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© 2015 Pearson Education, Inc. Chapter 3 Body Tissues Tissues – Groups of cells with similar structure and function – Four primary types: 1.Epithelial.

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Presentation on theme: "© 2015 Pearson Education, Inc. Chapter 3 Body Tissues Tissues – Groups of cells with similar structure and function – Four primary types: 1.Epithelial."— Presentation transcript:

1 © 2015 Pearson Education, Inc. Chapter 3 Body Tissues Tissues – Groups of cells with similar structure and function – Four primary types: 1.Epithelial tissue (epithelium) 2.Connective tissue 3.Muscle tissue 4.Nervous tissue

2 Epithelial Tissues Locations: – Body coverings – Body linings – Glandular tissue Functions: – Protection – Absorption – Filtration – Secretion © 2015 Pearson Education, Inc.

3 Epithelium Characteristics Cells fit closely together and often form sheets The apical surface is the free surface of the tissue – The unattached surface Can be exposed to exterior or cavity of an organ The lower surface of the epithelium (the basal lamina) rests on a basement membrane – Consists of reticular connective tissue

4 Epithelium Characteristics Avascular (no blood supply) – Relies on circulatory system to obtain food and oxygen Surrounding connective tissues supply via diffusion from nearby capillaries Regenerate easily if well nourished (through normal cell division) – Those on the exterior of the skin are exposed to friction and other hostile substances and are therefore lost

5 © 2015 Pearson Education, Inc. Classification of Epithelia Two name system: – First name = # of layers – Second name = shape of cells Names using number of cell layers include: – Simple—one layer – Stratified—more than one layer

6 Figure 3.17a Classification and functions of epithelia. Basal surface Apical surface Basal surface Apical surface Simple Stratified (a) Classification based on number of cell layers

7 © 2015 Pearson Education, Inc. Classification of Epithelia Names using shape of cells – Squamous Flattened, like fish scales – Cuboidal Cube-shaped, like dice – Columnar Column-like

8 Figure 3.17b Classification and functions of epithelia. Squamous Cuboidal Columnar (b) Classification based on cell shape

9 Figure 3.17c Classification and functions of epithelia. Remember these general characteristics and you will be able to classify each type a lot easier !! Diffusion and filtration Secretion in serous membranes Protection Secretion and absorption; ciliated types propel mucus or reproductive cells Protection; these tissue types are rare in humans Protection; stretching to accommodate distension of urinary structures (c) Function of epithelial tissue related to tissue type Number of layers Cell shape One layer: simple epithelial tissues More than one layer: stratified epithelial tissues Squamous Cuboidal Columnar Transitional

10 © 2015 Pearson Education, Inc. Simple Epithelia Simple squamous – Single layer of flat cells – Location—usually forms membranes Lines air sacs of the lungs Forms walls of capillaries Forms serous membranes (serosae) that line and cover organs in ventral cavity – Functions in diffusion, filtration, or secretion in membranes

11 Figure 3.18a Types of epithelia and their common locations in the body. Nucleus of squamous epithelial cell Basement membrane Air sacs of lungs Nuclei of squamous epithelial cells (a) Diagram: Simple squamous Photomicrograph: Simple squamous epithelium forming part of the alveolar (air sac) walls (275×).

12 © 2015 Pearson Education, Inc. Simple Epithelia Simple cuboidal – Single layer of cube-like cells – Locations: Common in glands and their ducts Forms walls of kidney tubules Covers the surface of ovaries – Functions in secretion and absorption; ciliated types propel mucus or reproductive cells

13 Figure 3.18b Types of epithelia and their common locations in the body. Nucleus of simple cuboidal epithelial cell Basement membrane Simple cuboidal epithelial cells Basement membrane Connective tissue (b) Diagram: Simple cuboidal Photomicrograph: Simple cuboidal epithelium in kidney tubules (250×).

14 © 2015 Pearson Education, Inc. Simple Epithelia Simple columnar – Single layer of tall cells Goblet cells secrete mucus – Location: Lines digestive tract from stomach to anus Mucous membranes (mucosae) line body cavities opening to the exterior – Functions in secretion and absorption; ciliated types propel mucus or reproductive cells

15 Figure 3.18c Types of epithelia and their common locations in the body. Basement membrane Mucus of a goblet cell Nucleus of simple columnar epithelial cell Simple columnar epithelial cells (c) Diagram: Simple columnar Photomicrograph: Simple columnar epithelium of the small intestine (575×).

16 © 2015 Pearson Education, Inc. Simple Epithelia Pseudostratified columnar – All cells rest on a basement membrane – Single layer, but some cells are shorter than others giving a false (pseudo) impression of stratification – Location: Respiratory tract, where it is ciliated and known as pseudostratified ciliated columnar epithelium – Functions in absorption or secretion

17 Figure 3.18d Types of epithelia and their common locations in the body. (d) Diagram: Pseudostratified (ciliated) columnar Photomicrograph: Pseudostratified ciliated columnar epithelium lining the human trachea (560×). Basement membrane Pseudo- stratified epithelial layer Cilia Connective tissue

18 © 2015 Pearson Education, Inc. Stratified Epithelia (two or more cell layers) Stratified squamous – Named for cells present at the free (apical) surface, which are flattened – Functions as a protective covering where friction is common – Locations—lining of the: Skin (outer portion) Mouth Esophagus

19 Figure 3.18e Types of epithelia and their common locations in the body. Basement membrane Connective tissue Stratified squamous epithelium (e) Diagram: Stratified squamous Photomicrograph: Stratified squamous epithelium lining of the esophagus (140×). Nuclei

20 © 2015 Pearson Education, Inc. Stratified Epithelia Stratified cuboidal—two layers of cuboidal cells; functions in protection Stratified columnar—surface cells are columnar, and cells underneath vary in size and shape; functions in protection Stratified cuboidal and columnar – Rare in human body – Found mainly in ducts of large glands

21 © 2015 Pearson Education, Inc. Stratified Epithelia Transitional epithelium – Unique type of epithelium because of its ability to become temporarily modified in arrangement and shape – Composed of modified stratified squamous epithelium – Shape of cells depends upon the amount of stretching – Functions in stretching and the ability to return to normal shape – Locations: urinary system organs

22 Figure 3.18f Types of epithelia and their common locations in the body. Basement membrane Connective tissue Transi- tional epithelium Transitional epithelium (f) Diagram: Transitional Photomicrograph: Transitional epithelium lining of the bladder, relaxed state (270×); surface rounded cells flatten and elongate when the bladder fills with urine.

23 © 2015 Pearson Education, Inc. Glandular Epithelium Gland – One or more cells responsible for secreting a particular product – Secretions contain protein molecules in an aqueous (water-based) fluid – Secretion is an active process

24 © 2015 Pearson Education, Inc. Glandular Epithelium Two major gland types – Endocrine gland Ductless; secretions diffuse into blood vessels All secretions are hormones Examples include thyroid, adrenals, and pituitary

25 © 2015 Pearson Education, Inc. Glandular Epithelium Two major gland types – Exocrine gland Secretions empty through ducts to the epithelial surface Include sweat and oil glands, liver, and pancreas Includes both internal and external glands


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