University:
Texas A&M University
Course:
BIOL 319 | Integrated Human Anatomy and Physiology I
Academic year:

2019
Views:

207

Pages:

39
Author:

strofamay58

Basics Epithelium and junctions Larry Johnson Texas A&M University Epithelium - function Ref code #18 • 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 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 CLASSIFICATION OF EPITHELIA 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 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 Rat intestine 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. ConnectiveIntestinal tissue Goblet cell absorptive cell nuclei EM 3 EM 3: Intestine (Basal part of cell) Basal lamina Connective tissue Intestinal absorptive cells 148 Ref code #5 Kidney (PAS) Basement membrane of epithelium Simple squamous epithelium Simple cuboidal in medulla and cortex Ileum Intestinal absorptive cells and goblet cells Brush border Goblet cells Simple columnar epithelium 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 10f); however, under pathological conditions, it is thickened as in the lymphatic vessel and seminiferous epithelium (Sertoli cell) of an aged-rat testis (EM 8h). EM 10f EM 8h 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 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. EM 4: Intestine (Apical) Tight junction, zonula adherens, Goblet cells terminal web 148 EM 2: Liver – Gap junction, – desmosome, tight junction EM 2a: LiverGap junctions EM 2 vein valve Simple squamous epithelium cells viewed “face on” venule Lumen of lymphatic vessel capillary 250 valve Simple squamous epithelium cells viewed on their sides valve 109 arteriole capillary 19680 testis Lumen of lymphatic vessels 196 Simple squamous epithelium valve vein EM 10A showing capillary endothelial cells Simple squamous epithelium : cells viewed on the side 109 Stratified squamous epithelium Keratinized dead flattered cells at surface Skin, hand, monkey prickle cell" layer (desmosomes) dermis epidermis Skin, hand, monkey Fat cells dermis Stratified cuboidal is only found in sweat ducts of skin (Slide 109). epidermis Stratified squamous epithelium Nonkeratinized tongue and vagina Nuclei present in flat cells at surface stratified squamous epithelium non-keratinized HISTO052 tongue Vagina (Slide 178) #5 Lung air space 432 – Simple squamous lining the air spaces of lungs – Pseudostratifie d epithelium lining tracheal lumen – Ciliated epithelium of trachea, goblet cells, thick basement membrane Trachea, monkey tracheal lumen (Slide 133), Plasma cells transition of the luminal epithelium from stratified squamous of vocal cords to pseudostratified, ciliated epithelium pseudostratified, ciliated epithelium human larynx, Slide called respiratory epithelium stratified squamous Note thickened basement membrane typical of this epithelium Transitional epithelium urinary bladder ureter Image of the Urinary bladder Transitional epithelium Mesothelium Lumen of bladder HISTO052 (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. 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

Basics Epithelium and Junctions

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