Inferior Vena Cava (IVC) Definition: Inferior vena cava (or IVC) is a large vein that carries de-oxygenated blood from the lower body to the heart. It is also referred to as the posterior vena cava. Its walls are rigid and have valves so the blood does not flow down via gravity. It is formed by [.....
Oxidative Stress (Effects: Health, Biological, and Chemical) Definition: Oxidative stress reflects an imbalance between free radicals and antioxidants in our body. It occurs when excess oxygen radicals are produced in cells, which could overwhelm the normal antioxidant capacity. Free radicals a.....
DNA repair (Mechanisms) Definition: DNA repair mechanisms comprise relatively simple single-step enzyme reactions catalyzed by monomeric proteins which directly reverse base damage to DNA. In some cases, these reversal reactions require specific cofactors, in some cases not. It is a collection of.....
DNA repair (Damage and Sources) Definition: DNA repair, any of several mechanisms by which a cell maintains the integrity of its genetic code. In human cells, both normal metabolic activities and environmental factors such as radiation can cause DNA damage, resulting in as many as 1 million indiv.....
Meiosis (Functions and Importance) Definition: Meiosis (/maɪˈoʊsɪs/; from Greek μείωσις, meiosis, which means lessening) is the process in eukaryotic, sexually-reproducing animals that reduces the number of chromosomes in a cell before reproduction. Many organisms package these cells i.....
Meiosis (Phases) Definition: Meiosis (/maɪˈoʊsɪs/; from Greek μείωσις, meiosis, which means lessening) is a specialized form of cell division that produces reproductive cells, such as plant and fungal spores and sperm and egg cells. This process occurs in all sexually reproducing singl.....
Respiratory System (Anatomy) Definition: The respiratory system (also referred to as the ventilator system) is a complex biological system comprised of several organs that facilitate the inhalation and exhalation of oxygen and carbon dioxide in living organisms (or, in other words, breathing). Mo.....
Pulmonary Alveolus Definition: Pulmonary alveolus (plural: alveoli, from Latin alveolus, “little cavity”), informally known as air sac, is any of the innumerable minuscule, thin-walled, capillary-rich hollow cavities in the mammalian lung that serve as the primary sites of gas exchang.....
Epidermis Definition: The epidermis is the outer layer of the three layers that make up the skin, the inner layers being the dermis and hypodermis. It is mostly made up of flat, scale-like cells called squamous cells. Under the squamous cells are round cells called basal cells. The deepest part o.....
Metencephalon Definition: Metencephalon is generally considered a part of the brain that largely consists of the brain’s cerebellum and pons. It contains a portion of the fourth ventricle and the trigeminal nerve (CN V), abducens nerve (CN VI), facial nerve (CN VII), and a portion of the ve.....
Lymphatic System Definition: Lymphatic System is a collection of organs, tissues, ducts, and vessels that help to make or transport lymph. Lymph is a clear-to-white fluid circulating in the vessels and ducts of the lymphatic system that contains white blood cells, proteins, and fat. It was first .....
Vitex Peduncularis Plant Vitex is a genus of about 250 species of shrubs and trees from 1-35 m tall, native to tropical, subtropical and also warm temperature regions throughout the world. In the past widely included in the family Verbenaceae, it has recently been transferred to the family Lamiac.....