2 Anatomy of the GI System Flashcards
What are the 4 layers that make up the gut tube? What are the sublayers of each of these layers?
-
Mucosa
- Epithelial layer
- Lamina propia
- Muscularis mucosa
- Submucosa (Meissner’s Plexus)
-
Muscularis Propria
- Circular muscle
- (Auerbach’s Plexus)
- Longitudinal muscle
- Circular muscle
- Serosa
What are the functions of the layers of the mucosa?
-
Epithelial:
- Selectively permeable:
- Promote absorption
- Produce hormones
- Produce mucus
- Selectively permeable:
-
Lamina propria
- Lymphoid nodules and macrophages
- Produce antibodies
-
Muscularis mucosa
- Keep epithelium in contact with gut contents
What is contained within the sub mucosa?
- Dense CT
- Meissner’s plexus
- Blood vessels
- Glands
- Lymphoid tissue
What is contained within the serosa layer?
Blood and lymph vessels, adipose tissue
= continuous with mesenteries
Which cells types make up the epithelia of the gut?
Oesophagus and distal anus: Stratified squamous
Everything in between: Simple columnar
What is the function of the enterocyte and how is it specialised for this function?
Transport nutrients through apical membrane and basolateral membrane
Features:
Blood vessels and lymphatics immediately below
Microvilli
Apart from enterocytes, name and describe 2 other specialised cells which can be found in the lining of the gut.
- Goblet cell
- In between enterocytes
- Increase in number towards colon
- Produce mucous
- Protect from friction, acid and bacteria
- Foveolar cell (Gastric surface mucous cells)
- Secrete mucus/HCO3 (barrier to acid)
What are the names for each of the following folds in the
gut tube?
- Permanent circular folds
- Temporary folds in stomach
- Permanent sacculations in the large bowel (sac like)
- Permanent circular folds: Plica circulares
- Temporary folds in stomach: Rugae
- Sacculations in the large bowel: Haustra
What are crypts and where can they be found?
Intestinal glands
In small and large intestine
What specialised cells do crypts contain? (3)
- Stem cells
- Paneth cells
- Enteroendocrine cells
What do paneth cells do?
Secrete antibacterial proteins- protect stem cells
What do enteroendocrine cells do?
Secrete hormones that control function of gut eg:
- Gastrin
- Secretin
- Cholecystokinin
What are the layers in between the skin and the parietal peritoneum in the abdominal wall?
- Superficial fascia
- Deep fascia
- Muscles (see image)
- Transversalis fascia
- Parietal peritoneum
What is the rectus sheath?
Aponeuroses of the three flat muscles and encloses the rectus abdominis and pyramidalis muscles
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