Systems in the Body. Arnold Berthold. Chapter 5

Transcription

1 Chapter 5 Majority of illustra3ons in this presenta3on are from Biological Psychology 4th edi3on ( Sinuer Publica3ons) Systems in the Body 1. Two systems in the body, the nervous system and the endocrine system regulate behavior. 2. Aristotle ( BC) observed changes in behaviors of men and birds when castrated. A whole branch of Greek medicine was focused on bodily fluids (humors) affec3ng behavior and temperaments. Fluid Temperament Character Yellow bile Choleric Irritable Black bile Melancholic Depressed Blood Sanguine Op3mis3c Phlegm Phlegma3c Sluggish 2 Arnold Berthold Berthold no3ced that if male chicks were castrated early in development they loose their sexual drive and secondary sexual characteris3cs. Comb Wattle

2 Berthold s Experiment 4 Testes Replaced Group 1. When testes were replaced in the abdominal cavity they established blood supply (not nerves) and the rooster develops normal sexual behavior and secondary sexual characteris3cs. 2. So there had to be some chemicals that lead to such changes. Indeed testes secrete testosterone hormone! 5 Hormones from Greek, to excite are chemical messengers in the bloodstream released by endocrine glands. Hormones & Glands 6 2

3 Body s Internal Environment 1. Bernard proposed that our internal environment independently regulates itself in the ever changing external environment. 2. Based on Bernard s ideas Cannon proposed the concept of homeostasis which is maintaining a constant internal environment by an array of mechanisms in the body including the endocrine system. (Bernard; ) Canon; Types of Communica6on Synap3c Communica3on Synap3c communica3on or neurocrine func3on is chemical communica3on between neurons at the synap3c clea or neurons releasing chemical onto blood vessels. 9 3

4 Autocrine Communica3on Autocrine Communica3on involves chemical ac3vity that regulates cell s own func3ons. Nega3ve feedback effect of NT on autocrine receptors in neurons to control NT release. 10 Paracrine Communica3on Paracrine Communica3on involves regula3ng chemicals that affect distant target cells. 11 Endocrine Communica3on Endocrine Communica3on involves chemicals that travel via blood (vessels) to effect/regulate distant target 3ssue. 12 4

5 Pheromone Communica3on Pheromone Communica3on involves chemicals that travel outside the body of an animal to affect the behavior of another animal of the same specie. 13 Allomone Communica3on Pitcher plant releasing chemicals to entice insects. Allomone Communica3on involves chemicals that travel outside the body of an animal/plant to affect the behavior of another animal specie. 14 Hormonal- Neural Communica3on Differences Neural Works like telephone system. Communicates messages through fixed anatomical connec3ons to specific cells/targets. Rapid message on the order of milliseconds. Digi3zed messages (all- or- none) Hormonal Works like television system. Communicates messages through blood vessels affec3ng many cells at the same 3me. Slower messages, on the order of seconds or minutes. Analog messages (graded) 15 5

6 Hormonal- Neural Communica3on Differences Neural Neurotransmifers (chemicals) travel short distances across neurons. Hormonal Hormones (chemical) travel large distances to affect target cells. Voluntary control of messages sent to target cells or 3ssues. There are excep3ons. Heart rate cannot change with voluntary command. Vagus nerve. No voluntary control on messages sent to target cells or 3ssue. There are excep3ons. Milk let down from breast through oxytocin. 16 Hormonal- Neural Communica3on Similari3es Neural Neurotransmifers (chemicals) are synthesized, stored and released. Hormonal Hormones (chemical) are also synthesized, stored and released. Mechanism for neurotransmifer release is based on s3mula3on. Mechanism for hormonal release is also based on s3mula3on Variety of neurotransmifers exist in nerve cells. Variety of hormones exist in endocrine glands. 17 Hormonal- Neural Communica3on Similari3es Neural Neurotransmifers react with receptors on the postsynap3c membrane of the nerve cells. Epinephrine Norepinephrine Hormonal Hormones also react with receptors on the membranes of target cells. Epinephrine Norepinephrine 18 6

7 Kinds of Hormones Protein Hormones: Hormones composed with many amino acids, e.g., Adrenocor3cotropic hormone (ACTH) 19 Protein Hormones 20 Kinds of Hormones Amine Hormones: Hormones composed with a single amino acid, e.g. Thyroxine hormone 21 7

8 Steroid Hormones: Hormones composed of four interconnected carbon rings, e.g., testosterone 22 Amine & Steroid Hormones 23 Hormone Ac3on Protein hormones have higher mol. wt. (5000 Daltons) can t diffuse through membranes therefore require receptors Steroid hormones have lower mol. wt. (200 Daltons) and are lipid soluble, therefore diffuse through membrane. 24 8

9 Hormones & Glands 1. Pineal 2. Pituitary 3. Thyroids 4. Thymus 5. Adrenals 6. Pancreas 7. Ovaries 8. Testes Master gland. Pea Size (1 cm 3 ) with a weight of 1 gram. 2. Two lobes (anterior and posterior). 3. Connects to the hypothalamus via the pituitary stalk (infundibulum). Pituitary Gland 26 Pituitary Gland 1. Hypothalamic neurons descend from SON and PVN to posterior pituitary and directly pour hormones into the blood stream (neurocrine func3on). 2. Other neurons of the hypothalamus secrete hormones in vessels in the hypothalamus and pass them to the anterior pituitary (neurocrine func3on). 27 9

10 Pituitary Gland 1. Anterior Pituitary Growth Hormone (GH) Adrenocor3cotropic Hormone (ACTH) Thyroid S3mula3ng Hormone (TSH) Follicle S3mula3ng Hormone (FSH) Luteinizing Hormone (LH) Prolac3n (PRL) 2. Posterior Pituitary Oxytocin Vasopressin 28 Anterior Pituitary Anterior Pituitary Growth Hormone (GH) Thyroid S3mula3ng Hormone (TSH) Adrenocor3cotropic Hormone (ACTH) Follicle S3mula3ng Hormone (FSH) Luteinizing Hormone (LH) Prolac3n (PRL) Func3on S3mulates growth S3mulates thyroids affects growth and development S3mulates adrenal cortex in stress response S3mulates egg and sperm produc3on S3mulates egg release and testosterone release in males Promotes lacta3on in females 29 Posterior Pituitary Posterior Pituitary Oxytocin Vasopressin Func3on Reproduc3ve/Parental behavior, uterine contrac3ons Inhibits urine, increases blood pressure 30 10

11 Growth Hormone When the pituitary gland produces excess growth hormone (GH) it results in acromegaly. Thick, coarse, oily skin; skin tags; enlarged lips, nose and tongue; deepening of the voice due to enlarged sinuses and vocal cords; fa3gue and weakness; headaches; impaired vision; abnormali3es of the menstrual cycle; diabetes mellitus hypertension, arthri3s, carpal tunnel syndrome, and increased risk of cardiovascular disease. Acromegaly or pituitary gigan3sm 31 Growth Hormone Dwarfism Growth hormone deficiency involves abnormally short stature with normal body propor3ons. Growth hormone deficiency can be categorized as either congenital (present at birth) or acquired Thyroid S3mula3ng Hormone TSH directly affects thyroid gland and in turn is affected by thyroid hormones in the blood. Increased thyroid hormones in the blood decrease TSH from pituitary and vice versa (nega3ve feedback)

12 Adrenocor3cotropic Hormone Adrenocor3cotropic hormone (ACTH) s3mulates the adrenal cortex. More specifically, it s3mulates secre3on of glucocor3coids such as cor3sol in response to many types of stress. 34 Follicle S3mula3ng & Luteinizing Hormones FSH and LH from pituitary gland lead to maturing of follicles in females, sperm in males. LH affects testes to produce testosterone. 35 Prolac3n Prolac3n from the pituitary is secreted to promote mammary development and produc3on of milk. In ringdoves it promotes crop milk

13 Oxytocin Oxy (rapid) tokos (child birth). Oxytocin causes contrac3ons of the uterus for childbirth. Oxytocin triggers milk letdown reflex. Sucking at the nipple s3mulates skin cells which ac3vate neurons in the hypothalamus, oxytocin from neurons is released and through the blood vessels s3mulates the mammary gland for release of milk. Oxytocin may also contribute to pleasurable feeling during sexual climax, in both men and women. 37 Vasopressin Vasopressin or the an3dure3c hormone (ADH) released from the pituitary directly affects the kidneys to reabsorb water and increase blood pressure by constric3ng blood vessels. hfp://www- unix.oit.umass.edu Thyroxine (T 4 ) and triiodothyroxine (T 3 ) Regulate growth processes and carbohydrate use Deficiency of thyroxine leads to hypothyroidism, Hashimoto s autoimmune disease and cre3nism. Excess leads to hyperthyroidism, Graves autoimmune disease. 2. Calcitonin Calcium deposi3on in bones Thyroid Glands hfp://

14 Hypothyroidism 1. Reduc3on in thyroid hormones (T 3 and T 4 ) results in a condi3on called hypothyroidism. 2. More women (5) than men (1) are affected. 3. Reduced release of thyroid hormones results in elevated TSH, causing thyroids to secrete more thyroid hormone enlarging (goiter) the thyroid. 4. Thyroid hormone therapy is given to alleviate this condi3on. hfp:// Hashimoto s Autoimmune Disease hfp:// A condi3on in which the body's immune system mistakenly iden3fies the thyroid cells as "foreign," and ac3vate immune response by sending "an3bodies" to afack and destroy thyroids; in turn reducing thyroid hormone. 41 Cre3nism hfp:// Deficiency of thyroid hormones during early development result in a condi3on called cre3nism resul3ng in mental retarda3on. hfp://

15 Hyperthyroidism 1. Hyperthyroidism or thyrotoxicosis results from excess quan33es of thyroid hormone in the body, caused by tumors or inflamma3on of the thyroid, or inges3on of thyroid hormone or iodine. 2. In Graves Autoimmune Disease (GAD) the immune system manufactures an3bodies which behave like TSH and s3mulate the thyroid uncontrollably. 43 Adrenal Hormones 1. Adrenal Cortex Glucocor3coids: Carbohydrate metabolism. Glucocor3coids (cor3sol) inhibit inflamma3on, can destroy neurons, and can affect appe3te and muscular ac3vity Mineralocor3coids: Salt balance. Sex steroids: (Androgens) Hair growth. 2. Adrenal Medulla Epinephrine Norepinephrine Medulla Kidney Cortex hfp://um- endocrine- surgery.org 44 Cushing s Syndrome hfp://cnserver0.nkf.med.ualberta.ca Prolonged exposure of the body's 3ssues to high levels of cor3sol. Could be due to pituitary or adrenal tumors. Symptoms include: upper body obesity, rounded face, increased fat around the neck, thinning arms and legs, skin becomes fragile and thin, bruises easily and heals poorly

16 1. Testes Testosterone: Promotes changes in puberty, hair growth, voice change, genital size Androgens: Development, growth and maintenance of sex organs 2. Ovaries Estrogen: Development and growth of female sex organs Proges3n: Implanta3on of ovum and maintenance of pregnancy Gonadal Hormones 46 Androgen Insensi3vity Hormone 1. An X- linked recessive disorder (affec3ng males). The male brain and body remain unresponsive to androgens and are feminized due to maternal estrogens. 2. At puberty the testes do not descend and secondary female sexual characteris3cs appear due to circula3ng estrogens. 3. Individuals are oaen reared as girls and do not discover that they are male un3l they fail to menstruate at puberty. 47 Congenital Adrenal Hyperplasia 1. An autosomal recessive disorder. The adrenal glands are unable to produce sufficient quan33es of cor3sol. ACTH is not inhibited and produced in large amounts 2. The fetus is exposed to excessive amounts of androgens which have a masculinizing effect 3. Affected females display masculinized genitals and behavior. Affected males may show precocious puberty