Histology

Chapter Overview

4.1 Human Tissue Classifications

4.2 Epithelial Tissue

4.3 Connective Tissue

4.5 Muscular Tissue

4.6 Nervous Tissue

4.7 Tissue Repair

Histology

Essential Terms

Tissue

Histology

pathologist

Introduction1. While cells are basic functional and structural

unit of life, they function in groups as tissues to carry out specialized activities

2. Tissues are influenced by factors –1. _________________

2. _________________

3. Tissues may be hard, semisolid, or liquid

4. Vary with kind of _________, cellular ___________, and types of _____ present

Human Body Tissue ClassificationClassified into four groups according to

function structure

Groups

1. epithelial

2. connective

3. muscle

4. nervous

Epithelial Tissues

General FeaturesEpithelium (singular) or epithelia (plural)

1. Characteristics:

2. Locations:

Figure 4.1

Epithelial TissueBasement membrane functions:

Epithelium characteristics ___________ ___________

because apical surface cells sloughed off, worn off, and damaged then replaced

two types1. covering and lining2. glandular

Covering and Lining EpitheliaClassified according to

1. arrangement of cells in layers

2. cell shapes• squamous = • cuboidal = • columnar = • transitional =

Figure 4.2

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Glandular Epithelia1. Gland:2. Glandular cell function is secretion3. Classification of glands

exocrine into ducts onto a surface or inside a lumen Secretion Examples:

endocrine into the blood Secretes: Examples:

Table 4.1 pt 8

Table 4.1 pt 9

Concept 4.3 Connective Tissues

Connective Tissue Most abundant tissue type

Functions

Examples and Locations

General FeaturesTwo basic elements

1. cells

2. extracellular matrix

Characteristics:

Figure 4.3

Types of Cells in C.T. immature “blast” cells Macrophages Mast cells Adipocytes White blood cells Plasma Cells

Extracellular Matrix determines classification of connective

tissues two components

ground substance fibers

Ground Substance between cells and fibers can be fluid, semifluid, or calcified Functions:

Ground Substance contains large organic molecules

polysaccharides and proteins glycosaminoglycans or GAGs

trap water example: hyaluronic acid

Fibers Function to strengthen and support Three major types

1. Collagen – leave space

2. Elastic -space

3. reticular

Collagen Fibers very strong resist pulling forces parallel bundles most abundant protein in body 25% of total

proteins found in most connective tissue types

bone cartilage tendons ligaments

Figure 4.3

Elastic Fibers smaller in diameter than collagen branch and join together forming network protein named elastin can stretch up to 150% of relaxed length

without breaking ability to return to original shape plentiful in

skin blood vessel walls lung tissue

Reticular Fibers collagen arranged in fine bundles provide support in walls of blood vessels help form the basement membrane form network around cells of some tissues

areolar adipose smooth muscle plentiful in reticular connective tissue

Mature Connective Tissue1. loose

• areolar connective tissue• adipose tissue• reticular connective tissue

2. dense • dense regular• dense irregular• elastic connective

3. cartilage• hyaline• fibrocartilage• elastic cartilage

4. bone 5. liquid

• blood

Figure 4.4

Table 4.2a

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Table 4.2k

Muscular Tissues

Muscular Tissue

Characteristics

Locations:1. skeletal2. cardiac3. smooth

Skeletal Muscle

striated long cells (up to 30-40cm) cylindrical in shape many nuclei at periphery of cell fibers are parallel voluntary

Cardiac Muscle ________ ________ ________

sometimes two nuclei ________

cell junctions strengthen tissue and hold cells together provide route for quick conduction of impulses

________

Smooth Muscle _________ _________ _________ _________ _________ _________

cell junctions strengthen tissue and hold cells together provide route for quick conduction of impulses

_________

Nervous Tissues

Nervous Tissue two principal types of cells

1. Neurons:– sensitive to various stimuli– convert stimuli into impulses– conduct impulses to:

2. Neuroglia:

3. Locations:

Table 4.4

Tissue Repair

Tissue Repair ability to repair depends on

extent of damage tissue type

Epithelium -

connective -

muscle -

nervous -

Tissue Repair New cells originate by cell division from

parenchyma (functioning part of tissue)

stroma (supporting connective tissue)

tissue repair affected by 1. 2.

Tissue Repair Animations:

http://www.sumanasinc.com/webcontent/animations/content/inflammatory.html

http://faculty.riohondo.edu/rbethel/videos/micro_inflammation.swf

Figure 4.5c

Figure 4.5c

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Epithelial Tissuebasement membrane thin extracellular layer made up of

basal lamina

reticular lamina