Endocrine I -Hormone Flashcards
Chemical control system
- Metabolism
- Reproduction
- Homeostatic Maintenance
- Growth/Development
Description of organs of the Endocrine System
Not clustered, often small, mostly glandular tissue
Releases materials into ducts that open onto epithelium
Exocrene Gland
Releases materials directly into the blood stream
Endocrine Gland
Hormones are secreted into the blood into capillaries
Endocrine Gland
Chemicals produced by the gland and is secreted
Exocrene Gland
Protein chain of amino acids; water soluble, bind to receptors in lipid membrane
Polypeptides
Water soluble, bind to receptors in lipid membrane
AA derivatives
Comes from cholesterol; lipid soluble, travel to lipid membrane and bind to a receptor inside the bilayer
Steriods
Adrenal =
Glucocorticoid
Gonadal =
Sex steroids
Most hormones in the body
Polypeptides
Large proteins synthesized in ER of Endocrine cells
Vast array of sizes (3 A.A – 200 A.A)
Polypeptides
Mechanism of Action: cell surface and water soluble
Polypeptides
Modifies and repackages all polypeptides so they can leave the cell
Golgi Apparatus
Is the parent amino acid for catecholamines and thyroid hormones
Tyrosine
Are made by modifying the side groups of tyrosine
Catecholamines
Are synthesized from two tyrosines and iodine (I) atoms
Thyroid hormones
Catecholamines are water soluble or lipid soluble?
Water soluble
Thyroid hormones are water soluble or lipid soluble?
Lipid soluble
- More than 1 hormone needed for full effect
- 1 hormone ‘prepares’ the system for the other
Permissiveness
- Occurs in situations where more than one hormone can produce the same effect
- Combined effect of multiple hormones is greater than the effect of 1 alone
Synergism
1 hormone opposes the action of another
Antagonism
Activation of surface receptor
Plasma Membrane Receptor
Passage through plasma and nuclear membranes
Intracellular Receptors
substances that respond to hormones; only going to be released when a hormone is present. They are inactive until hormone comes and they just wait in the cell
2nd messenger
Hormone release caused by altered levels of certain critical ions or nutrients
Humoral Stimulus
Stimulus: Low concentration of Ca2+ in capillary blood
Response: Parathyroid glands secrete parathyroid hormone, which increases blood Ca2+
Humoral Stimulus
Hormone release cause by neural input
Neural stimulus
Stimulus: action potential in preganglionic sympathertic fibers to adrenal medulla
Response: adrenal medulla cells secrete epinephrine and norepinephrine
Neural stimulus
Hormone release caused by another hormone
hormonal stimulus
Stimulus: hormones from hypothalamus
Response: Anterior pituitary gland secretes hormones that stimulate other endocrine glands to secrete hormones
Hormonal stimulus
- Response enhances or exaggerates the original stimulus
- May exhibit a cascade or amplifying effect as feedback causes variable to continue in same direction as initial change
Positive feedback
-Most-used feedback mechanism
- Response reduces or shuts off original stimulus
- Variable changes in opposite direction of initial change
Negative feedback
