Class 3 - Station 1: Gut Tube part 2 - Small & Large Intestine, Rectum and Anal Canal Flashcards
What are the 3 parts of the small intestine?
Duodenum
Jejunum
Ileum
Which part of the small intestine recieves the opening for the bile and pancreatic duct?
2nd part of the duodenum at the ampulla of vater.
Where is the midgut-foregut boundary?
Just inferior to the ampulla of vater.
How is the duodenum peritonised?
Retroperitoneal
How is the jejunum peritonised?
Intraperitoneal
How is the ileum peritonised?
Intraperitoneal
What are the differences between the jejunum and the ileum?
write this out
What are arterial arcades?
Arterial loops and arches
Which part of the small intestine has many small arterial arcades?
Ileum
Which of the autonomic divisions acts as a motility reducer and a vasocontrictor on the small intestine?
Sympathetic
What is the path of the sympathetic to the small intestine?
Greater splanchnic nerves T5 to L1/2
Leading to superior mesenteric ganglion and coeliac ganglion
How can the large intestine be differentiated from the small intestine?
- Taeniae coli
- Haustra
- Epiploic appendages
What are taenia coli and what innervates them?
Longitudinal muscle that contracts to form the haustra.
Innervated by pelvic parasympathetic nerves.
What are haustra?
- Sacculations in the colon
- When they fill they distent and then contract to move chyme through the colon
What are epiploic appendages?
Small pockets of fat in the surrounding peritoneum
How is the caecum peritonised?
Intraperitoneal
How is the ascending colon peritonised?
Retroperitoneal
How is the transverse colon peritonised?
Intraperitoneal
How is the descending colon peritonised?
Retroperitoneal
How is the sigmoid colon peritonised?
Intraperitoneal
Hint: LOOK AT WHERE THEY SUPPLY
- SMA
- Middle colic artery
- Marginal artery
- Right colic artery
- Iliocolic artery
- Appendicular artery
- Middle rectal artery
- Superior rectal artery
- Sigmoidal arteries
- Left colic
- IMA
Where is the midgut/hindgut boundary?
2/3rds distally down the transverse colon (note the blood supply)
In what abdominal region is the caecum and appendix?
Right Iliac Fossa (rec. Macburney’s point)
What two structrures open into the cavity of the caecum?
Ileal orifice
Orifice of veniform appendix
What is Macburney’s point?
Site of greatest intensity of pain in appendicitis - commonly located between the appendix and umbilicus
What is the arterial supply and venous drainage of the superior 1/3rd of the rectum? And the peritonisation
- Superior rectal artery
- Superior rectal vein
Retroperitoneal
What is the arterial supply and venous drainage of the middle 1/3rd of the rectum? And the peritonisation
- Middle rectal artery
- Middle rectal vein
Retroperitoneal
What is the arterial supply and venous drainage of the inferior 1/3rd of the rectum? And the peritonisation
- Inferior rectal artery
- Inferior rectal vein
Extraperitoneal
- Gastric veins
- Portal vein
- Superior mesenteric vein
- Colic veins
- Appendicular
- Inferior and middle rectal veins
- Superior rectal veins
- Sigmoidal veins
- Left colic veins
- Inferior mesenteric vein
- Splenic vein
- Oesophageal veins
Identify the superior, middle and inferior rectal folds
The folds of mucosa
What is the function of the rectal folds?
Support faeces so as they don’t constantly infringe on the internal anal sphincter
What is the role of the internal and external sphincters?
Internal (above pectinate line) - visceral nerve supply, when rectum is full this relaxes so that faeces put pressure on the external
External (below pectinate line) - somatic control, can be opened to allow defacation
What arteries supply the anus below the pectinate line?
Branches of the internal iliac arteries
What is the venous drainage of the anus below the pectinate line?
Into the porto caval anastomosis to enter the portal system
What is the lymphatic drainage of the anus below the pectinate line?
Superficial inguinal lymph nodes
