The Development, Anatomy and Molecular Interactions of the Pancreas

1. Introduction

Pancreas is an endocrine gland that produces hormones such as insulin and glucagon, which regulate blood sugar levels. It is also responsible for secreting digestive enzymes that help in the digestion of food. The pancreas is a unpaired gland and is located in the abdomen behind the stomach. In this review, we will be discussing the development of the pancreas in chimpanzees, its gross and microscopic anatomy and molecular interactions that take place in this gland.

2. Development of the Chimpanzee Pancreas

Pancreas develops from two sources, the ventral and dorsal pancreatic buds. The ventral pancreatic bud gives rise to the body and tail of the pancreas, while the dorsal pancreatic bud contributes to the head of the pancreas. The ventral bud develops first and then the dorsal bud grows into it and fuses with it to form a single gland (Figure 1).
Figure 1: Diagrammatic representation of ventral and dorsal pancreatic buds (1)

2. 1 Fetal Development

During early stages of development, both ventral and dorsal pancreatic buds are present as separate outgrowths from the primitive gut tube. These buds grow towards each other and fuse around day 28 to form a single gland. By day 35, the pancreas has assumed its final position in the abdomen behind the stomach. After fusion of the two buds, further growth occurs due to proliferation of cells in both acinar and islet regions (Figure 2).

Figure 2: Schematic diagram depicting development of the pancreas (2)

2. 2 Postnatal Development

Postnatally, there is an increase in size of individual acinar cells and beta cells within islets due to cell proliferation. There is also an increase in number of islets as new ones are formed by budding off from existing ones. The overall size of the pancreas increases till puberty after which it remains constant till adulthood (3).
3. Pancreas Anatomy and Histology
The pancreas is a long slender gland that measures about 12 cm in length and weighs around 80-130 grams (4). It is located behind the stomach in the abdomen and extends from duodenum to splenic flexure. It has a wide base which tapers towards its distal end where it joins with duodenum via pancreatico-duodenal junction (5). The pancreas can be divided into four regions – head, neck, body and tail based on its anatomical location (Figure 3). Figure 3: Diagrammatic representation of different regions of pancreas (6)

3. 1 Gross Anatomy

Head – It is rounded or triangular in shape and lies at the level of L2 vertebra. It measures about 2-3 cm in length/width and weighs around 20-30 grams. The head receives its blood supply from superior mesenteric artery (SMA) through pancreaticoduodenal arcade which runs along its medial surface. It drains into splenic vein along with that from body and tail through gastrosplenic ligament (5). Neck – It is a constricted region that connects head to body of pancreas. It measures about 1 cm in length and is located at the level of L3 vertebra (6). Body – It is the longest and largest region of pancreas that extends from neck to splenic flexure. It measures about 8-10 cm in length and weighs around 50-70 grams. The body receives its blood supply from SMA through two pancreaticoduodenal arcades, one along the medial surface and other along the lateral surface (5). Tail – It is the narrowest and most tapered region of pancreas that extends from splenic flexure to hilum of spleen. It measures about 2-3 cm in length and weighs around 10-20 grams. The tail receives its blood supply from splenic artery which runs along its superior border (5). Pancreatic duct – It is a hollow tube that originates from tail and runs through the entire gland to reach the duodenum at pancreatico-duodenal junction where it opens via major duodenal papilla (6).

3. 2 Microscopic Anatomy

Pancreas consists of three types of tissue – exocrine, endocrine and connective tissue. Exocrine tissue comprises of acinar cells that secrete digestive enzymes while endocrine tissue is made up of clusters of cells called islets of Langerhans that produce hormones such as insulin, glucagon etc. Connective tissue forms the ducts, stroma and capsule of pancreas (7).

4. Molecular Interactions in the Pancreas

Pancreatic acinar cells produce digestive enzymes such as trypsin, chymotrypsin, elastase etc. that are secreted into pancreatic ducts. These enzymes are inactive in their zymogen form and are activated only when they reach the small intestine via major duodenal papilla (8). Trypsinogen is activated by enterokinase present in brush border of duodenal epithelial cells while chymotrypsinogen is activated by enteropeptidase (9). Elastase is activated by proteases present in pancreatic juice (10). Inhibition of any one of these activators results in reduced activity of digestive enzymes and can lead to pancreatitis.

Pancreatic beta cells secrete insulin in response to rise in blood sugar levels while alpha cells secrete glucagon which acts opposite to insulin by stimulating liver to release glucose into circulation (11). Both these hormones maintain blood sugar levels within a normal range. Insulin secretion is stimulated by glucose while glucagon secretion is stimulated by amino acids (12).

5. Conclusions

In conclusion, we have discussed the development, gross and microscopic anatomy as well as molecular interactions taking place in the pancreas. Pancreas is an important gland that plays a vital role in regulating blood sugar levels and digestion of food. Further research is necessary to understand the functions of pancreas in health and disease condition.

FAQ

The development of the chimpanzee pancreas was influenced by a variety of factors, including diet, genetics, and environment.

The evolution of the pancreas had a significant impact on the overall health and function of chimpanzees.

It is important to study the pancreas in relation to other organs in chimpanzees because it can provide insight into pancreatic development and function.

We can learn about pancreatic development from studying chimps by observing how the organ develops over time and how it responds to different environmental factors.

This research helps us understand Pancreatic diseases in humans by providing information about the evolution and function of the pancreas.

Some potential implications of this research for future studies on Pancreatism and diabetes include a greater understanding of the role that diet plays in pancreatic function and a better understanding of how genetic factors influence pancreatic development.