pathologies and mucous membranes

Question 1

what is mucus

Answer 1

A viscid/sticky, slippery secretion that is usually rich in mucins and is produced by mucous membranes

Question 2

mucous

Answer 2

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

Question 3

Mucous membrane

Answer 3

The lining of a body cavity or passage which communicates directly or indirectly with the outside body

Question 4

3 layer of a mucosal membrane

Answer 4

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)

Question 5

what is mucus made of

and can it be modified

Answer 5

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

Question 6

mucin is the main component of mucus and is stored in granules what are the two main types

Answer 6

gel-forming mucins - mesh - all epithelial cells

transmembrane mucine - remain attached to cells - goblet cells

Question 7

what cells secret mucus

Answer 7

Goblet cells (majority of areas); Foveolar cells (stomach)

Question 8

goblet cells mainly found in respiratory and intestinal epithelium secrete mucus by exocytosis

depending on location provides what function

Answer 8

protection -stomach
lubrication -pasasgae of food
cleaning - remove debris
hydration - lining of upper airway moist

Question 9

small intestine
Single discontinuous mucus layer - allows nutrient absorption and enzyme release

Contains high levels of antibacterial peptides & proteins

large intestine how many?

Answer 9

large intestine

Two continuous mucus layers (especially in distal colon)

Outer layer = Loosely adhesive, contains multiple bacteria

Inner layer = strongly adhesive, predominantly ‘sterile’

Question 10

CF is a

Answer 10

autosomal recessive disorder

Question 11

normal CFTR functions as

compared to in CF

Answer 11

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…

Question 12

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

Answer 12

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)

Question 13

consequences of defective CFTR in resp

Answer 13

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

Question 14

CF in pancreas obstructs duct so reduced enzymes leading to malabsorption and cause inflamtmona dn fibrosis

CF could cause what at brith

Answer 14

meconium ileus - GI tract

skin - fluid loss and salty skin

Question 15

adenocarcinoma

Answer 15

A malignant neoplasm arising from epithelial cells of the glands or glandular like structures

Aden means gland structure

Question 16

what is the cancer staging system

Answer 16

TMN system
T(tumour) - how far grown
N(nodal) - spread to nodes regional or distant
M( metastasis)- there part of body

Question 17

Tumour staging levels

Answer 17

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)

Question 18

Nodal staging

Answer 18

N0- no lymph lodes
N1- up to 3 nearby LN
N2- cancer cells in 4 or over Ln nearby

Question 19

M(metastasis)

Answer 19

M0- hasn’t spread to distant organs

M1- spread to distant organs such as liver or lungs

Question 20

stages of cancers

Answer 20

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

Question 21

acute inflammation what cells

Answer 21

neutrophils - mast , dendritic , macro

Question 22

chronic inflammation what cells

Answer 22

macrophages, lymphocytes, plasma cells and fibroblasts

Question 23

example of acute ifnalmmton

what is tonsillitis

Answer 23

inflammatory infection of tonsils caused by invasion of mcuuosu membranes by virus can spread to cause peritonsillar abscess

Question 24

nflammatory Bowel Disease: Chronic inflammation

two types

Answer 24

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

Question 25

crohns features

Answer 25

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

Question 26

ulcerative colitis functions

Answer 26

Confined to colon and rectum
Continuous inflammation
Diffuse, mucosal-only
Can progress to large mucosal ulcers with copious purulent exudate