Epithelial Tissues & Glands Flashcards
What are the 4 general tissue types?
Epithelial, Connective, Muscle, Nervous
What is the apical surface?
the top layer of an epithelial cell that faces the outside of the body or the lumen of an organ
What is the lumen of an organ?
Space within the organ or body cavity
What is the basal surface?
the bottom layer of an epithelial cell, closest to the basement membrane
What anchors epithelial cells to one another?
Desmosomes & Tight Junctions
What is the thin proteinaceous layer on epithelial tissue known as?
The basement membrane
What is a simple epithelia?
When there is one layer of cells
What is a stratified epithelia?
When there is more than one layer of cells
What type of epithelia have flat cells?
Squamous epithelial
What type of epithelia have roundish/squarish cells?
Cuboidal epithelial
What type of epithelia have rectangular/long cells?
Columnar epithelial
What is the function of the microvilli?
Increase the apical surface area which allows for the cells to be better at absorption and secretion
What is the function of the cilia?
Sweep mucus and trapped particles superiorly so that you unconsciously swallow it
What is the function of goblet cells?
Secret mucus that traps inhaled particles
What are the major layers in the epidermis?
Stratum Basale, Stratum Spinosum, Stratum Granulosum, Stratum Lucidum (only found in thick skin), Stratum Corneum
Where are simple squamous epithelial tissues found?
Lungs, Kidney, and Cardiovascular System
What is the function of simple squamous epithelial tissues?
Facilitates diffusion, Filtration, and Secretion
Where are simple cuboidal epithelial tissues found?
Kidney tubules, Glands, and Ducts
What is the function of simple cuboidal epithelial tissues?
Secretion and Absorption
Where are simple columnar epithelial tissues found?
Digestive tract (stomach, intestine), and Respiratory tract (with cilia)
What is the function/special features of simple columnar epithelial tissues?
Absorption (Microvilli), and Secretion (Goblet Cells)
Where are Pseudostratified Columnar Epithelium found?
Respiratory tract (trachea, bronchi), and Male reproductive Ducts
What is the function/special features of Pseudostratified Columnar Epithelium?
Secretion (Goblet Cells) and movement of substances (cilia)
Where are Stratified Squamous Epithelium found?
Skin (keratinized), mouth, esophagus, vagina (non-keratinized).
What is the function of Stratified Squamous Epithelium?
Protection against abrasion, pathogens, and dehydration.
Where is the Transitional Epithelium found?
Urinary bladder, ureters.
What is the function of the Transitional Epithelium?
Allows stretching and expansion.
Where are Stratified Cuboidal Epithelium found?
Sweat glands, mammary glands, salivary glands.
What is the function of Stratified Cuboidal Epithelium?
Protection and secretion.
What is the function of the exocrine glands?
Secrete onto body surfaces (e.g., sweat, salivary, mammary).
What is the function of the endoocrine glands?
Secrete hormones into the bloodstream (e.g., pancreas, thyroid).
What are Unicellular glands?
scattered in epithelial tissues that are predominantly nonsecretory (can be exocrine or endocrine)
What are the different modes of secretion?
Merocrine, Apocrine, Holocrine
What is Merocrine Secretion?
The glandular cells package their secretions into vesicles, which then fuse with the cell membrane and release the secretion without damaging the cell.
What is the key characteristic of the merocrine secretion?
The cell remains intact and continues to function normally.
Example glands that use merocrine secretion?
-Lacrimal glands (tear production)
-Salivary glands
-Pancreatic glands
-Most sweat glands (eccrine glands)
What is Apocrine Secretion?
The secretion accumulates at the apical (top) part of the cell. Then, a portion of the cell membrane pinches off along with the secretion.
What is the key characteristic of the apocrine secretion?
The cell loses part of its cytoplasm, but it can regenerate and continue functioning.
Example glands that use apocrine secretion?
-Mammary glands (milk fat secretion)
-Some sweat glands (axillary & pubic regions)
What is Holocrine Secretion?
The glandular cells accumulate their product until they burst, completely disintegrating in the process. This means the entire cell becomes part of the secretion.
What is the key characteristic of the Holocrine secretion?
The cell is destroyed, so new cells must replace the old ones.
Example glands that use holocrine secretion?
-Sebaceous (oil) glands (secrete sebum for skin & hair)
-Tarsal glands (eyelid oil production)
