CRR Histology Lab 2
Mostly Epithelial Tissues
CRR 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 at first 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
find its location. 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?
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(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)
Slides 61, 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.
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Question--On each specimen, what type of 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 note differences 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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Slides 30, salivary glands (within tongue)
Slides 31, 32, salivary glands
Slides 41, 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
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properties of epithelial tissue. Question--What are the
general properties 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 duct epithelium. 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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(OVER)
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 < http://projects.galter.northwestern.edu/rhodin/ >
For any example of epithelial tissue, distinguish apical
and basal surfaces.
Find a keratinocyte (epidermal cell). Identify
desmosomes and tonofilaments.
Find the basement membrane between an epithelium and
underlying connective tissue.
Find a ciliated columnar epithelial cell. Identify cilia.
For any example of a simple columnar or cuboidal
epithelium, distinguish cellular features that establish
apical / basal polarity, including the junctional complex.
□
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.