1. 1 EggLarvaPupaAdult CHAPTER 45 CHEMICAL SIGNALS IN ANIMALS

2. 2 Introduction Endocrine system الجهاز الهرموني is one of the main internal communication وسائل الاتصال الداخلي systems.Endocrine system الجهاز الهرموني is one of the main internal communication وسائل الاتصال الداخلي systems. The animal hormone-secreting cells الخلايا المفرزة للهرمونات constitute the endocrine system.The animal hormone-secreting cells الخلايا المفرزة للهرمونات constitute the endocrine system. Hormone secreting organs are called Endocrine Glands (ductless glands الغدد الصماء ).Hormone secreting organs are called Endocrine Glands (ductless glands الغدد الصماء ). Hormone is a chemical signal اشارة كيميائية secreted into blood stream يتم افرازها الى تيار الدم and regulates communicating messages تنظم وسائل الاتصال within the body.Hormone is a chemical signal اشارة كيميائية secreted into blood stream يتم افرازها الى تيار الدم and regulates communicating messages تنظم وسائل الاتصال within the body. Target cell الخلية المستهدفة is the site of action of the hormone موقع العملTarget cell الخلية المستهدفة is the site of action of the hormone موقع العمل Types of hormones areTypes of hormones are Polypeptide Hormones Polypeptide Hormones Amino acid derivatives Hormones Amino acid derivatives Hormones Steroid Hormones Steroid Hormones Tropic hormones: Tropic hormones: الهرمونات المحفزة ( المنبهة ) target other endocrine glands

3. 3 Most chemical signals bind to plasma-membrane proteins, initiating signal-transduction pathways. Fig. 45.3a, Page 959 Mechanism of chemical signaling: The chemical signals secreted by a cell either: I ): Protein hormones : Bind to a receptor protein بروتين مستقبل on the surface of the target cell. Bind to a receptor protein بروتين مستقبل on the surface of the target cell.

4. 4 II ) Steroid hormones: Penetrate تخترق the cell and bind to a receptor protein inside the target cell Fig. 45.3b, Page 959 Estrogen, progesterone, vitamin D.Estrogen, progesterone, vitamin D.

5. 5  Tropic hormones ( الهرمون المنبه للغدد ) ( الهرمون المنبه للغدد )  T arget other endocrine glands. Human has 9 endocrine glands.Human has 9 endocrine glands. The Vertebrate Endocrine System Fig. 45.5, Page 960 الصنوبرية النخامية الدرقية الكظرية

6. 6 The hypothalamus integrates endocrine and nervous function.The hypothalamus integrates endocrine and nervous function. –Neurosecretory cells of the hypothalamus produce hormones. a)Releasing hormones stimulate the anterior pituitary to secrete hormones. b)Inhibiting hormones prevent the anterior pituitary from secreting hormones. The hypothalamus and pituitary integrate many functions of the vertebrate endocrine system 1)- Pituitary gland: secrets 9 hormonesthe anterior part and 2 hormones by the posterior part). 1)- Pituitary gland: secrets 9 hormones ( 7 hormones by the anterior part and 2 hormones by the posterior part).

7. 7 A)- Anterior pituitary hormones. 1)Growth hormone (GH): a protein. Stimulates growth and metabolism.Stimulates growth and metabolism. Gigantism: العملقة excessive GH during development.Gigantism: العملقة excessive GH during development. Acromegaly تضخم الاطراف : excessive GH production during adulthood.Acromegaly تضخم الاطراف : excessive GH production during adulthood. dwarfism القزمية : childhood GH deficiency.dwarfism القزمية : childhood GH deficiency. 2)Prolactin (PRL): a protein. Stimulates milk production انتاج اللبن and secretion from mammary gland الغدد اللبنية.Stimulates milk production انتاج اللبن and secretion from mammary gland الغدد اللبنية. 3)Gonadotropins (Gonotropic محفز للمناسل ): glyocoproteins. Follicle-stimulating hormone (FSH).Follicle-stimulating hormone (FSH). –Stimulates production of sperms and ova. Luteinizing hormone (LH) المُحفز لتكوين الجسم الأصفر.Luteinizing hormone (LH) المُحفز لتكوين الجسم الأصفر. –Stimulates ovaries and testes.

8. 8 4)Thyroid-stimulating hormone (TSH): a glycoprotein. Stimulates thyroid gland.Stimulates thyroid gland. 5)Adrenocorticotropic hormone (ACTH): a peptide Stimulates adrenal cortex secretion of glucocorticoidsStimulates adrenal cortex secretion of glucocorticoids 6)Melanocyte-stimulating hormone (MSH) الهرمون المحفز : a peptide. May play a role in fat metabolism.May play a role in fat metabolism. 7)Endorphins: peptides. Inhibit pain perception.Inhibit pain perception. Effects mimicked by heroin and other opiate drugs.Effects mimicked by heroin and other opiate drugs.

9. 9 Fig. 45.6b, Page 963 The anterior pituitary gland hormones Also called gonadotropine hormones هرمونات المناسل Adrenocorticotropic Melanocyte- stimulating H.

10. 10 B)- Posterior pituitary hormones هرمونات الفص الخلفي للغدة النخامية. –Oxytocin: a peptide. Stimulates contraction of the uterus and mammary glands.Stimulates contraction of the uterus and mammary glands. –Antidiuretic hormone (ADH): مُضاد لإدرار البول a peptide. Promotes retention of water الحفاظ على الماء by the kidneysPromotes retention of water الحفاظ على الماء by the kidneys High level decreases urination يقلل التبول and vice versa.High level decreases urination يقلل التبول and vice versa. Secretion regulated by water/salt balance. الاتزان بين الماء والاملاح في الجسمSecretion regulated by water/salt balance. الاتزان بين الماء والاملاح في الجسم 2- Pineal gland: الغدة الصنوبرية is a small mass قطعة صغيرة of tissue near the center of the brain and involved in biorhythms تنظيم النمط الحيوي. –The pineal gland secretes the hormone, melatonin. Involved in biological rhythms associated with reproduction.Involved in biological rhythms associated with reproduction. Secretion regulated by light/dark cycles.Secretion regulated by light/dark cycles.

11. 11  Posterior pituitary  Posterior pituitary stores and secretes hormones produced by the hypothalamus. Fig. 45.6a, Page 963 Antidiuretic H