Endocrine System Flashcards
Neuroendocrine reflexes
Neural input to hypothalamus stimulates hormonal action
Endocrine glands
Ductless, secretions release directly from cells into bloodstream for circulation to target cells. Act as ligands.
Slower than circulatory system, binds with receptors either inside or on cell surface, causes metabolic change in cell activity
Paracrine action
Molecule released from signaling cell to act on nearby target cells
Second messenger system
Signaling molecule does not enter cell, secondary internal molecule relays message to cause effect
Ion channel linked
Rapid signaling (common in nervous system)
G protein
Receptor has effect on another membrane protein with G protein intermediate
Enzyme linked
Receptor activation causes phosphorylation of cellular proteins
Agonists
Ligands which trigger typical response of a given receptor
Antagonists
Bind to receptor, but do not trigger response
Hormonal stimulation
Triggered by another hormone binding to receptors (good for master regulation, pituitary releasing FSH)
Humoral stimulation
Triggered by nutrient levels in blood (ex: insulin)
Nervous stimulation
Nervous signal triggers release (sns causing release of fight or flight hormone in adrenal gland)
3 major categories of circulating hormones
- Steroids
- Proteins
- Biogenic amines
Autocrine stimulation
Cell produces hormone to trigger own receptors
Paracrine stimulation
Cell releases hormone with nearby cells as target
