Chapter 40 Animal Hormones Flashcards
Endocrine signaling can act locally or at a distance
Endocrines that enter the blood are hormones
Hormones and paracrines can have autocrine functions as a means of
Providing negative feedback to control their own rates of secretion
Endocrine glands
Aggregations of endocrine cells in secretory organs
(A single endocrine gland may secret multiple hormones
Exocrine glands
Secret substances through ducts to the outside of the body
e.g, sweat glands and salivary glands
3 chemical groups of hormones
Protein hormones
Steroid hormones
Amine hormones
Peptide and protein hormones
Make up the majority of hormones
Chains of 3-80+ amino acids
e.g, insulin
Are water-soluble, this easily transported in the blood
Steroid hormones
Synthesized from cholesterol
Lipid-soluble and pass easily through cell membranes
Diffuse out of cells that make them and are usually bound to carrier molecules in the blood
Amine hormones
Mostly synthesized from the amino acid tyrosine
Some amino hormones are water-soluble and others are lipid-soluble. Modes of release differ accordingly
Receptors for water-soluble hormones that cannot pass through cell membranes have 3 domains
A binding domain that projects outside the cell membrane
A transmembrane domain that anchors the receptor in the membrane
A cytoplasmic domain that extends into the cytoplasm of the cell
Hormone structure is ____ through evolution, but _____
Conserved
Functions change
Advantage of hormone signals
They can originate from a localized source but reach cells in all areas of the body and coordinate their activity
Disadvantage of hormones
Relatively slow in delivering and terminating their messages
Neuroendocrine systems
Consists of neutrons in the central nervous system (CNS
Classical endocrine system
Consist of non-neural (often epithelial) cells that secret hormones into the blood
Only in more complex invertebrates and vertebrates
Indicate that it evolved later than neuroendocrine system
First-order hormones
Act directly on target tissue
e.g, testosterone
