7: Intestines Flashcards
What is the difference in MOBILITY between the Small and Large intestines?
Small
- Duodenum NOT mobile
- Jejunum / Ileum mobile
Large
- Ascending & Descending colon NOT mobile
- Caecum NOT mobile
- Transverse colon mobile
What is the difference in Lumen Diameter between the Small and Large intestines?
Small: Smaller
Large: Larger
What is the difference in Logitudinal Muscle between the Small and Large intestines?
Small: Continuous layer
Large: 3 bands: teniae coli
What is the difference in FATTY TAGS between the Small and Large intestines?
Small: NONE
Large: Attached to wall
What is the difference in the WALLS between the Small and Large intestines?
Small: Smooth
Large: Sacculated (sac formation), forms Haustra (small pouches)
What is the difference in the Mucous Membrane between the Small and Large intestines?
Small: Permanent folds = plicae circularis
Large: Incomplete folds may be present
What is the difference in LYMPHATIC TISSUE between the Small and Large intestines?
Small: = lymphatic tissue
Large: NONE
What is the blood supply of the DUODENUM? (2 things)
Duodenum derived from Foregut & Midgut
- Foregut supplied by Coeliac Trunk
Coeliac Trunk → Gastroduodenal Artery → Sup Pancreaticoduodenal Artery
- Midgut supplied by Sup Mesenteric Artery (SMA)
Abd. Aorta → SMA → Inf Pancreaticoduodenal Artery
What is the blood supply of the Jejunum and Ileum?
Jejunum & Ileum derived from Midgut
Midgut supplied by Sup Mesenteric Artery (SMA)
- Abd Aorta → SMA → Jejunal Arteries
- Abd Aorta → SMA → Ileal Arteries
Jejunal Arteries unite → form Arterial Arcades (loops)
Arterial Arcades give rise to Vasa Recta (straight arteries)
(Ileal arteries do same thing)
What is the venous drainage of the Duodenum? (2 points)
- Veins of duodenum follow arteries
- Drain → Hepatic Portal Vein:
- Directly
- Through Sup Mesenteric & Splenic Veins
What is the difference in COLOUR between the Jejunum and Ileum?
Jejunum: Deep red
Ileum: Paler pink
What is the difference in VASA RECTA between the Jejunum and Ileum?
Jejunum: Long
Ileum: Short
What is the difference in PLICAE CIRCULARIS FOLDS between the Jejunum and Ileum?
Jejunum: Large + Tall + Closely packed
Ileum: Low + Sparse + Absent in distal part
What is the difference in LYMPHOID NODULES (PEYERS PATCHES) between the Jejunum and Ileum?
Jejunum: Few
Ileum: Many
What is the difference in FAT IN MESENTRY between the Jejunum and Ileum?
Jejunum: Less
Ileum: More
What is the difference in LOOPS between the Jejunum and Ileum?
Jejunum: Few LARGE loops
Ileum: Many SHORT loops
What is the difference in VASCULARITY between the Jejunum and Ileum?
Jejunum: Greater
Ileum: Less
What is the difference in DIAMETER between the Jejunum and Ileum?
Jejunum: Thick and heavy
Ileum: Thin and light
What are the 8 parts of the large intestine?
- Caecum
- Appendix
- Ascending Colon
- Transverse Colon
- Descending Colon
- Sigmoid Colon
- Recum
- Anal Canal
What is the blood supply of the Caecum?
Caecum is Midgut derived
Midgut supplied by Sup Mesenteric Artery (SMA)
Abd Aorta → SMA → Ileocolic Artery
What is the blood supply of the Appendix?
Appendix is Midgut derived
Midgut supplied by Sup Mesenteric Artery (SMA)
Abd Aorta → SMA → Ileocolic Artery → Appendicular Artery
What is the venous drainage of the Caecum and Appendix?
Through Ileocolic Vein → Sup Mesenteric Vein (SMV) → Portal Vein
What is the blood supply of the Ascending Colon and Right Colic Flexture?
Ascending Colon and RCF derived from Midgut
Midgut supplied by Sup Mesenteric Artery (SMA)
- Abd Aorta → SMA → Ileocolic Artery (AC)
- Abd Aorta → SMA → Right Colic Artery (RCF)
How is the Marginal Artery of the large intestine formed?
3 arteries:
- Ileocolic Artery (supplies AC)
- Right Colic Artery (supplies RCF)
- Right branch of Middle Colic Artery (supplies TC)
Arteries anastamose with each other → Anastomotic Arcade
Asatomotic Arcade continues round large intestine to form a continuous arterial channel: Marginal Artery
What is the venous drainage of the Ascending Colon and Right Colic Flexture?
Ileocolic + Right Colic Veis → drain into Sup Mesenteric Vein (SMV) → Portal Vein
What is the blood supply of the Transverse Colon?
Transverse Colon is Midgut & Hindgut derived
Midgut supplied by Sup Mesenteric Artery (SMA)
Abd Aorta → SMA → Middle Colic
Abd Aorta → SMA → Right Colic
Hindgut supplied by Inf Mesenteric Artery (IMA)
Abd Aorta → IMA → Left Colic
What is the venous drainage of the Transverse Colon?
Middle colic vein → SMV → Portal vein
What is the blood supply of the Descending and Sigmoidal colons?
Descending and Sigmoidal colons are Hindgut derived
Hindgut supplied by Inf Mesenterc Artery (IMA)
Abd Aorta → IMA → Left Colic Artery (Desc)
Abd Aorta → IMA → Sigmoid Arteries (Sigmoid)
What is the venous drainage of the Descending and Sigmoid Colons?
Left Colic + Sigmoid Veins → Inf Mesenteric Vein (IMV) → Splenic & Portal Veins
What is the blood supply of the Rectum & Anal Canal?
Proximally: Rectum & Anal Canal are Hindgut derived (IMA)
Hindgut supplied by Inf Mesenteric Artery (IMA)
Abd Aorta → IMA → R & L Sup Rectal
Distally: Common Iliac Artery (CIA)
Abd Aorta → CIA → R & L Internal Iliac
- R & L Internal Iliac → R & L Middle Rectal
- R & L Internal Iliac → Inf Pudendal → R & L Inf Rectal
What is the venous drainage of the Rectum and Anal canal?
Sup + Middle + Inf Rectal Veins
- Sup Rectal Vein → Inf Mesenteric Vein (IMV) → Splenic + Portal Veins
- Middle + Inf Rectal Veins → Systemic System
What are the paracolic gutters?
Spaces between colon and abdominal wall
What does the Duodenum secrete? (5 things)
- HCO3-
- Water
- Bile
- Protease / Carbohydrase
- Secretin / Gastrin / Cholecystokin (CCK)