Endocrine Physiology Flashcards
What is a hormone?
A signaling molecule that is released by the cell. It is carried throughout the body by the blood stream, neural axons, or by local diffusion to cells in target tissues
What is the chemical nature of a hormone?
It can be a protein, peptide, catecholamine, steriod, or iodinated tyrosin derivative
What does a hormone do at the target tissue?
Regulate existing metabolic pathways by the use of secondary messengers, regulate synthesis of enzymes and other proteins, regulate the rate of specific reactions
What is the function of the endocrine system?
Regulate metabolism, regulate fluid status, regulate growth, regulate sexual development, regulate reproduction
What two systems work together to maintain homeostasis?
Endocrine and nervous system
What are the four types of hormonal action by which the signal reaches the target cells?
Autocrine, Paracrine, Endocrine, Neurocrine
What is autocrine?
When the hormone acts on the cell that released it.
What is paracrine hormone action?
Hormone acts on adjacent cells without having to enter the blood stream
What is endocrine hormone action?
Hormone will enter the blood stream to reach target cells
What is neurocrine hormone action?
Hormones is a neuron and affects a particular cell
What are the four categories of hormone?
Peptides, Catecholamine, Thyroid, Steroid
What happens when hormones are released in the bloodstream?
Bound to other plasma constituents, or circulate freely
Where are receptors located for lipophobic hormones?
Located in the target cell membrane
Where are receptors located for lipophilic hormones found?
Nuclear receptors
What are first messengers?
Basically the hormones themselves. Don’t need an intermediary substance to help them penetrate the plasma membrane of the cell
