Environmental Theory PDF

“What nursing has to do… is to put patient in the best condition for n...

“What nursing has to do… is to put patient in the best condition for nature to act upon him.” 🦖 major component of nursing: manipulation of physical environment “What nursing has to do… is to put patient in the best condition for nature to act upon him.” NURSING 🦖 Nursing “ought to signify the proper use of fresh air, light, warmth, cleanliness, quiet, and the proper selection and administration of diet – all at the least expense of vital power to the patient.” Florence Nightingale improved the standards – presence of pure air of care of war – pure water casualties in Crimea – efficient drainage that earned her the title – light “Lady with the Lamp”. – direct sunlight – purifying effect of direct sunlight upon room air – breathe air that is as pure as external air; 🦖 defined in relation to his/her environment and the impact of the environment without chilling – source of the air in the patient’s room upon him/her 🦖 referred to as a patient – proper room temperature – patient’s body temperature 🦖 balance between human and his/her environment 🦖 being well and using every power (resource) to the fullest extent in living life 🦖 Disease and illness – reparative process that nature instituted when a person did not attend to health concerns 🦖 Health maintenance through prevention of disease via environmental control Wake patient intentionally or and social responsibility accidentally during the first part of sleep. 🦖 used by FlorenceNightingale whispered and long 🦖described components of surroundings conversations unnecessary noise —Bed should be placed in the lightest part of the room and placed so the patient could see out a window. −Care giver should never lean against, sit upon, or unnecessarily shake the bed of a patient. −clean, neat, and dry −positioning the patient for maximum comfort – need for changing color and form – reading, needlework, writing and cleaning as activities to relieve the sick of boredom – personal (patient, nurse) – physical environment dirty environment – source of infection  Jean watson CARATIVE FACTORS CLINICAL CARITAS Jean Watson is one of the few nursing theorists who consider Humanistic-altruistic Practice of loving kindness not only the cared for but also thecaregiver. system of value within context of caring consciousness PERSONHOOD (Human Being) Being authentically present PERSON, LIFE, SELF Faith-Hope and enabling the beliefs of Personhood= one’s soul possess a body the one being cared for and “a unity of mind/body/spirit/nature” the one giving care “fully functional integrated self “ “greater than and different from, the sum of his or her parts” Cultivation of one’s own Sensitivity to self HEALTH and others spiritual practices, going beyond self, opening to “Health is not only the absence of infirmity and disease but also a others with compassion and state of physical, mental and social well-being.” - WHO sensitivity 3 OTHER ELEMENTS a high level of overall physical, mental and social functioning Helping-trusting, Developing and maintaining a general adaptive-maintenance level of daily functioning human care a trusting, authentic, caring the absence of illness (or the presence of efforts that leads its relationship relationship absence) ENVIRONMENT/SOCIETY Expressing positive Being present to and supporting the positive Caring (and nursing) has existed in every society. and negative and negative feelings A caring attitude is transmitted by the culture of the profession as a feelings with a connection of a unique way of coping with its environment. deeper spirit Nurse’s role in the environment:attending to supportive, protective, and or corrective mental, physical, societal, and spiritual Creative problem Creative use of self environments solving caring process NURSING Transpersonal Engaging in genuine Consists of knowledge, thought, values, philosophy, commitment, teaching-learning teaching learning and action, with some degree of passion experience concerned with promoting health, preventing illness, caring for the sick and restoring health Supportive, protective, Creating healing Theory of and/or corrective environment at all mental, physical, transpersonal societal, and spiritual levels caring environment CARING Assisting with basic the essence of nursing Human needs needs with a caring responsiveness between the nurse and the person assistance consciousness to align Purpose: to assist the person in gaining control and mind/body/spirit becoming knowledgeable, and in the process promote health changes Existential- Soul care for the one phenomenological- 3 Major Conceptual being cared for spiritual forces Elements of Watson’s Theory: Carative Factors (evolving toward the “Clinical Caritas Processes”) Transpersonal Caring Moment TRANSPERSONAL CARING RELATIONSHIP Caring Moment/Caring Occasion a special kind of human relationship dependent on : CARATIVE FACTORS Nurse’s commitment on protecting and enhancing human dignity guide for the core of nursing and a deeper/higher self The carative factors honor the human dimension of nursing's work and the inner life world and subjective experiences of the people we Nurse’s caring consciousness to preserve and honor the serve. embodied spirit, thereby not reducing the patient to a moral status Caritas - “to cherish and to give special loving attention” of an object Caring factors became Clinical Caritas. CARING OCCASION/MOMENT moment when the nurse and another person come together in such a way that an occasion for human caring is created The one caring for and the one being cared for are influenced by the choices and actions decided within the relationship. “The nurse is temporarily the consciousness of the unconscious, the love of life for the suicidal, the leg of the amputee, the eyes of the newly blind, a means of locomotion for the infant, knowledge and confidence for the mother, the mouthpiece for those too weak or withdrawn to speak and so on.” a complete and independent being with biological, sociological and spiritual components the ability to perform independently the 14 basic needs Health is basic to human functioning and that promotion of health is more important than care of the sick. “the aggregate of the external conditions and influences affecting the life and development of an organism” —Webster the effects of 7 components (light, temperature, air movement, atmospheric pressure, proper waste disposal, absence of injurious chemicals, cleanliness of surroundings) on the life and development of a person The unique function of the nurse is to assist the individual, sick or well, in the performance of activities contributing to health or its recovery. -Breathe Normally -Maintain body temperature -Eat and drink adequently -Avoid dangers in the environment and -Eliminate body wast avoiding other -Move and maintain desirable -Worship according to one’s faith postures -Work sin such a way that there is a sense -Sleep and rest of acomolishment -Select suitable clothes -playor participate in various forms of -Keep the body clean & well recreation groomed; protect the integument  SELF-CARE DEFICIT THEORY OF NURSING THEORY OF SELF-CARE HUMAN BEINGS acquired ability or power to SELF-CARE 🥀 distinguished from other living things engage in self-care AGENCY 🥀 have the potential for learning and developing 🥀 integrated human functioning SOCIETY/ENVIRONMENT BASIC CONDITIONING FACTORS 🥀 an external source of influence in the internal interaction of a person’s different aspects THEORY OF SELF-CARE HEALTH 🥀 the reasons for which self- 🥀 “a state of physical, mental, and social well-being and not merely the absence of disease or infirmity” SELF-CARE REQUISITES care is undertaken 🥀 “The physical, psychological, interpersonal and social aspects of UNIVERSAL DEVELOPMENTAL 🥀 express the intended or health are inseparable in the individual.” HEALTH DEVIATION desired results 🥀 concept of preventive health care NURSING 🥀 helping clients to establish or identify ways to perform self-care 🥀 The maintenance of a sufficient THEORY OF SELF-CARE activities 🥀 nursing actions: geared towards independence of theclient intake of air a distinguished human service 🥀 The maintenance of a sufficient 🥀 based on values intake of water 🥀 The maintenance of a sufficient SELF-CARE DEFICIT THEORY OF intake of food NURSING SELF-CARE 🥀 The provision of care 3 related theories: 🥀 THE THEORY OF SELF-CARE REQUISITE associated with elimination 🥀 THE THEORY OF DEPENDENT CARE UNIVERSAL 🥀 The maintenance of balance 🥀 THE THEORY OF SELF-CARE DEFICIT between activity and rest 🥀 THE THEORY OF NURSING SYSTEMS 🥀 The maintenance of a balance solitude and social interaction 🥀 The prevention of hazards to human life, human functioning, and human well-being 🥀 The promotion of human functioning and development THEORY OF SELF-CARE actions to be undertaken that THEORY OF SELF-CARE 🥀 activities that individuals will provide developmental growth: carry out on their own SELF-CARE 🥀 Provision of conditions that behalf REQUISITE promote development SELF-CARE 🥀 deliberate, have pattern DEVELOPMENT 🥀 Engagement in self- development and sequence, developed 🥀 Prevention of the effects of from day-to-day living human conditions that threatens life THEORY OF SELF-CARE SELF-CARE required in illness or injury or as a REQUISITE result of medical tests or HEALTH treatments to correct a condition DEVIATION THEORY OF NURSING SYSTEM Basic nursing education in 1972 By developing an interpersonal relationship with the patient, the nurse Bachelors in Public Health Nursing in 1973 is able to help the patient verbally express feelings regarding the Masters in teaching Natural Sciences in 1942 disease process and its effects. First director of Loeb Center for Nursing Patient is able to gain self-identity and further develop maturity. Nursing experience in clinical, education, research and supervisor role Patient is able to make conscious decisions Nursing Philosophy based on patient care Care based on pathological and therapeutic sciences Nurse helps patient through the medical, surgical and rehabilitative Theory developed in late 1960’s prescriptions made by the physician Nursing care can be delivered on three interlocking levels The cure aspect is different from the care circle because many of the nurse’s actions take on a negative quality of avoidance of pain rather than a positive quality of comforting. Nurses role changes to positive quality to negative quality. Emphasis placed on the importance of total person. Importance placed on all three aspects functioning together All three aspects interact and change in size Patient care only from trained nurses Size of the circles represents the degree to which the patient is Defines nursing as care performed by a professional progressing. Care focused on individuals, families and communities Care focused on maintaining optimal health and quality life from birth to end of life Human who is 16 years older and past the acute stage of long-term illness is the focus of nursing care in Hall’s work. Hall emphasizes the importance of an individual as unique, capable of growth and learning, and requiring a total person approach. Inferred to be a state of self-awareness with conscious selection of behaviors. Hall stresses the need to help the person explore the meaning of his or her behavior to identify and overcome problems through developing self-identity and maturity. Nurturing component of care and is exclusive to nursing “mothering” (care and comfort of the person) Provides teaching and learning activities Identified as consisting participation in the care, core, and cure aspects Nurses goal is to give “care” and “comfort” to the patient of patient care. Nurse provides bodily care for the patient Care is the sole function of nurses. Patient may explore and share feelings with the nurse Major purpose of care is to achieve an interpersonal relationship with When functioning in the care circle, the nurse applies knowledge of the the individual. natural and biological sciences. The patient views the nurse as a potential comforter, one who provides care and comfort through the laying of hands. Patient care is based on social sciences Involves the use of therapeutic use of self, and is shared with other members of the team  21 NURSING PROBLEMS FAYE GLENN ABDELLAH I N D I V I D U A L S (HUMAN BEINGS) recipients of nursing may also be families, society areas of importance: To maintain good hygiene and physical comfort To promote optimal activity; exercise, rest and sleep To promote safety though the prevention of accident, injury, or other trauma and through the prevention of the spread of infection To maintain good body mechanics and prevent and correct deformities To facilitate the maintenance of a supply of oxygen to all body cells To facilitate the maintenance of nutrition of all body cells To facilitate the maintenance of elimination To facilitate the maintenance of fluid and electrolyte balance HEALTH To recognize the physiological responses of the body to disease conditions pathological, physiological, and compensatory not specifically defined To facilitate the maintenance of regulatory mechanisms and functions purpose of nursing services To facilitate the maintenance of sensory functions IN NURSING as a comprehensive To identify and accept positive and negative expressions, feelings and service: ✓ “total health needs” reactions ✓ “a healthy state of mind To identify and accept the interrelatedness of emotions and organic and body” illness SOCIETY To facilitate the maintenance of effective verbal and non-verbal communication does not discuss society as a To promote the development of productive interpersonal relationships patient nor define society To facilitate progress toward achievement of personal spiritual goals by providing service to individuals To create and/or maintain a therapeutic environment and families, society is served To facilitate awareness of self as an individual with varying physical, included in “planning for optimum emotional, and developmental needs health on local, state, national, To accept the optimum possible goals in the light of limitations, physical and international levels” and emotional To use community resources as an aid in resolving problems arising NURSING from illness a comprehensive service that is based on an art and science To understand the role of social problems as influencing factors in the use of the problem-solving approach with key nursing problems related to the cause of illness health needs of people grouped into the 21 problem areas to guide care and promote the use of nursing judgment NURSING PROBLEM a condition faced by the patient or patient’s family that the nurse, through the performance of professional functions, can assist them to meet “nursing functions”/”nursing goals” may be : overt covert  Simple epithelium consists of a single layer of cells, with each cell extending from the basement membrane to the free surface. A tissue is a group of cells with similar structure and function, plus the extracellular substance surrounding them. Stratified epithelium consists of more than one layer of cells, but only Histology is the study of tissues. the basal layer attaches the deepest layer to the basement membrane. Pseudostratified columnar epithelium is a special type of simple epithelium, that appears to be falsely stratified. There are four tissue types in the human body: 1. Epithelial– a covering or lining tissue It consists of one layer of cells, with all the cells attached to the 2. Connective– a diverse primary tissue type that makes up part of basement membrane. every organ in the body Due to variations in the shape of the cells, the epithelia appears 3. Muscle– a tissue that contracts or shortens, making movement stratified. possible There are three types of epithelium based on idealized shapes of the 4. Nervous– responsible for coordinating and controlling many body epithelial cells: activities 1. Squamous cells are flat or scalelike. 2. Cuboidal cells are cube-shaped—about as wide as they are tall. Epithelium, or epithelial tissue, covers and protects surfaces, both 3. Columnar cells tend to be taller than they are wide. outside and inside the body. Included under the classification of epithelial tissue are the exocrine and endocrine glands. Simple squamous epithelium is a single layer of thin, flat cells. Some substances easily pass through this thin layer of cells, but other substances do not. 1. Mostly composed of cells 2. Covers body surfaces The lungs, simple squamous epithelium, allows for gas exchange. 3. Distinct cell surfaces The kidneys, simple squamous epithelium, helps filter wastes from the 4. Cell and matrix connections blood while keeping blood cells inside the blood vessels. 5. Nonvascular 6. Capable of regeneration 1. Protects underlying structures 2. Acts as a barrier 3. Permits passage of substances 4. Secretes substances 5. Absorption of substances Simple cuboidal epithelium is a single layer of cube-like cells that carry out active transport, facilitated diffusion, or secretion. They have a greater secretory capacity than simple squamous epithelial cells. Epithelial tissues are classified primarily according to the number of cell layers and the shape of the superficial cells. The cell layers can be simple, stratified, or pseudostratified. The cell shapes can be squamous, cuboidal, columnar, or a special transitional shape, that varies with the degree of stretch.  Simple columnar epithelium is a single layer of tall, thin cells. The large size of these cells enables them to perform complex functions, such as secretion. The simple columnar epithelium of the small intestine produces and secretes mucus and digestive enzymes. Stratified cuboidal epithelium consists of more than one layer of cuboidal epithelial cells. This epithelial type is relatively rare and is found in sweat gland ducts, ovarian follicular cells, and the salivary glands. It functions in absorption, secretion, and protection. Stratified columnar epithelium consists of more than one layer of Pseudostratified columnar epithelium secretes mucus, which covers its epithelial cells; the surface cells are columnar but the deeper cells are irregular or cuboidal in shape. free surface. Like stratified cuboidal epithelium, stratified columnar epithelium is Cilia in the airways move the mucus and accumulated debris toward relatively rare, found in the mammary gland ducts, the larynx, and a the throat, where it is swallowed. portion of the male urethra. This epithelium carries out secretion, protection, and some absorption. Transitional epithelium is a special type of stratified epithelium that can be greatly stretched. The shape of the cells change as the epithelium is stretched. Transitional epithelium lines cavities that can expand greatly, such as the urinary bladder. It also protects underlying structures, like the urinary bladder, from Stratified squamous epithelium forms a thick epithelium because it the caustic effects of urine. consists of several layers of cells. Though the deepest cells are cuboidal or columnar and are capable of dividing and producing new cells, the naming is based on the shape of the surface cells. There are two types of stratified squamous epithelia: keratinized stratified squamous and nonkeratinized stratified squamous epithelia. Most epithelia have a free surface that is not in contact with other cells and faces away from underlying tissues. The characteristics of the free surface reflect its functions. The outer layer of the skin is comprised of a keratinized squamous epithelium. The free surface can be smooth or lined with microvilli or cilia. The keratin reduces the loss of water from the body. Cilia move materials over the top of the cell. Microvilli increase surface area. Stratified squamous epithelium of the mouth is a moist Cells have several structures that hold one cell to one another or to nonkeratinized stratified squamous epithelium. the basement membrane. This nonkeratinized stratified squamous epithelium provides These structures do three things: mechanically bind the cells protection against abrasion and acts as a mechanical barrier. together, help form a permeability barrier, and provide a mechanism for intercellular communication. Water, however, can move across it more readily than across the skin (keratinized stratified squamous). Desmosomes are mechanical links that bind cells together. Hemidesmosomes are half desmosomes that anchor cells to the basement membrane.  Exocrine glands can also be classified according to how products leave the cell. Merocrine secretion involves the release of secretory products by Tight junctions prevent the passage of materials between epithelial exocytosis. cells because they completely surround each cell, similar to the way a belt surrounds the waist. Apocrine secretion involves the release of secretory products as pinched-off fragments of the gland cells. Materials that pass through the epithelial layer must pass through the cells, so those cells regulate what materials can cross. Holocrine secretion involves the shedding ofentire cells. Tight junctions are found in the lining of the intestines. Gap junctions are small channels that allow small molecules and ions to pass from one epithelial cell to an adjacent one. Most epithelial cells are connected to one another by gap junctions, and researchers believe that molecules or ions moving through the gap junctions act as communication signals to coordinate the activities of the cells. Connective tissue is a diverse primary tissue type that makes up part of every organ in the body. Connective tissue differs from the other three tissue types in that it consists of cells separated from each other by abundant extracellular matrix. Connective tissue is diverse in both structure and function. Connective tissue is comprised of cells, protein fibers, and an extracellular matrix. Glands are secretory organs that secrete substances onto a surface, into a cavity, or into the bloodstream. Glands are composed primarily of epithelium, with a supporting network of connective tissue. 1. Enclose and separate other tissues 2. Connecting tissues to one another Glands with ducts are called exocrine glands. 3. Supporting and moving parts of the body 4. Storing compounds Both the gland and its ducts is lined with epithelium. 5. Cushioning and insulating 6. Transporting Endocrine glands are ductless glands; they secrete 7. Protecting their products (termed hormones) into the bloodstream. Most exocrine glands are multicellular, comprised of many cells. The specialized cells of the various connective tissues produce the extracellular matrix. Some exocrine glands are composed of a single cell, like goblet cells, that secrete mucus. The name of the cell identifies the cell functions. Multicellular exocrine glands can be classified according to the Osteoblasts form bone, osteocytes maintain it, and osteoclasts break it structure of their ducts and secretory regions. down. Simple glands have a single, non-branched duct, some have branched Fibroblasts are cells that form fibrous connective tissue, and fibrocytes ducts. maintain it. Compound exocrine glands have multiple, branched ducts. Chondroblasts form cartilage and chondrocytesmaintain it. Glands with secretory regions shaped as tubules (small tubes) are Found in connective tissue are cells associated with the immune system, called tubular, whereas those shaped in saclike structures are called such as white blood cells. acinar or alveolar. Macrophages are large cells that are capable of moving about and Tubular glands can be straight or coiled. ingesting foreign substances, including microorganisms in the connective tissue. Glands with a combination of the two are called tubuloacinar or tubuloalveolar. Mast cells are nonmotile cells that release chemicals, such as histamine, that promote inflammation. The extracellular matrix of connective tissue has three major components: protein fibers, ground substance, and fluid. Ground substance consists of non-fibrous protein and other molecules. The structure of the matrix is responsible for the functional characteristics of connective tissues—for example, they enable bones and cartilage to bear weight.  Dense collagenous connective tissue has an extracellular matrix consisting mostly of collagen fibers. Three types of protein fibers—collagen, reticular, and elastic—help form most connective tissues. Dense collagenous connective tissue having the collagen fibers oriented in the same direction is termed dense regular. Collagen fibers, which resemble microscopic ropes, are very flexible but resist stretching. Examples of dense regular are tendons and ligaments. Reticular fibers are very fine, short collagen fibers that branch to form a Dense collagenous connective tissue having the collagen fibers oriented in supporting network. the multiple directions is termed dense irregular. Elastic fibers have the ability to return to their original shape after being Examples of dense irregular are in the dermis of the skin and in organ stretched orcompressed, giving tissue an elastic quality. capsules. The ground substance consists of non-fibrous molecules and is shapeless. It consists of proteoglycans, which are large molecules that consist of a protein core attached to many long polysaccharides. Proteoglycans trap large quantities of water between the polysaccharides, Dense elastic connective tissue has abundant elastic fibers among its which allows them to return to their original shape when compressed or collagen fibers. deformed. The elastic fibers allow the tissue to stretch and recoil. Examples include the dense elastic connective tissue in the vocal cords. A genetic condition called Marfan syndrome results from, in part the The two main types of connective tissue are embryonic and adult inability to properly maintain and form elastic fibers. connective tissue. By eight weeks of development, most of the embryonic connective tissue has become specialized to form the types of connective tissue seen in adults. The two main types of connective tissue are embryonic and adult connective tissue. By eight weeks of development, most of the embryonic connective tissue has become specialized to form the types of connective tissue seen in adults. Cartilage is composed of chondrocytes, located in spaces called lacunae Loose connective tissue consists of relatively few protein fibers that form within an extensive matrix. a lacy network, with numerous spaces filled with ground substance and fluid. Collagen in the matrix gives cartilage flexibility and strength. Three subdivisions of loose connective tissue are areolar, adipose, and Cartilage is resilient because the proteoglycans of the matrix trap water. reticular. Cartilage provides support, but if bent or slightly compressed, it resumes Areolar connective tissue primarily consists of collagen fibers and a few its original shape. elastic fibers. There are three types of cartilage: hyaline, fibrocartilage, and elastic The most common cells in loose connective tissue are the fibroblasts. cartilage. Adipose tissue consists of adipocytes, or fat cells, which contain large Hyaline cartilage is the most abundant type of cartilage and has many amounts of lipid for energy storage. functions, such as covering the ends of bones, where they form joints. Adipose tissue pads and protects parts of the body and acts as a thermal Fibrocartilage has more collagen than does hyaline cartilage and is able to insulator. withstand compression and resist tearing or pulling. Reticular tissue forms the framework of lymphatic tissue, such as in the Fibrocartilage is found in the intervertebral disks. spleen and lymph nodes, as well as in bone marrow and the liver. Fibrocartilage has more collagen than does hyaline cartilage and is able to withstand compression and resist tearing or pulling. Dense connective tissue has a relatively large number of protein fibers that Fibrocartilage is found in the disks between the vertebrae (bones of the form thick bundles and fill nearly all of the extracellular space. back) and in some joints, such as the knee and temporomandibular (jaw) joints. There are two major subcategories of dense connective tissue: collagenous and elastic. Elastic cartilage contains elastic fibers in addition to collagen and proteoglycans. Dense collagenous connective tissue has an extracellular matrix consisting mostly of collagen fibers. The elastic fibers appear as coiled fibers among bundles of collagen fibers. Elastic cartilage is able to recoil to its original shape when bent. The external ear, epiglottis, and auditory tube contain elastic cartilage.  Cardiac muscle is the muscle of the heart; it is responsible for pumping blood. Cardiac muscle cells are cylindrical but much shorter than skeletal muscle cells. Cardiac muscle cells are striated and usually have one nucleus per cell. They are often branched and connected to oneanother by intercalated disks. Bone is a hard connective tissue that consists of living cells and a mineralized matrix. Osteocytes are located within lacunae. The strength and rigidity of the mineralized matrix enables bones to support and protect other tissues and organs. Two types of bone tissue exist: spongy bone and compact bone. Smooth muscle forms the walls of hollow organs; it is also found in the skin and the eyes. Spongy bone has spaces between trabeculae or plates, of bone and therefore resembles a sponge. Smooth muscle is responsible for a number of functions, such as moving food through the digestive tract and emptying the urinary Compact bone is more solid, with almost no space between many thin bladder. layers of mineralized matrix. Smooth muscle cells are tapered at each end, have a single nucleus, and are not striated. Nervous tissue forms the brain, spinal cord, and nerves. Blood is a liquid connective tissue It is responsible for coordinating and controlling many body activities. It contains a liquid matrix, termed the plasma, along with formed elements. Nervous tissue consists of neurons and support cells, termed glial cells. The formed elements are erythrocytes, leukocytes, and platelets. The neuron is responsible for conducting action potentials. It functions in transport of food, oxygen, waste, hormones, and other It is composed of three parts: a cell body, dendrites, and an axon. substances. The main function of muscle tissue is to contract, or shorten, making movement possible. A tissue membrane is a thin sheet or layer of tissue that covers a structure or lines a cavity. Muscle contraction results from contractile proteins located within the muscle cells. Most membranes consist of epithelium and the connective tissue on which the epithelium rests. The three types of muscle tissue are skeletal, cardiac, and smooth. There are four tissue membranes in the body: cutaneous, mucous, serous, Skeletal muscle attaches to the skeleton and enables the body to move. and synovial. Skeletal muscle cells are striated, or banded, because of the arrangement The skin, termed the cutaneous membrane, is an external body surface of contractile proteins within the cells. membrane. The mucous membranes line cavities that open to the outside of the body, such as the digestive, respiratory, and reproductive tracts. Mucous membranes consist of epithelial cells, their basement membrane, and a thick layer of loose connective tissue. Many, but not all, mucous membranes secrete mucus. The functions of mucous membranes include protection, absorption, and secretion. Serous membranes line cavities that do not open to the exterior of the body, such as the pericardial, pleural, and peritoneal cavities. Serous membranes consist of three components: a layer of simple squamous epithelium, its basement membrane, and a delicate layer of loose connective tissue. Serous membranes do not contain glands, but they secrete a small amount of fluid called serous fluid, which lubricates the surface of the membranes. Synovial membranes line the cavities of freely movable joints. They are made up of only connective tissue and consist of modified connective tissue cells. Synovial membranes produce synovial fluid, which makes the joint very slippery, thereby reducing friction and allowing smooth movement within the joint. Inflammation is usually a beneficial process occurring when tissues are damaged. When viruses infect epithelial cells of the upper respiratory tract, inflammation and the symptoms of the common cold are produced. The inflammatory process occurs in stages. Inflammation mobilizes the body’s defenses and isolates and destroys microorganisms, foreign materials, and damaged cells so that tissue repair can proceed. Inflammation produces five major symptoms: redness, heat, swelling, pain, and disturbance of function. Tissue repair involves substitution of dead cells for viable cells. Tissue repair can occur by regeneration or by fibrosis. In regeneration, the new cells are the same type as those that were destroyed, and normal function is usually restored. In fibrosis, or replacement, a new type of tissue develops that eventually causes scar production and the loss of some tissue function. Regeneration can completely repair some tissues, such as the skin and the mucous membrane of the intestine. In these cases, regeneration is accomplished primarily by stem cells. Stem cells are self-renewing, undifferentiated cells that continue to divide throughout life. Tissue repair occurs in sequential steps.