Hormones and Nerves Life Science 2010 鄭先祐 (Ayo)

Hormones and Nerves2 Hormone and Pheromone A hormone ( 荷爾蒙 ) is a chemical that is produced in one part of the body and carried by the blood to another part of the body, where it influences some process. Hormones are produced by endocrine ( 內分泌 ) glands( 腺體 ). A pheromone ( 費洛蒙 ) behaves much as a hormones does, except it is released by one organism and acts on another organism.

Hormones and Nerves3 Invertebrate Hormones (a) development in a beetle. (b) An experiment showing the importance of hormones in insect development. Growth hormones produced in the head.

Hormones and Nerves4 Human Hormones The pituitary( 腦下垂體 ) is called the "master gland". But it influences are regulated by a part of the brain called the hypothalamus( 下視丘 ). Pituitary is composed of two major parts, the anterior and posterior lobes, with a central midlobe area. The pituitary is only about the size of a bean, but its size belies its physiological complexity.

Hormones and Nerves5 Anterior lobe of pituitary ： –thyroid-stimulating hormone (TSH)( 甲狀腺刺激素 ) –Follicle-stimulating hormone (FSH)( 卵泡刺激素 ) –Luteinizing hormone (LH) ( 黃體化激素 ) –Growth hormone (GH, somatotropin) ( 成長激素 ) –Adrenocorticotropic hormone(ACTH) ( 腎上腺皮質刺激素 ) –Prolactin ( 催乳素 ) Midlobe of pituitary ： –Melanocyte-stimulating hormone ( 黑色素刺激素 ) Posterior lobe of pituitary ： –Oxytocin ( 催產素 ) ，子宮收縮、乳腺分泌乳汁 –ADH (vasopressin) ( 抗利尿素 ) 參閱 Table 21.1

Hormones and Nerves6 Fig The major endocrine glands in the human. Thyroid (thyroxine) Parathyroid Testes (testosterone) Ovary (estrogens) Adrenal medulla Adrenal cortex Pancreas (Insulin) Heart (ANF)

Hormones and Nerves7 Fig (a) Sudden increases in the production of growth hormone after maturity produce growth in only certain body parts, such as those of the face and hands. (acromegaly) (b) giantism and dwarfism (a) (b)

Hormones and Nerves8 Thyroid –Throxine -- increases metabolism –calcitonin -- inhibits the release of calcium from bone. Parathyroid ( 副甲狀腺 ) –parathyroid hormone -- stimulates calcium release from bone. Testes –testosterone -- stimulates production of sperm and secondary sex characteristics. Ovary –estrogens ( 動情素 ) -- stimulates female secondary sex characteristics, prepares uterine lining for pregnancy. –Progesterone ( 黃體酮 ) -- prepares and maintains uterine lining for pregnancy. 參閱 Table 21.1

Hormones and Nerves9 Adrenal medulla –epinephrine(adrenaline) ( 腎上腺素 ) 和 norepinephrine ( 新腎上腺素 ) -- augment actions of sympathetic nervous system. 刺激戰備反應，升高 血醣量。 Adrenal cortex –cortisol, cortisone ( 皮質醇 ) -- controls carbohydrate metabolism, raises blood glucose level; reduces inflammation. –Aldosterone ( 醛固酮 ) -- controls salt and water balance, promotes sodium reabsorption 參閱 Table 21.1

Hormones and Nerves10 Pancreas –Glucagon ( 升醣素 )-- stimulates breakdown of glycogen into glucose, elevates blood sugar level. –Insulin ( 胰島素 ) -- lowers blood sugar level, increases formation and storage of glycogen. Heart –Atrial natriuretic factor ( 心臟利尿激素 )-- regulates blood pressure through the excretion of sodium and water. Pineal gland ( 松果腺 ) Thymus Gland ( 胸腺 ) 參閱 Table 21.1

Hormones and Nerves11 Essay 21.1 Hormones and test-taking The level of sex hormones in the blood of women can affect their reasoning, coordination, and verbal ability. When estrogen is high, women increased their scores by about 10%.

Hormones and Nerves12 How hormones work Second Messenger systems (peptide hormones) –hormone itself is called the first messenger. –The hormone attaches to a receptor on the specific site of the target cell membrane. –Then cause ATP to give up two phosphates and to form a molecule called cyclic AMP (second messenger) Direct gene-activation systems (steroid hormones)

Hormones and Nerves13 Fig How a peptide hormone works. The first messenger attaches to a receptor on the target cell, which causes ATP to form cAMP. cAMP becomes the second messenger and triggers a biochemical cascade.

Hormones and Nerves14 Fig How a steroid hormone works. A steroid hormone enters the cell, joins with a receptor, enters the nucleus, and binds to the chromosome activating mRNA transcription.

Hormones and Nerves15 Essay 21.2 Prostaglandins, endorphins, and runner's high Prostaglandins (first found in the prostate gland) is comprised of about 16 different molecules. –One kind dilates the blood vessel and respiratory tubules. –Another functions in regulating the menstrual cycle and in stimulating uterine contractions during childbirth. –Another brings on fever in response to infection. –Prostaglandins are also associated with pain. Aspirin can reduce pain and fever, apparently by modifying prostaglandins and decreasing their effectiveness.

Hormones and Nerves16 endorphins and runner's high Enkephalins and endorphins produced in the brain can kill pain. Long distance running may trigger these opiate relatives producing the fabled response call " runner's high".

Hormones and Nerves17 Fig TSH and thyroxine feedback The anterior pituitary secretes TSH, which causes the thyroid gland to secrete thyroxine. Rising levels of thyroxine suppress the secretion of TSH until the decreased levels of thyroxine that result trigger the release of more TSH.

Hormones and Nerves18 Essay 21.3 Human pheromones In 1970, psychologist found that women living together in a college dormitory tended to menstrually cycle together. They swabbed ( 塗抹 ) underarm secretions from men on the upper lip of women with unusually long or unusually short menstrual cycles. Within three months all the women were cycling at about 29 days. Male essence contains something that promotes reproductive health in women.

Hormones and Nerves19 Female pheromones Placed underarm sweat from women under the noses of ten women with normal cycles. After three months they were all cycling roughly in unison with the women who donated the sweat. Essay 21.3

Hormones and Nerves20 The relationship of hormones and nerves 1. They are structurally related. A number of endocrine glands are formed from nervous tissue. 2. The two systems are functionally related. 3. The two systems are chemically related. A number of chemicals are used to send messages between nerve cells and to act as hormones. ( 譬如： epinephrine)

Hormones and Nerves21 Nerves A neuron ( 神經元 ) is simply a nerve cell. Neurons come in a variety of sizes and shapes and there are billions of them in the human body. A neuron is composed of a cell body, dendrites, and the axon. The cell body contains the nucleus of the cell and most of its cytoplasm.

Hormones and Nerves22 Fig (a) sensory neuron. dendrites axon Myelin sheath cell body dendrites

Hormones and Nerves23 Fig (b) an interneuron. Axon cell body dendrites

Hormones and Nerves24 Fig (c) a motor neuron Axonal tips of endings axon (with myelin sheath) cell body dendrites

Hormones and Nerves25 Fig The myelin sheath and fast conduction. Saltatory propagation

Hormones and Nerves26 The mechanism of the impulse Instead of being like a current of electricity in a copper wire, the nerve impulse is more like a line of falling dominoes ( 骨牌 ). Each domino triggers the fall of the next, but once triggered, each domino falls with the same energy. And just as dominoes must be set back up before they can repeat their performance, so must the potential energy of a neuron be restored before it can be fired again.

Hormones and Nerves27 Resting potential The electrical potential, the difference between the net electrical charges of the cell's interior and its surroundings is called the cell's resting potential. Typically, this potential difference is about -70 millivolts. The potential is established and maintained by the permeability of the membrane and the cell's sodium-potassium pump. (sodium out potassium in)

Hormones and Nerves28 Sodium-potassium pump The membrane is not very permeable to sodium ions, but it lets potassium ions through relatively easily. Therefore, the positively charged potassium ions accumulate inside, attracted by the negatively charged proteins within. Any sodium ions that leak inside are pumped right back out by the sodium-potassium pump.

Hormones and Nerves29 Fig the resting potential

Hormones and Nerves30 Fig The action potential (AP) occurs as a wave of depolarization and repolarization sweeps along the axon.

Hormones and Nerves31 Fig Synaptic transmission.

Hormones and Nerves32 Fig Synaptic transmission.

Hormones and Nerves33 Essay 21.4 Why do fools fall in love Who are in love……. Comes that giddy( 昏眩 ) rush that may be accompanied by trembling( 戰慄 ), flushed skin, and heavy breathing. It's that reaction early in a relationship when just a whisper, or the scent of a rose, can cause the heart to swell with dizzying love.

Hormones and Nerves34 隨時間而逐漸消逝 …….. Some of those chemicals flooding the body at the first blush of love are chemically related to amphetamines ( 安非他命 ). They include the neurotransmitters dopamine, norepinephrine, and phenyl-ethylamine(PEA). As the months go by, it takes more and more to reach the same euphoria ( 幸福感 ). After two or three years, the effect wears off entirely.

Hormones and Nerves35 Mature love The first crazy kind of love may, by then, have been replaced by a quieter, more devoted more "mature" love. The chemical flooding the body at each hug is an endorphin, a naturally produced morphine( 嗎啡 )- like substance that promotes feelings of peace, calm, and security. At nuzzling( 緊貼 ) and cuddling( 擁抱 ), Oxytocin is also produced. It may enhance orgasms as it floods the body during lovemaking.

Hormones and Nerves36 Fig Excitement and inhibition among neurons

Hormones and Nerves37 Fig Excitement and inhibition among neurons

Hormones and Nerves38 Fig Short-lived insecticides such as malathion have largely replaced the use of DDT in the United States.

Hormones and Nerves39 Malathion ( 馬拉松 ) However, malathion, in large amounts, can block the effects of acetylcholinesterase. It destroys the enzymes that break down neurotransmitters, causing impulses to fire wildly and indiscriminately and bringing on convulsions ( 痙攣 ) and possibly death.

Hormones and Nerves40 An ethical concern ： DHEA A chemical called DHEA is the most plentiful steroid hormone in the body. DHEA stops, or reverses, many of the effects of aging. Mice taking the hormone live 30 percent longer and keep a more youthful appearance longer. Many older people who take DHEA report the vitality of much younger people. It is currently available in some form in health food stores, but the Drug Enforcement Administration is considering regulating its sale, although few side effects have been found.

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