Related Concept Videos

Herpes01:28

Herpes

Herpes simplex type 1 (HSV‑1) is a widespread pathogen responsible for orolabial lesions. It is an enveloped, double-stranded DNA (dsDNA) virus belonging to the family Herpesviridae. Once the virus infects a host cell, its double‑stranded DNA genome is delivered into the nucleus, where a coordinated cascade of immediate‑early, early, and late gene expression directs viral DNA replication, structural protein synthesis, and virion assembly. After primary infection of epithelial cells, HSV-1...
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)...
Cirrhosis I: Introduction01:23

Cirrhosis I: Introduction

Cirrhosis is a chronic, irreversible liver disease characterized by the widespread replacement of healthy liver tissue with fibrotic scar tissue and the formation of regenerative nodules.Etiology of cirrhosisCirrhosis results from sustained liver injury that triggers progressive fibrosis and structural remodeling. The underlying causes are diverse, encompassing common and less frequent clinical conditions. Regardless of the origin, all causes lead to chronic inflammation, hepatocyte loss, and...