Related Concept Videos

Formation of Muscle Fibers from Myoblasts01:13

Formation of Muscle Fibers from Myoblasts

De novo myogenesis, or the formation of muscle fibers, begins during the early embryonic stages. The skeletal muscle is formed from somites– blocks of embryonic cell layers. The somites are further divided into dermatomes, myotomes, sclerotomes, and syndetomes. Among these, the myotomes give rise to muscle fibers.
Muscle progenitor cells (MPCs) are formed from the myotomes. MPCs express genes that encode the transcription factors Pax3 and Pax7. Along with Pax 3/7, other transcription factors...
Satellite Stem Cells and Muscular Dystrophy01:21

Satellite Stem Cells and Muscular Dystrophy

Satellite stem cells or myosatellite cells are quiescent stem cells that Alexander Mauro first identified in 1961. These cells are located between the sarcolemma, the plasma membrane of muscle fibers, and the basal lamina, the connective tissue sheath covering it. These mononucleated cells are activated in response to muscle injury, can transform into myoblasts, and may form or repair muscle fibers. Myosatellite cells can provide additional myonuclei for muscle regeneration or return to a...
Gross Anatomy of the Stomach01:16

Gross Anatomy of the Stomach

The human stomach is a vital part of the digestive system, performing multiple functions. It is located within the peritoneum, a serous membrane that lines the abdominal cavity. The stomach plays a central role in processing food substances and interacts with other digestive organs through coordinated digestive processes. The stomach has a characteristic J-shape and is divided into four main regions. The cardia is the first section where the esophagus connects to the stomach and is the entry...
Mucosal Barrier of the Stomach01:25

Mucosal Barrier of the Stomach

The gastric glands contain parietal cells that secrete hydrochloric acid (HCl) for digestion. The cells secrete HCl because it is highly corrosive and essential for breaking down food. To achieve this, they secrete hydrogen and chloride ions into the lumen of the gastric glands, which combine to form HCl.
Within parietal cells, carbonic acid is first formed through the reaction of water and carbon dioxide. The dissociation of carbonic acid releases bicarbonate and hydrogen ions. The bicarbonate...
Esophageal Achalasia01:27

Esophageal Achalasia

Esophageal achalasia is a chronic neurogenic disorder characterized by impaired relaxation of the lower esophageal sphincter (LES) and absent or ineffective peristalsis in the distal esophagus. This leads to a functional obstruction without a physical blockage, despite significant disruption of esophageal motility.EtiologyAchalasia is caused by degeneration of the myenteric (Auerbach's) plexus, specifically the loss of inhibitory ganglion cells that produce vasoactive intestinal peptide (VIP)...
Pyloric Obstruction01:11

Pyloric Obstruction

Pyloric obstruction, also referred to as gastric outlet obstruction, is a condition characterized by narrowing or blockage at the pylorus—the muscular valve regulating the flow of stomach contents into the duodenum. When this passage becomes impaired, the stomach cannot effectively empty its contents into the small intestine. This disruption leads to a range of gastrointestinal symptoms, including early satiety, bloating, epigastric pain, postprandial nausea, persistent vomiting, and...