Digestive System 1 - Introduction Flashcards
Name the two main parts of the digestive system?
Alimentary canal (aka gastrointestinal or GI tract)
Accessory digestive organs
What organs are found in the gastrointestinal (GI) tract?
–> Oral cavity
–> Pharynx
–> Oesophagus
–> Stomach
–> Small intestine (made of the duodenum, jejunum and ileum)
–> Large intestine (made of the caecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum and anal canal).
What organs are found in the accessory digestive organs?
Teeth
Tongue
Salivary glands
Liver
Gallbladder
Pancreas
What is the function of the GI tract and accessory digestive organs?
GI tract:
A continuous tube through which ingested materials is propelled.
Accessory digestive organs:
Assists in the digestion of ingested materials.
What is the primary germ layer that the digestive system is derived from?
The endoderm (with a small contribution from the mesoderm).
Briefly describe the embryological development of the digestive system?
- At the end of the 3rd week: The folding of the embryo transforms the endoderm and the most lateral parts of the mesoderm into a primitive gut tube.
- This tube eventually connects to the mouth and the anus.
- A double-layered membrane called the dorsal mesentery helps to anchor the gut tube to the posterior body wall.
- A portion of the gut tube is also attached to the anterior body wall by a membrane called the ventral mesentery.
Name the digestive organs that are derived from the foregut?
GI tract organs:
Stomach
First part of the duodenum (part of the small intestine)
Accessory digestive organs:
Liver
Gallbladder
Pancreas
Name the digestive organs that are derived from the midgut?
GI tract organs:
Most of the duodenum (part of the small intestine)
Jejunum (part of the small intestine)
Ileum (part of the small intestine)
Caecum (part of the large intestine)
Ascenging colon (part of the large intestine)
Proximinal 2/3 of the transverse colon (part of the large intestine)
Name the digestive organs that are derived from the hindgut?
GI tract organs:
Distal 1/3 of the transverse colon (part of the large intestine)
Descending colon (part of the large intestine)
Sigmoid colon (part of the large intestine)
Rectum (part of the large intestine)
Superior part of the anal canal (part of the large intestine)
What is the peritoneum?
The serous membrane lining the abdominopelvic cavity.
What are the 3 layers of the peritoneum?
Outer parietal peritoneum
Inner visceral peritoneum
Peritoneal cavity
Describe the different layers of the peritoneum?
Outer parietal peritoneum:
Lines the walls of the abdominopelvic cavity.
Inner visceral peritoneum:
Lines the surface of the organs within the abdominopelvic cavity.
Peritoneal cavity:
The thin serous peritoneal fluid in this cavity reduces friction during movement of the abdominopelvic organs.
What are the 2 spaces that the peritoneal cavity can be divided into?
Greater sac
Lesser sac
Identify the main folds of the peritoneum?
Where do the greater & lesser omentum develop from?
Greater omentum:
It develops from the dorsal mesentery of the primitive gut tube.
Lesser omentum:
It develops from the ventral mesentery of the primitive gut tube.
Describe the location of the main folds of the peritoneum?
Greater omentum:
Extends from the greater curvature of the stomach & drapes over most of the abdominal organs.
Lesser omentum:
Extends from the lesser curvature of the stomach and the duodenum to the liver.
Mesocolon:
Suspends parts of the large intestine from the posterior abdominal wall.
Mesentery proper:
Suspends most of the small intestine from the posterior abdominal wall.
Define intraperitoneal and retroperitoneal?
Intraperitoneal:
Organs that are completely surrounded by visceral peritoneum.
Retroperitoneal:
Organs that are only covered by parietal peritoneum on their anterior surfaces.
Name the digestive organs that are intraperitoneal?
Stomach
First part of the duodenum (part of the small intestine)
Jejunum (part of the small intestine)
Ileum (part of the small intestine)
Caecum (part of the large intestine
Transverse colon (part of the large intestine)
Sigmoid colon (part of the large intestine)
Liver (except for a small area)
Gallbladder
Tail of the pancreas
Name the digestive organs that are retroperitoneal?
Oesophagus
Most of the duodenum (part of the small intestine)
Most of the pancreas
Ascending colon (part of the large intestine)
Descending colon (part of the large intestine)
Rectum (part of the large intestine)
List the basic functions of the digestive system?
Ingestion
Motility
Secretion
Digestion
Absorption
Elimination of wastes
Describe the basic functions (ingestion, motility, secretion) of the digestive system?
Ingestion:
The first step in the process of digesting and absorbing nutrients.
Motility:
The movement of ingested material through the GI tract, which involves peristalsis and mixing.
Secretion:
The process of producing and releasing substances such as mucous, acid, bile and digestive enzymes into the lumen of the GI tract.
Describe the basic functions (digestion, absorption and elimination of wastes) of the digestive system?
Digestion:
This is the breaking down of ingested material into smaller, usable components through both mechanical and chemical digestion.
Absorption:
This is the passage of nutrients, vitamins, electrolytes and water into the blood and lymphatic vessels within the wall of the GI tract.
Elimination of wastes:
This is the removal of all undigestible material and waste products secreted by the digestive organs through the process of defecation.
Fill in the table?
