Intro to Endocrine Flashcards
3 basic components of Endocrine System
- endocrine glands
- hormones
- target organs/cells
Endocrine Glands
synthesize and secrete hormones
Hormones
chemical messengers that are transported by blood to target organs/cells
Neuroendocrine
- neuron secretes signal molecule
- signal molecule acts like hormone (travels through blood to target)
Paracrine
target cell = near by
receptor on adjacent cells
act locally
Autocrine
like paracrine, except receptor on same cell
Major Endocrine Glands
- hypothalamus
- pituitary gland
- thyroid gland
- parathyroid glands
- adrenal glands
- pancreas
- ovaries
- testes
Hypothalamus Hormones
Releasing/Inhibiting Hormones
Anterior Pituitary Hormones
- ACTH
- TSH
- GH
- LH
- FSH
- PRL
- SST
Posterior Pituitary Hormones
- oxytocin
- ADH
Thyroid Hormones
T3, T4, Calcitonin
Parathyroid Hormones
PTH
Adrenal Cortex Hormones
- aldosterone
- cortisol
Adrenal Medulla Hormones
- epinephrine
- norepinephrine
Pancreas Hormones
- insulin
- glucagon
Ovaries Hormones
- estrogen
- progesterone
- inhibin
Testes Hormones
- Testosterone
- Inhibin
3 major classes of hormones
- proteins/peptides
- steroids & steroid-like molecules
- tyrosine-derived hormones
Protein/Peptide Hormones
- hydrophilic (water-soluble)
- usually circulate in blood in free form
- short half-life
- bind to membrane receptors on target cells
Steroids and Steroid-like Hormone Examples
- aldosterone
- cortisol
- estradiol
- progesterone
- testosterone
- 1,25(OH)2D3
Steroids and Steroid-like Hormones Characteristics
- released by diffusion through plasma membrane
- lipid-soluble
- mostly circulate in blood coupled to binding protein
- long half-life
- have intracellular (and membrane) receptors at target cells
Steroids and Steroid-like Hormone Synthesis
intracellular synthesis
NOT stored in vesicles
Protein/Peptide Hormone Synthesis
intracellular synthesis
stored in secretory granules
Examples of Tyrosine-Derived Hormones
- dopamine
- EPI
- NE
- thyroxine (T4)
- triiodothyronine (T3)
Tyrosine-Derived Hormone Synthesis & Secretion: Catecholamine
- stored in secretory granules
- released via exocytosis
- hydrophilic (water-soluble)
- circulate in blood in free form
- short half-life
- bind to membrane receptors at target cells
Tyrosine-Derived Hormone Synthesis & Secretion: Thyroid
- stored in thyroid follicles or released immediately after synthesis via diffusion through plasma membrane
- lipid-soluble
- circulate in blood coupled to binding protein
- long half-life
- have intracellular receptors at target cells
