pathologies and mucous membranes Flashcards
what is mucus
A viscid/sticky, slippery secretion that is usually rich in mucins and is produced by mucous membranes
mucous
Covered with, or as if with, mucus i.e a mucous surface
Relating to, or resembling, mucus i.e a mucous secretion
Secreting or containing mucus i.e mucous glands
Mucous membrane
The lining of a body cavity or passage which communicates directly or indirectly with the outside body
3 layer of a mucosal membrane
serosa/adventita
outer longitudinal muscle and inner circular muscle make up the muscular externa
submucosa
then the mucosal membranes Muscularis mucosa Inner layer, sits on the muscle layer of tube/organ lamina propria Middle layer, connective tissue Epithelium Outer layer, mucus sits on this layer Composed of epithelial cells (stratified or columnar)
what is mucus made of
and can it be modified
Water - makes up >95% of mucus
Glycoproteins e.g. Mucin
Inorganic salts e.g. NaCl
Antimicrobial enzymes e.g. lysozyme
Immunoglobulins - predominantly IgA
Mucus can be modified depending on environment
Example: Increased extracellular transport of HCO3- ions
Alkaline mucus to protect stomach lining from acid
mucin is the main component of mucus and is stored in granules what are the two main types
gel-forming mucins - mesh - all epithelial cells
transmembrane mucine - remain attached to cells - goblet cells
what cells secret mucus
Goblet cells (majority of areas); Foveolar cells (stomach)
goblet cells mainly found in respiratory and intestinal epithelium secrete mucus by exocytosis
depending on location provides what function
protection -stomach
lubrication -pasasgae of food
cleaning - remove debris
hydration - lining of upper airway moist
small intestine
Single discontinuous mucus layer - allows nutrient absorption and enzyme release
Contains high levels of antibacterial peptides & proteins
large intestine how many?
large intestine
Two continuous mucus layers (especially in distal colon)
Outer layer = Loosely adhesive, contains multiple bacteria
Inner layer = strongly adhesive, predominantly ‘sterile’
CF is a
autosomal recessive disorder
normal CFTR functions as
compared to in CF
CFTR functions as an anion channel: conducts Cl- and HCO3-
There is deficient synthesis/gating/conductance or reduced stability of CFTR Cl− channels (depends on mutation)
Production of abnormally thick, sticky mucus
Respiratory airways and pancreas most affected…
Airway surface liquid (ASL) lines airway lumen & has 2 layers:
Outer layer = mucus that traps debris
Inner layer = surrounds cilia that act to remove debris
ASL regulates antimicrobial activity, ciliary function and mucociliary transport
what is the role of the CFTR gene in this
CFTR transports Cl- + HCO3- into airway
Water follows Cl- + HCO3- by osmosis
Na+ = absorbed via epithelial sodium channel (ENaC)
Contributes to ASL hydration & mucociliary transport
Produces thinner mucus (mucus thick upon secretion)
consequences of defective CFTR in resp
Thick bacteria-laden mucus + defective mucociliary action + mucus plugging of airways
Repeated respiratory infections especially those by opportunistic bacteria e.g. pseudomonas aeruginosa
Inflammatory reaction triggers production of excessive amounts of thick, sticky mucus
Repetitive infections + persistent inflammation
Damages structure of lung
Further increases work of breathing - already increased due to thick mucus
CF in pancreas obstructs duct so reduced enzymes leading to malabsorption and cause inflamtmona dn fibrosis
CF could cause what at brith
meconium ileus - GI tract
skin - fluid loss and salty skin
adenocarcinoma
A malignant neoplasm arising from epithelial cells of the glands or glandular like structures
Aden means gland structure
what is the cancer staging system
TMN system
T(tumour) - how far grown
N(nodal) - spread to nodes regional or distant
M( metastasis)- there part of body
Tumour staging levels
Tis = Grown into the mucosa but no further (in situ)
T1 = Grown into the submucosa
T2 = Grown into the muscle layer of the bowel wall
T3 = Grown into the serosa
T4 = Grown through the serosa and through the membrane covering the outside of the bowel wall (peritoneum)
Nodal staging
N0- no lymph lodes
N1- up to 3 nearby LN
N2- cancer cells in 4 or over Ln nearby
M(metastasis)
M0- hasn’t spread to distant organs
M1- spread to distant organs such as liver or lungs
stages of cancers
Stage 0: Tumour is at its earliest stage and only in the mucosa. TNM = TisN0M0
Stage 1: Tumour has grown into the submucosa or muscle. The cancer has not spread to the lymph nodes or elsewhere. TNM = T1N0M0, T2N0M0
Stage 2: Tumour has grown through muscle wall or through outer layer of the bowel and may be growing into tissues nearby. The cancer has not spread to the lymph nodes or elsewhere.
TNM = T3N0M0, T4N0M0
Stage 3: Tumour is any size and has spread to lymph nodes nearby. The cancer has not spread anywhere else in the body. TNM = AnyTN1M0, anyT N2M0
Stage 4: Tumour is any size - may have spread to regional lymph nodes. The cancer has spread to other parts of the body. TNM = AnyTanyNM1
acute inflammation what cells
neutrophils - mast , dendritic , macro
chronic inflammation what cells
macrophages, lymphocytes, plasma cells and fibroblasts
example of acute ifnalmmton
what is tonsillitis
inflammatory infection of tonsils caused by invasion of mcuuosu membranes by virus can spread to cause peritonsillar abscess
nflammatory Bowel Disease: Chronic inflammation
two types
Characterised by chronic inflammation within GI tract
Complex pathophysiology but involves leaky gut (i.e. defective intercellular junctions) leading to excessive inflammation
Two main types: Crohn’s disease and Ulcerative colitis
crohns features
Any part of GI tract (often ileum and colon)
Discontinuous inflammation
All bowel layers (transmural)
Mucosal ulcers combine into deep linear ulcers, oedema and thickening of bowel wall
Abscesses and fistulas = common
Can progress to fibrosis & stricture formation
ulcerative colitis functions
Confined to colon and rectum
Continuous inflammation
Diffuse, mucosal-only
Can progress to large mucosal ulcers with copious purulent exudate
