Medical School Histology Basics Epithelium and junctions VIBS

Medical School Histology Basics Epithelium and junctions VIBS 243 lab Larry Johnson Texas A&M University Ref code # 18

Epithelium - function • Epithelium forms the outer protective surface of the body and all the glands. It lines the walls of most closed cavities of the body and all passages leading to the exterior, and it lines blood and lymphatic vessels. skin gland kidney cavities bladder vessels Ref code #18

Epithelium - function Epithelial tissues participate in the metabolism of the body through: i) the absorption of substances from the exterior, e. g. , from the lumen of the intestines; and ii) the elimination of other substances to the outside. All substances, including gases, normally received and given off from the body must pass through epithelia. For the performance of secretory functions, the epithelial tissues form specialized structures called glands. Intestine Sweat gland

Origin and Distribution of Epithelium Ectoderm - epidermis of skin and epithelium of cornea together covers the entire surface of the body; ECTODERM sebaceous and mammary glands Endoderm - alimentary tract, liver, pancreas, gastric glands, intestinal glands • Endocrine glands - lose connection with surface Mesoderm MESODERM • Endothelium - lining of blood vessels • Mesothelium - lining serous cavities ENDODERM Ref code # 4

CLASSIFICATION OF EPITHELIA Ref code # 6 NUMBER OF LAYERS – SIMPLE - ONE LAYER – STRATIFIED - MORE THAN ONE LAYER SHAPE OF SUPERFICIAL CELLS – SQUAMOUS - FLAT – CUBOIDAL - CUBE – COLUMNAR – COLUMN OTHER – PSEUDOSTRATIFIED - NOT TRULY STRATIFIED – TRANSITIONAL - URINARY TRACT

Slide 109: Skin, hand, monkey dermis Simple squamous endothelial cells lining blood lymph vessels – Stratified squamous epithelium of skin – Stratified cuboidal of sweat ducts Yu, Fei dermis Sweat gland Stratified cuboidal epidermis Ref code # 6

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32409 Rat intestine Ref code # 6 Smooth muscle Simple columnar epithelium 148 Goblet cells Small intestinal villi

32409 EM 3: region of basal lamina and Brush connective tissue beneath intestinal border epithelial absorptive cells 1. Plasma membrane 2. Basal lamina 3. Connective. Intestinal tissue Goblet cell absorptive cell nuclei EM 3

EM 3: Intestine (Basal part of cell) Basal lamina Connective tissue Intestinal absorptive cells 148

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Slide 258: Kidney (PAS) Ref code # 6 Basement membrane of epithelium Simple squamous epithelium Simple cuboidal in medulla and cortex

148 Ileum Ref code # 6 Intestinal absorptive cells and goblet cells Brush border Goblet cells Simple columnar epithelium

249 Ileum, monkey (PAS) Basement membrane of epithelium Simple columnar epithelium Connective tissue Brush border Goblet cells Cell nuclei Basement membrane, brush border and goblet cells are PAS positive for

The basal lamina of epithelial cells usually is thin (EM 10 f); however, under pathological conditions, it is thickened as in the lymphatic vessel and seminiferous epithelium (Sertoli cell) of an aged-rat testis (EM 8 h). EM 10 f EM 8 h basal lamina

SPECIALIZATION OF EPITHELIA MAINTAIN EXTENSIVE CONTACTS AMONG CELLS STRUCTURALLY AND FUNCTIONALLY POLARIZED JUNCTIONS ZONULA OCCLUDENS - TIGHT JUNCTION (BELT) ZONULA ADHERENS – ADHERING BELT DESMOSOME (MACULA ADHERENS) - SPOT ATTACHMENT GAP JUNCTIONS - COMMUNICATION Ref code # 6

Ref code # 7, 12 Terminal bars 32409

148 Goblet cells 32409 Intestinal absorptive cells 250 Terminal bars belt 250 Terminal bars are part of a belt (zonula) around the cells. Ref code # 7

EM 4: Intestine (Apical) Tight junction, zonula adherens, Goblet cells terminal web 148

EM 2: Liver – Gap junction, – desmosome, tight junction Ref code # 6

EM 2 a: Liver Gap junctions EM 2

133 vein 133 valve Simple squamous epithelium cells viewed “face on” venule Lumen of lymphatic vessel capillary 250 valve Simple squamous epithelium cells viewed on their sides Ref code # 6

109 valve arteriole capillary 19680 testis Lumen of lymphatic vessels 196 Simple squamous epithelium valve vein

EM 10 A showing capillary endothelial cells Simple squamous epithelium : cells viewed on the side 109

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109 Stratified squamous epithelium Keratinized dead flattered cells at surface

Slide 109: Skin, hand, monkey prickle cell" layer (desmosomes) dermis epidermis

Slide 109 : Skin, hand, monkey dermis Stratified cuboidal is only found in sweat ducts of skin (Slide 109). Fat cells epidermis Ref code # 5, 6

Stratified squamous epithelium Nonkeratinized tongue and vagina Ref code # 5

Nuclei present in flat cells at surface stratified squamous epithelium non-keratinized HISTO 052 tongue Vagina (Slide 178)

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Lung air space Slide 133: Trachea, monkey 133 432 – Simple squamous lining the air spaces of lungs – Pseudostratifie d epithelium lining tracheal lumen – Ciliated epithelium of trachea, goblet cells, thick basement membrane Ref code # 6

tracheal lumen (Slide 133), Plasma cells transition of the luminal epithelium from stratified squamous of vocal cords to pseudostratified, ciliated 133 epithelium pseudostratified, ciliated epithelium human larynx, Slide 429 called respiratory epithelium stratified squamous Note thickened basement membrane typical of this epithelium

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Transitional epithelium urinary bladder (Slide 160) (Slide 262) ureter Ref code # 6

Slide 160 Image of the Urinary bladder Transitional epithelium Mesothelium Lumen of bladder

HISTO 052 (tongue) to observe mucus and serous glands

In summary Ref code # 18 All substances, including gases, normally received and given off from the body must pass through epithelia.

Many illustrations in these VIBS Histology You. Tube videos were modified from the following books and sources: Many thanks to original sources! 1. Alberts, et al. , 1989. Molecular Biology of the Cell. 2 nd Edition. Garland Publishing, Inc. New York. ISBN 0 -8240 -3695 -6. 2. Alberts, et al. , 1994. Molecular Biology of the Cell. 3 nd Edition. Garland Publishing, Inc. New York. ISBN 0 -8153 -1619 -4. 3. Bloom, W. and Fawcett, D. W. , 1968. A Textbook of Histology. 9 th Edition. W. B. Saunders Company. Philadelphia. Library of Congress #67 -17445. 4. Elias, H. et al. , 1978. Histology and Human Microanatomy. A Wiley Medical Publication. John Wiley & Sons, New York. ISBN 0 -47104929 -8. 5. Eroschenko, V. 2000. Di Fiore’s Atlas of Histology with Functional Correlations. 9 th Edition. Lippincott Williams & Wilkins. Philadelphia. ISBN 07817 -2676 -X. 6. Fawcett, D. W. , 1986. Bloom and Fawcett. A Textbook of Histology. 11 th Edition. W. B. Saunders Company. Philadelphia. ISBN 0 -72161729 -8. 7. Fawcett, D. W. , 1986. Bloom and Fawcett. A Textbook of Histology. 12 th Edition. Chapman and Hall. New York. ISBN 0 -412 -04691 -1. 8. Guyton, A. C. 1971. Textbook of Medical Physiology. 4 th Edition. W. B. Saunders Company. Philadelphia. Library of Congress # 74118589. 9. Ham, A. W. 1974. Histology. 7 th Edition. J. B. Lippincott Company. Philadelphia. ISBN 0 -397 -52062 -X. 10. Ham, A. W. and Cormack, D. H. 1979. Histology. 8 th Edition. J. B. Lippincott Co. Philadelphia. ISBN 0 -397 -52089 -1. 11. Junqueria, et al. , 1995. Basic Histology. 8 th Edition. Appleton and Lange. Norwalk, Connecticut. ISBN 08385 -0567 -8. 12. Junqueira, et al. , 1998. Basic Histology. 9 th Edition. Appleton and Lange. Stamford, Connecticut. ISBN 0 -8385 -0590 -2. 13. Knobil, E. et al. 1988. The Physiology of Reproduction. Volume 1. Raven Press. New York. ISBN 0 -88167 -281 -5. 14. Langley, et al. , 1974. Dynamic Anatomy and Physiology. 4 th Edition. Mc. Graw-Hill Book Company. New York. ISBN 0 -07 -036274 -2. 15. Mescher, A. L. , 2010. Junqueira’s Basic Histology Text and Atlas. 12 th Edition. Mc. Graw Hill Medical. New York. ISBN 978 -0 -07 -1604314. 16. Tuttle, W. W. and Schottelius, B. A. 1969. Textbook of Physiology. 16 th Edition. The C. V. Mosby Company. Saint Louis. Library of Congress # 75 - 89848. 17. Varner, D. et al. 1991. Diseases and Management of Breeding Stallions. American Veterinary Publications. Goleta, California. ISBN 0939674 -33 -5. 18. Von Hagens, Gunther and A. Whalley, 2007. Body Worlds – The Anatomical Exhibition of Real Human Bodies. ISBN 978 -3 -937256 -04 -7 19. Weiss, L. 1983. Histology: Cell and Tissue Biology. 5 th Edition. Elsevier Biomedical. New York. ISBN 0 -444 -00716 -4. 20. Weiss, L. and Greep, R. 1977. Histology. 4 th Edition. Mc. Graw-Hill Book Company. New York. ISBN 0 -07 -069091 -X.

Questions on Epithelia Which item(s) is/are characteristic of epithelia? a. secretory cells of glands b. covers organs c. line urinary tract d. a & b e. a, b, & c Which junction - description pair match? a. Zonula occludes – tight junction around the cell b. Zonula adherens – adhering junction around the cell c. Hemidesmosome – spot attachment of cells to the CT below d. a & b e. a, b, & c Which embryonic origin - distribution of epithelium do not match? a. endoderm - endothelium b. endoderm - alimentary tract c. mesoderm - mesothelium d. ectoderm - mammary gland e. ectoderm - epidermis

On road from Fort Stockton to Big Bend National Park, TX Ranch just south of Fort Stockton, TX

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