Hormones Secreted by endocrine glands endocrine cells and
Hormones 荷爾蒙 • Secreted by endocrine glands, endocrine cells, and certain neurons • Animal hormones travel through the bloodstream to nonadjacent target cells
An Orchestra of Hormones 賀爾蒙或激素的作用 • Hormones influence the growth, development, and reproductive cycles of nearly all animals • They influence behavior(行為), physical appearance(活動), and well-being(健康)
Endocrine System 內分泌系統 Main Sources • Pituitary gland腦下腺 • Adrenal glands腎上腺 • Thyroid gland甲狀腺 • Parathyroid glands副甲狀腺 • Pineal gland松果腺 • Thymus gland胸腺 • Gonads性腺
Two Main Hormone Types • Steroid hormones 類固醇(脂溶性激素) – Derived from cholesterol (膽固醇) – Estrogens(雌激素), progestins(黃體激素), androgens (such as testosterone)(男性荷爾蒙), cortisol( 皮質醇), aldosterone(醛固酮) • Peptide hormones 胜肽類(水溶性激素) – Peptides, proteins, or glycoproteins – Glucagon(胰血糖素), ADH, oxytocin(催產素), TRH, insulin(胰島素) , somatotropin(生長激素), prolactin, FSH, LH, TSH
Steroid Hormones hormone • Most diffuse across the plasma membrane and bind to a receptor • Hormone-receptor complex acts in nucleus to inhibit or enhance transcription receptor hormone-receptor complex gene product
Protein Hormone • Hormone binds to a receptor at cell surface • Binding triggers a change in activity of enzymes inside the cell glucagon receptor ATP cyclic AMP + Pi c. AMP activates protein kinase A Protein kinase A converts phosphorylase kinase to active form and inhibits an enzyme required for glucagon synthesis.
The Hypothalamus下視丘 hypothalamus • Region in the forebrain (前腦) • Contains hormone -secreting cells • Interacts with pituitary (腦下腺) pituitary gland
Pituitary Gland (腦下垂腺體) • Pea-size(豌豆大小) gland at base of hypothalamus • Two lobes (兩葉) – Posterior lobe後葉 stores and secretes hormones that were synthesized in the hypothalamus(下視丘) – Anterior lobe前葉 produces and secretes its own hormones
Posterior Lobe • Antidiuretic hormone (ADH ) 抗利尿激素 cell body in hypothalmus axons • Oxytocin (OCT)催產素 to the general circulation
Abnormal Somatotropin (生長激素) (STH) Output • Gigantism(巨大症)results from overproduction of STH during childhood • Pituitary dwarfism(侏儒症)results from underproduction of STH during childhood • Acromegaly (肢端肥大症) results from overproduction of STH during adulthood
Feedback Mechanisms • Negative feedback 負回饋 – An increase in concentration of a hormone triggers activities that inhibit (抑制) further secretion • Positive feedback 正回饋 – An increase in concentration of a hormone triggers activities that stimulate (促進) further secretion
Feedback Control of Ovaries (卵巢) • Pituitary (腦下垂腺體) produces hormones (LH促濾泡, FSH促黃體素) that stimulate egg maturation (濾泡成熟) and ovulation(排卵) in the ovary • They also stimulate ovary to produce progesterone(黃體素) and estrogen(雌性激素) • After ovulation, rising levels of these hormones inhibit further secretion of LH and FSH
Diabetes Mellitus 糖尿病 • Disease in which excess glucose accumulates in blood, then urine • Effects include – Excessive urination 頻尿 – Constant thirst 易渴 – Weight loss 體重下降 – Ketone 丙酮 formation and acid-base imbalances 不平衡
Two Types of Diabetes • Type 1 青年型 • Autoimmune disease • Usually appears in childhood • Treated with insulin injections • Type 2 老年型 • Target cells don’t respond • Usually appears in adults • Treated with diet, drugs
隨機破壞(stochastic或random damage) 基因預設(genetic program)
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