Histology Flashcards
what are the 3 types of cell-cell connections
Gap junctions
Tight junctions
Desmosomes
Gap junctions
Hollow protein channels that allow for cell-cell communication
Tight junction
Interlocking proteins that form a leak-proof barrier
Desmosomes
Sticky glycoprotiens that adhere cells together for structural purposes
How are tissues classified?
Cell structure
cell function
extracellular matrix
What are the 4 primary tissue types
Epithelial
Connective
Muscle
Nervous
What are the characteristics of epithelium
No extra cellular matrix Polar (different surface) Basal surface Attached to basal surface Avasucular & innervated Regenerating: stem cells continually divide to replace surface epithelial cells Sheets/Layers
What are the surfaces of epithelium?
Apical
Lateral
Basal
Simple squamous
Function: Diffusion Location: -blood & lymph vessles -Lung alveoli -Kidney tubules -Serous membranes
Stratified Squamous
Function: protection against abrasion, barrier for water loss/infection
Location:
-Skin (skin)
-Throat, Anus, Vagina (non keratinized)
Simple cubodial
Function: Secretion and absorption
Location:
-Kidney tubules
-Glands/ducts
Stratified Cuboidal
Function: Secretion, absorption, proctection
Location:
-Ducts of sweat glands and salivary glands
Simple columnar
Secretion (stomach, intestine)
Absorption (intestine)
Movement (ciliated cells in bronchioles)
Stratified Columnar
Function: Protection, secretion Location: -Larynx -Mammary gland duct -Male urethra
Pseudostratified Columnar
Function: -Secretion -Absorption -Protection Location: -Nasal cavity and sinuses -Bronchi of lungs -Trachea
Transitional Epithelium
Function: -expansion and recoil Location -Bladder -Ureters
What does exocrine glandular epithelium do?
Releases secretions via ducts
What does endocrine glandular epithelium do?
Ductless, release secretions into blood
Whats an example of a unicellular exocrine glands
Goblet cell
What are the two types of multicellular exocrine glands?
Simple (ducts have no branches)
Compound (ducts have branches)
How are the shapes of multicellular exocrine glands specified?
Tubular
Alveolar
What are the modes of secretion for multicellular exocrine glands?
Merocrine
Apocrine
Holocrine
Merocrine
Secrete products by exocytosis
Apocrine
Secretions accumulate near cell surface, pinched off to release product and some cytoplasm
Holocrine
Accumulates product, then ruptures to release (even cell fragments)
Characteristics of Endocrine glands
Produce horomones
Ductless
Usually compact and multicellular
