Anatomy: Oesophagus to Mouth Flashcards
What are the 9 regions of the abdomen?
Left hypochondrium Right hypochondrium Epigastric region Left lumbar Right lumbar Umbilical region Left iliac Right iliac Hypogastric
Which organ would you find in the right hypochondrium?
Liver
From superficial to deep, what are the three anterolateral muscle layers that comprise the anterior abdominal wall?
External oblique, internal oblique and transversus abdominis muscle
What is the external oblique? What happens at its inferior border?
External oblique has fibres which run in an anterior inferior direction (as if you were putting your hands in your pockets).
Look at the inferior border of external oblique. It forms the inguinal ligament between ASIS and the pubic tubercle.
What is the internal oblique?
Internal oblique has fibres which run in an posterior inferior direction (the opposite to external oblique).
What is the transversus abdominis?
Transversus abdominis has fibres which run in a transverse direction.
What is the rectus abdominis?
There is a FOURTH anterior vertical muscle: rectus abdominis.
Bands of tendons – tendinous intersections – divide the rectus abdominis muscle horizontally to give the characteristic ‘six pack’. The vertical midline tendinous intersection is called the linea alba (‘white line).
What is the inguinal ligament?
The free inferior border of external oblique runs between ASIS and the pubic tubercle. This border is called the inguinal ligament.
What is the linea alba?
The central tendinous band in the rectus abdominis is called the linea alba
Where does food reach after the oesophagus?
The food then reaches the stomach, which secretes highly acidic contents and has a variety of different muscular layers to help to churn contents and pass them through to the next part of the GI tract.
What does the stomach feed into? What does this allow for?
The stomach feeds into the pyloric sphincter which opens to allow contents through into the small intestine.
What are the three parts of the intestine?
The small intestine has 3 main parts:
- Duodenum
- Jejenum
- Ileum
Where does the ileum feed into the colon?
The ileum then feeds into the first part of the large intestine at the ileocaecal juntion.
What are the 9 parts of the colon?
- Caecum (note the small extension coming off of the caecum, this is the appendix!)
- Ascending colon
- Hepatic flexure
- Transverse colon
- Splenic flexure
- Descending colon
- Sigmoid colon
- Rectum
- Anal canal
What anatomical relationship does the pancreas have to the stomach?
Posterior
What anatomical relationship does the greater omentum have to the stomach?
Inferior
The greater omentum hangs down from the greater curvature of the stomach to lie anterior to the small intestines.
What artery supplies the foregut?
Coeliac trunk
What artery supplies the midgut?
Superior mesenteric artery
What artery supplies the foregut?
Inferior mesenteric artery
At which vertebral level does the oesophagus pass through the diaphragm?
T10
What region is the stomach found in? What is its function?
It is a muscular sac which acts to churn food and mix it with stomach acid.
What are the parts of the stomach from top to bottom?
Fundus
Body of stomach
Antrum
Phyloric sphincter (a thick smooth muscle sphincter which guards the entrance to the duodenum)
Lesser curvature (top curve of stomach shape)
Greater curvature (bottom curve)
In a normal chest x-ray which part of the stomach can be visualised?
Fundus
An air bubble within the fundus of the stomach can often be seen underneath the left hemi-diaphragm.
What are the features of the duodenum?
The duodenum is largely retroperitoneal, and found on the posterior abdominal wall. It is a short c-shaped section of small intestine which curls around the head of the pancreas.
Both the pancreas and bile ducts drain into the duodenum.
What are the 4 part of the duodenum?
Superior
Descending region (has the bile ducts and pancreatic ducts draining into it - end of the foregut)
Horizontal
Ascending
Which structures drain their contents into the duodenum?
Stomach
Gall bladder
Pancreas
Which structure helps to prevent heartburn?
Lower oesophageal sphincter
Heartburn is experienced when stomach acid enters the lower part of the oesophagus.
The lower oesophageal sphincter is a physiological sphincter, not an anatomical sphincter. Which anatomical structures help to reinforce this sphincter?
Diaphragm
The oesophagus passes through the diaphragm at the level of T10, before terminating in the stomach. The diaphragm is a muscular sheet and its contraction helps to reinforce the LOS.
If pressure within the abdomen increased which part of the stomach would be most likely to be pushed superiorly through the oesophageal hiatus?
Fundus
Decreased abdominal muscle tone and increased pressure within the abdominal cavity could lead to the development of a hiatal hernia.
Thus, people who are obese and women who are pregnant may be at an increased risk for developing a hiatal hernia.
A hiatus hernia is when the fundus of the stomach passes through the oesophageal hiatus so stomach acid can pass into the oesophagus.
Which organs are located in the foregut?
Liver
Stomach
Which organs are located in the midgut?
Jejunum
Ileum
Appendix
Ascending colon
Which organs are located in the hindgut?
Descending colon
Sigmoid colon
Rectum
Which arterial branch from the aorta supplies the midgut?
Superior mesenteric artery
What is the main function of the small intestine? What features allow for this? Which part of the small intestine is best for its function?
The main function of the small intestine is absorption of the products of digestion. To do this it has a very large surface area.
The jejunum is the site of maximum absorption. The ileum has less absorption occurring, but features oval groups of lymphoid tissue, called peyers patches in its wall.
What are the endoscopic features of each part of the small intestine?
Duodenum has neither many plicae circulares or Peyer’s Patches
Jejunum has numerous plicae circulares (inwards folds of mucosal lining)
Ileum has few plicae circulares but does have Peyer’s Patches