Lecture 42 & 44: GIT Flashcards
What structure delineates the thorax and abdomen?
The diaphragm
What structure delineates the abdomen and pelvis?
Trick question: there is no clear demarcation
What are the two planes of the abdomen?
Transumbilical plane = x-axis
Median plane = y-axis
What are the 5 hollow abdominal viscera?
Esophagus, stomach, small intestine, large intestine, gallbladder.
What are the three viscera of the GI tract?
Esophagus, stomach, small intestine
What are the 5 solid viscera of the abdominal cavity?
Liver, pancreas, spleen, kidneys, adrenals
What are the four facts about each abdominal viscera that we need to know?
Hollow/solid, intraperitoneal/extraperitoneal, identifying feature(s), principle vascular supply
What are the principle muscle layers of the abdominal wall?
Lateral aspect: external obliques, internal obliques, transversus abdominus.
Anterior aspect: Rectus abdominus
What are the three muscles of the posterior abdominal wall? What are their movements?
Psoas major (hip flexion), quadrus lumborum (lateral flexion of the thoracic spine), iliacus (hip flexion)
What shape is the cross section of the abdomen? Why?
Kidney shaped because of the lumbar spine.
What are the three roles of the mesentery?
Holds viscera in place, gives viscera mobility, creates nervous and vascular pathway to the viscera.
What are the two subtypes of peritoneum? Describe them.
Parietal peritoneum – that which covers the abdominal walls
Visceral peritoneum – that which covers the viscera
What is inside the potential space of the peritoneal membrane?
Serous fluid
What is the role of the serous fluid?
Reduces friction, thus increasing motility of the viscera
At what spinal level does the esophagus start?
C6
At what spinal level does the esophagus pass into the abdominal cavity?
T10
What is the role of the esophagus?
Pass food into the stomach
Where is the anatomical sphincter of the esophagus?
At the beginning just below the pharynx.
Where is the functional sphincter of the esophagus?
At the end as it passes obliquely through the muscular diaphragm.
What causes the narrowing in the middle of the esophagus?
The compression of adjacent viscera - ie the left main bronchus and the arch of the aorta
What is the name of the sharp, immediate change in esophageal lining as it enters the stomach?
Esophagogastric junction
What is the function of the stomach?
Store food and begin digestion
What is the location of the stomach?
LUQ
What are the two orifices of the stomach?
Cardiac orifice (opens to the terminal esophagus) Pyloric orifice (opens to the duodenum)
What is the shape of the stomach? (Remember to include the curves.)
J-shapes; lesser curvature (medial) and greater curvature (lateral)
What is the stomach’s relationship to the peritoneum?
Intraperitoneal
Where does air tend to stay in the stomach?
The fundus (up the top)
What is the name of the lining of the stomach that is just distal to the cardiac orifice?
The cardia
What is the largest segment of the stomach?
The body
What is the role of the pylorus of the stomach?
Forms a tunnel to the duodenum
What are the two parts of the pylorus?
Antrum (superior) and canal (narrow, funnel-like, inferior)
What is the role of the pyloric orifice as an anatomical sphincter?
Controls the movement of stomach contents into the duodenum
What are the internal foldings of mucosal lining in the stomach called?
Rugae
What happens to the pattern of the rugae as it tends from fundus to pylorus?
It becomes more massive
What is the first part of the small intestine?
Duodenum
What shape is the duodenum?
C-shaped
What are the four parts of the duodenum?
1 - duodenum cap/superior part
2 - descending part (L1-L3)
3 - Inferior/horizontal part
4 - Ascending part
Describe the location of the duodenum.
RUQ: Medial to the right kidney and closely attaches to the pancreas.
What is the physical relationship between the pancreas and the duodenum?
Medial head of the pancreas sits inside the C-shaped duodenum
What is the relation of the duodenum to the peritoneum?
Retroperitoneal (ie, peritoneum is only on the anterior surface of the duodenum)
Through what feature does the bile AND pancreatic enzyme enter the duodenum?
The major duodenal papilla in the descending duodenum
Where is the minor duodenal papilla relative to the major duodenal papilla? What enters through the minor duodenal papilla?
Proximal; pancreatic enzyme ONLY.
What two ducts join together to form the common bile duct?
Gall duct and hepatic duct
What enzyme is secreted by the pancreas into the duodenum?
Pancreatic enzyme
At what spinal level is the horizontal/inferior part of the duodenum?
L3
What is the relation of the rest of the small intestine (after the 4th part of the duodenum) to the peritoneum?
Intraperitoneal
What are the three parts of the small intestine? (Proximal to distal)
From proximal to distal: Duodenum, jejunum, ileum
What ~% of the small intestine is jejunum? In which quadrant is it located?
~40%; predominately LUQ