1 bio 101 laboratory 3 epithelial tissues and integument

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Bio 101Laboratory 3

Epithelial Tissuesand

Integument

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Tissues• Tissues to be examined under the microscope

– Epithelial Tissue (p. 67-74 Lab Manual)– Integument (p. 91-104 Lab Manual)– Connective Tissue (p. 74 - 81Lab Manual)– **We will be doing muscle and nervous tissues later in the

semester– Lab Guide (handout) for a checklist of tissues/structures you are

responsible for

• Objectives– Learn to recognize each of the tissue types under the light

microscope by structure, not color, and how they are constructed– Provide at least one example of where each tissue is found in the

body on lab exam

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Tissues - Overview

• Recall that tissues are layers or masses of cells that have common functions

• The study of tissues is called…?

• Usually the cells within tissues are separated by nonliving, intercellular materials that the cells produce.

Histology

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Sectioning and Staining of Tissues for Microscopy

Four steps in tissue preparation

- Fixation stabilizes and preserves the tissue

- Embedding converts the tissue into a solid form which can be sliced ("sectioned")

- Sectioning (slicing) provides the very thin specimens needed for microscopy (2-D)

- Staining provides visual contrast and may help identify specific tissue components.

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Hematoxylin and Eosin (H&E) Stain

Hematoxylin – deep purple or blueEosin – red (pink) color

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Epithelial Tissue

• Widespread throughout body

• A “covering and lining” tissue

• Always has a free surface

• Underside of tissue is anchored to a “basement

membrane” (nonliving layer)

• Lacks blood vessels

• Cells are tightly packed

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Epithelial Tissue - Epithelial tissues are

classified by a combination of two characteristics:- Cell shape

• Squamous (flat)

• Cuboidal (cube-shaped)

• Columnar (elongated; rectangles)

– Layering (or stratification)

• Simple (single layer)

• Stratified (two or more layers)

• Pseudostratified (‘false’ stratification – really one layer)

• Transitional (can change shape when stretched)

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Simple Squamous Epithelial Tissue

Free surface

Found lining air sacs of lungs, blood vessels, ventral body cavities, kidney glomeruli, lymphatic vessels

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Stratified Squamous Epithelium

Found as 1) outer layer of skin (keratinized, non-mucous)2) Mucous nonkeratinized linings in esophagus, mouth, vagina

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Simple Cuboidal Epithelium

Simple cuboidal: Found in kidney tubules, ducts of sweat glands and other glands, surface of ovary.

(Stratified cubioidal)

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Simple Columnar Epithelium

Note ‘brush border’ on the free surface of simple columnar cells and scattered goblet (mucus-producing) cells

Found throughout digestive tract, uterine tubes, some regions of uterus

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Pseudostratified Ciliated Epithelium

Appears stratified because nuclei are located at different levels

However, ALL cells reach the basement membrane

Note how different cilia look as compared to microvilli of brush border on simple columnar cells

Found in trachea and most of the upper respiratory tract.

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Transitional Epithelium

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Integumentary SystemThe Integument is an Organ. Why?

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Integumentary System

From: http://www.lab.anhb.uwa.edu.au/mb140/CorePages/Integumentary/Integum.htm#sebaceous

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Sebaceous glands

Hair follicles

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Sweat gland

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Light Microscope View of Sweat Glands

From: Martini, Anatomy & Physiology, Prentice Hall, 1998

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Review

• Epithelium– Simple squamous – single layer of flattened cells– Simple cuboidal – single layer of square cells– Simple columnar – single layer of rectangular cells;

may have goblet (mucus) cells– Stratified squamous – stacked squamous cells– Pseudostratified ciliated columnar

• Look like stratified by they are not

• Have cilia

• Have goblet cells

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Review

• Integument– Layers

• Epidermis, dermis = skin

• Subcutaneous (hypodermis, superficial fascia)

– Accessory structures• Hair follicles – in which hair grows

• Sebaceous glands– Look ‘fatty’

– Look similar to adipose tissue except nucleus is in center of cell

– Usually found in a cluster of cells attached to a hair follicle

• Sweat glands– Much more solid in appearance than sebaceous glands

– Ducts of sweat glands are lined with simple cuboidal epithelium

– Section through ducts gives varied appearance, i.e., some are circular, some longitudinal, some oblique

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What you should do in lab today…• Using the microscope and the slide boxes

– Look at the slides listed on your Laboratory Guide (handed out in first lab) for:

• Epithelial tissue• Integumentary System

• BE SURE you can recognize each of the tissue types listed in your Laboratory Guide; check off ONLY after you can recognize a tissue– KNOW at least one place in the body where each of

the tissue types is found for lab exam

• Get tested on slides for today (identification only – not location in body)

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For Next Lab…

• On Your Own: Do the Review Sheet Exercises for Exercise 6 and 7• Tissue Structure and Function - General review, p. 85

• Epithelial Tissue, pp. 85 – 87

• Integument, pp. 101 - 103

• Read ahead: Connective Tissues– Pages 74 through 81 in your Laboratory Manual

1 bio 101 laboratory 3 epithelial tissues and integument

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