Orthopedists commonly treat bone and joint injuries but they also treat other bone conditions including curvature of the spine Lateral curvatures (scoliosis) can be severe enough to slip under the shoulder blade (scapula) forcing it up as a hump Spinal curvatures can also be excessive dorsoventrally (kyphosis) causing a hunch back and thoracic compression These curvatures often appear in preteens as the result of poor posture, abnormal growth, or indeterminate causes Mostly, they are readily treated by orthopedists As people age, accumulated spinal column injuries and diseases like osteoporosis can also lead to curvatures of the spine, hence the stooping you sometimes see in the elderly Some orthopedists sub-specialize in sports medicine, which addresses both simple injuries, such as a sprained ankle, and complex injuries, such as a torn rotator cuff in the shoulder Treatment can range from exercise to surgery Mineral Storage, Energy Storage, and Hematopoiesis On a metabolic level, bone tissue performs several critical functions For one, the bone matrix acts as a reservoir for a number of minerals important to the functioning of the body, especially calcium, and potassium These minerals, incorporated into bone tissue, can be released back into the bloodstream to maintain levels needed to support physiological processes Calcium ions, for example, are essential for muscle contractions and controlling the flow of other ions involved in the transmission of nerve impulses Bone also serves as a site for fat storage and blood cell production The softer connective tissue that fills the interior of most bone is referred to as bone marrow ([link]) There are two types of bone marrow: yellow marrow and red marrow Yellow marrow contains adipose tissue; the triglycerides ...Wireless CommunicationsUnderstanding Radio Frequency Communications 2Objectives•List the components of a radio system•Describe how different factors affect the design of a radio system•Explain the radio frequency spectrum 3Components of a Radio System•Components include:–Filters–Mixers–Amplifiers–Antennas 4Filters•Filter–Removes unwanted RF signals•RF filter–Either passes or rejects a signal based on frequency•Types of filters–Low-pass filter–High-pass filter–Bandpass filter 5Mixers•Combine two radio frequency inputs to create a single output–Output is in the range of the highest sum and the lowest difference of the two frequencies–Sum and differences are known as the sidebands of the frequency carrier•Shield transmitted signal from “stray” signals•Used to convert an input frequency to a specific desired output frequency 6Mixers (continued) 7Amplifiers•Increase the amplitude of an RF signal•RF signals tend to lose intensity (amplitude)–When they move through circuits, air, or space•Amplifier is an active device–Must be supplied with electricity•Increases a signal’s intensity or strength–By using the input signal to control a circuit that “shapes” the output•To reflect the shape of the input signal exactly 8Amplifiers (continued) 9Antennas•Transmit or receive an RF signal 10Multiple Access•Only a limited number of frequencies are available for radio transmission–Conserving the use of frequencies is important•Conserving a frequency–Share a frequency among several individual users•Methods that allow multiple access–Frequency Division Multiple Access (FDMA)–Time Division Multiple Access (TDMA)–Code Division Multiple Access (CDMA) [...]... signal strength falls near the level of noise – Interference can take place • To reduce the interference of noise – Boost the strength of the signal – Use of filters when receiving the signal • Attenuation – A loss of signal strength • Multipath distortion – As a radio signal is transmitted, the electromagnetic waves spread out 13 Multiple Access (continued) • Time Division Multiple Access (TDMA) – Divides... (TDMA) – Divides the transmission time into several slots – Each user is assigned the entire frequency for the transmission • For a fraction of time on a fixed, rotating basis – Advantages • Uses the bandwidth more efficiently • Allows both data and voice transmissions to be mixed using the same frequency 14 Multiple Access (continued) 3 Components of a Radio System • Components include: – Filters – Mixers – Amplifiers – Antennas ... include: – Filters – Mixers – Amplifiers – Antennas 22 Signal Strength • Strength of the signal in a radio system – Must be sufficient for the signal to reach its destination • With enough amplitude to be picked up by the antenna • And for the information to be extracted from it • Electromagnetic interference (EMI) – One factor that affects radio Lesson 15-The power systems of Diesel Engine The power systems of a diesel engine are a primary part of a power plant, the function of which is to guarantee proper operation of the power plant and which mainly consist of F. O. system, L. O. system, cooling system and compressed air system. Let us deal with them one by one. 1. The Fuel Oil System The basic mission of F. O. system is to supply M. E. , aux.engine and aux. boiler with sufficient clean fuel oil.The fuel oil needed by a vessel is to be fed and stored through oil filling port and via oil charging piping. For medium and large vessels, fuel oil to be stored in F. O. tanks in the double bottom. F. O. transfer pumps are required for F. O. delivery among various tanks, such as service tank, storage tank, settling tank and separate F. O. tanks. Any fuel oil must go through filtering, settling and centrifugal separation before it enters the engine so as to ensure the reliable and continuous running of the engine since it contains a certain amount of impurities and water. On the condition that a heavy oil with high viscosity is in service, it should be pre-heated before coming into use. Moreover, for the measurement and indication of F. O. tank level, a level gauge is to be equipped with; for a timely mastery of M. E. oil consumption, a F. O. meter will be relied upon; for the measurement of F. O. temperature, a thermometer is not dispensable. In a word, the functions of F.O.system can be described as feeding,transferring,purifying, measuring and supplying. 2. The Lube Oil System The task of lube oil system is to provide the surfaces of different moving parts with a moderate amount of lube oil so as to form a lubricant film and avoid a dry friction between various parts. In addition to the reduction of friction resistance and wearing off, the lube oil system serves to help a lot in cooling, flushing, gas tightness, rust prevention and decrease of vibration. Fig. 15.1 1-oil tank-két dầu ; 2-filter bầu lọc ; 3-pressure adjusting valve-van điều chỉnh áp lực; 4-oil purifier-bộ tinh lọc dầu ; 5-filter-bộ lọc ; 6-cooler-bầu làm mát In fact, the lube oil system for a diesel power plant can be subdivided into two components, the inner system and the exterior one. The lube oil for the inner system is to be provided together with that for the diesel engine; whereas most exterior systems are of forced lubrication, with lube oil forced to each friction position by a lube oil pump. And this lubrication method is widely used at the present time. As usual, a low-speed marine diesel engine owns five independent lubrication systems: (1)Lubrication for moving parts, e. g. main bearings, crosshead, etc. (2)Lubrication for M. E. camshaft. (3)Lubrication between piston and cylinder. (4)Lubrication for turbocharger. (5 )Lubrication for aux. machinery. Furthermore, different lubrication positions should match with different kinds of lube oil. For instance, incombustible cylinder oil with high viscosity to be adopted for the lubrication between piston and cylinder liner since the lubrication is fulfilled under the condition of the high temperature of combustion gas; turbine oil with low viscosity to be employed for the lubrication of turbocharger owing to its high rpm. In respect to the rest of the lubrication positions, general engine oil may be safely taken. 3. The Cooling System Some mechanical equipment in a diesel power plant will turn out continuous heat during operation, part of which derives from the hot combustion gas in cylinders and the rest of which results from the friction of moving parts. If the above heat should not be carried away in Basic Immunology Updated Functions and Disorders of the Immune System Abul K Abbas, MBBS Professor and Chair Department of Pathology University of California San Francisco, School of Medicine San Francisco, California Andrew H Lichtman, MD, PhD Professor of Pathology Harvard Medical School Brigham and Women’s Hospital Boston, Massachusetts Illustrated by David L Baker, MA, and Alexandra Baker, MS, CMI 1600 John F Kennedy Blvd Ste 1800 Philadelphia, PA 19103-2899 BASIC IMMUNOLOGY: FUNCTIONS AND DISORDERS OF THE IMMUNE SYSTEM Copyright © 2011 by Saunders, an imprint of Elsevier Inc ISBN: 978-1-4160-5569-3 All rights reserved No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher Permissions may be sought directly from Elsevier’s Rights Department: phone: (+1) 215 239 3804 (US) or (+44) 1865 843830 (UK); fax: (+44) 1865 853333; e-mail: healthpermissions@elsevier.com You may also complete your request on-line via the Elsevier website at http://www.elsevier.com/permissions Notice Knowledge and best practice in this field are constantly changing As new research and experience broaden our knowledge, changes in practice, treatment, and drug therapy may become necessary or appropriate Readers are advised to check the most current information provided (i) on procedures featured or (ii) by the manufacturer of each product to be administered, to verify the recommended dose or formula, the method and duration of administration, and contraindications It is the responsibility of the practitioner, relying on his or her own experience and knowledge of the patient, to make diagnoses, to determine dosages and the best treatment for each individual patient, and to take all appropriate safety precautions To the fullest extent of the law, neither the Publisher nor the Editors assumes any liability for any injury and/or damage to persons or property arising out of or related to any use of the material contained in this book The Publisher Previous editions copyrighted 2009, 2006, 2004, 2001 Library of Congress Cataloging-in-Publication Data Abbas, Abul K Basic immunology: functions and disorders of the immune system / Abul K Abbas, Andrew H Lichtman – 3rd ed p ; cm Includes bibliographical references and index ISBN 978-1-4160-5569-3 Immunology Immunity I Lichtman, Andrew H II Title [DNLM: Immunity Hypersensitivity Immune System–physiology Immunologic Deficiency Syndromes QW 504 A122b 2009] QR181.A28 2009 616.07’9–dc22 2007030085 Acquisitions Editor: William Schmitt Developmental Editor: Rebecca Gruliow Editorial Assistant: Laura Stingelin Design Direction: Gene Harris Printed in China Last digit is the print number: Working together to grow libraries in developing countries www.elsevier.com | www.bookaid.org | www.sabre.org To Ann, Jonathan, Rehana, Sheila, Eben, Ariella, Amos, Ezra This page intentionally left blank PREFACE T he third edition of Basic Immunology has been revised to incorporate recent advances in our understanding of the immune system and to improve upon how we present information to maximize its usefulness to students and teachers We have been extremely gratified with how well the previous two editions of Basic Immunology have been received by students in the courses that we teach, and the guiding principles on which the book is based have not changed from the first edition As teachers of immunology, we are becoming increasingly aware that assimilating detailed information and experimental approaches is difficult in many medical school and undergraduate courses The problem of how much detail is appropriate has become a pressing one because of the continuous and rapid increase in the amount of information in all the biomedical sciences This problem is compounded by the development of integrated curricula in many medical schools, with reduced CHAPTER 24 The Skeletal System 24-2 Learning Outcomes (cont.) 24.1 Describe the structure of bone tissue 24.2 Explain the functions of bones 24.3 Compare intramembranous and endochondral ossification 24.4 Describe the skeletal structures and one location of each structure 24-3 Learning Outcomes (cont.) 24.5 Locate the bones of the skull 24.6 Locate the bones of the spinal column 24.7 Locate the bones of the rib cage 24.8 Locate the bones of the shoulders, arms, and hands 24-4 Learning Outcomes (cont.) 24.9 Locate the bones of the hips, legs, and feet 24.10 Describe the three major types of joints and give examples of each 24.11 Describe the common diseases and disorders of the skeletal system 24-5 Introduction • Bones provide structure and support • 206 bones plus joints and connective tissue • Divisions – Axial ~ 80 bones • Skull • Vertebral column • Rib cage – Appendicular ~ 126 bones • Arms and legs • Pectoral girdle • Pelvic girdle 24-6 Bone Structure • Bones contain various kinds of tissues – – – • Osseous tissue Blood vessels Nerves Osseous tissue can appear compact or spongy Spongy (Cancellous) Bone Compact Bone 24-7 Bone Structure (cont.) • Structures within compact bone – – – – – • Osteons Bone matrix Lamella Lacunae Canaliculi All bones are made up of both compact and spongy bone 24-8 Bone Structure (cont.) • Long bones – Femur and humerus – Parts • Diaphysis • Epiphysis • Articular cartilage • Medullary cavity • Periosteum • Endosteum 24-9 Bone Structure (cont.) • Short bones • Flat bones • Irregular bones • Sesamoid bones 24-10 Gender Differences in Skeletal Structure • Male Skull – Larger and heavier • Male pelvis – Bones are heavier and thicker – Forehead shorter – Cavity is narrower – Face less round – Jaw larger 24-45 Joints (cont.) • Cartilaginous joints – Disc of cartilage – Slightly moveable – Between vertebrae 24-46 Joints (cont.) • Synovial joints – Covered with hyaline cartilage – Fibrous joint capsule – Freely movable – Ligaments hold bones together 24-47 Apply Your Knowledge Match the following: ANSWER: A Fibrous joints B Cartilaginous joints C Synovial joints A Between cranial bones and facial bones C Covered with hyaline cartilage B Between vertebrae C Freely movable A Sutures in the skull 24-48 Common Diseases and Disorders of the Skeletal System • Arthritis – Osteoarthritis • • Degenerative joint disease (DJD) Weight-bearing joints – Rheumatoid arthritis • • Chronic systemic inflammatory disease Smaller joints and surrounding tissues Common Diseases and Disorders of the Skeletal System (cont.) • Bursitis – inflammation of the bursa • Ewing sarcoma family of tumors (ESFT) – Primarily affect bone – Usually lower extremities • Gout – deposits of uric acid crystals in joints 24-49 Common Diseases and Disorders of the Skeletal System (cont.) • Kyphosis – humpback • Lordosis –swayback • Osteogenesis imperfecta – brittle-bone disease • Osteoporosis – thin, porous bones 24-50 24-51 Common Diseases and Disorders of the Skeletal System (cont.) • Osteosarcoma – bone cancer from osteoblasts • Paget’s disease – bones enlarge, become deformed, and weak • Scoliosis – an abnormal S-shaped curvature of the spine 24-52 Apply Your Knowledge What is the difference between osteoarthritis and rheumatoid arthritis? Osteoarthritis is a degenerative joint disease that primarily affects weight-bearing joints Rheumatoid arthritis chronic systemic ... prescribe the use of a brace that reinforces the underlying bone structure it is being used to support (credit: Juhan Sonin) 3/7 The Functions of the Skeletal System While the origin of the word... and fat, and hematopoiesis Together, the muscular system and skeletal system are known as the musculoskeletal system Review Questions Which function of the skeletal system would be especially important... cartilage and has many functions Choose three of these functions and discuss what features of the skeletal system allow it to accomplish these functions It supports the body The rigid, yet flexible