Practical 4 Flashcards
(53 cards)
Describe the small intestines
Extends from pyloric orifice to the ileocaecal junction
Duodenum, jejunum and ileum
How do you know when the duodenum becomes the jejunum?
When retroperitoneal duodenum gains a mesentery and becomes intraperitoneal (just below and L of attachment of transverse mesocolon to post ab. wall
How does the jejunum differ from the ileum?
Wall of jejunum is thicker and more vascular with more plicae circulares and no Peyer’s patches.
Ileum is thinner, less vascular, no plicae circulares and large numbers of peyer’s patches
Where does the mesentery attach?
Obliquely across post. ab. wall from L of L2 vetebra to R sacroiliac joint
Describe the blood supply of the jejunum and ileum
Both by branches of superior mesenteric artery arranged in arcades
Jejunal, ileal (L side) and ileocolic (R side) branches
Name the branches of the superior mesenteric artery
Inferior pancreaticoduodenal, jejunal, ileal, ileocolic and R and middle colic arteries
What are the anastamoses of the ileal and jejunal blood supply called? Where are they most abundant?
Arcades
Many in ileum, fewer in jejunum
Describe the ileocolic artery
From R sided branch of superior mesenteric artery, passes to R iliac fossa and supplies terminal ileum and ascending colon (+caecum and appendix)
Describe the blood supply of the colon
Sup mes a.: Ileocolic= caecum, appendix and ascending colon R colic= ascending colon Middle colic= transverse colon Inf mes a.: L colic ascending and descending= transverse and descending colon 2-3 sigmoid= sigmoid colon Superior rectal= rectum
Where are Peyer’s patches found?
In lamina propria and submuscosa of terminal ileum
Describe the route of lymph from the small intestines
Peyer’s patches-> nodes in mesentery-> arterial arcades-> origin of sup. mes. a.-> cisterna chyli
Describe the sympathetic and parasympathetic supply of the small intestines
Symp: T9-T10-> celiac or sup. mes. ganglia-> small intestine (+pain)
Para: Vagus (+reflex)
What are the 3 bands of outer longitudinal muscle called in the large intestine?
Teniae coli
What are teniae coli?
3 bands of outer longitudinal muscle in the large intestine
What is the large intestine covered in?
Appendices epilocae (fatty tags)
What are appendices epilocae?
Fatty tags between colonic wall and the visceral peritoneum
What are the defining features of the large intestine?
Appendices epilocae (fatty tags), teniae coli (3 bands of outer longitudinal muscle) and haustra
What are haustrations also called?
Sacculations
Describe the caecum
Blind ended sac, continuous superiorly with ascending colon. Ileocaecal junction on medial wall. Vermiform appendix where teniae coli converge on posteriomedial wall
Where is pain from an inflamed appendix felt?
Initially in umbilical region (visceral, referred to belly button)
Later localises to R iliac region (parietal, somatosensory innervation localised to anatomical location of appendix)
Where does the ascending colon turn into the transverse colon?
At the visceral surface of the liver where is bends anteriorly and to the left (at the R colic flexure)
What is different about the ascending colon?
No mesentery, direct contact with fascia over post.ab. wall muscles. Therefore fixed in position
How does the L colic flexure maintain its position?
Via the phrenicocolic ligament where is attaches to the underside of the diaphragm
Where is the paracolic gutter? Significance?
Between abdominal wall and colon. Allows distension of bowels when chyme is passing through
