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The Tissue Level of Organization Ch 4 Instructor presentation Objectives Describe the four major categories of tissues and give general characteristics of each Describe the function of epithelial tissue depending on their location Describe the functions of connective tissue and relate them to the function of the body or an organ system Objectives Explain the basic differences between smooth, skeletal and cardiac muscle Describe in brief nervous tissue Name the organs made of nerve tissue Describe the location of pleural membranes, pericardial membranes, and the peritoneum-mesentery Objectives State the location of mucous membranes and state the function of mucus Name some membranes made of connective tissue Introduction In today’s modern medical practice it involves aiding the body’s own homeostatic mechanisms. The human body has a tremendous capacity to heal itself. For example, a child with a fix leg will be able to bear full weight in 5-6 weeks. Within a year, the fix site will no longer be visible on xrays.except for the liver, bone is unique among all body tissues in that it will form new bone, not scar tissue, when it heals after a fix. Great News Discovery Did you know that someone has finally released the ingredients contained in Viagra….ummmmmmmmmm! Contents: 3% Vitamin D 2% Aspirin 2% Ibuporfen 1% Vitamin C 5% Spray Starch 87% Fix-A-Flat Types of Tissues Major Type Epithelial Tissue types Specific type Simple squamous Simple cubodial Simple columnar Pseudostratified columnar Stratified squmous transitional Types of Tissues Major Type Connective Tissue types Specific type Loose (areolar Adipose Dense fibrous Reticular Cartilage Bone Blood Types of Tissues Major Type Nervous Tissue types Specific type Neurons Neuroglia Types of Tissues Major Type Muscle Tissue types Specific type Skeletal Smooth Cardiac Categories of Tissues Epithelial tissue Connective tissue Muscle tissue Nervous tissue Tissue Levels The study of tissues is called histology Properties of Epithelial Tissue A layer of cells that forms a barrier with specific properties A free surface exposed to the environment or to some internal chamber or passageway Attachment to underlying connective tissue by a basement membrane The absence of blood vessels except to the basement membrane Surfaces of Epithelial Cells Functions of Epithelial Tissues Providing physical protection – Protects internal body surfaces from abrasion, dehydration, and destruction from chemical or biological agents – aids in the removal of foreign substances from internal passageways Controlling permeability – Everything that enters or leaves the body must cross an epithelium – some types more permeable than others Functions of Epithelial Tissues Providing sensations – Specialized cells that can detect environmental changes and relay that information to the nervous system – Ex. Touch receptors in deep layers of the epithelium of the skin respond by stimulating neighboring sensory nerves. Functions of Epithelial Tissues Producing specialized secretions – Gland cells • Exocrine glands – secretions discharged onto the surface of the epithelial tissue • Ex. Enzymes entering the GI tract, perspiration on the skin and milk produced by mammary gl. • Endocrine glands – secretions discharged into the surrounding tissues and blood • Ex. The secretions are hormones, regulated by tissues, organs, organ systems. Classifying Epithelia Epithelia are classified according to the # of cell layers and the shape of the exposed cells. 2 types: simple and stratified with 3 shapes that are: 1. Squamous 2. Cuboidal 3. Columnar Squamous Epithelium Areas of absorption or to provide a slippery surface to reduce friction – exchange surfaces of the lung, interior of the heart Simple Squamous Epithelium The delicate cell type is found in protected regions where absorption takes place. Ex. – Kidney tubules, – Lungs – Lining of body cavities – Lining of blood vessels and the heart. Simple Squamous Epithelium pg 86 Cuboidal Epithelium Limited protection, secretion and absorption – pancreas, salivary glands, kidney tubules Columnar Epithelium Provides some protection and may occur in areas of absorption or secretion Lines the stomach, the intestinal tract, and may excretory ducts Columnar Epithelium Columnar Epithelium (nasal cavity, bronchi, trachea) Name this type of tissue Name this portion What is this layer Called beneath this line What causes a bed sore? A bed sore is another name for a pressure ulcer, or a decubitus ulcer. The ulcer is caused by an interruption of blood supply to a tissue. Pressure ulcers frequently develop in patients who have been bedridding for long periods. What causes a bed sore? They are caused by the weight of the body on the skin overlying a bony area (ie, elbow, heel, hip). The weight of the body compresses, or squeezes, the blood vessels, cutting off the supply of blood to the tissues. Deprived of its blood supply, the tissues dies, forming an ulcer. Transitional Epithelium (bladder, ureters) Connective tissue Pseudostratified Columnar Epithelium Nuclei at varying distances from the surface gives a layered look. All cells still in contact with the basement membrane Most are ciliated Line the nasal cavity, the trachea, the bronchi, and part of the male reproductive tract Pseudostratified Columnar Epithelium – #3 Holocrine – the whole cell is released – sebaceous glands – Endocrine – products are released into the blood stream (ductless) Glands Based on shape – Cellular – (goblet cells) – tubular sweat glands – Alveolar – sebaceous gland – attached to hair follicles Based on 3 methods they release secretion: – #1 Merocrine – release fluid through their membrane – sweat and saliva glands (exocytosis) – #2 Apocrine – pinches off the end of the cell and releases it – milk, apocrine sweat gland Based on what they secrete – Serous – watery solution containing enzymes – parotid salivary gland – Mucous – thick, slippery mucous – sublingual salivary gland – Mixed – more than 1 type – submandibular salivary gland Merocrine Glands Apocrine and Holocrine Glands Structural Classification of Exocrine Glands Connective Tissues Are considered the deep tissues that are never exposed to the environment outside the body. Their functions include: #1 Supporting and protecting #2 Transporting materials #3 Storing energy reserves #4 Defending the body Functions of Connective Tissue #1 Supporting and protecting – Provide a bony structural framework, protect delicate organs, and surround and interconnect other tissue types #2 Transporting materials – Provides the means for transporting dissolved material from one part of the body to another #3 Storing energy reserves – Fats stored in adipose tissue until needed #4 Defending the body – Cell-to-cell interactions and the creation of antibodies to ward off bacterial invasion Classifications of Connective Tissue Connective tissue proper – Many types of cells and fibers surrounded by a syrupy ground substance – tissue that underlies the skin, fat, tendons, ligaments Fluid connective tissue – Blood and lymph Supporting connective tissue – Cartilage and bone Connective Tissue Proper Fibroblasts – Most abundant – produce fibers and ground substance Macrophages – Phagocytes Fat cells – Large lipid-containing vacuoles dominate the cytoplasm Mast cells – Mobile, found near blood vessels, packed with vesicles filled with chemicals released in response to injury or infection Connective Tissue Proper Connective Tissue Proper Adipose Tissue Question? Why do overweight men and women “round out” into different shapes? Overeating results in the storage of fat in adipose tissue. Because fat metabolism is affected by the sex hormones estrogen and testosterone, storage sites differ for males and females. In males excess fat is stored primarily in the abdomen region, while in the female, excess fat is stored around the breasts and hips. Connective Tissue Proper Fluid Connective Tissue Blood and lymph Supporting Connective Tissue Cartilage – Chondrocytes reside in the gel matrix Types of cartilage – Hyaline – most common – supports the respiratory tract, lines bony articulations, connects the ribs to the sternum – Elastic – flexible – pinna of the ear, epiglottis, tip of the nose – Fibrocartilage – tough, less flexible – between the vertebrae, some joints and tendons Hyaline and Elastic Cartilage Fibrocartilage Fibrocartilage pg 94 Bone Osteocytes within the matrix Fed by a rich blood supply Formed by a combination of hard calcium compounds combined with flexible collagen fibers Bone Membranes Four types of membranes made of connective tissue: – #1 Mucous membranes • • • • • • • Line cavities that communicate with the exterior Kept moist at all times Combined epithelial and connective tissue Line the: digestive Respiratory Reproductive urinary tracts Membranes – #2 Cutaneous membrane • The skin lining of the outer surface of the body • Thick, usually dry, waterproof Membranes – #3 Serous membranes • Consist of simple epithelium supported by loose connective tissue • Pleura line the lines the pleural cavity and covers the lung • Peritoneum lines the abdominal cavity and covers the organs covered within the cavity • Pericardium lines the pericardial cavity and covers the heart (2 layers) • Parietal layers (lines the cavity walls) • Visceral layer (covers the internal organs) Question? Why is pleurisy so painful? Pleurisy refers to an inflammation of the pleura and decrease in serous fluid. As the inflamed and “dry” pleural membranes slide past one another during breathing movements, the person experiences pain. Membranes – #4 Synovial membranes • Bones of the skeleton contact one another at joints called articulations • Creates a fluid that helps separate the cartilage-covered bone ends of mobile joints • Lines the joint capsule (lubricates joints to provide smooth movement) • Consists primarily of loose connective tissue, the epithelial layer is incomplete Membranes Muscle Tissue Muscle cell contraction involves interaction between filaments referred to as myosin and actin proteins found in the cytoskeleton of many human body cells. Muscle cells have numerous filaments so that their interaction produces a contraction of the entire muscle cell. Muscle Tissues Three types, all specialized for contraction – #1 Skeletal muscle – #2 Smooth muscle – #3 Cardiac muscle Muscle Tissue #1 Skeletal muscle • Striated • under voluntary control from the nervous system • Contractions of muscle tissue causes bones to move Muscle Tissue – #2 Smooth Muscle • Line all of the hollow structures of the body such as: • Urinary bladder • Respiratory • Circulatory • Digestive reproductive • Non-striated, involuntary control Smooth Muscle Muscle Tissue – #3 Cardiac Muscle • Found only in the heart • Branched and connected cells joining at intercalated discs give this muscle the principle of conductivity • Specialized pacemaker cells have the principle of automaticity • Striated, involuntary muscle, although the nervous system can alter the rate Skeletal and Cardiac Muscle Neural Tissue Specialized for the conduction of electrical impulses to convey information from one part of the body to another Two types of cells that make up both the CNS and PNS organs – Neurons • Transmit the electrical impulse • Soma – cell body, dendrites – receptor ends, axon – effector end which ends at a synapse – Neuralgia • Provide physical support, defend from infection, maintain chemical composition of tissue fluids Nerve Cell Disorders of Cellular Growth Atrophy – Without nourishment, atrophy is a decrease in the size, shape, leading to a wasting away of tissues and organs. Dysplasia – Abnormal growth. Dysplasia is an alteration in cell size, shape, and organization. The concern is that these alterations can result in cancer. Disorders of Cellular Growth Hyperplasia – Overgrowth. Hyperplasia is an increase in the number of cells, resulting in an increase in the size of tissues and organs. Metaplasia – Transformation of one cell type into another (ie, the change of columnar cells in the breathing passages of a smoker into a different cell type) Disorders of Cellular Growth Necrosis – Death of cells or groups of cells. Neoplasm – abnormal new growth, also called a tumor. A malignant neoplasm is a cancerous tumor. A benign neoplasm is a noncancerous tumor. Malignant neoplasms tend to metastasize, or spread, from an orginal (primary site) to another secondary site. Any questions