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Unformatted text preview: Biology Study Guide Chapter 32 32.1- Intro to vertebrate endocrine system Cells respond to changing conditions by taking up and releasing various chemical substances 1 cell type signals other types in response to cues from internal and external stimuli Signals influence: o Metabolic activity o Gene expression o Growth development o Reproduction Signaling molecules used in communication are: o Neurotransmitters o Local signaling molecules o Pheromones target= any cell that has receptors for the signaling molecule and can change an activity in response to it May or may not be next to the cell that sends a signal Animal hormones= cell products secreted from: Endocrine glands Endocrine cells Few neurons Neurotransmitters= secreted by neurons into the synaptic cleft between a neuron and a target cell Local signaling molecules= secreted by many cell types into extracellular fluid Broken down quickly Persist only long enough to affect the nearby tissue o Ex: damaged tissue secretes prostaglandins that affect smooth muscle in walls of adjacent blood vessels Pheromones= signals diffused through water into the air to target cells in other individual of the same species Help integrate social behavior o Ex: female secretes sex pheromone to attract mate; many vertebrates have vomersonal organ in nose to respond to pheromones Physiologists Bayliss and Starling What triggers the secretion of pancreatic juices when food travels through a dogs gut? o Blocked the nerves but not the blood vessels to the small intestine o Pancreas still responded o Responded to extracts of cell in intestinal lining o Lining is a type of glandular epithelium o Substance called secretin Starling coined term hormone Major sources of human hormones: Hypothalamus- part of brain o Secretes 6 releasing and inhibiting hormones(anterior lobe) ACTH TSH FSH LH Prolactin Growth Hormone o Produces (Posterior lobe): ADH- conserves water Oxytocin- roles in childbirth, milk secretion Adrenal Gland one pair o Cortex Cortisol- glucose metabolism Aldosterone- conserves sodium o Medulla Epinephrine Norepinephrine Both interact with sympathetic nervous system to help adjust organ activities Ovaries- one pair of female gonads o Estrogen o Progesterone Testes- one pair of male gonads o Testosterone Pineal Gland o Melatonin- biological clock; activity level; reproductive cycle Parathyroid Glands- four o Parathyroid hormone- increases blood level of calcium Thymus Gland o Thymosins- white blood cell functioning Pancreatic Islets o Insulin-lowers blood glucose level o Glucagon- raises blood level of glucose Endocrine system= all sources of hormones in the animal body Linked structurally and functionally with the nervous system in intercellular communication 32.2- Nature of hormone action Cell communication 1) Signal activates a target cell receptor...
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