19 - Organization of Hypothalamus and Pituitary Gland Flashcards
how are hormones classified?
as protein and polypeptide, amine, steroid
what are the peptide hormones?
consist of specific amino acids
synthesized as large precursor proteins
stored in membrane enclosed compartments
hydrophilic
what is the relationship between the protein and polypeptide hormone receptor?
- Surface receptor
- Hormone binds
- Transduction
- Enzyme activation
- Open channels
- Second messenger systems
- Synthesis
what aa are amine hormones derived from?what do these include?what happens to them after they are synthesized?
tyrosine; thyroid and catecholamines; stored until secreted
what are the receptors for amine hormones?
surface and intracellular
describe the amine hormone? examples?
Small size, OH group
Benzene ring
examples being thyroxin and epinephrine
what is the precursor for steroid hormones?
cholesterol
T/F, steroid hormones are lipophilic?
T
what happens to steroid hormones after they are synthesized?
Immediately released from the cell following synthesis
where are the receptors for steroid hormones located?
cytoplasmic or nuclear receptors
describe the steroid hormones? examples?
- Activate DNA for protein synthesis
- Slower acting, longer half-life
cortisol, estrogen, testosterone
what is the function of the hypothalamus?
Integrates functions that maintain chemical and temperature homeostasis
Functions with the limbic system
Controls the release of hormones from the anterior and posterior pituitary
what are the hypophysiotropic hormones synthesized and released by the hypothalamus?
- Thyrotropin-releasing hormone (TRH)
- Corticotropin-releasing hormone (CRH)
- Gonadotropin-releasing hormone (GnRH)
- Growth hormone-releasing hormone (GHRH)
- Growth hormone-inhibiting hormone (GHIH)
- Prolactin-releasing factor (PRF)
- Prolactin-inhibiting hormone (PIH)
T/F, hypothalamus is influenced by emotions?
T
T/F, Can be influenced by the metabolic state of the individual
T
T/F, Delivered to the anterior pituitary via the hypothalamic-hypophyseal portal system
T
T/F, Usually initiates a three-hormone sequence
T
what are the three levels of integration in endocrine control?
Hypothalamic stimulation–from CNS
Pituitary stimulation–from hypothalamic trophic hormones
Endocrine gland stimulation–from pituitary trophic hormones
posterior pituitary is comprised of ending of axons from cell bodies in the _____?
the hypothalamus (supraoptic and paraventricular)
axons pass from the hypothalamus to the posterior pituitary via the _____?
the hypothalamohypophysial tract
posterior pituitary hormones are synthesized where?
in the cell bodies of neurons in the supraoptic and paraventricular nuclei
what are the principal hormones of the posterior pituitary gland?
Vasopressin & Oxytocin
describe oxytocin?
Smooth muscle contraction of uterus and vas deferens and “let’s milk down”
describe vasopressin?
Regulates plasma osmolality
o Decreases water excretion by kidneys (V2 receptors)
o Constricts blood vessels (V1 receptors)
o Increases adrenocorticortropin Hormone (V1B receptors)
