Hormones Essays (994 words) - Endocrine System, Anatomy,

Hormones Hormones are organic substances that are secreted by plants and animals and that function in the regulation of physiological activities and in maintaining homeostasis. They carry out their functions by evoking responses from specific organs or tissues that are adapted to react to minute quantities of them. The classical view of hormones is that they are transmitted to their targets in the bloodstream after discharge from the glands that secrete them. This mode of discharge (directly into the bloodstream) is called endocrine secretion. The meaning of the term hormone has been extended beyond the original definition of a blood-borne secretion, however, to include similar regulatory substances that are distributed by diffusion across cell membranes instead of by a blood system. . Among animals, the hormones of the vertebrates--particularly those of humans and other mammals--are the best known. Most vertebrate hormones originate in specialized tissues, called endocrine tissues, and are carried to their targets through the bloodstream. Endocrine glands. A major endocrine gland in vertebrates is the pituitary, which consists of two distinct sections: the anterior pituitary (or adenohypophysis) and the posterior pituitary (or neurohypophysis). The anterior pituitary is sometimes called the "master gland," because it secretes several hormones that affect the other endocrine glands. For example, the anterior pituitary hormones thyrotropin and adrenocorticotropic hormone (ACTH) regulate endocrine activity in the thyroid and the outer region (cortex) of the adrenal glands, respectively. The anterior pituitary also secretes hormones that affect the sex glands. One of these is follicle-stimulating hormone (FSH), which stimulates egg production in the ovaries and sperm production in the testes. Another is luteinizing hormone (LH). In females, LH works in conjunction with FSH to regulate the female reproductive cycle and the secretion of female sex hormones. In males, LH controls the production of the male sex hormones. Other hormones produced in the anterior pituitary include growth hormone, which is responsible for normal body growth, and prolactin, which promotes milk production in female mammals. Its designation as the master gland notwithstanding, the anterior pituitary itself is regulated by substances called releasing hormones that are secreted by the hypothalamus, the part of the brain located directly above the pituitary. These hypothalamic hormones stimulate--or, in some cases, inhibit--the secretions of the anterior pituitary. The posterior pituitary stores and releases two hormones: oxytocin, which causes the uterus to contract during birth, and vasopressin, which acts on the kidneys to restrict the output of urine. These two hormones are actually produced by the hypothalamus, which is linked directly to the posterior pituitary. Other endocrine glands in vertebrates include the thyroid, parathyroids, adrenals, pancreas, and gonads (sex glands). The thyroid produces hormones that control metabolic rate and oxygen consumption. Hormones from the parathyroids are concerned with calcium concentration in the blood, and the pancreas releases insulin and glucagon, hormones that, respectively, lower and raise the blood-sugar level. Hormones from the adrenal cortex regulate glucose and sodium metabolism. Those secreted by the central portion (medulla) of the adrenals affect the heart and the circulatory and respiratory systems; these hormones are important in helping an individual cope with stress. The heart itself releases a hormone-- atrial natriuretic peptide--that helps regulate blood pressure, blood volume, and the salt and water balance within the blood. (see also Index: thyroid hormone, parathormone) The female sex hormones--the estrogens and progesterone--are produced by the ovaries. Together with FSH and LH, these hormones control the cyclical changes in the female reproductive system--the menstrual cycle in human females and the estrous cycle in other female mammals. The estrogens also are responsible for female sexual characteristics. Progesterone is concerned with the maintenance of pregnancy. Male sex hormones--known as androgens--include testosterone, which is secreted by the testes. Testosterone is responsible for the maintenance of male sexual characteristics. Hormone chemistry. Structurally, vertebrate hormones fall into two main classes. Those of the adrenal cortex and the sex organs are steroids, a major class of lipid compounds. Virtually all other known vertebrate hormones consist of amino acids. Most nonsteroidal hormones are composed of chains of amino acids--either short chains (polypeptides) or long chains (proteins). The hormones of the adrenal medulla, however, are composed of amino acid derivatives called amines, those of the thyroid of a single amino acid combined with atoms of iodine. It is believed that hormones achieve their effects on target tissues and organs through either of two mechanisms. The steroid hormones and the hormones of the thyroid can, as a result of their chemical structures, pass through cell membranes. These hormones apparently enter a target cell and combine with an intracellular receptor protein. The hormone-receptor complex then enters the cell's nucleus, where it apparently

Overview of Amphicoelias

Overview of Amphicoelias Amphicoelias is a case study in the confusion and competitiveness of paleontologists in the late 19th century. The first named species of this sauropod dinosaur is easy to address; judging by its scattered fossil remains, Amphicoelias altus was an 80-foot-long, 50-ton plant eater very similar in build and behavior to the more famous Diplodocus (in fact, some experts believe Amphicoelias altus really was a species of Diplodocus; since the name Amphicoelias was coined first, this may one day occasion a historic renaming of this dinosaur similar to the day when Brontosaurus officially became Apatosaurus). Name: Amphicoelias (Greek for double hollow); pronounced AM-fih-SEAL-ee-us Habitat: Woodlands of North America Historical Period: Late Jurassic (150 million years ago) Size and Weight: Up to 200 feet long and 125 tons, but more likely 80 feet long and 50 tons Diet: Plants Distinguishing Characteristics: Enormous size; quadrupedal posture; long neck and tail The confusion and competitiveness pertain to the second named species of Amphicoelias, Amphicoelias fragilis. This dinosaur is represented in the fossil record by a single vertebra measuring five by nine feet long, truly enormous proportions that correspond to a sauropod measuring about 200 feet from head to tail and weighing over 125 tons. Or rather, one should say that Amphicoelias fragilis WAS represented in the fossil record since this gigantic bone subsequently disappeared off the face of the earth while under the care of the famous paleontologist Edward Drinker Cope. (At the time, Cope was embroiled in the notorious Bone Wars with his arch-rival Othniel C. Marsh, and may not have been paying attention to detail.) So was Amphicoelias fragilis the biggest dinosaur that ever lived, heftier even than the current record-holder, Argentinosaurus? Not everyone is convinced, especially since we no longer have that all-important backbone to examineand the possibility remains that Cope slightly (or greatly) exaggerated his discovery, or perhaps made a typographical error in his papers under the pressure of constant, long-distance scrutiny by Marsh and others in his antagonistic camp. Like another supposedly enormous sauropod, Bruhathkayosaurus, A. fragilis is only provisionally the world-champion dinosaur heavyweight, pending the discovery of more convincing fossil evidence.

Management Accounting Case Study Assignment Example | Topics and Well Written Essays - 3000 words

Management Accounting Case Study - Assignment Example Lastly, this report looks at the financial position of the company and its capability to fund the project under consideration. The main strengths of Moonsnail Soapworks are: its unique selling proposition; high quality, all natural and handmade products; intensive product development effort; strong brand equity; and strategic marketing and location. Moonsnail Soapworks suffers from weaknesses which includes Ms. Ridgway's inadequate knowledge in management and the company's exposure to losses from product obsolescence. Opportunities abound for Moonsnail. The major opportunity for the company is the introduction of additional products to broaden and lengthen the product line and widen its customer base. As customers are becoming more and more concerned with having a natural lifestyle, it is expected that they will seek for product offerings like the ones provided by Moonsnail. The firm should also maximize the use of the internet to efficiently market its products. The major threat for Moonsnail is the unstable tourist arrival due to external circumstances. Another is the rising prices in oil prices which can further dampen the demand for tourism activities. Moonsnail is financially capable of investing in Moon Baby Cream. The company is records remarkable profitability, high efficiency, and liquidity. Its huge cash account can be utilized to introduce its new product. One of the biggest challenges faced by business organ... Conclusion 12 References 13 Appendix 14 I. Introduction One of the biggest challenges faced by business organizations is decision making. Through this feat, the company chose among a host of possible opportunities to take advantage of and shapes its future. In decision making, a firm critically assesses possible alternatives to determine which course of action will bring maximum benefits at the same time helping the company in realizing its vision. It is imperative that in coming up with a business decision, an organization looks at its competitive position to efficiently determine if it is ready to undertake a significant move. Another factor which is equally important to take into consideration is the firm's financial position and readiness as financial resources are always needed to back company projects like product introduction. This report will examine the most pressing issue faced by Moonsnail Soapworks-the introduction of a new product called Moon Baby Cream. As stated previously, the readiness of the company to launch a product can be assessed by looking at the competitive performance and the financial position of the business organization. The next section will then take a closer look at the company by employing frameworks which are designed to determine the internal strengths and weaknesses of the Moonsnail as well as its external environment. The financial position of the firm will also be examined through ratio analysis. Lastly, the feasibility and profitability of introducing Moon Baby Cream is also analyzed through cost and benefit analysis. This report will conclude with its recommendations. II. Moonsnail Soapworks: Competitive Position SWOT Analysis SWOT (Strengths, Weaknesses,