| A | B |
|---|
| circadian rhythms | cyclic pattern of physiology activity based on 24 hours |
| synergistic | two hormones working together to produce an action |
| antagonistic | action of one hormone inhibits another hormone |
| permissive | one horomone increases the responsiveness of the target organ to another hormone |
| receptor proteins | molecules on the outside of cells that accept the hormone; on target cells |
| hormone | molecule secreted into the bloodstream that influence cells and tissue to respond |
| steroids | hormones made from cholesterol; lipophilic hormones that can easily get into the cell; interact with transcription factors |
| polypeptide and glycoprotein hormones | cannot be taken orally because they are digested in stomach by protein enzymes |
| half-life | how long it takes for a hormone level to be reduced in half |
| downregulation | high concentration of polypeptide hormones causes a decrease in the number of receptors on target cells |
| second messengers | molecules that take the message from a hormone on the outside of a cell to the inside (signal-transduction) |
| trophic hormones | hormones produced by one endocrine gland that causes another gland to secrete hormones |
| hydrophobic | water hating; can easily get through membrane; nonpolar molecules without a charge |
| lipophilic | fat loving; nonpolar molecules are attracted to these; these molecules are also hydrophobic |
| hydrophilic | water loving; polar molecules; these do not pass through the membrane easily |
| genomic action | increase in gene expression (making of proteins) due to steroid influence on transcription factors |
| autocrine regulators | regulatory molecules produced by a certain cell or tissue and it affects the same tissue |
| paracrine regulators | molecules produced by a cell that influence another type of cell within the same organ; prostaglandins |
| endocrine glands | glands without tubes that secrete hormones into blood stream |
| exocrine glands | glands that secrete molecules into ducts |
| target cell | cell that responds to hormones |
