UNIFIED PRACTICAL1 EPITHELIUM (1).pdf

UNIFIED PRACTICAL1 EPITHELIUM HIHD-211 TERM-3 Basic Science Department COSHP, KSAU-HS, KSA Learning Outcomes By the end of this session, the student will be able to identify: Epithelial membranes: 1. Simple squamous epithelium 2. Non-keratinized stratified squamous epithelium 3. Keratinized stratifi...

UNIFIED PRACTICAL1 EPITHELIUM HIHD-211 TERM-3 Basic Science Department COSHP, KSAU-HS, KSA Learning Outcomes By the end of this session, the student will be able to identify: Epithelial membranes: 1. Simple squamous epithelium 2. Non-keratinized stratified squamous epithelium 3. Keratinized stratified squamous epithelium 4. Simple cuboidal epithelium 5. Stratified cuboidal epithelium 6. Simple columnar epithelium with goblet cells 7. Pseudo-stratified ciliated columnar epithelium with goblet cells 8. Transitional epithelium Epithelial glands: 9. Simple tubular gland 10. Simple branched tubular gland 11. Simple coiled tubular 12. Simple acinar 13. Compound acinar 14. Glands on the basis of mode of secretion 15. Basement membrane and its layers What is the shape of cells and their nuclei lining the internal cavities of the body indicated by arrows? Flat (squamous) cells with flattened nuclei How many layers of these cells are there? Single layer of cells What type of the epithelium this could be? SIMPLE SQUAMOUS EPITHELIUM This micrograph shows the surface epithelium of the mesovarium covered by mesothelium, a name given to the simple squamous epithelium that lines the internal cavities of the body. The mesothelial cells (MC) are recognized by their nuclei at this low magnification. Beneath the mesothelial cells is a thin layer of connective tissue (CT) and adipose cells (A). Th e inset reveals at higher magnifi cation the nuclei (N) of the mesothelial cells. LO-1 Surface layer cells LO-2 What is the shape of surface layer cells? Squamous What is the shape of basal layer cells? Cuboidal Basal layer What is the shape of surface layer cells? Squamous Surface layer cells What is the shape of basal layer cells? Cuboidal What type of the epithelium this could be? STRATIFIED SQUAMOUS EPITHELIUM Basal layer LO-2 What is shape of the cells and their nuclei indicated by arrows, lining a tubular organ? A B How many layers of the cells could you recognize? Many layers Identify the luminal and basal surface cells Luminal surface cells are indicated by “A” and basal surface cells by “B” What type of the epithelium this could be? STRATIFIED SQUAMOUS EPITHELIUM FROM ESOPHAGUS It is multilayered with squamous surface cells; therefore, it is a stratified squamous epithelium LO-3 What is the shape of cells, and their nuclei present on surface layer indicated by the arrows? Flat/compressed cells with flattened nuclei How many layers of the epithelial cells are there? Many What is the structure marked as ‘K’ Keratin What type of the epithelium this could be? STRATIFIED SQUAMOUS KERATINIZED EPITHELIA FROM SKIN Simple cuboidal epithelium Micrograph (b) shows the cells lining a collecting tubule in the kidney. Although the boundaries between individual cells are indistinct, the nuclear shape provides an approximate indication of the cell size and shape. The underlying basement membrane BM appears as a prominent blue line with the Azan staining method, What is the shape of cells and their nuclei lining the organ? cuboidal LO-4 7 STRATIFIED CUBOIDAL EPITHELIUM What is the shape of the cells present on the luminal surface? Cuboidal What is the number of cell rows of epithelial cells?2-3 layers/rows What type of the epithelium this could be? STRATIFIED CUBOIDAL EPITHELIUM, EXCRETORY DUCT OF A SWEAT GLAND LO-5 Simple columnar epithelium 1. Simple columnar epithelium 2. Nucleus of columnar epithelial cell 3. Lumen of venule Simple columnar epithelium lines the small and large intestines, inner lining of the stomach, major ducts of glands, convoluted tubules of the kidney, gallbladder, small bronchi of the lungs, and parts of the male and female reproductive tracts. LO-6 9 PSEUDOSTRATIFIED COLUMNAR CILIATED EPITHELIUM 1. Ciliated border 2.Pseudostratified ciliated columnar (respiratory) epithelium 3. Goblet cell 4.Basement membrane 1 3 2 4 Single layer of the columnar cells, but all cells do not reach to surface, hence giving false appearance of stratification Nuclei are located on different levels giving pseudo-appearance of stratification Fine cilia are seen on the luminal surface of the columnar cells LO-7 In the nondistended state, as here, it is about four or five cells deep. The surface cells are large and domeshaped ( asterisks). The cells immediately under the surface cells are pearshaped and slightly smaller. The deepest cells are the smallest, and their nuclei appear more crowded. Dome shaped surface layer cells Multiple layers TRANSITIONAL EPITHELIUM When the bladder is distended, the superficial cells are stretched into squamous cells, and the epithelium is reduced in thickness to about three cells LO-8 deep.. LO-9 Is the ducts simple or branched? Simple What is the shape of secretory portion (tube like or acinar) Tube like What are type of the glands SIMPLE TUBULAR GLAND Such glands are present throughout the intestines In the colon largest and straight tubular glands extend from the surface of the colon into the underlying connective tissue LO-10 Is the ducts simple or branched? Simple What is the shape of secretory portion (tube like or acinar) Tube like Is the secretory portion simple or branched Branched What are type of the glands SIMPLE BRANCHED TUBULAR GLAND In stomach several tubular secretory T portions converge onto a single duct D LO-11 Is the ducts simple or branched? Simple What is the shape of secretory portion (tube like or acinar) Tube like Is the secretory portion simple or branched Simple coiled What are type of the glands SIMPLE COILED TUBULAR GLAND Sweat glands have a terminal secretory portion S lined by simple cuboidal epithelium, which gives way to a non-secretory (excretory) duct D lined by stratified cuboidal epithelium. e.g Sweat glands LO-12 Is the ducts simple or branched? Simple What is the shape of secretory portion (tube like or acinar) Acinar Is the secretory portion simple or branched Simple What are type of the glands SIMPLE ACINAR GLANDS e.g Penile urethra LO-13 Are the ducts simple or branched? Branched What is the shape of secretory portion (tube like or acinar) Acinar What are type of the glands COMPOUND ACINAR e.g Pancreas The pancreas shown in this micrograph consists of numerous acini, each of which drains into a minute duct. These minute ducts D, which are just discernible in the centre of some acini, drain into a system of branched excretory ducts E of increasing diameter which are lined by simple cuboidal epithelium. LO-14 How are secretory products found in the cells of the shown gland? The secretory products are present in membranebound secretory vesicles What is mode of secretion? The secretory vesicles move to the apical surface of the cell. The vesicles coalesce/fuse with the membrane on the apical surface to release the product What term is used for this mode of secretion? MEROCRINE OR ECCRINE GLAND Most glands are merocrine in their mode of secretion e.g. large intestine glands 17 LO-14 What mode of secretion is depicted in the shown picture? The secretory vesicles alien on the apical surfaces of the glandular cells. A portions of the cells is pinched off and lost during the secretory process. The secretory product contains a variety of components including those of the membrane What term is used for glands with such type of secretion? Give any example. APOCRINE GLANDS e.g. Mammary glands release their products in this manner LO-14 What mode of secretion is depicted in the shown picture? ▪ The secretory cell, as whole, is released from the gland into the duct ▪ There it breaks apart and the contents of the cell become the secretory product What term is used for glands with such mode of secretion? Give any example HOLOCRINE GLAND. Some sweat glands located in the axilla and sebaceous glands LO-15 Identify BM Basement membrane Identify the cells with pink stain on their luminal surfaces Mucus secreting cells Identify the structures marked by ‘A’ Basement membrane ▪ Micrograph (a) is of a duodenal crypt lined by mucus secreting cells stained with PAS. The PAS reacts with the complex carbohydrates in the proteoglycans of the basement membrane BM and with the mucin M in secretory vacuoles in the apical cytoplasm of the epithelial cells. ▪ In (b), a silver impregnation method with affinity for reticulin highlights the basement membrane BM of renal tubules A A A LO-15 Identify the structures marked by ‘A’, ‘B’, ‘C’ and ‘D’ ▪ ▪ ▪ ▪ A= lamina lucida B= lamina densa C= collagen fiber D= lamina fibroreticularis Electron micrograph of basement membrane A B D 22