The axillary lymph nodes are located in the armpit. They are divided into two sets: superficial and deep. These lymph nodes receive lymph from the vessels of the arm and the upper nodes receive lymph from vessels in the upper chest area near the pectoralis muscles (pectoralis major and pectoralis minor muscles) and the mammary glands. There are about 35 lymph nodes in the breast and armpit area. Most of the lymph nodes are located in or near the armpit. If cancer forms in the breast area it often spreads to the nodes because the lymph, along with other debris, can carry cancerous cells. Lymph flows in all directions, but about three- quarters of lymphatic vessels in the breast empty into the axillary nodes, which often become the first site of the cancer spread beyond the breast. Research Axillary Lymph Nodes
In the female, once a graafian follicle discharges its mature ovum, the cavity once occupied by the egg is replaced by luteal cells made of a yellow lipoid material. Together, the erupted graafian follicle and its clot of luteal cells compose the corpus luteum. If the ovum is fertilized, the corpus luteum will eventually create hormones which regulate the development of the placenta, the suppression of menstruation, the growth of the mammary glands, and the eventual development of more mature ova. If the ovum is not fertilized, the corpus luteum will become interpenetrated by bloodcapillaries and will eventualy disintegrate to leave a small scartissue called the corpus albicans. Research Corpus Luteum
The lactiferous tubules are the small ducts through which the milk flows to the openings of the nipple in the mammary glands. The lactiferous ducts are composed of areolar tissue and elastic fibres. The number of ducts in each mammary gland varies from fifteen to twenty. These ducts increase in capacity during pregnancy and in breast-feeding the pressure of the baby's gums on the areola stimulates the milk flow. Research Lactiferous Tubules
The mammary glands are half-sphere-shaped glands that overlie the muscles of the chest, predominantly the pectoralis major, in an area between the third and sixthribs on each side of the chest. The mammary glandtissue is attached to the overlying skin by straps of fiber called Cooper' s ligaments. Mammary glands exist in the male as well as the female, but only in a rudimentary state in the former. They appear in the human featus in the sixthweek and by the time the baby is born they consist of an intricate network of ducts that empty into the nipple, which look like a tiny circle of thickened skin. In girls, the development of mammary glands is usually the first sign of puberty. Research Mammary Glands
The pituitary gland (or hypophysis),is a gland within the brain concerned with regulating growth and regulating other ductless glands. The pituitary gland , consists of three lobes, the anterior lobe, the intermediate lobe, which in primates is present for only a short part of the life span, and the posterior lobe. It is situated at the base of the brain and has been called the master controlling gland of the body. The anterior and the posterior lobes of the pituitary secrete different hormones. The anterior lobe secretes various hormones that stimulate the function of other endocrine glands, for example, adrenocorticotropic hormone, or ACTH, which stimulates the adrenal cortex; thyroid- stimulating hormone, or thyrotropin, known as TSH; follicle-stimulating hormone (FSH) and luteinizing hormone (LH), which stimulate the sex glands; and prolactin, which, with other special hormones, influences milk production of the mammary gland.
In addition, the anterior pituitary is the source of growthhormone, also called somatotropin, which promotes the development of body tissues, particularly of bone matrix and muscle, and influences carbohydrate metabolism. The anterior pituitary also secretes a hormone called melanocyte-stimulating hormone, which regulates the intensity of pigmentation in pigmented cells. In the 1970s scientists found that the anterior pituitary also produces substances called endorphins. These are peptides that act on the peripheral and central nervous systems to reduce sensitivity to pain. The hypothalamus, secretes an antidiuretic hormone named vasopressin, which is stored in the posterior lobe of the pituitary gland. The posterior lobe of the pituitary also stores another hormone secreted by the hypothalamus. This hormone, known as oxytocin, stimulates muscular contractions, especially of the uterus, and ejection of milk from lactating mammary glands. Not long ago it was found that secretion of three anterior pituitary hormones is under regulation of the hypothalamus: thyrotropin secretion is stimulated by thyrotropin-releasing factor (TRF), and luteinizing- hormone secretion by luteinizing-hormone releasing hormone (LHRH). Release of growthhormone is inhibited by somatostatin, which is also made by the pancreas. Research Pituitary gland
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Axillary Lymph Nodes
