What is Dermatitis: Dermatitis is a broad term used to describe inflammation of the skin, resulting in symptoms such as redness, swelling, itching, pain, dryness, scaling, and sometimes blister formation. It is one of the most common dermatological conditions encountered in clinical practice and can affect individuals of all ages, from infants to the elderly….
What is Psoriasis: Psoriasis is a chronic, immune-mediated, inflammatory skin disease characterized by excessive proliferation of skin cells, abnormal differentiation of keratinocytes, inflammation, and the formation of well-defined erythematous (red), scaly plaques. It is one of the most common chronic dermatological disorders, affecting approximately 2–3% of the global population, although its prevalence varies among different…
Structure and Functions of Skin: The skin is the largest organ of the human body and serves as the first line of defense against the external environment. It forms a protective covering over the entire body and performs a wide variety of essential functions that are necessary for survival. In an average adult, the skin…
Morphology of Cell Injury: The morphology of cell injury refers to the structural and functional changes that occur in cells when they are exposed to physiological stress or harmful stimuli. Cells are constantly subjected to changes in their internal and external environment. Under normal conditions, they adapt to these changes to maintain their normal function…
Causes of Cellular Injury: A cellular injury is a state in which a cell is unable to maintain its normal structure and function due to exposure to harmful stimuli. Cells continuously adapt to physiological and environmental changes; however, when the intensity or duration of a harmful stimulus exceeds the cell’s adaptive capacity, injury occurs. Cellular…
Components and Types of Feedback Systems: A feedback system in human physiology is a regulatory mechanism by which the body monitors and controls its internal environment to maintain homeostasis. Homeostasis refers to the ability of the body to maintain a relatively constant internal environment despite continuous changes in external and internal conditions. Feedback systems ensure…
What are Tissues: The human body is an extraordinarily organized and complex structure composed of millions of cells. These cells do not function independently; instead, they group together in an organized manner to perform specialized activities essential for life. A tissue can therefore be defined as a group of structurally similar cells, along with their…
Forms of Intercellular Signalling: Intercellular signalling is the process through which cells communicate with each other to regulate various functions of the body. In multicellular organisms, cells must exchange information continuously for proper growth, metabolism, immunity, development, and maintenance of homeostasis. This communication occurs through signalling molecules such as hormones, neurotransmitters, cytokines, and growth factors….
General Principles of Cell Communication: Cell communication, also known as cell signaling, is a fundamental biological process through which cells detect, interpret, and respond to signals from their internal and external environments. In multicellular organisms, billions of cells must coordinate their activities to maintain growth, development, metabolism, immunity, tissue repair, and homeostasis. Without proper communication…
Cell junctions are specialized structures in the cell membrane that facilitate communication, adhesion, and coordination between adjacent cells in multicellular organisms. These junctions are crucial in maintaining tissue integrity, allowing cells to work together, and ensuring the proper functioning of various organs and tissues. There are several cell junctions, each with specific functions and structures….