BIOLOGY 116 Chapter Notes - Chapter 7: Muscle Atrophy, Epididymis, Pineal Gland
Document Summary
Two major systems: endocrine + nervous system (both use chemical messengers) Endocrine system: utilizes hormones, chemical signals, that are produced in one body region but affect another. Reproductive hormones: affect reproductive organs + bring secondary sex characteristics. Nervous system works quickly, but endocrine is slower. Steroid hormones: 4 fused rings, 3 hexagon + 1 pentagon attached to side chains. Soluble in plasma + can cross plasma membranes + enter cell. intracellular/nuclear receptors. Hormone receptor complex bind to dna, activating particular genes produce proteins/changes in cell metabolism. Not soluble in plasma membrane/can"t pass through plasma membrane. Peptide hormones (1st messenger) binds to receptor + activate 2nd messenger cascade. Pheromones: chemical signals that act on the members of the opposite sex. Male sweat can stimulate the flow of blood to the brain of females. Male armpit sweat can regulate period cycles. Women living in the same household have synchronous periods. Animals have vno system that detects pheromones.
