Session 3 - Setting The Scene - Anatomy Flashcards
Name the layers of the gut tube
Mucosa
Submoca
Muscle layer
Serosa
What are the elements of the mucosa?
Epithelium
Lamina propria
Muscularis mucosa
What is the function of the epithelium?
Absorption
Mucus production
Hormone production
What is contained in the lamina propria?
Lymphoid nodules
Antibodies (IgA)
What is the function of the musclaris mucosa?
Maintains the shape of the epithelium
Keeps the epithelium in contact with food
Prevents stagnation within the crypts.
What is contained within the submucosa?
The submucosal plexus.
Blood vessels
Dense connective tissue
What is in the external muscle layers?
Circular muscle
Myenteric plexus
Longitudinal plexus.
What is in the serosal layer?
Blood vessels
Adipose tissue
What type of epithelium is the gut composed of?
In mouth and distal anus - stratified squamous
Everything in between - simple columnar
What is the predominant cell of the GI tract?
Enterocyte
What features does the enterocyte have to enable it to perform its function?
1 cell layer thick
Microvilli - brush border
which cells produce mucus?
Goblet cells
What is the protective function of mucus?
Protects against friction
Protects against acid - chemical damage
Protects against bacteria - by forming a physical barrier
Which cells secrete mucus in the stomach?
Gastric surface mucus cells
where are gastric surface mucous cells found?
Lining the gastric mucosa/gastric pits
What do gastric surface mucous cells do ??
Secrete mucus or bicarb to form a barrier against acid.
What adaptations does the gut tube have to increase its surface area?
Permanent folds
Villi
Microvilli
what adaptation of the stomach makes it easily expandable?
Rugae
Where in the intestine are villi found?
Areas of absorption - eg the SI
Where are intestinal crypts found?
The small and large intestine
What specialised cels do the intestinal crypts contain?
Paneth cells
Enteroendocrine cells
Stem cells
How often is the epithelia replaced in the intestine?
Every 2-4 days
What is the function of the paneth cell?
Protect stem cells by secreting antibacterial proteins.
Describe the feedback cycle of acid production in the stomach - starting with somatostatin production.
D cells produce somatostatin .
Somatostatin negatively feeds back on G cells - less gastrin produced
Reduced gastrin feedback on ECL cells. Less histamine is produced
Less histamine feedback on parietal cells - less hydrogen ionss produced
Less hydrogen ions - D cells stop producing somatostatin
Name the layers a needle would o through when performing an aspiration of peritoneal fluid?
Skin Fat External oblique muscle Internal oblique muscle Transvese abdominus (+/- rectus abdominus) Transversalis fascia Parietal peritoneum
Where is the arcuate line?
Halfway between the umbilicus and pubic crest
What is the significance of the arcuate line?
DON’T FORGET THE OTHER ONE!!!!
Above the arcuate line the rectus abdominus lies on the aponeurosis of transversus abdominus and internal oblique.
Below the arcuate line the rectus abdominus lies only on the transversalis fascia.
It is the point at which the inferior epigastric vessels pierce the rectus abdominus
Define mesentry?
A double fold of peritoneum which connects abdominal organs to the posterior abdominal wall.
Define peritoneal ligament ?
A double fold of peritoneum which connects organ to eachother or the anterior abdominal wall
What is an omentum?
Name the origins of the 2 in the body?
A double fold of peritoneum.
Greater omentum - hangs off the greater curve of the stomach
Lesser omentum - connects the lesser curve of the stomach to the liver.
What is the purpose of sphincters in the GI tract?
To divide the tube into segments
To control movement of material along the tube
To prevent reflux of material
