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The digestive system and the respiratory system
Published in Frank J. Dye, Human Life Before Birth, 2019
The ventral pancreatic bud is one of the two rudiments that give rise to the pancreas. At about the level of the hepatic diverticulum, the dorsal pancreatic bud grows out of the foregut. The ventral pancreatic bud and the dorsal pancreatic bud fuse when the duodenal loop of the foregut and midgut rotates in a clockwise direction. The dorsal pancreatic duct regresses and the pancreas opens (together with the common bile duct) into the duodenum through the ventral pancreatic duct (see Figure 16.4).
Single Best Answer Questions
Published in Vivian A. Elwell, Jonathan M. Fishman, Rajat Chowdhury, SBAs for the MRCS Part A, 2018
Vivian A. Elwell, Jonathan M. Fishman, Rajat Chowdhury
With regard to the exocrine pancreas:It secretes digestive juices with a pH of 4–5It develops from a single ventral pancreatic budSecretion is inhibited by cholecystokininThe main stimulation for secretion occurs during the intestinal phaseIt produces secretin
Gastrointestinal Tract Development and Its Importance in Toxicology
Published in Shayne C. Gad, Toxicology of the Gastrointestinal Tract, 2018
Alma M. Feldpausch, Joseph V. Rodricks, Rosalind A. Schoof, Brittany A. Weldon
The earliest differentiated organ in the GI system is the liver, which is formed from the liver bud of the open GI tube beginning at week 3 of development (Table 4.1). Soon after, the pancreatic bud begins to form around weeks 3 to 4 (Podolsky et al., 2015). The midgut is a herniated umbilicus external to the abdomen during this stage of development.
Regional variation of human pancreatic islets dimension and its impact on beta cells in Indian population
Published in Islets, 2019
Praveen Kumar Ravi, Suvendu Purkait, Usha Agrawal, Susama Patra, Madhumita Patnaik, Sudipta Ranjan Singh, Pravash Ranjan Mishra
Regional variation of islets size, architecture and insulin-secreting capacity in response to glucose are also linked with their source of development.28–30 Islets derived from the dorsal pancreatic bud (present in the body and tail regions) are larger in size and its insulin secretion in response to the glucose stimuli is significantly higher in comparison to islet-derived from ventral pancreatic bud.24,28–30 Islet size plays a crucial role in the composition and arrangements of the various endocrine cells within it, which in turn regulate their activities via paracrine effect.26 The smaller islets (diameter less than 50 µm) are rich in beta cells in comparison to larger islets which have more alpha cells with the intermingling of beta and non-beta cells.26,31 Disorganized or intermingled arrangement of alpha and beta cells in the larger islets allowed the beta cells to respond even to lower concentration of blood glucose to which smaller islets are usually blind.18,26,32 Thus, the larger islets with a smaller proportion of beta cells are functionally more active via a paracrine effect in comparison to smaller islets. The larger islets were frequently reported in conditions of increased insulin demand like insulin resistance, obesity, pregnancy and diabetes.18,31