Flashcards in Epithelial Barrier Deck (50):
Epithelial cells are tightly joined together by?
Adhesion molecules and right junction proteins
Epithelial cells have _____ morphology
What are the two sides of epithelial cells and what are each exposed to?
Apical side exposed to commensal microbes and environment. Basolateral side protected from microbial exposure.
PRRs are concentrated on what side of the epithelial cell?
Why are PRRs concentrated on the specific side they are?
To alert the immune system if invading microbes and/or tissue damage
This organ is a peripheral sensory organ, involved in nutrient synthesis, thermoregulation, osmoregulation, and act as a protective barrier against environmental stressors
What are examples of environmental stressors?
UV radiation, chemical exposure, and microbial invaders
What type of fish has placoid-scales that rose out of the epidermis to protect underlying skin?
Cartilaginous fish (ex. Sharks and rays)
What type of fish are covered with a multilayered epidermis that is coated with mucus that contains anti microbial proteins and peptides?
Bony fish species
What are the cells that produce mucus called?
What are melanophores?
Provide skin pigmentation and help sequester reactive oxygen species generate during oxidative stress in bony fish
What is the non-viable layer of cells on the epidermis of birds and mammals called?
The stratum corneum
The non-viable layer of cells on the epithelial of birds and mammals is constantly replaced by epithelial cells called?
Keratinocytes that differentiate from pluripotent stem cells
Unlike mammalian skin, avian skin lacks what?
Instead of having sebaceous glands, birds have what type of glands that do what?
Uropygial glands that produce lipids to condition the feathers to repel water
Avian feathers and mammalian hair are both comprised of _____ produced by ______?
True or false - keratinocytes are immune cells
The sub-epithelial immune system of the skin is referred to as?
Skin-associated lymphoid tissue (SALT)
What characteristics of the stratum corneum are highly variable within and across mammalian species?
Thickness, amount of melanocytes pigmentation, and sebaceous gland secretions
People of what race have a thicker stratum corneum, higher lipid content, and is replaced more rapidly?
What are the two benefits of people with dark skin?
More effectively retain water and more resistant to chemical and microbial exposure
Neural tube defect (ex. Spins bifida) is cause by?
UV-induced folio acid depletion during pregnancy
Offspring of people win what colour skin are more susceptible to rickets and immunodeficiency?
Rickets and immunodeficiency results from?
Insufficient vitamin D production
Sheep secrete a moisture barrier called?
In what mammal are sweat glands distributed all over the body?
What are examples of two anti microbial peptides?
Der codon and lactoferrin
The sweat glands of hoofed animals are concentrated where?
What are sweat gland concentrated for pigs, dogs and cats?
Footpads and snout
What are haptens?
Small molecular weight reactive chemicals the immune system can become sensitized to found in cosmetics, jewellery, etc
Repeated exposure to haptens can cause?
Cell-mediated hypersensitivity rxn that can cause allergic contact dermatitis
Mucus is a _________ comprised of ________ and _______
Gel gradient, mucin proteins, lipids
Very basically, what are the 7 important functions of mucus?
Physical barrier preventing attachment of pathogenic microbes and commensals, lubricates the epithelium, traps and removed microbes and antigens, maintains hydration, adhesive surface for commensal microbes, concentrate anti microbial proteins, facilitates removal of motile immune cells
What is the sub-epithelial immune system associated with the lining of the nasal, oral cavities, trachea and bronchi called?
Nasal and bronchi associated lymphoid tissues
The nasal and oral cavities, trachea, bronchi and bronchioles contain goblet cells as well as? Why does the latter do?
Clara cells that secrete anti microbial proteins and peptides
Specialized epithelial cells called ______ have also been found in the bronchi.
What do M-cells do?
Sample antigens from the mucus and pass them along to underlying tissue macrophages and DCs for antigen presentation
What two parts of the respiratory system is considered a sterile environment except in cases of pneumonia?
Bronchioles and alveolar sacs
What are the epithelial cells making up the alveolar sacs called?
How are surfactant proteins produced and what do they do?
Type 2 pneumocytes replace type 1 pneumocytes which produce surfactant proteins. They reduce surface tension preventing lung collapse and haw anti microbial properties
Why are the two ways in which mucus is removed from the bronchioles, bronchi, an trachea?
Beating of ciliates epithelial cells and coughing
What is a microbiome?
Colonization of commensal microbe populations in the GIT
When does the microbiome develop?
What is the hygiene hypothesis?
Lack of exposure to certain microbes during early life development can affect immune development and increase risk of atopic disease (ie asthma, food allergy)
How are atopic diseases caused?
Antibody-mediated hypersensitivity reactions (ex. IgE)
The small intestine epithelium is comprised of finger-like _____ and gland-like invaginated ______.
Villi and crypts
The gland-like structure in small intestinal epithelium contain?
Pluripotent stem cells that proliferate and differentiate into various epithelial cell types
What two cell types are found in the crypts of the small intestine? What does the latter do?
Goblet and panth cells which secrete anti microbial peptides
True or false - the large intestine is lined with villi like the small intestine