DNA does not exist as a naked double helix in the nucleus of a cell, however, is complexed with proteins to form a great filamentous material called chromatin. In many cells, the chromatin takes place as 46 long filaments called chromosomes. There is a stupendous quantity of DNA in one nucleus-- about 2 m (6 [...]
Common disorders of the skeletal system may be categorised as disorders of bones or disorders of joints. Orthopaedics (or-tho-pe-diks) is the branch of medicine that specialises in treating diseases and abnormalities of the skeletal system. Disorders of Bones Fractures are broken bones. Fractures are the most common type of bone injury. Fractures are categorised [...]
Plasma is the fluid portion of the blood and consists of over 90% water. Water is the liquid carrier of plasma solutes (dissolved substances) and formed elements, in addition to being the solvent of all living systems. Plasma contains a great variety of solutes, such as nutrients, enzymes, hormones, antibodies, waste products, electrolytes, and respiratory [...]
Infectious Disorders Acquired immunodeficiency syndrome (AIDS) is a viral disease that is approaching epidemic proportions. It is caused by the human immunodeficiency virus (HIV), which attacks and kills helper T cells and invades macrophages, which serve as a reservoir for the virus. In time, the immune defenses of the victim are greatly reduced, and the [...]
Male Disorders Prostatitis is acute or chronic inflammation of the prostate gland and is often associated with tenderness and enlargement of the prostate. It is usually caused by bacteria in connection with urinary tract infections or sexually transmitted diseases. It also occurs without a known cause. Benign prostatic hyperplasia (BPH) is the enlargement of the [...]
Homeostasis, a term presented by W. B. Cannon, describes the mechanism by which the constancy of the internal environment is maintained and ensured Homeostasis is the maintenance of a fairly steady internal environment by self-regulating physiological processes Homeostasis keeps body temperature and the structure of blood and interstitial fluids within their regularrange This fairly steady [...]
Stem cells are the primary cells capable of reforming themselves through mitotic division and differentiating into specialized cells. These cells serve as repair system of the body and are present in all multicellular organisms. Types of Stem Cells Stem cells are of two types: Embryonic stem cells derived from embryo Adult stem cells derived [...]
A synapse is a junction of an axon with either another neuron or an effector cell. At a synapse, the terminal bouton of the presynaptic neuron fits into a small depression on the postsynaptic neuron's dendrite or cell body or on a cell within a muscle, a gland, or adipose tissue. There is a tiny [...]
The heart is a four-chambered muscular pump that is located within the mediastinum in the thoracic cavity. It lies between the lungs and just superior to the diaphragm. The apex of the heart is the inferior pointed end, which extends toward the left side of the thoracic cavity at the level of the fifth rib. [...]
The J-shaped stomach is a pouchlike portion of the alimentary canal. It lies just inferior to the diaphragm in the left upper quadrant of the abdominopelvic cavity. The basic functions of the stomach are temporary storage of food, mixing food with gastric juice, and starting the chemical digestion of proteins. Structure The stomach may be [...]