Chapter 04. Lecture Outline. See separate PowerPoint slides for all figures and tables pre-inserted into PowerPoint without notes.

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1 Chapter 04 Lecture Outline See separate PowerPoint slides for all figures and tables pre-inserted into PowerPoint without notes. Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2 Chapter 4-Tissues What is a tissue? group of cells with similar structure and function plus extracellular substance (matrix) Histology: study of tissues 2

3 Types of Tissues 1. Epithelial 2. Connective 3. Muscular 4. Nervous 3

4 Epithelial Tissues Location: - cover body (internal and external) - Ex. Skin, kidney, trachea, glands, etc. 4

5 Characteristics: - cells close together (very little extracellular matrix) - form most glands - have free surface - Basal surface: attaches epithelial cells to underlying tissues 5

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7 Functions of Epithelial Tissues 1. Protect: Ex. Skin 2. Act as a barrier: Ex. Skin keeps bacteria out 3. Diffusion and Filtration: Ex. Lungs and kidneys 4. Secretion: Ex. Sweat glands 5. Absorption: Ex. Small intestine 7

8 Classification of Epithelial Tissue Classified according to number of cell layers and cell shape Simple and stratified = number of cell layers Squamous, cuboidal, columnar, transitional= cell shape 8

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10 Types of Epithelial Tissues Simple Epithelium Structure: 1 layer of cells Stratified Epithelium Structure: many layers of cells 10

11 Simple Squamous Structure: 1 layer of flat, tile-like cells Function: diffusion and filtration Location: blood vessels, lungs, heart, kidneys Simple Cuboidal Structure: 1 layer of square-shaped cells Function: secretion Location: glands, ovaries, kidneys 11

12 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. TABLE 4.2 Simple Epithelium (a) Simple Squamous Epithelium Structure: Function: Location: Single layer of flat, often hexagonal cells; the nuclei appear as bumps when viewed in cross section because the cells are so flat Diffusion, filtration, some secretion, and some protection against friction Lining of blood vessels and the heart, lymphatic vessels, alveoli of the lungs, portions of the kidney tubules, lining of serous membranes of body cavities (pleural, pericardial, peritoneal) Lung alveoli Free surface Nucleus Basement membrane Simple squamous epithelial cell LM 640x a(2): McGraw-Hill Higher Education, Inc./Dennis Strete, photographer 12

13 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. TABLE 4.2 continued (b) Simple Cuboidal Epithelium Structure: Single layer of cube-shaped cells; some cells have microvilli (kidney tubules) or cilia (terminal bronchioles of the lungs) Function: Location: Active transport and facilitated Kidney tubules, glands and their ducts, diffusion result in secretion and choroid plexuses of the brain, lining absorption by cells of the kidney of terminal bronchioles of the lungs, tubules; secretion by cells of glands and surfaces of the ovaries and choroid plexuses; movement of particles embedded in mucus out of the terminal bronchioles by ciliated cells Kidney Free surface Nucleus Simple cuboidal epithelial cell Basement membrane LM 640x b(2): Victor Eroschenko 13

14 Simple Columnar Structure: 1 layer of tall, narrow cells Function: secrete mucus and absorption Location: stomach, intestines, resp. tract Pseudostratified Columnar Structure: 1 layer of tall, narrow cells appears stratified but isn t Function: secrete mucus and propel debris out of resp. tract (cilia) Location: nasal cavity and trachea 14

15 TABLE 4.2 continued Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (c) Simple Columnar Epithelium Structure: Function: Location: Single layer of tall, narrow cells; some cells have cilia (bronchioles of lungs, auditory tubes, uterine tubes, and uterus) or microvilli (intestines) Movement of particles out of the bronchioles of the lungs by ciliated cells; partially responsible for the movement of oocytes through the uterine tubes by ciliated cells; secretion by cells of the glands, the stomach, and the intestine; absorption by cells of the intestine Glands and some ducts, bronchioles of lungs, auditory tubes, uterus, uterine tubes, stomach, intestines, gallbladder, bile ducts, and ventricles of the brain Lining of stomach and intestines Free surface Goblet cell containing mucus Nucleus Simple columnar epithelial cell Basement membrane LM 640x c(2): Victor Eroschenko 15

16 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. TABLE 4.2 continued (d) Pseudostratified Columnar Epithelium Structure: Function: Location: Single layer of cells; some cells are tall and thin and reach the free surface, and others do not; the nuclei of these cells are at different levels and appear stratified; the cells are almost always ciliated and are associated with goblet cells that secrete mucus on to the free surface Synthesize and secrete mucus on to the free surface and move mucus (or fluid) that contains foreign particles over the surface of the free surface and from passages Lining of nasal cavity, nasal sinuses, auditory tubes, pharynx, trachea, and bronchi of lungs Trachea Bronchus Cilia Free surface Goblet cell containing mucus Pseudostratified columnar epithelial cell Nucleus Basement membrane LM 413x d(2): Victor Eroschenko 16

17 Stratified Squamous Structure: many layers of flat, tile-like cells Function: protect and acts as a barrier Location: skin, mouth, throat, esophagus Transitional Structure: special type of stratified epi. changes shape (stretched squamous, not stretched cuboidal) Function: hold fluids Location: urinary bladder 17

18 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. TABLE 4.3 Simple Epithelium (a) Stratified Squamous Epithelium Structure: Function: Location: Several layers of cells that are cuboidal Protects against abrasion, forms in the basal layer and progressively a barrier against infection, and flattened toward the surface; the reduces loss of water from the body epithelium can be nonkeratinized (moist) or keratinized; in nonkeratinized stratified squamous epithelium, the surface cells retain a nucleus and cytoplasm; in keratinized stratified epithelium, the cytoplasm of cells at the surface is replaced by a protein called keratin, and the cells are dead Keratinized outer layer of the skin; nonkeratinized mouth, throat, larynx, esophagus, anus, vagina, inferior urethra, and corneas Skin Cornea Mouth Esophagus Free surface Nonkeratinized stratified squamous epithelial cell Nuclei Basement membrane LM 286x a(2): Victor Eroschenko 18

19 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. TABLE 4.3 continued (b) Transitional Epithelium Structure: Stratified cells that appear cuboidal when the organ or tube is not stretched and squamous when the organ or tube is stretched by fluid Function: Accommodates fluctuations in the volume of fluid in an organ or a tube; protects against the caustic effects of urine Location: Lining of urinary bladder, ureters, and superior urethra Free surface Transitional epithelial cell Ureter Urinary bladder Urethra Nucleus Basement membrane LM 413x Free surface Tissue not stretched Transitional epithelial cell Nucleus LM 413x Tissue stretched Basement membrane b(2, 3): Victor Eroschenko 19

20 Free Cell Surfaces Surface not in contact with other cells Smooth to reduce friction, Ex. Blood vessels Microvilli: - increase cell s surface area - Ex. Small intestine 20

21 Cilia: - move materials across cell s surface - Ex. Trachea Goblet cells: - produce mucus - Ex. Stomach 21

22 Cell Connections Tight junctions: - bind adjacent cells together - Ex. Intestines Desmosomes: mechanical links that bind cells 22

23 Hemidesmosomes: bind cells to basement membrane Gap junctions: - small channels that allow molecules to pass between cells - allow cells to communicate - most common 23

24 Figure 4.2

25 What are they? Glands structures that secrete substances onto a surface, into a cavity, or into blood Exocrine glands: - glands with ducts - Ex. Sweat or oil glands Endocrine glands: no ducts (directly into bloodstream) Ex. Thyroid, thymus, pituitary glands, etc. 25

26 Secretion in duct Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pinched-off portion of cell in the secretion Dying cell releases secretory products Vesicle releasing contents into duct Vesicle containing secretory products Secretory products stored in the cell Replacement cell Cell shed into the duct (a) Merocrine gland Cells of the gland produce secretions by active transport or produce vesicles that contain secretory products, and the vesicles empty their contents into the duct through exocytosis. (b) Apocrine gland Secretory products are stored in the cell near the lumen of the duct. A portion of the cell near the lumen containing secretory products is pinched off the cell and joins secretions produced by a merocine process. (c) Holocrine gland Secretory products are stored in the cells of the gland. Entire cells are shed by the gland and become part of the secretion. The lost cells are replaced by other cells deeper in the gland. 26

27 Types of Exocrine Glands Simple: no branches Compound: many branches Tubular: end of duct Alveolus: sac-like structure 27

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29 Connective Tissues Characteristics Cells far apart Contain large amounts of extracellular matrix Classified based on type of extracellular matrix and function Ex. Blast cells build, clast cells carve Extracellular matrix contains 3 components (in varying amounts): protein fibers, ground substance, fluid Ground substance: proteins and sugars 29

30 Types of Protein Fibers Collagen fibers: look like ropes and are flexible but resist stretching Reticular fibers: supporting network that fills spaces between organs and tissues Elastic fibers: recoil after being stretched 30

31 Functions of Connective Tissue 1. Enclose and separate: Ex. around organs and muscles 2. Connect tissues: Ex. Tendons: connect bone to muscle Ex. Ligaments: connect bone to bone 3. Support and Movement: Ex. bones 31

32 4. Storage: Ex. bones store calcium and adipose tissue stores fat 5. Cushion and insulate: Ex. adipose tissue protects organs and helps conserve heat 6. Transport: Ex. Blood 7. Protect: Ex. Immune cells 32

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34 Types of Ordinary Connective Tissue Loose Location: between organs, muscles, glands, skin Structure: collagen fibers far apart Function: support and protect 34

35 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. TABLE 4.5 Connective Tissue Proper: Loose Connective Tissue (a) Areolar Connective Tissue Structure: Function: Location: A fine network of fibers (mostly collagen fibers with a few elastic fibers) with spaces between the fibers; fibroblasts, macrophages, and lymphocytes are located in the spaces Loose packing, support, and nourishment for the structures with which it is associated Widely distributed throughout the body; substance on which epithelial basement membranes rest; packing between glands, muscles, and nerves; attaches the skin to underlying tissues Elastic fiber Nucleus Collagen fiber Epidermis Dermis Skin Loose connective tissue with fat Muscle LM 400X (a): Ed Reschke 35

36 Dense Location: tendons, ligaments, skin Structure: collagen fibers packed close together Function: connect and can withstand pulling forces Adipose Location: under skin and around organs Structure: collagen and elastic fibers, cells filled with lipids Function: storage, insulate, cushion 36

37 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. TABLE 4.6 Connective Tissue Proper: Dense Connective Tissue (a) Dense Collagenous Connective Tissue Structure: Function: Location: Matrix composed of collagen fibers running in somewhat the same direction in tendons and ligaments; collagen fibers run in several directions in the dermis of the skin and in organ capsules Withstand great pulling forces exerted in the direction of fiber orientation due to great tensile strength and stretch resistance Tendons (attach muscle to bone) and ligaments (attach bones to each other); also found in the dermis of the skin, organ capsules, and the outer layer of many blood vessels Nucleus of fibroblast Ligament Tendon Collagen fibers LM 165x (a): Victor Eroschenko 37

38 TABLE 4.6 continued (b) Dense Elastic Connective Tissue Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structure: Matrix composed of collagen fibers and elastin fibers running in somewhat the same direction in elastic ligaments; elastic fibers run in connective tissue of blood vessel walls Function: Capable of stretching and recoiling like a rubber band with strength in the direction of fiber orientation Location: Elastic ligaments between the vertebrae and along the dorsal aspect of the neck (nucha) and in the vocal cords; also found in elastic connective tissue of blood vessel walls Elastin fibers Nucleus of fibroblast Base of tongue Vocal folds (true vocal cords) Vestibular fold (false vocal cord) LM 100x (b): Victor Eroschenko 38

39 TABLE 4.5 (b) Adipose Tissue continued Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Structure: Function: Location: Little extracellular matrix surrounding cells; the adipocytes, or fat cells, are so full of lipid that the cytoplasm is pushed to the periphery of the cell Packing material, thermal insulator, energy storage, and protection of organs against injury from being bumped or jarred Predominantly in subcutaneous areas, mesenteries, renal pelves, around kidneys, attached to the surface of the colon, mammary glands, and in loose connective tissue that penetrates into spaces and crevices Adipose tissue Nucleus Mammary gland Adipocytes or fat cells LM 100x (b): Ed Reschke 39

40 Cartilage Type of connective tissue Composed of chondrocytes Contains collagen Withstands compressions Provides support, flexibility, strength 40

41 Types of Cartilage Hyaline cartilage Location: covers ends of bones Structure: some collagen fibers Function: reduces friction (cushion) Fibrocartilage Location: between vertebra Structure: lots of collagen fibers Function: can withstand compression 41

42 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. TABLE 4.7 Supporting Connective Tissue: Cartilage (a) Hyaline Cartilage Structure: Collagen fibers are small and evenly dispersed in the matrix, making the matrix appear transparent; the cartilage cells, or chondrocytes, are found in spaces, or lacunae, within the firm but flexible matrix Function: Allows growth of long bones; provides rigidity with some flexibility in the trachea, bronchi, ribs, and nose; forms strong, smooth, yet somewhat flexible articulating surfaces; forms the embryonic skeleton Location: Growing long bones, cartilage rings of the respiratory system, costal cartilage of ribs, nasal cartilages, articulating surface of bones, and the embryonic skeleton Bone Chondrocyte in a lacuna Nucleus Matrix Hyaline cartilage LM 240x (a): Carolina Biological Supply/PhototakeUSA.com

43 Elastic cartilage Location: ear and tip of nose Structure: elastic fibers Function: can recoil 43

44 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. TABLE 4.7 continued (b) Fibrocartilage Structure: Collagen fibers similar to those in hyaline cartilage; the fibers are more numerous than in other cartilages and are arranged in thick bundles Function: Somewhat flexible and capable of withstanding considerable pressure; connects structures subjected to great pressure Location: Intervertebral disks, pubic symphysis, and articular disks (e.g., knees and temporomandibular [jaw] joints) Chondrocyte in lacuna Nucleus Intervertebral disk Collagen fibers in matrix LM 240x (c) Elastic Cartilage Structure: Similar to hyaline cartilage, but matrix also contains elastin fibers Function: Provides rigidity with even more flexibility than hyaline cartilage because elastic fibers return to their original shape after being stretched Location: External ears, epiglottis, and auditory tubes Elastic fibers in matrix Chondrocytes in lacunae Nucleus LM 240x (b); Victor Eroschenko; (c): Victor Eroschenko

45 Hard connective tissue Bone 2 types: compact and spongy Composed of osteocytes 45

46 TABLE 4.8 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Supporting Connective Tissue: Bone Structure: Hard, bony matrix predominates; many osteocytes (not seen in this bone preparation) are located within lacunae; the matrix is organized into layers called lamellae Function: Provides great strength and support and protects internal organs, such as the brain; bone also provides attachment sites for muscles and ligaments; the joints of bones allow movements Location: All bones of the body Lacuna Central canal Spongy bone LM 240x Matrix organized into lamellae Compact bone Trent Stephens

47 Blood Liquid connective tissue Erythrocytes, leukocytes, platelets Transport food, oxygen, waste, hormones 47

48 TABLE 4.9 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fluid Connective Tissue: Blood Structure: Blood cells and a fluid matrix Function: Transports oxygen, carbon dioxide, hormones, nutrients, waste products, and other substances; protects the body from infections and is involved in temperature regulation Location: Within the blood vessels; white blood cells frequently leave the blood vessels and enter the interstitial spaces Red blood cells White blood cells LM 400x Ed Reschke

49 Muscular Tissue Muscle type Nucleus/i Nucleus/i location Striated Skeletal many peripheral Y (most muscle) Cardiac 1 centrally Y (heart) Smooth 1 centrally N (organs) 49

50 50

51 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. TABLE 4.10 Muscle Tissue (a) Skeletal Muscle Structure: Skeletal muscle cells or fibers appear striated (banded); cells are large, long, and cylindrical, with many nuclei Function: Movement of the body; under voluntary control Location: Attached to bone or other connective tissue Muscle Nucleus (near periphery of cell) Skeletal muscle fiber Striations LM 800x a(2): Ed Reschke

52 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. TABLE 4.10 continued (b) Cardiac Muscle Structure: Cardiac muscle cells are cylindrical and striated and have a single nucleus; they are branched and connected to one another by intercalated disks, which contain gap junctions Function: Pumps the blood; under involuntary (unconscious) control Location: In the heart Nucleus Cardiac muscle cell Intercalated disks (special junctions between cells) Striations LM 800x b(2): Ed Reschke

53 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. TABLE 4.10 (c) Smooth Muscle continued Structure: Smooth muscle cells are tapered at each end, are not striated, and have a single nucleus Function: Regulates the size of organs, forces fluid through tube, controls the amount of light entering the eye, and produces goose bumps in the skin; under involuntary (unconscious) control Location: In hollow organs, such as the stomach and intestine; skin and eyes Wall of stomach Wall of colon Wall of small intestine Nucleus Smooth muscle cell LM 800x c(2): Victor Eroschenko

54 Nervous Tissue Consist of neurons or nerve cells Found in brain, spinal cord, and peripheral nerves Controls and coordinates body movements Includes axons, dendrites, cell bodies 54

55 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. TABLE 4.11 Nervous Tissue Structure: A neuron consists of dendrites, a cell body, and a long axon; neuroglia, or support cells, surround the neurons Function: Neurons transmit information in the form of action potentials, store information, and integrate and evaluate data; neuroglia support, protect, and form specialized sheaths around axons Location: In the brain, spinal cord, and ganglia Brain Spinal cord Spinal nerves Dendrite Cell body of neuron Nucleus of neuron Nuclei of neuroglia Neuroglia Axon LM 240x Trent Stephens 55

56 What is it? Tissue Repair substitution of dead cells for viable cells Regeneration: cells of same type develop (no scar) Replacement: cells of a different type develop (scar) 56

57 Inflammation Occurs when tissues are damaged Signals the body s defenses (white blood cells) to destroy foreign materials and damaged cells so repair can occur. Chemical mediators: - released after injury - cause dilation of blood vessels 57

58 Symptoms of Inflammation 1. Redness: blood vessels dilate 2. Heat: due to increased blood flow 3. Swelling: from water and proteins 4. Pain: nerve endings are stimulated by damage and swelling 58

59 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Splinter Bacteria introduced 1 A splinter in the skin causes damage and introduces bacteria. Chemical mediators of inflammation are released or activated in injured tissues and adjacent blood vessels. Some blood vessels rupture, causing bleeding. 1 Epidermis 2 Chemical mediators cause capillaries to dilate and the skin to become red. Chemical mediators also increase capillary permeability, and fluid leaves the capillaries, producing swelling (arrows). 2 Dermis Blood vessel Bacteria proliferating 3 White blood cells (e.g., neutrophils) leave the dilated blood vessels and move to the site of bacterial infection, where they begin to phagocytize bacteria and other debris. 3 Neutrophil phagocytizing bacteria Neutrophil migrating through blood vessel wall