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
Fill in the missing labels:
What is the arcuate line?
Lower limit of posterior layer of rectus sheath
Half way between umbilicus (belly button) and pubic crest
- Above arcuate line- aponeurosis equally distributed around muscles*
- Below arcuate line- aponeurosis not equally distributed around muscles- on anterior surface*
What’s the name for viscera which is enveloped by the peritoneum? Whats the name for vicera which lies posterior to the peritoneal cavity?
Intraperitoneal viscera
Retroperitoneal viscera (not enveloped)
Differentiate between the parietal peritonium and the viceral peritoneum.
- Parietal:
- In contact with abdominal wall
- Somatic development- sense of pain
- Viceral:
- Different development
Which parts of the viscera does a double fold of peritoneum attach to the posterior abdominal wall?
What is the name for this double fold?
- Jejenum
- Ileum
- Appendix
- Transverse colon
- Sigmoid colon
- Rectum
Double fold= Mesentery
What is contained within the mesentery?
- Blood vessels
- Lymph vessels
- Nerves
- Fat
Carry blood vessels to and from aorta and inferior vena cava
What structures of the cut form the foregut, midgut and hindgut?
Foregut–> midgut in duodenum where pancreatic and hepatic secretions enter duodenum
