Hormones Essays - Endocrine System, Peptide Hormones,

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 Hormones Essays - Endocrine System, Peptide Hormones, Hormones IntroductionHormones 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 tissue s, 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 hu man 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

Five Terms Related to Submitting a Manuscript

Five Terms Related to Submitting a Manuscript Five Terms Related to Submitting a Manuscript Five Terms Related to Submitting a Manuscript By Maeve Maddox A reader asks about some terms: I’m confused: Whats the difference between Submissions and Query Letters and Cover Letters and Biographies and Resumà ©s? As these terms are often used interchangeably on writing sites, the reader’s confusion is understandable. Perhaps the following explanations can help. 1. Query Letter A query letter is a one-page letter intended to interest an editor in something a writer has written or intends to write. It should address the editor by name (spelled correctly) and begin with a hook: a strong statement that piques the editor’s interest. If the query is about a magazine article, the hook might be the first paragraph of the article. The query should give the editor an idea of the structure and content of the piece being offered. If the offered work is a novel, the letter should include a description of the main theme and story line, including conflict and resolution (how it ends). A query letter should tell why the author is qualified to write the article or book and end with a direct request for the desired magazine assignment or for permission to send a manuscript. 2. Cover Letter When the editor asks to see a manuscript or sample pages, the writer includes a cover letter with the submission: a brief letter to accompany the manuscript or sample. Editors receive hundreds of queries. The cover letter is a practical and courteous way to remind the editor of the particulars of your initial query. Keep it short and don’t try to do any additional selling. It’s enough to say something like this: â€Å"Here’s the short story I queried you about on March 20, 2016. I look forward to hearing from you.† 3. Author’s Bio The shortening bio for biography is the norm in the context of marketing written material. The bio focuses on the writer’s credentials. Publishers want to know if the writer has published before and is qualified to write about the material being offered. They do not want to know about the writer’s dogs, cats, children, hobbies, or any other irrelevancies. 4. Resumà © A resumà © is a brief account of ones education and professional experience. Some of the same information that belongs in a resumà © can also have a place in an author’s bio, but a resumà © will be more comprehensive regarding past employment. A writer who is applying for a job as an editor or a blogger will certainly offer a resumà © to the potential employer. Note: Although the French original is spelled with two accent marks (rà ©Ã‚ ·su ·mà ©) American spelling recognizes both resume and resumà ©. I favor a single accent for two reasons: the first accent is meaningless to most English speakers, but the final accent mark distinguishes the noun and its pronunciation from the verb resume.   For example: â€Å"I started writing my resumà © today, but was interrupted. I’ll resume work on it in the morning.† 5. Submission When an editor asks to see a partial or completed manuscript, the writer prepares a submission that includes a manuscript (partial or complete) and whatever additional material has been requested by an editor or publisher. Before preparing a submission, the writer will consult the publisher’s guidelines to see how the manuscript should be formatted, how it should be sent (by mail or electronically), and what additional enclosures are wanted. The manuscript included in a submission should be as complete and as correct as the writer can make it. Want to improve your English in five minutes a day? Get a subscription and start receiving our writing tips and exercises daily! Keep learning! Browse the Fiction Writing category, check our popular posts, or choose a related post below:Program vs. ProgrammeEnglish Grammar 101: Verb MoodEspecially vs. Specially

Tracing Dimensions of Changing Culture Essay Example | Topics and Well Written Essays - 1750 words

Tracing Dimensions of Changing Culture - Essay Example The book is a collection of seven short stories beginning with â€Å"Girl with Lizard†, which tells about a boy and his obsession and desire for a mysterious painting he inherited from his parents, which drove him to unconsciously ruin his relationships with women while discovering his parent’s dark past. â€Å"A Little Fling†, a story about a husband’s political betrayal of his wife for her sake, a wife’s betrayal of her husband to spite him, the narrator’s betrayal of his friend as a result of his own naivety, and the revelation, which destroyed the intimate relationship they all shared. â€Å"The Other Man†, a story, which recounts a man’s discovery of his late wife’s affair and his realization about the truth of his marriage. The middle story, â€Å"Sugar Peas†, tells about a narcissistic man balancing his relationships with three women. â€Å"The Circumcision†, which tells of the relationship between a German man and a Jewish girl in New York, is a foray into the sensitive topic of the division caused by their culture and religion. â€Å"The Son†, on the other hand, tells of filial love, described in a dramatic fashion. The book then ends with â€Å"Woman at the Gas Station†; which narrates of a man and his decision to leave his wife. All these stories are bound by the themes of betrayal brought about by obsession, desperation, and historical circumstance – all because of and in spite of love. The themes, embodied in Flights of Love are best exemplified in his opening story â€Å"Girl with Lizard†.