Digestive system Flashcards
Muscular tube running between the pharynx and the stomach
Oesophagus
The oesophagus begins where and end where?
AT level C6 and ends at the cardiac opening of the stomach.
Relation of the oesophagus to the thoracic aorta
Moves anteriorly and to the left as it approaches diaphragm
- Crossing from the right of the thoracic aorta
- Final position is anterior to the aorta
at which level does it pass through the esophageal hiatus of diaphragm
T10
Posterior mediastinum (Relations)
Anterior
- Trachea superior to bifurcation
- Right pulmonary artery and left main bronchus (Inferiorly)
- Posterior to left atrium
Left – Thoracic aorta
Right – Parietal pleura
Posterior
- Thoracic duct and azygos, hemi-azygos and accessory veins
- Posterior intercostal vessels
constriction sites oesophagus.
Junction of the oesophagus with the pharynx
Crossing of arch of the aorta in superior mediastinum
Crossing of left main bronchus in posterior mediastinum
Oesophageal hiatus in the diaphragm
arterial supply of the oesophagus are ?
bronchial arteries
thoracic aorta
left gastric artery
venous draining
azygos vein, hemi-azygos and accessory hemi azygos veins
lymphatic drainage
posterior mediastinal and left gastric node.
The innervation of the oesophagus?
from vagus and sympathetic trunks
innervation of the superior striated fibers by
brachial afferent from the vagus nerves
smooth muscle fibers by
Parasympathetic part of autonomic division of peripheral nervous system
Sensory innervation by visceral afferent fibres from
Vagus nerves, sympathetic trunks and splanchnic nerves
Innervation (Oesophageal plexus)
Spread of branches from vagus nerves
- Fibres converge to form 2 trunks
Anterior vagal trunk (Mainly left vagus)
- Anterior surface of the oesophagus
Posterior vagal trunk (Mainly right vagus)
- Posterior surface of the oesophagus
Trunks continue through diaphragm to supply the stomach
The most dilated part of the gastrointerstinal tract?
Stomach.
Stomach lies within 3 abdominal regions
name these 3 region
Epigastric, umbilical and left hypochondrium.
stomach is divided into 4 parts.
cardia-Surrounds opening of oesophagus in stomach
fundus-Area above the level of cardial orifice
body-Largest region of the stomach
pylorus-Pyloric antrum and canal
the most dilated part of the stomach
Pylorus
Pylorus is makrked by?
pyloric constrition
Contains a thickened ring of circular muscle (Pyloric sphincter)
- Sphincter surrounds pyloric orifice at distal end
Pylorus office lies at the level of ?
level of L1-transpyloris line.
The stomach has 2 curvature that give it shape.
Greater curvature-
attachment for gastrosplenic ligament and greater omentum with transverse colon.
lesser curvature-
attachment of lesser omentum-with liver.
cardiac notch- superior angle at which esophagus entering stomach.
arterial supply of the stomuch
Left gastric artery from Coeliac trunk
Right gastric artery from Proper hepatic artery
Left gastro-omental artery from Splenic artery
Right gastro-omental artery from Gastroduodenal artery
The longest part of the gastrointestinal tract
Small intestines
the content of the small intestine.
Extends from the pyloric orifice to ileocoecal fold
- Approximately 6m to 7m long
- Narrow throughout its course
Made up of the duodenum, ileum and jejunum
Duodenum
C-shaped structure made up of 4 parts
- In relation to the head of the pancreas
The first part of duodenum
First part starts at the pyloric orifice the run horizontally to the right along the superior head of the pancreas.
Extends from pyloric orifice to gallbladder neck
Lies at the level of L1
Runs anteriorly over
- Common bile duct, gastroduodenal artery, portal vein and Inferior Vena Cava
(IVC)
First part is connected to the liver via ?
hepatoduodenal ligament
- It is a part of the lesser omentum
second part of duodenum
descend vertically lateral to the pancreas.
It extends from the gallbladder neck to inferior
border of L3
structures related to the sec part
Its anterior surface is crossed by the transverse colon
Right kidney is found on its posterior surface
Head of the pancreas is found on its medial surface
It contains the major duodenal papilla (Common bile and pancreatic ducts)
- Minor duodenal papilla may be present for accessory pancreatic duct
Duodenum (Third part)
run horizontally to the left from L3 border along the inferior head of pancreas.
Longest section of the duodenum
Crosses the IVC, aorta and vertebral column
Crossed anteriorly by the superior mesenteric artery.
Duodenum (Fourth part)
Passes upwards on or to the left of aorta
- Approximately at the level of L2
Terminates at the duodenojejunal junction
Duodenojejunal junction is surrounded by a peritoneal fold
- Fold contains suspensory ligament
Jejunum
Lies mostly in the left upper quadrant
Has a large diameter and thick walls
Inner mucosal lining has numerous prominent folds that circle the lumen (Plicae circulares)
Ileum
It represents the distal 3/5 of small intestines
Mostly in the right lower quadrant
Has a thin wall
Inner mucosal lining has fewer and less prominent folds than the jejunum (Plicae circulares)
Ileum opens into the large intestine Where ?
The caecum and ascending colon meet
2 flap of ileum project into large intestine lumen
Called Ileocaecal folds and surround an opening
Musculature of the ileum continues into the flaps
Musculature of the ileum continues into the flaps
- To create a sphincter around the opening
- Called the ileocaecal valve
Large intestines
Extends from the distal end of the ileum to anus
Absorbs fluids and salts from gut contents
- To create faeces
Large intestines Consists
- Caecum, appendix, colon, rectum and the anus
Begins in right inguinal region as the caecum, with its appendix- Continues as the ascending colon
- Through right lateral region, to terminate at the right hypochondrium
- Continues as the ascending colon
Ascending colon
terminates at right colic flexure
- Flexes to the left, to cross abdomen as transverse colon
Transvere colon
terminates at the left hypochondrium
- At the left colic flexure, to continue as descending colon
Descending colon
runs through left lateral and inguinal regions
- It enters upper pelvic area as the sigmoid colon
Sigmoid colon
continues on posterior pelvic wall as the rectum
- It terminates as the anal canal
summary
Begins at the cecum to the liver but not beyond it but run horizontaly to the right to create corner / flection / heptic flexure then continuen as transvece colon to meet the spleen then curve / colic flexure
Then descend till the illium then create a S shape (sigmoid colon) them medially to the true pelvic
Large intestine has…………. along the length of colon.
omental appendices.
3 narrow bands (Taeniae coli) found along colon
- Create sacculations of the colon (Haustra-folds in the
Large inte..bends they pull the LI then forms sich glamds)
Caecum
Caecum is the first part of large intestine
- Found inferior to ileocaecal opening
Caecum is continuous with the ascending colon
- At the entrance of the ileum
appendix
is a blind-ended tube connect to the caecum
- It is suspended from terminal ileum by mesoappendix
- It contains the appendicular vessels
Appendix location is variable, may be
- Posterior to caecum (Retrocaecal)
- Suspended over pelvic brim (Pelvic)
- Below the caecum (Subcaecal)
- Anterior to terminal ileum (Pre-ileal)
the Ascending and descending colons are …..
retroperitoneal/ immobile - can not not move
directly visible after one opens the peritoneal cavity, but they are fixed to the back wall, thus they are not
fixed to the abdominal wall
Transverse and sigmoid colons are
intraperitoneal- mobile/ moves
not fixes agaist the abdominal wall.
The right colic flexure/ Hepatic flexure transition s which colons
ascending to the transverse colon
suspended via hepatocolic ligament.
The left colic flexure transition which colons and suspended via which ligament
from descending colon to sigmoid colon
via phenocolic ligament
