Hormones and the Endocrine System Chapter 45

Overview Read the Overview section and answer the following questions: 1. List 5 examples of how hormones function 2. What substances do hormones travel in? 3. What cells do hormones affect?

45.1 ~Endocrine vs. Nervous system Differences Nervous system: high speed electrical signals along neurons. Endocrine: slower longer-acting responses that secrete directly into blood. Similarities Neurosecretory cells Epinephrine (fight-or-flight hormones & neurotransmitter)

Feedback loops Negative feedback – the effector response reduces the initial stimulus and eventually the response ceases Positive feedback – reinforces the stimulus and leads to an even greater response Nursing mother

Basic hormone control pathways

45.2 ~ Signaling pathway 3 major classes of molecules function as hormones Proteins & peptides Amines Steroids (NOT water soluble) All 3 types signal using the signal transduction pathway Reception Transduction (affect target cells) Response

Water soluble vs. lipid soluble signaling

Location of Endocrine Glands