Chapter 26 - BIOL1320
Chapter 26 - BIOL1320 BIOL 1320
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This 5 page Class Notes was uploaded by Ailia Owen on Thursday February 5, 2015. The Class Notes belongs to BIOL 1320 at University of Houston taught by Brian C Mahon in Spring2015. Since its upload, it has received 223 views. For similar materials see General Biology in Natural Sciences and Mathematics at University of Houston.
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Date Created: 02/05/15
Hormones and the Endocrine System 2515 306 PM THE NATURE OF CHEMICAL REGULATION chemical and electrical signals coordinate body functions through Endocrine group of interacting glands throughout the body that produce and secrete hormones that maintain body functions and activities lasts longer 0 Components Hormones chemical signals a 2 different chemical properties 0 Watersoluble most do not have to enter cell 0 Proteins Short polypeptides Single amino acids modified versions 0 cannot pass through phospholipid bilayer of plasma membrane Lipidsoluble enters cell 0 Steroids small molecules made from cholesterol 0 Can pass through phospholipid bilayer Endocrine glands make and secrete hormones Endocrine cells release hormones into blood vessels n Secretory Vesicle Target cells hormones only affect cells that have receptors for a specific hormone o Signaling Reception hormone binds to a specific receptor protein on or in target cell a WSH Receptor protein at plasma membrane of target cell a LSH Receptor protein inside cell Signal Transduction converts signal from one form to another a WSH relay molecule carries it through the cell Response change in the cell s behavior a WSH Cytoplasmic response or gene regulation Nervous system communicates regulates and uses electrical signals by neurons reacts faster 0 Stimulus originates in cell body of neuron o Nerve impulse travels along axons 0 Response limited to cells that connect by specialized junctions to an axon transmitting an impulse 0 Organ system have to communicate with each other to Maintain homeostasis Carry out coordinated functions SCIENTIFIC THINKING Endocrine disruptors mimic estrogen LSH o Atrazine weed killers o BPS food and beverage containers 0 Controlled experiment 0 Exposed growing male frogs to low levels of atrazine for 3 years Equal number of controlled and exposed male frogs were put into a space with female frogs Mating contest between controlled and exposed male frogs n Recorded male frog s ability to hold female with its front arms during mating amplexus Demasculating results from atrazine 0 Reduced mating behavior 0 Testosterone deficiencies 0 Some sex reversal THE VERTEBRATE ENDOCRINE SYSTEM 12 major glands Some glands secrete hormones to blood thyroid Some glands have endocrine and nonendocrine functions pancreas Other organs are nonendocrine but secrete some hormones heart and liver Penal gland pea sized near center of brain 0 Melatonin helps regulate biological rhythms in connection with environment light conditions sleep cycle Hypothalamus main control center o Receives input from nerves about the internal conditions of the body and external environment Responds by sending nervous or endocrine signal 0 Directly controls pituitary gland Pituitary gland base of brain 0 00000 TSH gt Thyroid ACTH gt Adrenal cortex FSH and LH gt Testes or ovaries Prolactin PRL gt Mammary glands Growth hormone CH gt entire body Anterior neurosecretory cells secrete 2 kinds of hormones into short blood vessels that connect to PP Releasing hormones stimulate AP to secrete 1 specific hormones Inhibiting hormones induce AP to stop secretion of 1 specific hormones Posterior set of neurosecretory cells extends from the hypothalamus into the PP Oxytocin stimulates mammary gland cells contraction of uterus and promotes mating and maternal bonds n Levels rise when mothers look into eyes of their babies dogs stare into owners eyes Antidiuretic hormone ADH promotes retention of water by kidneys Thyroid gland Thyroid hormone affects metabolic processes Calcitonin lowers blood calcium Parathyroid gland Parathyroid hormone raises blood calcium Adrenal glands atop kidneys o Adrenal medulla Epinephrine and Norepinephrine raise blood glucose increase metabolic activities and constrict some blood vessels 0 Adrenal cortex Glucocorticoids raise blood glucose Mineralocorticoids promote reabsorption of sodium Na and excrete potassium K in kidneys Pancreas dual functions 0 Secretes digestive enzymes to small intestines o Maintains homeostatic set pointquot of glucose level 0 Antagonistic hormones effects of one oppose effects of the other 2 negative feedbacks o Insulin lowers blood glucose Stimulus breakfast gt BCL rise stimulating pancreas gt Beta cells release insulin gt Insulin stimulates all cells to take up glucose gt Liver and muscle cells use glucose to form glycogen stores gt BCL decreases beta cells stop gt set pointquot achieved Diabetes mellitus inability to produce andor use insulin n Hypoglycemia decreased glucose absorption from blood raises BCL n Muscle or fat cells take up glucose to lower BCL a Type 1 insulindependent autoimmune disease destruction of insulinproducing cells 0 Treatment multiple human insulin engineered injections daily a Type 2 noninsulin dependent reduced response to insulin from being overweightunderactive 90 n Gestational diabetes can affect pregnant women and can lead to dangerously large babiescomplicated delivery 0 Glucagon raises blood glucose Stimulus skipped lunch gt BCL lowers stimulating pancreas gt Alpha cells release glucogen gt Liver cells break down glycogen stores return glucose to blood gt BCL increases alpha cells stop gt set pointquot achieved Testes males Androgens support sperm formation and promote development of male secondary sex characteristics Ovaries females Estrogen stimulate uterine lining growth and promote development of female secondary sex characteristics Progestines promote uterine lining growth What stimulates an endocrine gland to produce a hormone Stimulus 3 types 0 Change in levels of certain ions and nutrients o Stimulated directly by nervous system 0 Hormones Effects 0 Regulating ion and nutrient levels water balance and metabolism 0 Controlling reproduction development and growth 0 Initiating responses to stress and the environment HORMONES AND HOMEOSTASIS Gonads sex glands 0 Secret sex hormones Estrogens Progestins progesterone prepare uterus for embryo Androgens testosterone o Gametes ova and sperm 0 Steroid sex hormones o Affect growth and development 0 Regulates reproductive cycles and sexual behavior 0 Synthesis of sex hormones o Regulated by hypothalamus and pituitary Hypothalamus gt releasing hormone gt Anterior pituitary gt FSH and LH gt Gonads gt sex hormones
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