Anatomy- how do our intestines work? Flashcards
How is the inner layer of smooth muscle in the intestine wall arranged?
Circularly
How is the outer layer of smooth muscle in the intestine wall arranged?
Longitudinally
Which cavities are contained within the abdominal cavity?
The peritoneal cavity and the retroperitoneum.
name the 9 regions of the abdomen.
Right and left hyperchondrium, epigastric, Right and left lumbar/flank, umbilical, right and left inguinal/iliac fossa, pubic.
What is muscle guarding?
The involuntary contraction of anterolateral abdominal wall muscles to protect a damaged organ. It is a sign which alerts doctors to a pathology in the abdominal cavity.
What are the abdominal organs?
The liver the terminal oesophagus The stomach The gallbladder The pancreas Most of the intestines (part of the small intestines hang inferiorly into the pelvic cavity) The kidneys The adrenal glands
What is the pelvic part of the lower GI tract?
Rectum, anal canal and anus
What are the foregut organs?
the oesophagus to the mid duodenum including the liver, spleen, gallbladder and half of the pancreas
What are the midgut organs?
The mid duodenum to the proximal 2/3 of the transverse colon and half of the pancreas
What are the hindgut organs?
The distal 1/3 of the transverse colon to the proximal half of the anal canal.
How many layers of skeletal muscles are in the anterolateral abdominal wall?
3
Where is the retroperitoneum?
In the abdominal cavity, posterior to the peritoneum
What is an intraperitoneal organ?
How mobile is it?
An organ which is almost completely covered with visceral peritoneum. It is not in the peritoneum. It is minimally mobile.
What is a retroperitoneal organ?
It is located in the retroperitoneum and only has visceral peritoneum on its anterior surface.
What is an organ with a mesentery?
How mobile are these organs?
An organ which is covered in visceral peritoneum and is suspended from the posterior abdominal wall by a mesentery, which is an organ’s double layer of visceral peritoneum.
The organs are highly mobile.
What are often contained within the mesenteries?
Arteries, veins, nerves and lymphatics passing between the intestines and the retroperitoneum.
What can cause peritonitis?
Blood, pus or bowel contents in the peritoneal cavity
Where in the abdominal cavity does the inferior vena cava ascend?
In the retroperitoneum
Where in the abdominal cavity does the abdominal aorta descend?
In the retroperitoneum
What are the three midline branches of the abdominal aorta and which organs do they supply?
- The coeliac trunk- supplies the organs of the foregut
- The superior mesenteric arery- supplies the organs of the midgut
- The inferior mesenteric artery- supplies the organs of the hindgut
Which vein drains the organs of the hindgut?
Where does it drain the blood to?
The inferior mesenteric vein. It drains the blood into the splenic vein.
Which vein drains the organs of the midgut?
Where does it drain the blood to?
The superior mesenteric vein. It drains the blood into the hepatic portal vein.
Which vein drains the organs of the foregut?
Where does it drain the blood into?
The splenic vein. It drains the blood into the hepatic portal vein.
What are the two venous systems of the liver?
Describe the passage of blood through the liver via these venous systems.
The portal venous system (the hepatic portal vein) and the systemic venous system the IVC and the SVC).
The hepatic portal vein carries venous blood from the portal venous system to the liver. The liver then passes the blood to the IVC via the hepatic veins to return to the heart.
Describe the lymphatic drainage of the foregut organs.
The foregut structures drain their lymph via nodes located along the splenic artery towards the coeliac nodes located around the origin of the coeliac trunk.
Describe the lymphatic drainage of the organs of the midgut.
The midgut structures drain their lymph via nodes located along the superior mesenteric artery, towards the superior mesenteric nodes located around the origin of the superior mesenteric artery.
Describe the lymphatic drainage of the organs of the hindgut.
The structures of the hindgut drain their lymph via nodes located along the inferior mesenteric artery, towards the inferior mesenteric artery nodes, located around the origin of the inferior mesenteric artery.
Name a sphincter made of skeletal muscle.
The external anal sphincter.
What kind of pain is caused by an obstruction?
What causes this pain?
Colickly pain. This is caused by increased peristalsis proximal to the obstruction to try and dislodge it.
What sort of control is the smooth muscle in the wall of the GI tract under?
Autonomic control
What is the name of the folds in the stomach?
Rugae
Name a disease in which the villi of the small intestine are damaged.
Coeliac disease
Is the internal anal sphincter made of smooth or skeletal muscle?
Smooth muscle
Where is the anus located?
The perineum
What is it called when drugs reach the liver via the portal venous system and are slightly metabolised there?
First pass metabolism
What is the name for the specialised lymphatic capillaries found in the capillary beds of the villi of the small intestine into which some digested fat molecules are absorbed?
Lacteals
