41.1
What Are Hormones and How Do They
Work? 875
Hormones can act locally or at a distance
875
Hormonal communication arose early
in evolution 876
Hormones from the head control molting
in insects 876
Juvenile hormone controls development
in insects 877
Hormones can be divided into three
chemical groups 878
Hormone receptors are found on the
cell surface or in the cell interior
878
Hormone action depends on the nature
of the target cell and its receptors
879
41.2 How Do the Nervous and Endocrine
Systems Interact? 880
The pituitary connects nervous and
endocrine functions 880
The anterior pituitary is controlled
by hypothalamic hormones 882
Negative feedback loops control hormone
secretion 883
41.3
What Are the Major Mammalian Endocrine
Glands and Hormones? 883
Thyroxine controls cell metabolism
883
Thyroid dysfunction causes goiter
885
Calcitonin reduces blood calcium 885
Parathyroid hormone elevates blood
calcium 885
Vitamin D is really a hormone 886
PTH lowers blood phosphate levels
887
Insulin and glucagon regulate blood
glucose levels 887
Somatostatin is a hormone of the brain
and the gut 887
The adrenal gland is two glands in
one 887
The sex steroids are produced by the
gonads 889
Changes in control of sex steroid
production initiate puberty 889
Melatonin is involved in biological
rhythms and photoperiodicity 890
The list of hormones is long 890
41.4 How
Do We Study Mechanisms of Hormone
Action? 890
Hormones can be detected and measured
with immunoassays 891
A hormone can act through many receptors
892
A hormone can act through different
signal transduction pathways 893
