Histo Lecture 19
Card Set Information
Histo Lecture 19
How does the Hypothalamus control endocrine function?
Receives sensory input from various organ systems
Directs pituitary gland secretion of various "releasing hormones"
Pituitary gland stimulates hormone secretion from the major endocrine organs of the body
What hormones is the pancreas associated with?
What hormones are the Parathyroid glands associated with?
What hormones are the adrenal glands associated with?
What hormones is the Thyroid gland associated with?
, Thyroxine - T
What hormones are the gonads associated with?
How does the basic endrocine signaling system work?
Regulated secretion of hormones
Diffusion of hormones through the systemic circulation
Diffusion of hormones out of the vasculature, to the target cell
Binding to specific hormone receptor on cell
Most endocrine system utilize what feedback?
Negative feedback loop
What is physiologic response-driven feedback?
Hormone production is inhibited by change in physiologic parameter
What are some examples of a physiologic response-driven feedback?
Blood Na+, K+, H+
How does endocrine axis-driven feedback work?
Hypothalamus secretes releasing hormones
Releasing hormones stimulates secretion of tropic hormones (from pituitary glands)
Tropic hormones stimulate release of hormones from peripheral endocrine glands
Neural input provides stimulus for secretion of:
Daily rhythm of hormone release occurs due to input from the:
What does the Pineal gland do?
Secretes melatonin in cyclical fashion to inform the system of the light-dark cycle
Systemic and psychological stress also stimulates what?
What are the three types of hormones released?
Proteins & polypeptides
Tyrosine derivatives - amines
What three things does the hormone type determine?
Mode of transport
Binding to target cell
Action on target cells
Protein/peptide and amine hormones are produced and stored where?
in intracellular vesicles
Steroid/thyroid hormones are produced from what?
Steroid/thyroid hormones circulate how?
Bound to plasma protein
What do protein-bound hormones allow for?
Provides a reservoir of circulating hormones
Increases the half-life of hormones
Controls movement of hormones into target cells
Binding of cell membrane receptors (proteins, peptides, catecholamines) activates what?
Intracellular 2nd messenger system that stimulates target cells
Binding to intracellular receptors (steroid hormones) activates what?
Binds to DNA and stimulate/repress transcription
Binding to nuclear receptors (thyrod hormones) affects what?
Directly affects gene transcription to promote metabolic activity of cells
Thyrotropin releasing hormone (TRH) stimulates what?
Release of TSH
Gonadotropin releasing hormone (GnRH) stimulates what?
release of FSH/LH
Corticotropin-releasing hormone (CRH) stimulates what?
release of ACTH
Growth hormone-releasing hormone (GHRH) stimulates what?
Release of GH
Where is Oxytocin released from?
paraventricular nucleus of hte hypothalamus
-Stimulates breast duct contraction (milk ejection)
Where is ADH released from?
supra-optic nucleus of the hypothalamus
What are some facts about the anterior pituitary (adenohypophysis)?
Contains a collection of tropic hormone-releasing cells
Each hormine is secreted by only one type of cell
What are some facts about hte posterior pituitary (neurohpophysis)?
Distal continuation of the hypothalamus; modified neurons
Nuclei of the hypothalamus secrete hormone and sore them in axon terminals of the posterior pituitary
Hormones are released upon appropriate stimulation
Name the 6 pituitary hormones
ACTH - adrenocorticotropic hormone
TSH - thyrod-stimulating hormone
FSH - follicle-stimulating hormone
LH - Leutenizing hormone
GH - growth hormone
PRL - prolactin
What do somatotropes do?
What do cotricotropes do?
Release ACTH to stimulate release of adrenal hormones
What do thyrotrops do?
Release TSH to stimulate release of thyroid hormones (T3/T4)
What do gonadotrops do?
Release FSH and LH to stimulate sex steroid release from gonads
What do lactotropes do?
Release PRL to stimulate milk production