Human Anatomy & Physiology Chapter 4: Histology PDF

Human Anatomy & Physiology Second Edition Chapter 04 Histology PowerPoint® Lectures created by Suzanne Pundt, University of Texas at Tyler...

Human Anatomy & Physiology Second Edition Chapter 04 Histology PowerPoint® Lectures created by Suzanne Pundt, University of Texas at Tyler Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved MODULE 4.3 CONNECTIVE TISSUES Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissues (1 of 3) Connective tissues are divided into two basic groups; differ in cell types and ECM components: Connective tissue proper Specialized connective tissue Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissues (2 of 3) Connective tissue functions: Connecting and binding – anchor tissue layers in organs and link organs together Support – bone and cartilage support weight of body Protection – bone tissue protects internal organs; cartilage and fat provide shock absorption; components of immune system are throughout connective tissues Transport – blood is fluid connective tissue; main transport medium in body Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissues (3 of 3) Connective tissue consists of cells and ECM – Cells are surrounded by protein fibers and embedded in ground substance – ECM is a characteristic feature; plays extensive role in function of connective tissue type Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (1 of 21) Connective tissue proper (general connective tissue) Widely distributed in body Connect tissues and organs to one another Components of internal architecture of some organs Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (2 of 21) Cells of connective tissue proper – resident cells permanently inhabit tissue; migrant cells migrate to areas of body depending on situation – Fibroblasts – Adipocytes – Mast cells – Phagocytes – Other immune system cells Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (3 of 21) Cells of connective tissue proper (continued): – Fibroblasts – most common resident cell  Mature cells with properties of immature “blast” cell  Make protein fibers and ground substance (components of ECM); continually produce collagen proteins Figure 4.12a Cells of connective tissue proper. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (4 of 21) Cells of connective tissue proper (continued): – Adipocytes (fat cells) – in many different connective tissues; cytoplasm filled with a single large lipid inclusion Figure 4.12b Cells of connective tissue proper. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (5 of 21) Cells of connective tissue proper (continued): – Mast cells – largest resident cell  Immune system cells filled with cytosolic inclusions (granules) of inflammatory mediators (histamine)  Release mediators (degranulate) when stimulated, causing inflammation (protective response that activates immune system) Figure 4.12c Cells of connective tissue proper. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (6 of 21) Cells of connective tissue proper (continued): – Phagocytes – immune system cells; ingest foreign substances, microorganisms, and dead or damaged cells by phagocytosis; include macrophages (resident or migrant) and neutrophils (migrant cells) – Other immune system cells migrate in and out of connective tissues depending on body’s needs Figure 4.12d Cells of connective tissue proper. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (7 of 21) Four basic types of connective tissue proper: – Loose connective tissue – Dense connective tissue – Reticular tissue – Adipose tissue Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (8 of 21) Types of connective tissue proper (continued): – Loose connective tissue (areolar tissue) – mostly ground substance; contains all three types of protein fibers, fibroblasts, and occasionally adipocytes, suspended in ground substance (Figure 4.13):  Beneath epithelium of skin, in membranes lining body cavities, and within walls of hollow organs  Contains and supports blood vessels vital to avascular epithelial tissues; houses immune system cells Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (9 of 21) Figure 4.13 Structure of loose connective tissue. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (10 of 21) Types of connective tissue proper (continued): – Dense connective tissue (fibrous connective tissue) – mostly protein fibers; three classes:  Dense irregular connective tissue – predominantly disorganized collagen bundles (Figure 4.14a) – Strong; resists tension in all three planes of movement – In high tension areas such as dermis (deep to skin) and surrounding organs and joints Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (11 of 21) Figure 4.14a Structure of dense connective tissue. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (12 of 21) Types of connective tissue proper (continued): – Dense connective tissue (continued):  Dense regular connective tissue (Figure 4.14b) – Organized into parallel collagen bundles – In tendons and ligaments; subject to tension in one plane of movement Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (13 of 21) Figure 4.14b Structure of dense connective tissue. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (14 of 21) Types of connective tissue proper (continued): – Dense connective tissue (continued):  Dense regular elastic connective tissue (elastic tissue) (Figure 4.14c) – Mostly parallel-oriented elastic fibers with randomly oriented collagen fibers – In walls of organs that must stretch to function (large blood vessels and certain ligaments) Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (15 of 21) Figure 4.14c Structure of dense connective tissue. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (16 of 21) Note: arrangement of fibers in dense regular and irregular connective tissues is example of Structure- Function Core Principle Figure 4.14 Structure of dense connective tissue. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (17 of 21) Types of connective tissue proper (continued): – Reticular tissue – mostly reticular fibers produced by fibroblasts (reticular cells)  Forms fine networks that support small structures such as blood and lymphatic vessels  Also in lymph nodes and spleen; forms weblike nets that trap old and foreign cells (Figure 4.15)  Forms part of basement membrane; supports all epithelia and internal structure of liver and bone marrow Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (18 of 21) Figure 4.15 Structure of reticular tissue. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (19 of 21) Types of connective tissue proper (continued): – Adipose tissue (fat tissue) – fat-storing adipocytes and surrounding fibroblasts and ECM; adipocytes can increase in size to a point where fibroblasts and ECM are scarcely visible (Figure 4.16); functions:  Fat storage (major energy reserve of body)  Insulation (retains warmth)  Shock absorption and protection Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissue Proper (20 of 21) Figure 4.16 Structure of adipose tissue. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Adipose Tissue and Obesity Obesity – condition of excess adipose tissue in proportion to lean body mass; two forms: – Hypertrophic – lipid inclusions accumulate fatty acids; increase in size up to 4 normal; number of adipocytes remains unchanged – Hypercellular – generally severe; number of adipocytes increases; correlates with development of obesity in infancy or early childhood (not adulthood); adult adipocytes lack ability to divide to form new cells Both increase risk for health problems; development of related disorders is complex; depends on distribution of adipose tissue and genetic factors Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Specialized Connective Tissues (1 of 15) Specialized connective tissues – more specific functions; include three types of tissue (Figures 4.17, 4.18, 4.19): Cartilage – in joints between bones, ear, nose, and segments of respiratory tract Bone tissue (osseous tissue) – supports body; protects vital organs; provides attachments for muscles that allow for movement; stores calcium; and houses bone marrow (produces blood cells and stores fat) Blood – unique connective tissue with liquid ECM (plasma); consists of mostly water, dissolved solutes, and proteins Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Specialized Connective Tissues (2 of 15) Specialized connective tissues (continued): Cartilage – tough, flexible tissue; absorbs shock and resists tension, compression, and shearing forces; ECM consists of collagen and elastic fibers, proteoglycans, and glycosaminoglycans – Populated with two cell types:  Chondroblasts – immature cells; divide by mitosis and make most of ECM  Eventually surround themselves in small cavities (lacunae) in ECM to become mature, largely inactive chondrocytes Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Specialized Connective Tissues (3 of 15) Cartilage (continued): – Essentially avascular, unlike most connective tissues; blood supply is limited to outer sheath (perichondrium) of dense irregular collagenous connective tissue – Oxygen and nutrients must diffuse from blood vessels in perichondrium through ECM to supply chondroblasts and chondrocytes; limits thickness of living cartilage Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Specialized Connective Tissues (4 of 15) – Cartilage can be further divided into three classes by ECM composition (Figure 4.17):  Hyaline cartilage – most abundant cartilage – ECM mostly ground substance made of small bundles of fine collagen; gives tissue glossy bluish-gray appearance – On ends of bones in joints (articular cartilage), linking sternum to ribs, framing sections of respiratory tract, and in nose – Most of fetal skeleton is hyaline cartilage; replaced with bone during development Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Specialized Connective Tissues (5 of 15) Figure 4.17a Structure of cartilage. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Specialized Connective Tissues (6 of 15) – Cartilage classes based on ECM composition (continued):  Fibrocartilage – filled with bundles of collagen fibers; little room for ground substance in ECM (Figure 4.17b) – Fibroblasts reside in tissue; also chondroblasts and chondrocytes; fill ECM with collagen and some elastic fibers – Tissue has great tensile strength with some degree of elasticity – In between bones of fibrous joints; forms articular discs that improve fit of bones in joints Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Specialized Connective Tissues (7 of 15) Figure 4.17b Structure of cartilage. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Specialized Connective Tissues (8 of 15) – Cartilage classes based on ECM composition (continued):  Elastic cartilage – mostly elastic fibers in ECM (Figure 4.17c) – Allows tissue to vibrate – In limited number of structures; external ear assists with detection of sound in air; larynx assists with production of sound Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Specialized Connective Tissues (9 of 15) Figure 4.17c Structure of cartilage. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Specialized Connective Tissues (10 of 15) Specialized connective tissues (continued): Bone – ECM is about 35% organic components (collagen fibers and ground substance (osteoid)); remaining 65% is inorganic calcium phosphate crystals, making bone one of the hardest substances in the body (Figure 4.18a) – Dynamic tissue capable of remodeling; occurs in regions of stress or inactivity; tension increases osteoblast activity and bone deposition; compression increases osteoclast activity and bone resorption Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Specialized Connective Tissues (11 of 15) Bone (continued): – Osteoblasts (Figure 4.18b)  “Bone-builders” on outer surface of bones; closely associated with dense irregular collagenous connective tissue covering (periosteum)  Carry out process of bone deposition; synthesize and secrete organic ECM and chemicals involved in trapping calcium in ECM Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Specialized Connective Tissues (12 of 15) Bone (continued): – Osteocytes – osteoblasts that have surrounded themselves with ECM in lacunae; mature cells, mostly inactive; continue to make and secrete substances important for bone maintenance – Osteoclasts – large, multinucleated bone destroyers; carry out process of bone resorption; secrete hydrogen ions and enzymes that break down both inorganic and organic ECM Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Specialized Connective Tissues (13 of 15) Figure 4.18 Structure of bone. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Specialized Connective Tissues (14 of 15) Specialized connective tissues (continued): Blood – unique; ECM is fluid (Figure 4.19) – Plasma proteins – not like fibers found in other connective tissues; smaller with a variety of functions, including transport of substances and blood clotting – Erythrocytes (red blood cells) bind to and transport oxygen throughout body – Leukocytes (white blood cells) function in immunity – Platelets – cell fragments; major role in blood clotting Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Specialized Connective Tissues (15 of 15) Figure 4.19 Components of blood. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissues (1 of 2) Figure 4.20 Summary of connective tissues. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved Connective Tissues (2 of 2) Figure 4.20 Summary of connective tissues. Copyright © 2019, 2016 Pearson Education, Inc. All Rights Reserved