BIOL 2002C 1st Edition Lecture 1 Outline of Last Lecture I Continuation of Chapter 15 Special Senses Outline of Current Lecture I Chapter 17 Functional Organization of the Endocrine System Current Lecture Chapter 17 Functional Organization of the Endocrine System 1 Describe the 4 classes of chemical messengers based on source and mode of transport and name an example each Table 17 1 a Autocrine chemical messenger is secreted by the same cell on which the receptor is on Ex Thromboxane which are helpful in clotting Prostaglandins and Leukotriene b Paracrine chemical messengers secreted by cells are received by nearby cells Ex Histamines aid in digestion in the stomach Somatostatin opposite effects of growth hormone c Endocrine affect distant cells Ex Hormones d Neurotransmitter produced by neurons Ex Norepinephrine and Epinephrine 2 Define hormone and target tissue Hormone a chemical messenger secreted by endocrine cells that travels through the blood stream and has its effect on a distant organ or tissue Target tissue where the hormone has its effect has receptors on membrane or inside the cell 3 Distinguish between endocrine and exocrine glands Endocrine secrete hormones into the bloodstream Exocrine secrete substances through ducts into other organs These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute 4 Compare and contrast the Nervous System to the Endocrine System Fig 17 2 Similarities 1 Both systems associated with the brain hypothalamus and epithalamus 2 May use same chemical messengers as neurotransmitter and hormone Ex Epinephrine 3 Two systems are cooperative Nervous system secretes neurohormones into circulatory system Some parts of endocrine system are innervated directly by nervous system Differences 1 Mode of transport Nervous axon Endocrine blood 2 Speed of response nervous instant milliseconds endocrine delayed seconds 3 Duration of response Nervous milliseconds seconds Endocrine minutes days 5 List the 3 general characteristics of hormones a stability depends on the half life b communication binding to receptors within cell or on the outside of cell c distribution determines where it goes in the body only one organ narrow distribution affect any cell organ broad distribution 6 Distinguish between bound hormones and free hormones Bound hormones lipid soluble bind to globulin protein long half life effects last longer Free hormone water soluble short half life membrane bound receptor 7 List and describe the 2 chemical categories of hormones Fig 17 3 a Lipid soluble needs to be bound to proteins to travel in blood stream can diffuse into cell examples are steroids testosterone progesterone estrogen and aldosterone b Water soluble free to travel in blood stream need receptor to enter cell made from amino acids polypeptides 8 Illustrate the 3 main patterns of hormone secretion Fig 17 4 a chronic relatively constant lipid soluble ex Thyroid b acute dramatically and irregular changes water soluble ex Adrenaline insulin epinephrine c episodic fairly regular intervals concentrations lipid soluble mostly ex Melatonin and hormones released during the menstrual cycle LSH FSH Progesterone Estrogen 9 List and describe the 3 stimulatory influences on hormone secretion and give an example for each a Fig 17 5 Humoral bodily fluids activate the hormone secretions ex Calcium ions in the blood affect the secretion levels of Parathyroid Hormone PTH b Fig 17 6 Neural neurotransmitter stimulate release of hormones ex Adrenal gland secreting norepinephrine c Fig 17 7 Hormonal hormone secretion stimulate the secretion of other hormones ex Tropic hormones from the anterior pituitary ACTH which acts on the adrenal cortex 10 List and describe the 3 inhibitory influences on hormone secretion and give an example for each a Humoral ex Blood pressure b Neural ex Hormones from Hypothalamus c Hormonal ex Thyroid hormone 11 Describe the 2 mechanisms by which hormone levels in the blood are regulated Fig 17 8 a Positive feedback b Negative feedback 12 Briefly explain how a change of the receptors in the target cell influences the response of that cell to a hormone Down regulation decrease in the number of receptor decrease its ability to respond endocytosis takes receptors into the cell and breaks them down Up regulation increase the number of receptors hormone increasing its ability to respond more receptors made within the cell and incorporated into the cell