Histology

Overview of Tissue Science Chapter 4

Histology Histology - The study of tissues. Tissues are collections of cells and extracellular material that perform a specific but limited range of functions. The four tissue types, in varying combinations, form all of the structures of the human body. Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Four basic tissue types Epithelial Connective Muscular Neural Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Epithelial Tissue A.Epithelia are layers that cover internal and external surfaces. 1. Important characteristics a)Cells are bound closely together b) A free (apical) surface exposed to the environment or some internal chamber. c)Attachment to underlying connective tissue by a basement membrane. d)The absence of blood vessels (avascular) e)Epithelial cells that are damaged or lost are continually replaced.

Epithelial Tissue 2.Functions of Epithelia a)Physical protection b)Permeability control c)Sensation trigger d)Specialized secretions Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Epithelial Tissue B.Classifying Epithelia a)Number of layers Simple (one cell thick) Stratified (multiple cells thick) b)Cell shape Squamous (flat) Cuboidal (cubic) Columnar (tall columns) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Epithelial Tissue Table 4-1

Epithelial Tissue Figure 4-5(a)

Epithelial Tissue Figure 4-5(b)

Connective Tissue

Connective Tissue is the most diverse tissue of the body. Highly vascular; distributed throughout the body, but are never exposed to the outside environment.

Connective Tissue Three basic components Specialized cells Protein fibers Ground substance-a fluid; the extracellular fibers and ground substance form the matrix

Connective Tissue Functions include Support and protection (Supportive) Transportation of materials (Blood and Lymph) Storage of energy reserves (Fat) Defense of the body (Lymph)

Adipose Tissue Figure 4.12c

Reticular Connective Tissue Figure 4.12d

Dense Irregular Connective Tissue Figure 4.12e

Dense Regular Connective Tissue Figure 4.12f

Elastic Connective Tissue

Hyaline Cartilage Figure 4.12g

Elastic Cartilage Figure 4.12h

Fibrocartilage Figure 4.12i

Bone Tissue Figure 4.12j

Blood Tissue Figure 4.12k

Muscle Tissue

Functions of Muscles Produce movement Maintain posture Support soft tissues Guard entrances and exits Control body temperature

Three Types of Muscles Skeletal Muscle - voluntary Cardiac Muscle - involuntary Smooth Muscle - involuntary

Muscle Tissue Figure 4-13(a)

Muscle Tissue Cardiac Muscle Tissue Only in heart Short, branched fibers Single nucleus Striated Involuntary contraction Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Muscle Tissue Figure 4-13(b)

Muscle Tissue Smooth Muscle Tissue Short, tapering cells No striations Involuntary contraction Blood vessels Urinary bladder Digestive organs Uterus Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Muscle Tissue Figure 4-13(c)

Neural Tissue

Properties of Neural Tissue Conduct electrical impulses Transfer, process, and store information Comprises neurons and neuroglia Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Neural Tissue Structure Neurons Dendrites Information entry Cell body Information integration Axon (nerve fibers) Information transmission Synaptic terminals Information transfer Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Neural Tissue Neuroglia Several types of neuroglia Provide physical support Maintain extracellular chemistry Supply nutrients Defend against infection Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Neural Tissue Figure 4-14