Ileum
General
The ileum is the final section of the small intestine
The ileum follows the duodenum and jejunum and is separated from the cecum by the ileocecal
valve (ICV). In humans, the ileum is about 2–4 m long.
The function of the ileum is mainly to absorb vitamin B12 and bile salts and whatever products of
digestion were not absorbed by the jejunum. The wall itself is made up of folds, each of which has
many tiny finger-like projections known as villi on its surface. In turn, the epithelial cells that line
these villi possess even larger numbers of microvilli. Therefore, the ileum has an extremely large
surface area both for the adsorption (attachment) of enzyme molecules and for the absorption of
products of digestion. The DNES (diffuse neuroendocrine system) cells of the ileum secrete various
hormones (gastrin, secretin, cholecystokinin) into the blood. Cells in the lining of the ileum secrete
the protease and carbohydrase enzymes responsible for the final stages of protein and carbohydrate
digestion into the lumen of the intestine. These enzymes are present in the cytoplasm of the
epithelial cells.
The villi contain large numbers of capillaries that take the amino acids and glucose produced by
digestion to the hepatic portal vein and the liver. Small lymph vessels present in villi also serve to
absorb fatty acid and glycerol, the products of fat digestion. Layers of circular and longitudinal
smooth muscle enable partly digested food and water to be pushed along the ileum to the colon by
waves of muscle contractions called peristalsis.
The ileum is of importance in medicine as it can be affected in a number of diseases, including:
Crohn's disease
Tuberculosis
Lymphoma
Neuroendocrine tumours
Experiment specific
Large organ bath: 20ml and on paper, ileum, atrium & vas deferens.
Small organ bath: 5ml and on computer, trachea & aorta.
In this practical you will receive four Ileum organ samples for your experiments.
In your experiments for this practical, you should use a large organ bath for ileums.
Reference (=known) compounds standard available for this ileums experiment are methacholine,
histamine and isporenaline.
General
The ileum is the final section of the small intestine
The ileum follows the duodenum and jejunum and is separated from the cecum by the ileocecal
valve (ICV). In humans, the ileum is about 2–4 m long.
The function of the ileum is mainly to absorb vitamin B12 and bile salts and whatever products of
digestion were not absorbed by the jejunum. The wall itself is made up of folds, each of which has
many tiny finger-like projections known as villi on its surface. In turn, the epithelial cells that line
these villi possess even larger numbers of microvilli. Therefore, the ileum has an extremely large
surface area both for the adsorption (attachment) of enzyme molecules and for the absorption of
products of digestion. The DNES (diffuse neuroendocrine system) cells of the ileum secrete various
hormones (gastrin, secretin, cholecystokinin) into the blood. Cells in the lining of the ileum secrete
the protease and carbohydrase enzymes responsible for the final stages of protein and carbohydrate
digestion into the lumen of the intestine. These enzymes are present in the cytoplasm of the
epithelial cells.
The villi contain large numbers of capillaries that take the amino acids and glucose produced by
digestion to the hepatic portal vein and the liver. Small lymph vessels present in villi also serve to
absorb fatty acid and glycerol, the products of fat digestion. Layers of circular and longitudinal
smooth muscle enable partly digested food and water to be pushed along the ileum to the colon by
waves of muscle contractions called peristalsis.
The ileum is of importance in medicine as it can be affected in a number of diseases, including:
Crohn's disease
Tuberculosis
Lymphoma
Neuroendocrine tumours
Experiment specific
Large organ bath: 20ml and on paper, ileum, atrium & vas deferens.
Small organ bath: 5ml and on computer, trachea & aorta.
In this practical you will receive four Ileum organ samples for your experiments.
In your experiments for this practical, you should use a large organ bath for ileums.
Reference (=known) compounds standard available for this ileums experiment are methacholine,
histamine and isporenaline.
