Endocrine System notes PDF

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Endocrine System: ● Endocrinolgy is the the study of internal secretions, for it was later discovered that the testes secreted testosterone (a hormone) into the blood which helps regulate the physiology of the body. ● Use of hormones to regulate relaxation, contraction,matbolism of smooth and cardiac muscles, metabolic processes, behavior, reproductive system, and cellular proliferation ● The major glands that it uses: hypothylamus, pituatory gland, thyroid gland,parathyroid glands, the pancreas, the adrenal glands and the gonads (testes and ovaries). They all produce and secrete hormones. ● Infidibulum is connecting stalk between the hypothalamus and the pituitary gland ● neurohypophysis and adenohypophysis are the functional portions of the pituitary gland ● The hypothalamohypophysial portal system carries hormones from the hypothalamus to the anterior pituitary.The hypothalamohypophysial tract carries neurons from the hypothalamus to the posterior pituitary. ● Iodine in the body is essential for the formation of thyroxine ● Low levels of calcium ions in the blood stimulates the release of PTH from the parathyroid gland. ● Cortisol is classified as a glucocorticoid.,Outer Zone of the adrenal cortex produces mineralocorticoids ● Tropic Hormones: Hormones that regulate the secretion of another hormone

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endocrine signaling:hormone produced by cells, released into the blood in minute quantities transported to act on tissues

● Paracrine and autocrine signaling: short and local distance singnaling. Paracrine is released into extracellular space and regulates nearby cells, doesnt even enter the blood. Autocrine signaling refers the action of a hormone on the same cell that secreted it or on another cell of the same type that produced the hormone.

Hormone Receptors: Hormones bind to specific receptors on binding cells. They are located in plasma membrane, cytosol of cell, and in the nucleus. Plasma Membrane: Gprotein coupled receptors/ receptor tyrosine kinases and receptor serine/threonine kinases.Activation produces other messangers such as cAMP, cGMP, or inositol triphosphate (IP3). These messangers activate other enzymes Role of calcium: Muscle contraction. Intracellular and nuclear receptors interact with DNA and affect mRNA synthesis. When Nuclear receptors are activated they stimulate transcription of various genes which produce new protiens, making it a new cell. Hydrophilic hormones easily dissolve in water, not easily enter cell this is because of the phospholipid layer. LIpid soluble hormone diffuses through membrane-hormone binds with receptor in cytoplasm thus forming a hormone complex-receptor hormone complex enters

and triggers gene transcription-transcribed mRNA transated into proteins altering cell activity n. Drugs that bind to and stimulate a receptor are called agonists, while those that bind to a receptor and block its effects are called antagonists. Regulation of release: endocrine gland create Secretion. Insulin secretion is regulated by the amount of glucose in the blood.Regulated by the nervous system. Insulin  hormone secreted by the beta cells of the Islets of Langerhans of the pancreas responsible for regulating the metabolism of glucose. Pancrease makes this. calcitonin and parathyroid hormones produce antagonistic results (An example of antagonistic effect is the effect between the opposing actions of insulin and glucagon to blood sugar level. While insulin lowers blood sugar glucagon raises it.) Diabetes mellitus DM is a systemic metabolic disorder that involves improper metabolism of carbohydrates, fats, and proteins. It is centered around the body's use of insulin, a protein that allows the body's cells to absorb glucose from the bloodstream. Diabetes is a chronic multisystem disease related to a decrease or absolute lack of insulin production by the beta cells of the islets of Langerhans in the pancreas or by impaired insulin use, or both.

Diabetes a condition in which the pancreas fails to produce enough insulin or the body's cells cannot use it properly, characterized by excessive thirst, weight loss/gain, frequent urination Type 1 diabetes mellitus results from progressive destruction of beta cell function in the pancreas as a result of an autoimmune process in a susceptible individual.The pancreatic islets of Langerhans cell antibodies and insulin autoantibodies cause an 80-90% reduction in beta cells before hyperglycemia and symptoms occur. Type 1 diabetes is an autoimmune disease probably stimulated by a virus eventually results in destruction of beta cells in the pancreatic islets and results in deficient insulin production; the patient retains normal sensitivity to insulin action The exact cause of both types of Diabetes Mellitus is unknown. A number of factors contribute to its development including genetics, viruses such as rubella, and mumps the aging process, diet and lifestyle, and ethnicity. Obesity is believed to be a major factor. The T lymphocytes may play a role in the autoimmune destruction of pancreatic insulin-producing cells....