Hormones Flashcards
What are hormones, and what do they do?
Hormones are chemical messenger molecules that regulate physiological functions by transmitting signals from endocrine glands to target cells and tissues.
What are the three main types of hormone molecules?
The three main types of hormone molecules are amines, peptides (short amino acid chains), and steroids (derived from cholesterol).
How does the polarity of a hormone affect its transport and reception?
The polarity of a hormone determines whether it can diffuse through the cell membrane or must bind to a receptor on the cell surface.
What are the characteristics of polar hormones?
Polar hormones can be transported directly in the blood but cannot diffuse through the cell membrane; they bind to receptors on the membrane and initiate a signaling pathway.
How do nonpolar hormones travel in the bloodstream?
Nonpolar hormones must be transported by water-soluble transport proteins in the blood but can diffuse directly through the cell membrane and bind to intracellular receptors.
What are examples of amine hormones, and what are their polarities?
Examples of amine hormones include melatonin (barely polar), thyroxine (nonpolar), and epinephrine (polar).
What are examples of peptide hormones, and what are their polarities?
Examples of peptide hormones include ADH, insulin, glucagon, and thyroid-stimulating hormone (TSH), all of which are polar.
What are examples of steroid hormones, and what are their polarities?
Examples of steroid hormones include estrogens, testosterone, and progesterone, all of which are nonpolar.
How do peptide hormones interact with target cells?
Peptide hormones bind to receptors on the target cell’s plasma membrane and use signal transduction to stimulate a response.
How do steroid hormones interact with target cells?
Steroid hormones diffuse through the plasma membrane and bind directly to intracellular receptors, acting as transcription factors to influence gene expression.
