Histology Flashcards
Characteristics of epithelia
Cellularity Polarity Attachment Avascular Innervation Regeneration
Junction:
Impermeable/cells function as barrier
Enwrap top region (apical membrane) to stop transfer of things across
Tight/occulding junctions
Junction:
Fluid-filled channels that connect apposed cells
Mediate communicate (move ion from one cell to another)
Connexin aggregates
Gap/communicating junction
different types of anchoring junctions
Adherens
Desmosome
Hemidesmosomes
anchoring junction:
Lateral adhesions involving cadherins that interact with actin filaments
Adherens
Anchoring junctions: lateral adhesions involving cadherins that interact w/intermediate filaments
“Stronger adhesion”
Desomosome
Basal adhesions involving integrins that & intermediate filaments that anchor to basal lamina
connective tissue to basement membrane
Prevent epithelial from ripping off
hemidesmosomes
Bacteria that cause “food poisoning” target which junction
Tight junctions
Result in loss of fluid
Which junction is involved with blisters of oral mucosa
Desmosomes
Apical specialization:
Cytoplasmic processes containing actin core
Specialized for absorption
Increase surface area
Microvilli
Disease caused by loss of microvilli on absorptive cells in SI
Celiac disease
Apical Specialization:
Long & less mobile microvilli
Restricted location to epididymis & inner ear hair cells
Stereocilia
Apical specialization:
Long highly motile structures containing internal arrays of microtubules
Cilia
Cilia that beat in a wave-like fashion to propel substance across tissue
Most common
Motile cilia
Cilia that is immotile, function as chemosensors, osmosensors, mechanosensors
One cell
Primary cilia
Cilia that is embryonic
Has role in L/R axis determination
Located at end of primitive streak
Nodal cilia
simple squamous
Located in lining of blood & lymphatic vessels
Endothelium
Simple squamous
Located in lining of serous membranes
Mesothelium
Simple squamous
Description:
Location:
Function:
Single & flat cells
Lining of alveoli in lungs, kidney & various ducts
Exchange, barrier & lubrication
Simple cuboidal
Description:
Location:
Function:
Single layer, cube shaped
Kidney tubules, covering of ovary
Absorption, barrier, secretion
Simple columnar
Description:
Location:
Function
Single layer; longer than wide; nuclei circular more than oval
Stomach, intestine (SI/LI), gallbladder, uterus
Absorption & secretion
Pseudostratified columnar ciliated
Description:
Location:
Function
“Simple epithelium”; cell vary in shape; look like multiple layers
Lining of nasal cavity, pharynx, trachea, bronchi
Absorption & secretion, debris & particulate movement
Urothelium
Description:
Location:
Function
aka transitional; “simple epithelium” looks like stratified
Urinary, bladder urethra, ureters
Barrier, distensible property
Nonkeratinized stratified squamous
Description:
Location:
Function
Lack keratin; flat apical surface
Oral cavity, anus, vagina, urethra, cornea; get abrasion consistently
Barrier & protection
Keratinized stratified squamous
Description:
Location:
Function
Keratin on surface; waterproof
Epidermis
Barrier & protection
Stratified cuboidal
Description:
Location:
Function
Two or more layers: cube shaped
Sweat glands & ducts, ovarian follicles, salivary glands
Barrier & passageway
Membrane: epithelial tissue that lines internal body cavities
Serous membrane
Membrane: epithelial tissue that secretes mucus
Mucous membrane
Mucous membrane lines
Body cavities & tubular organs including the gut & respiratory
Serous membrane includes
Peritoneum, pericardium & pleura
Simple squamous epithelium that comprises part of a serous membrane
Mesothelium
Unicellular glands
One cell that has a gland-like function
Simplest in structure
Goblet cell
Unicellular gland
Mucus secreting cell lining the intestines & respiratory tract
Acinus
Exocrine glands have these secretory cells
Functional tissue of an organ, does not include CT & other supporting tissues
Parenchyma