Term | Definition |
Hormones derived from cholesterol (steroid hormones) | Androgens, estrogens, progestins |
Hormones derived from amino acids | epinephrine, norepinephrine, dopamine, melatonin |
Negative feedback loop | Less hormones are produced when hormone levels have risen |
Down-regulation | Cells decrease amount of receptors due to high hormone levels |
Up-regulation: | Low levels of hormone cause target cells to make more receptors |
hormones | Long distance chemical messengers. Can be either steroid based or amino acid based. |
Endocrinology | Study of endocrine glands and hormones |
Lipid derived hormones (excluding steroids) | corticosteroids, mineralocorticosteroids, calcitriol, eicosanoids |
Second messengers | molecules that increase speed of enzymatic activity w/in the cell when hormone concentration is elevated |
Cyclic AMP (cAMP) | second messenger synthesized from ATP by enzyme adenylyl cyclase. Activates G Protein, as well as adenylyl cyclase to make more cAMP |
What does cAMP do | causes cell to use Protein Kinase A (PKA), which phosphorylates protein |
Phosphatidylinositol (PI) | Small portion of eukaryotic cell membrane. |
autocrine | A chemical that will exert a response on the same cell that it was released from |
paracrine | A chemical which affects a cell nearby, but different from the cell it was released from |
Hormones affect... | Growth and Development, Body Temperature, Mood, Metabolism Eliminaton & Breathing, Blood Circulation, Sexual Function & Reproduction, Mobilization of Immune Cells & Body Defenses |
hypothalamus | regulates certain body functions & endocrine functions |
Hormones released from hypothalamus | Thyrotropin-releasing hormone (TRH)
Gonadotropin-releasing hormone (GnRH)
Growth Hormone releasing hormone (GHRH)
Corticotropin-releasing hormone (CRH)
Somatostatin
Dopamine |
Tropic Hormones | Cause target organ to release hormones once tropic hormone binds to receptor |
Pituitary Gland (Hypophysis) | Has anterior & posterior lobe. Attached to hypothalamus in cranial cavity |
Hormones of anterior pituitary gland | Thyroid Stimulating Hormone (TSH)
Adencortotropic Hormone (ACTH)
Follicle Stimulating Hormone (FSH)
Luteinizing Hormone (LH)
Growth Hormone (GH aka somatotropin)
Prolactin (PRL) |
Hormones of posterior pituitary gland | Oxytocin (OXY)
Antidiuretic Hormone (ADH, aka vasopressin) |
pineal gland | located above 3rd ventricle of brain.
Pinealocytes release melatonin |
Melatonin | A sleep aid that regulates circadian rhythms |
Thymus gland | Produces thymosins & thymopoitins which aids immune system development |
Thyroid gland | Releases thyroxine (T4), triiodothyronine (T3), and calcitonin. T3 & T4 regulate metabolism. |
Parathyroid gland | Assists calcitonin in regulating blood calcium levels |
Pancreas | Endocrine cells cluster together to form islets of Langerhans. Pancreas hormones regulate blood sugar. |
Blood sugar regulation | Insulin lowers blood sugar when it is too high
Glucagon increases blood sugar when it is too low |
Adrenal glands | The inner portion is the adrenal medulla, outer portion termed adrenal cortex |
Adrenal medulla | releases epinephrine & nonepinephrine when synpathetic nervous system is activated |
Adrenal cortex | Produces various steroid based hormones |
Testes | Testosterone & male sex hormones are produced by interstitial cells w/in loose connective tissue between seminiferous tubules |
Ovaries | Produce estrogens & progesterone during female reproductive life. Located in the pelvic cavity |
Placenta | Releases the hormones estrogen, progesterone, human placental lactogen (hPL), human chorionic gonadotropin (hCG) |
dwarfism | occurs when not enough GH is secreted during early childhood |
gigantism | occurs when too much GH is secreted during childhood and adolescence |
acromegaly | occurs w/ hypersecretion of GH after growth plates of long bones have been ossified |