Epithelium tissue Flashcards
What are the 4 primary tissues
Nervous tissue, muscle tissue, epithelium tissue and connective tissue
What is the origin of the tissue. What are the 3 layers
Embryonic germ layer.
Ectoderm
Mesoderm
Endoderm
What does the ectoderm form
surface facing external environment
e.g. skin
What does the mesoderm form
Lining of cavity not exposing to external environment
Lining og kidney tubules, endothelium of blood vessels, mesothelium that covers the lungs, abdomen and heart
What does endoderm form
Lining of body cavity and hollow passageway
E.g. GI tract, respiratory tract
What are the 4 functions of epithelium tissue
- Protection
–>Form physical barrier with the connective tissue beneath - Secretion (Grandular epithelium)
- Sensation (retina and
- Absorption and excretion
What is between the connective tissue and epithelium tissue
Basement membrane
Is there any vascular tissue in epthelium
No
How can epthielium tissue obtain oxygen and nutrients
From the conective tissue beneath (which is highly vascularized)
What are the 3 functions of basement membrane
Act as a glue to connect epithelium tissue and connective tissue
Perform tissue-specific functions
Guiding cell migration during repair by attracting them
What are the layer(s) of basement membrane named and from.
Basal lamina: From secretion of epithelium tissue, Collagen IV
Reticular lamina
From secretion of fibroblast of connective tissue
Collagen III
What are the 6 characteristics of epthielium tissue
- Rest on basement membrane
- Avascular, dependent on the connective tissue beneath for material exchange
- With junctional complex
- Exhibit functional and morphological polarity
- Contains cyotkeratin
- With little or no intercellular matrix
How can epithelium tissue be classified according to the shape of epithelial cell
Squamous (flat)
cuboidal (Cubic)
columnar (Like column)
What are the characteristics of the 3 cell types
Squamous has flattened nuclei which is parallel to the Epithelium
Cuboidal is like a square with spherical nuclei
Columnar has nuclues closer to Basal side
How can epithelium tissue be classified according to the number of layer of cells
Simple (1 layer)
Stratified (>1)
Psedostratified (Like >1 but only 1 actually)
transitional (stretchable and more than 1 layer)
What is simple squamous epithelium for. Example
Material exchange, absorption and secretion
Lining in heart, blood vessels and lymphatics, lining of peritoneal and pleural cavity
Simple Cuboidal?
Secretion, excretion and absorption
–> Pancreatic duct, PCT (Proximal Convoluted Tubule)
Simple columnar
Transport of fluid, secretion, absorption
Lining of intestine, gall bladder
Simple ciliated columnar
Fallopian Tube, ie oviduct to sweep the ovum to uterus
What can Stratified squamous epithelium be further classified into
Keratinized or non-keratinized
What does non-keratinized Stratified squamous epithelium
For protection, containing superficial layer of squamous cells containing nuclei (alive)
Uterine cervix surface
How abt keratinized
Superficial layer is rich in keratin with no nuclei, Skin
Stratified Cuboidal epithelium
Uncommon, for excretory duct of exocrine glands
Stratified columnar
Protection and secretion, uncommon
Larnyx, larger duct of exocrine gland, like mammary gland duct
Transitional epithelium
ONly in urinary tract (ureter and urinary bladder)
Psedostratified ciliated Columnar Epithelium
In human only respiratory tract
Name 2 specialization at apical surface
Cilia and Microvilli
Point out 2 differences between microvilli and cilia
- Microvilli is non-motile while cilia is motile
- Microvilli is made of actin filament inside while cilia contains an organized core of microtubules
What is the significance of microvilli connecting to a network of filament below
To increase the distance between microvilli to increase surface area
What is the arrangement of microtubules inside the cilia
9+2, 9doublet on side 2 at centre and Join the basal body
What is the arrangement of microtubules inside the basal body
9+0 triplets arrangment pattern
Name the 3 junctional complex
TIght junction (Zondula Occludents, ZO)
Adhering junction (Zondula Adherens, ZA)
Desmosomes
What is the arrangement of ZO
A tight seal between adjacent cells, it restrict movement of substances and nearest to apical surface of cell
What is the arrangement of ZA
It attaches both membrane protein and microfilament on cytoskeleton
Composing of cadherin which is transmembrane glycoprotein, binding with the terminal network of Actin within the cell and the cadherin on another cell
What is the arrangement of Desmosomes
Interact with Keratin intermediate filament network
Gap junction?
Composes of connectin which allows communcation and exchange of small molecules and ions between neighbouring cell
Name 1 specialization at basal surface
Infolding, enhancing the surface area between epothelium and connective tissue beneath
What are the nature of glands
Epithelial cells ingrowing into the connective tissue with the basement membrae remaining at the same position to separate epithelium and connective tissue.
How to distinguish between endocrine glands and exocrine glands
Endocrine glands has no duct while exocrine has
What are the Endocrine glands in human
pineal gland, thymus gland, pituitary gland, thyroid gland, and the two adrenal glands
What are the 3 categories of exocrine glands according to the product
Serous gland, mucous gland, mixed gland
What are the characteristics of mucous gland
Flattened nuclei, secret glycoprotein (mucin), with PALE cytoplasm
E.g. Salivary gland
What are the characteristics of Serous gland
Round Nuclei, secrets protein/enzyme (ie watery), basophilic staining (darker colour)
e.g. pancreas
Is serous demilune what type of exocrine gland
Mixed, with serous cell arrangeed as a cap on mucous cell
What are the 3 method of secretions
Merocrine, Apocrine, Holocrine
Which of them consists of rupture of exocrine cell
Holocrine
Which of them consist of loss of part of cytoplasm
Apocrine
Which of them does not involve loss in cytoplasm and secretions leave by exocytosis
Merocrine (aka eccrine)
What are the 2 categories an exocrine gland for the branching of duct
Simple, compound
What are the 3 categories of exocrine duct accordng to shape of duct
tubular, acinar and aveolar
What epithelium does duct has
Cuboidal
What can be found on all epithelium contacting external world
Mucous membrane
What is the difference between acinar and aveolar glands
An acinar gland duct has a small lumen while the alveolar gland duct has a large lumen.
