CRRHistology Lab 2Mostly Epithelial TissuesCRR Week 2
There is a lot going on each of the slides listed below, including much that you may not have learned about yet.
But real tissues do not come in nice, step-by-step packages. So atfirst just try to see how much you can notice (use your histology text or atlas). And trust that we will understand more as we gain practice (and read, read, read).
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Slide 2, scalp
Slide 3, skin
(REVIEW) Distinguish epidermis and dermis.
Question--What type of tissue is epidermis?
Question--What type of tissue is dermis?
(EASY) Question--Where is the basement membrane? You probably can't see basement membrane, but you can finditslocation. A thicker, more-noticeable basement membrane underlies corneal epithelium, slide 25.
(EASY) Find a keratinocyte.
(HARDER) Find an epidermal cell that is not a keratinocyte. Question--What other cell type might it be? List at least three possibilities.
(EASY) Find the stratum corneum of the epidermis. Question--What is the composition of this layer?
(HARDER) Find the stratum granulosum of the epidermis. Question--What feature of this specimen provides definitive evidence for ketatinization?
(EASY) Find a hair follicle. Question--What type of tissue is the hair follicle? Question--Why do hair follicles present so many different appearances?
(EASY) Find a sweat gland. Question--What type of tissue is the sweat gland?
(HARDER) Distinguish the secretory portion of a sweat gland from its duct.
(EASY) Find a sebaceous gland. Question--What type of tissue is the sebaceous gland?
(HARDER) Find a dying cell with a pyknotic (shrunken) nucleus. Hint--Look in sebaceous glands. Note that pyknotic nuclei provide evidence of recent cell death.
□ /At your discretion, you may notify an instructor for a brief oral evaluation on this material.
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Slide 25, cornea(front surface of eyeball)
Slides61, 62, trachea & esophagus
Slide 43, colon
Slide 60, lung
On each of the specimens listed above, find surface epithelium. Compare / contrast the epithelium of each of these specimens with epidermis of skin.
Question--On each specimen, what typeof epithelium do you see? Is the epithelium simple or stratified? Is it squamous, cuboidal or columnar? Keratinized or not?
Observe differences in thickness and shape (especially basal surface shape) among these various examples of epithelial tissue. Also notedifferences in the appearance of the cells which comprise these epithelia.
□ /At your discretion, you may notify an instructor for a brief oral evaluation on this material.
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Slides30, salivary glands (within tongue)
Slides31, 32, salivary glands
Slides41, 42, pancreas
Slides 37, gastric glands (in stomach mucosa)
Slide 40, Brunner's glands (in duodenal submucosa)
Slide 73, 74, uterine glands
Find glandular tissue on each of specimens. Compare and contrast with the simple sweat and sebaceous glands of skin. Try to see (or at least mentally visualize) glandular epithelium as a tissue made of cells with the general properties of epithelial tissue. Question--What are the generalproperties of epithelial tissue?
Distinguish parenchyma (the proper glandular epithelial tissue) from stroma (supporting tissue, including connective tissue and blood vessels). Question--How can you tell an epithelial cell from a connective tissue cell?
For salivary glands and pancreas, distinguish secretory epithelium from ductepithelium. Question--Why do secretory cells and duct cells look different?
□ /At your discretion, you may notify an instructor for a brief oral evaluation on this material.
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ELECTRON MICROGRAPHS
Use Rhodin's Atlas of Histology (from the Learning Resources Center) or other any other collection of electron micrographs.
Rhodin's Atlas is also available online, at <
For any example of epithelial tissue, distinguish apical and basal surfaces.
Find the basement membrane between an epithelium and underlying connective tissue.
For any example of a simple columnar or cuboidalepithelium, distinguish cellular features that establish apical / basal polarity, including the junctional complex.
Find akeratinocyte (epidermal cell). Identify desmosomes and tonofilaments.
Find a ciliated columnar epithelial cell. Identify cilia.
Find an epithelial cell specialized for protein-secretion. Identify rough endoplasmic reticulum, ribosomes, Golgi apparatus, and secretory vesicles.
Find a simple squamous epithelial cell.
□ /At your discretion, you may notify an instructor for a brief oral evaluation on this material.