Pathophysiology

Pathophysiology Study Guide

©2018 of 131 are caused due to ion radiations, chemical carcinogens, genetic disorders, and exposure to ultraviolet rays. These neoplasms are mostly curable and are associated with the presence of cancer at other sites in the body. One of the most common types of skin cancer is basal cell carcinomas, which leads to the formation of hard, raised lesions of red color with a pearly surface. Squamous cell carcinomas are scaly, slightly elevated, and grow with ulcers and non-healing scabs. Another common kind is adenocarcinoma, which is the formation of tumors in the sebaceous or sweat glands. Melanoma is a metastatic cancer. Risk factors associated with skin neoplasm are fair complexion, xeroderma pigmentosa, vitiligo, seborrheic keratitis, radiation dermatitis, and hereditary basal cell nervous syndrome. The diagnosis process for skin neoplasms is a biopsy, which acts as the treatment along with radiotherapy for small lesions. For large lesions, surgery is recommended where bone, lymph, or cartilage are invaded. 2.2 Inflammation Inflammation is caused when tissues are damaged or injured. It is a kind of defense mechanism that helps protect the body and organisms from infection and injury. The aim of this response is to eliminate the agent causing infection by localizing and removing damaged tissues from the body, which governs the healing process. Consequences of inflammation are alterations in blood flow, augmented permeability of blood vessels, and movement of fluid, proteins, and leukocytes to the area where damage has occurred. The inflammatory response can be acute or chronic. Local Manifestation Local manifestations of inflammation are also known as cardinal signs, and include red appearance, heating sensation, loss of function, swelling, and pain. These are associated with vasodilation and accumulation of fluid in body tissues. Acute Inflammation Acute inflammation is usually beneficial, but often results in unpleasant sensations like pain and itching. As the injury occurs, the inflammatory response triggers vascular and cellular changes. This is called vasoconstriction; that is, the blood vessels squeeze in the affected area as the tissues are injured. Next, the blood vessels start to dilate in a process known as vasodilation, which enhances the amount of blood in the affected area. This makes the walls of blood vessels permeable. From this, the flow of blood is more sluggish and the white blood cells start to flow near the blood vessel after falling out of the axial stream. These white blood cells are phagocytes in nature, which ingest the bacteria causing infection and clean up the damage. In acute inflammation, the involved phagocytes are neutrophils, which contain granules of cell-destroying enzymes and proteins. In slight inflammation, phagocytes are obtained from blood in the body, while in extensive damage, these are released from bone marrow. The movement of neutrophils to the site of tissue damage is also possible from chemical substances, known as chemotactic factors. The origin of these chemicals occurs from blood plasma, white blood cells, blood platelets, mast cells, endothelial cells, and damaged tissue cells. Achieve Page 26