Endocrine System Flashcards
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Endocrine glands are ________ glands.
ductless
The endocrine system secretes _______.
Hormones
Endocrine glands secrete their molecular products (hormones) into the _________.
bloodstream
All endocrine organs have extensive distribution of many ________ ________.
blood vessels
The endocrine system and the nervous system both function to communicate signals throughout the body to bring about ________.
homeostasis
What is homeostasis?
State of dynamic constancy
Endocrine glands produce informational molecules called ________.
hormones
Hormones can only affect cells (target cells) or organs (target organs) the have __________ for a specific hormone.
receptors
Are cells and organs that do not have specific receptors for hormones affected by them?
no
What are the three major classes of hormone based on chemical structure?
- Peptide hormones
- Steroid hormones
- Biogenic amines
Describe peptide hormones.
Chain of amino acids with a peptide bond. They bind with receptors on a target cell. These are the most common type of hormone.
Describe steroid hormones.
Lipid based, derived from cholesterol, can diffuse across cell membranes. Receptors are inside the cell.
Describe biogenic amines.
Small molecules made from altering amino acids, some bind to receptors on cell surface, some inside cells.
What is the mechanism by which hormone secretion is regulated called?
feedback loop
Define positive and negetive feedback. Which is most common?
Negative feedback loop: a stimulus starts a process, and eventually either the hormone that is secreted or a product of its effects causes the process to slow down or turn off.
Positive feedback loop: accelerates the original process, either to ensure that the pathway continues to turn or speed up its activities.
Negative feedback loops are most common.
What is the interface between the nervous system and the endocrine system?
the hypothalamus
The hypothalamus is also called the ________ _________ of the endocrine system.
master gland
What are the three ways in which the hypothalamus controls most endocrine activity?
- Releases regulatory hormones that quickly reach the anterior pituitary gland
- Produces and transports hormones to the posterior pituitary gland for storage
- Controls the stimulation and secretion activities of the adrenal medulla (via SNS)
What is another name for the pituitary gland?
Hypophysis
Where is the pituitary gland located?
Just inferior to the hypothalamus