Functions of the Integumentary System

Functions of the Integumentary System Functions of the Integumentary System Bởi: OpenStaxCollege The skin and accessory structures perform a variety of essential functions, such as protecting the body from invasion by microorganisms, chemicals, and other environmental factors; preventing dehydration; acting as a sensory organ; modulating body temperature and electrolyte balance; and synthesizing vitamin D The underlying hypodermis has important roles in storing fats, forming a “cushion” over underlying structures, and providing insulation from cold temperatures Protection The skin protects the rest of the body from the basic elements of nature such as wind, water, and UV sunlight It acts as a protective barrier against water loss, due to the presence of layers of keratin and glycolipids in the stratum corneum It also is the first line of defense against abrasive activity due to contact with grit, microbes, or harmful chemicals Sweat excreted from sweat glands deters microbes from over-colonizing the skin surface by generating dermicidin, which has antibiotic properties Everyday Connection Tattoos and Piercings The word “armor” evokes several images You might think of a Roman centurion or a medieval knight in a suit of armor The skin, in its own way, functions as a form of armor—body armor It provides a barrier between your vital, lifesustaining organs and the influence of outside elements that could potentially damage them For any form of armor, a breach in the protective barrier poses a danger The skin can be breached when a child skins a knee or an adult has blood drawn—one is accidental and the other medically necessary However, you also breach this barrier when you choose to “accessorize” your skin with a tattoo or body piercing Because the needles involved in producing body art and piercings must penetrate the skin, there are dangers associated with the practice These include allergic reactions; skin infections; blood-borne diseases, such as tetanus, hepatitis C, and hepatitis D; and the growth of scar tissue Despite the 1/8 Functions of the Integumentary System risk, the practice of piercing the skin for decorative purposes has become increasingly popular According to the American Academy of Dermatology, 24 percent of people from ages 18 to 50 have a tattoo Tattooing has a long history, dating back thousands of years ago The dyes used in tattooing typically derive from metals A person with tattoos should be cautious when having a magnetic resonance imaging (MRI) scan because an MRI machine uses powerful magnets to create images of the soft tissues of the body, which could react with the metals contained in the tattoo dyes Watch this video to learn more about tattooing Sensory Function The fact that you can feel an ant crawling on your skin, allowing you to flick it off before it bites, is because the skin, and especially the hairs projecting from hair follicles in the skin, can sense changes in the environment The hair root plexus surrounding the base of the hair follicle senses a disturbance, and then transmits the information to the central nervous system (brain and spinal cord), which can then respond by activating the skeletal muscles of your eyes to see the ant and the skeletal muscles of the body to act against the ant The skin acts as a sense organ because the epidermis, dermis, and the hypodermis contain specialized sensory nerve structures that detect touch, surface temperature, and pain These receptors are more concentrated on the tips of the fingers, which are most sensitive to touch, especially the Meissner corpuscle (tactile corpuscle) ([link]), which responds to light touch, and the Pacinian corpuscle (lamellated corpuscle), which responds to vibration Merkel cells, seen scattered in the stratum basale, are also touch receptors In addition to these specialized receptors, there are sensory nerves connected to each hair follicle, pain and temperature receptors scattered throughout the skin, and motor nerves innervate the arrector pili muscles and glands This rich innervation helps us sense our environment and react accordingly 2/8 Functions of the Integumentary System Light Micrograph of a Meissneer Corpuscle In this micrograph of a skin cross-section, you can see a Meissner corpuscle (arrow), a type of touch receptor located in a dermal papilla adjacent to the basement membrane and stratum basale of the overlying epidermis LM × 100 (credit: “Wbensmith”/Wikimedia Commons) Thermoregulation The integumentary system helps regulate body temperature through its tight association with the sympathetic nervous system, the division of the nervous system involved in our fight-or-flight responses The sympathetic nervous system is continuously monitoring body temperature and initiating appropriate motor responses Recall that sweat glands, accessory structures to the skin, secrete water, salt, and other substances to cool the body when it becomes warm Even when the body does not appear to be noticeably ... Development of the Microfinance system in Russia Anna Kaganova National Business Incubation Association Russian Federation anna_kaganova@mail.ru Small business development in Russia  SMEs have been existing for 12 years;  >5.6 millions (including 4.5 millions of individual entrepreneurs);  90 % of the total number of establishments;  44 % of GDP;  45 % of employment. Sources of financing Commercial banks Regional (State) Funds for Support of Small Entrepreneurship Business partners, relatives or other people Microfinancial Institutes • convinient and especially attractive for entrepreneurs • represent a flexible form of a classical banking credit • permit to set up the business without start-up capital and credit history Basic conditions of Microfinance  IInterest rate is approximately 6-8 % per month in the first borrowing month with its further reduction to 3-4 % per month  TTotal first credit sum fluctuates between $ 500 – 1000 USD  TTerm of payment is till 3 months More advantageous for small size borrowers than classical bank loans Main objective of Microfinance creation of a high dynamic and an effective financial system for SMEs for an additional stimulation of goods and services production and distribution, and also for a mutuality of start-up enterprises in the acquisition of getting profits and a capital accumulation experience Main tasks of Microfinance  to stimulate efficiency access to the financial resources;  to create work places;  to grow of tax proceeds;  to create a credit history for the further development of SMEs through the bank sector;  to barrier SMEs for their transition to the shady sector of economics. Why not a bank? • lack of guarantees; • lack of credit history; • necessity in operating with a small sum of money ($ 500 – 1000 USD); • necessity in quick credit operating (for several days – week); • necessity in other forms of support and consulting; • existent distrust to banks. Microfinancing Programs Position, summary (on Jan, 2003)  Average monthly microloans interest credit rate – 6%  Average loan size – $400 USD  Average volume of credit on one client – $650 USD  Average percentage of a loan repayment – 95%  Loans distribution: • trade – 55%, • rendering of personal services – 24%, • farming – 11%.  63% of all loans are given to beginner entrepreneurs  Demand for Microloans is evaluated on $ 4.5 bln USA Total quantity of MFIs in Russia - approx. 300 MFIs Social Effect of MFIs MFIs create new work places MFIs give an opportunity for economic development for a lot of people in different Russian regions MFIs usually work with economically unprotected entrepreneurs in regions and give them opportunities for economic development More than 70% of program’s clients are women Example: “Credits for Small Enterprises” microfinance program  Credit sum is from $30 till $1000 USD  Term for accepting the decision 1 day  Interest rate is 4 % per month  Guarantee conditions are 2 warranties (husband/wife, business partner or relative) [...]... clients using given them loans  Nowadays: Microfinance activity has become more mature The models of successful operation of MFIs have been worked out, leading to the mature creation MFIs Development Perspectives SMEs meet depositors directly attracting resources from financial institutions reinvestments the National Business Incubator Association of Russia Founded in 1997 by 22 Russian business incubators... Our Projects   APEC Cooperation Center – New Channel for the NBIA of Russia International Networking; The ACC foundation initiated in 2002;  Aims at facilitating Russian businesses’ development through international cooperation and promotion, in the APEC region especially;  Building Cooperative Networks P1: SBT 9780521662161c04 CUNY946/Thomas 978 0 521 66216 1 July 11, 2007 12:28 4 The Critique of the Morality System ROBERT B. LOUDEN Underneath many of Bernard Williams’ sceptical attitudes and arguments in ethics is his flat-out rejection of what he calls “the morality system.” On his view, “we would be better off without it.” 1 But before we can assess this claim, we need to get a better sense of what exactly it is. 1. WHAT IS THE MORALITY SYSTEM? To begin with, it is fundamentally important to keep in mind that for Williams the words ethics and morality are not at all synonymous. Rather, he treats the latter as an unfortunate modern offshoot of the former. As he notes in Chapter 1 of Ethics and the Limits of Philosophy: Iamgoing to suggest that morality should be understood as a particular development of the ethical, one that has a special significance in modern Western culture. It particularly emphasizes certain ethical notions rather than others, developing in particular a special notion of obligation, and it has some peculiar presuppositions. In view of these features it is also, I believe, something we should treat with a special scepticism. 2 We can see already that Williams’ thesis about the morality system is in no small part historical.Hebelieves that human beings’ thinking about how they should live and act has changed drastically between ancient and modern times. 3 At the same time, in so far as he is particularly concerned with the 1 Williams (1985), p. 174. 2 Williams (1985), p. 6. Williams’ distinction between ethics and morality is analogous in several respects to Hegel’s famous contrast between Sittlichkeit (ethical life) and Moralit¨at (abstract morality). In both cases, a more concrete “world-guided” (or, to put it closer to Hegel’s language, a social-role-and-community-guided) conception of ethics is being contrasted to an abstract, universal one, and in both cases the villain defending the latter is Kant. See, e.g., Hegel (1991), §135. 3 Ancient here effectively means pre-Socratic. In Williams (1993), it is argued that “the basic ethical ideas possessed by the Greeks were different from ours, and also in better condition,” p. 4. But the Greeks he has in mind are not the philosophically familiar Plato and Aristotle. 104 P1: SBT 9780521662161c04 CUNY946/Thomas 978 0 521 66216 1 July 11, 2007 12:28 The Critique of the Morality System 105 concepts, presuppositions, and justifications (or lack thereof) employed by people past and present in their thinking on these matters, his position is also plainly philosophical. Needless to say, some readers may disagree with the historical facets of his position, some with the philosophical, and some with both. 4 What are the defining features of the morality system? At the end of Chapter 10 of Ethics and the Limits of Philosophy (in a chapter entitled, “Morality, the Peculiar Institution”), Williams summarizes his discussion as follows: Many philosophical mistakes are woven into morality. It misunderstands obligations, not seeing how they form just one type of ethical considera- tion. It misunderstands practical necessity, thinking it peculiar to the ethical. It misunderstands ethical practical necessity, thinking it peculiar to obliga- tions. Beyond all this, morality makes people think that, without its very special obligation, there is only inclination; without its utter voluntariness, there is only force; without its ultimately pure justice, there is no justice. Its philosophical errors are only the most abstract expressions of a deeply rooted and 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 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 ... required for vitamin D synthesis arteriole constriction folate production thermoregulation A One of the functions of the integumentary system is protection Which of the following does not directly... decrease of blood flow to the papillary layers of the skin This reduction of blood flow helps conserve body heat 7/8 Functions of the Integumentary System References American Academy of Dermatology... plump the tissue and injections of BOTOX® (the name brand of the botulinum neurotoxin) that paralyze the muscles that crease the skin and cause wrinkling Vitamin D Synthesis The epidermal layer of