Sheets of connective tissue divide the liver into thousands of small units called lobules. A lobule is roughly hexagonal in shape, with portal triads at the vertices and a central vein in the middle. The lobule is the structural unit of the liver and is rather easy to observe. It removes toxins from the body’s blood supply, maintains healthy blood sugar levels, regulates blood clotting, and performs hundreds of other vital functions.
Large intestines can be distinguished from the small intestines by the absence of villi, plicae circularis, and Paneth cells (in adults). Simple columnar epithelium lines its mucosa. The crypts of Lieberkühn are deeper in the colon and goblet cells become more abundant. The large intestine also called the large bowel, is where food waste is formed into poop, stored, and finally excreted. It includes the colon, rectum, and anus.
The stomach wall consists of 4 layers of tissue. From deep (external) to superficial (internal) these are the serosa, muscularis externa, submucosa and mucosa. This layered arrangement follows the same general structure in all regions of the stomach, and throughout the entire gastrointestinal tract. The stomach is a muscular organ located on the left side of the upper abdomen. The stomach receives food from the esophagus. As food reaches the end of the esophagus, it enters the stomach through a muscular valve called the lower esophageal sphincter. The stomach secretes acids and enzymes that digest food.
The appendix is made of inner mucosa layer just like the rest of the digestive tract and is also known as the vermix or the cecal appendix. Normally, the appendix sits in the lower right abdomen. The function of the appendix is unknown. One theory is that the appendix acts as a storehouse for good bacteria, “rebooting” the digestive system after diarrheal illnesses. Other experts believe the appendix is just a useless remnant from our evolutionary past.
The small intestinal mucosa is lined by a simple columnar epithelium which consists primarily of absorptive cells (enterocytes), with scattered goblet cells and occasional enteroendocrine cells. In crypts, the epithelium also includes Paneth cells and stem cells. A long tube-like organ that connects the stomach and the large intestine. It is about 20 feet long and folds many times to fit inside the abdomen. It helps to further digest food coming from the stomach.
The oral mucosa is the term used to describe the soft tissue lining of the oral cavity, including the buccal mucosa and the gingivae. It has many different functions and consists of a distinct layered structure that is similar to the structure and function of the skin. It is the first part of the digestive tract. It is adapted to receive food by ingestion, break it into small particles by mastication, and mix it with saliva. The lips, cheeks, and palate form the boundaries.
The gallbladder is a pear-shaped, hollow structure located under the liver and on the right side of the abdomen. Its primary function is to store and concentrate bile, a yellow-brown digestive enzyme produced by the liver. The gallbladder is part of the biliary tract.
The esophagus contains four layers—the mucosa, submucosa, muscular, and tunica adventitia. The mucosa is made up of stratified squamous epithelium containing numerous mucous glands. The submucosa is a thick, loose fibrous layer connecting the mucosa to the muscularis. The esophagus is the hollow, muscular tube that passes food and liquid from your throat to your stomach. It functions as part of your digestive system.
Smooth muscle is a type of muscle that contracts without any voluntary control, and it is made of a thin form of layers, which is made up of spindle-shaped, unstriated cells with only one nucleus and present in inner organs walls like bladder, intestine, stomach, blood vessels, etc. Smooth muscle is found in the wall of hollow organs, passageways, tracts, eyes, and skin. Fibers of a smooth muscle group in branching bundles allow for cells to contract much stronger than those of striated musculature.
The pancreas is both an exocrine accessory digestive organ and a hormone secreting endocrine gland. The bulk of the pancreatic tissue is formed by the exocrine component, which consists of many serous pancreatic acini cells. The structure of the pancreas is dominated by the fact that it is a dual function organ with both exocrine and endocrine cell types. The vast bulk of the pancreas is composed of exocrine tissue, and secretions from those cells flow into a series ducts for ultimate delivery into the duodenum.
Liver
Sheets of connective tissue divide the liver into thousands of small units called lobules. A lobule is roughly hexagonal in shape, with portal triads at the vertices and a central vein in the middle. The lobule is the structural unit of the liver and is rather easy to observe. It removes toxins from the body’s blood supply, maintains healthy blood sugar levels, regulates blood clotting, and performs hundreds of other vital functions.
Large Intestine
Large intestines can be distinguished from the small intestines by the absence of villi, plicae circularis, and Paneth cells (in adults). Simple columnar epithelium lines its mucosa. The crypts of Lieberkühn are deeper in the colon and goblet cells become more abundant. The large intestine also called the large bowel, is where food waste is formed into poop, stored, and finally excreted. It includes the colon, rectum, and anus.
Stomach
The stomach wall consists of 4 layers of tissue. From deep (external) to superficial (internal) these are the serosa, muscularis externa, submucosa and mucosa. This layered arrangement follows the same general structure in all regions of the stomach, and throughout the entire gastrointestinal tract. The stomach is a muscular organ located on the left side of the upper abdomen. The stomach receives food from the esophagus. As food reaches the end of the esophagus, it enters the stomach through a muscular valve called the lower esophageal sphincter. The stomach secretes acids and enzymes that digest food.
Appendix
The appendix is made of inner mucosa layer just like the rest of the digestive tract and is also known as the vermix or the cecal appendix. Normally, the appendix sits in the lower right abdomen. The function of the appendix is unknown. One theory is that the appendix acts as a storehouse for good bacteria, “rebooting” the digestive system after diarrheal illnesses. Other experts believe the appendix is just a useless remnant from our evolutionary past.
Small Intestine
The small intestinal mucosa is lined by a simple columnar epithelium which consists primarily of absorptive cells (enterocytes), with scattered goblet cells and occasional enteroendocrine cells. In crypts, the epithelium also includes Paneth cells and stem cells. A long tube-like organ that connects the stomach and the large intestine. It is about 20 feet long and folds many times to fit inside the abdomen. It helps to further digest food coming from the stomach.
Mouth
The oral mucosa is the term used to describe the soft tissue lining of the oral cavity, including the buccal mucosa and the gingivae. It has many different functions and consists of a distinct layered structure that is similar to the structure and function of the skin. It is the first part of the digestive tract. It is adapted to receive food by ingestion, break it into small particles by mastication, and mix it with saliva. The lips, cheeks, and palate form the boundaries.
Gallbladder
The gallbladder is a pear-shaped, hollow structure located under the liver and on the right side of the abdomen. Its primary function is to store and concentrate bile, a yellow-brown digestive enzyme produced by the liver. The gallbladder is part of the biliary tract.
Esophagus
The esophagus contains four layers—the mucosa, submucosa, muscular, and tunica adventitia. The mucosa is made up of stratified squamous epithelium containing numerous mucous glands. The submucosa is a thick, loose fibrous layer connecting the mucosa to the muscularis. The esophagus is the hollow, muscular tube that passes food and liquid from your throat to your stomach. It functions as part of your digestive system.
Smooth Muscle
Smooth muscle is a type of muscle that contracts without any voluntary control, and it is made of a thin form of layers, which is made up of spindle-shaped, unstriated cells with only one nucleus and present in inner organs walls like bladder, intestine, stomach, blood vessels, etc. Smooth muscle is found in the wall of hollow organs, passageways, tracts, eyes, and skin. Fibers of a smooth muscle group in branching bundles allow for cells to contract much stronger than those of striated musculature.
Pancreas
The pancreas is both an exocrine accessory digestive organ and a hormone secreting endocrine gland. The bulk of the pancreatic tissue is formed by the exocrine component, which consists of many serous pancreatic acini cells. The structure of the pancreas is dominated by the fact that it is a dual function organ with both exocrine and endocrine cell types. The vast bulk of the pancreas is composed of exocrine tissue, and secretions from those cells flow into a series ducts for ultimate delivery into the duodenum.