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