第二节 细胞通讯与信号传递 cell communication and signal transduction

1. 第二节 细胞通讯与信号传递 • cell communication and • signal transduction

2. CELL COMMUNICATION Cells communicate with one another using chemical signals. These signals are essential to regulation and coordination of cell activities. For a receiving cell, the three stages of signaling are reception, transduction, and response.

3. Overview of cell signaling Overview of cell signaling

4. 现象

5. Sex hormone • ectohormone(5) 外激素ectohormone • 信息素由外分泌腺通过导管离开身体刺激另一个体的靶细胞。

6. 昆虫的信息素 警戒素 性息素或性外激素 雌蛾最大量的分泌可引来100万只雄蛾。 接受器如何？ 触角是接受天线，能感受气味分子发射的红外光谱。 卡达汉的故事

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10. 作用

12. Cell signaling can affect virtually every aspect of cell structure and function: Activation of enzyme activity;  Change in cytoskeletal organization;  Change in ion permeability;  Initiation of DNA synthesis;  Activation or repression of gene expression.

14. Four features of signal-transducing systems

16. 原理

17. 枪响- 交感神经 糖原分解 内质网 葡萄糖 1磷酸 葡萄糖 6磷酸葡萄糖 肾上腺髓质 肾上腺素 肌肉细胞 肝细胞 与G蛋白偶联的膜受体 糖原分解 肌肉细胞 环化腺苷酸增高 1磷酸 葡萄糖 最终活化磷酸化酶 跨膜运输 6磷酸葡萄糖 放大阶式级联 内质网 胞质糖酵解 葡萄糖 ATP 线立体3羧酸循环 过线立体膜 丙酮酸 乳酸

18. Signaling pathways consist of a series of steps • Recognition of the stimulus by a specific plasma membrane receptor. • Transfer of a signal across the plasma membrane. • Transmission of the signal to effector molecules within the cell, which causes a change in cellular activities. • Cessation of the cellular response due to inactivation of the signal molecule. signal magnification

19. The Nervous and Endocrine Systems • The pituitary脑垂体 gland (often called the master gland) is located in a small bony cavity at the base of the brain. A stalk links the pituitary to the hypothalamus, which controls release of pituitary hormones. The pituitary gland has two lobes: the anterior and posterior lobes. The anterior pituitary is glandular.

20. The endocrine system in females and males. Image from Purves et al., Life: The Science of Biology, 4th Edition,

21. The hypothalamus contains neurons that control releases from the anterior pituitary. Seven hypothalamic hormones are released into a portal system connecting the hypothalamus and pituitary, and cause targets in the pituitary to release eight hormones.

22. The location and roles of the hypothalamus and pituitary glands. Images from Purves et al., Life: The Science of Biology, 4th Edition,

26. Growth hormone (GH) is a peptide anterior pituitary hormone essential for growth. GH-releasing hormone stimulates release of GH. GH-inhibiting hormone suppresses the release of GH. The hypothalamus maintains homeostatic levels of GH. Cells under the action of GH increase in size (hypertrophy肥大,过度生长, 过度增大) and number (hyperplasia增生, 数量性肥大). GH also causes

27. increase in bone length and thickness by deposition of cartilage 软骨at the ends of bones. During adolescence, sex hormones cause replacement of cartilage by bone, halting further bone growth even though GH is still present. Too little or too much GH can cause dwarfism or gigantism, respectively.

28. Hypothalamus receptors monitor blood levels of thyroid hormones. Low blood levels of Thyroid-stimulating hormone (TSH)cause the release of TSH-releasing hormone from the hypothalamus, which in turn causes the release of TSH from the anterior pituitary.

29. TSH travels to the thyroid where it promotes production of thyroid hormones, which in turn regulate metabolic rates and body temperatures.

30. Hypothalamus release TSH (Thyroid-stimulating hormone )-releasing hormone • TSH-releasing hormone causes anterior pituitary release TSH(Thyroid-stimulating hormone ). • TSH thyroid promotes production of thyroid hormones • thyroid hormones metabolic rates and body temperatures.

31. Gonadotropins促性腺激素 and prolactin催乳激素are also secreted by the anterior pituitary. Gonadotropins (which include follicle-stimulating hormone, FSH, and luteinizing促黄体hormone, LH) affect the gonads生殖腺by stimulating gamete formation and production of sex hormones. Prolactin is secreted near the end of pregnancy and prepares the breasts for milk production.

32. The Posterior Pituitary • The posterior pituitary stores and releases hormones into the blood. Antidiuretic 抗利尿剂hormone (ADH)and oxytocinare 催产素produced in the hypothalamus and transported by axons to the posterior pituitary where they are dumped into the blood.

33. ADH controls water balance in the body and blood pressure. Oxytocin 催产素is a small peptide hormone that stimulates uterine contractions during childbirth.

34. Other Endocrine Organs • The Adrenal Glands • Each kidney has an adrenal gland located above it. The adrenal gland is divided into an inner medulla and an outer cortex. The medulla synthesizes amine hormones, the cortex secretes steroid hormones.

35. The adrenal medulla consists of modified neurons that secrete two hormones: epinephrine and norepinephrine. Stimulation of the cortex by the sympathetic nervous system交感神经causes release of hormones into the blood to initiate the "fight or flight" response.

36. The adrenal cortex produces several steroid hormones in three classes: mineralocorticoids盐皮质激素,glucocorticoids糖皮质激素, and sex hormones. Mineralocorticoids maintain electrolyte balance.

37. Glucocorticoids produce a long-term, slow response to stress by raising blood glucose levels through the breakdown of fats and proteins; they also suppress the immune response and inhibit the inflammatory炎性的response.

38. The structure of the kidney as relates to hormones. Image from Purves et al., Life: The Science of Biology, 4th Edition,

39. The thyroid gland is located in the neck. Follicles 滤泡in the thyroid secrete thyroglobulin甲状腺球蛋白 , a storage form of thyroid hormone. • Thyroid stimulating hormone (TSH) from the anterior pituitary causes conversion of thyroglobulin into thyroid hormones T4 and T3. Almost all body cells are targets of thyroid hormones.

40. Thyroid hormone increases the overall metabolic rate, regulates growth and development as well as the onset of sexual maturity. Calcitonin is also secreted by large cells in the thyroid; it plays a role in regulation of calcium.

41. The Pancreas • The pancreas contains exocrine cells that secrete digestive enzymes into the small intestine and clusters of endocrine cells (the pancreatic islets). The islets secrete the hormones insulin and glucagon, 胰高血糖素which regulate blood glucose levels.

42. After a meal, blood glucose levels rise, prompting the release of insulin, which causes cells to take up glucose, and liver and skeletal muscle cells to form the carbohydrate glycogen.

43. As glucose levels in the blood fall, further insulin production is inhibited. Glucagon胰高血糖素 causes the breakdown of glycogen into glucose, which in turn is released into the blood to maintain glucose levels within a homeostatic range.

44. Glucagon胰高血糖素production is stimulated when blood glucose levels fall, and inhibited when they rise.

45. Diabetes results from inadequate levels of insulin. Type I diabetes is characterized by inadequate levels of insulin secretion, often due to a genetic cause. Type II usually develops in adults from both genetic and environmental causes. Loss of response of targets to insulin rather than lack of insulin causes this type of diabetes.

46. Diabetes causes impairment in the functioning of the eyes, circulatory system, nervous system, and failure of the kidneys. Diabetes is the second leading cause of blindness in the US. Treatments involve daily injections of insulin, monitoring of blood glucose levels and a controlled diet.

47. Other Chemical Messengers • Interferons are proteins released when a cell has been attacked by a virus . They cause neighboring cells to produce antiviral proteins. Once activated, these proteins destroy the virus.

48. Prostaglandins前列腺素 are fatty acids that behave in many ways like hormones. They are produced by most cells in the body and act on neighboring cells.

49. Pheromones 信息素,外激素are chemical signals that travel between organisms rather than between cells within an organism. Pheromones are used to mark territory, signal prospective mates, and communicate. The presence of a human sex attractant/pheromone has not been established conclusively.

50. Biological Cycles • Biological cycles ranging from minutes to years occur throughout the animal kingdom. Cycles involve hibernation冬眠 • , mating behavior, body temperature and many other physiological processes.