introduction Flashcards
Signal transduction by second messengers allows many layers of flexibility to allow the organism to respond precisely to its environment. An important feature of this process is the ____________
amplification of the original signal.
Enzymatic cascades frequently mediate the signal transduction in a particular pathway.
Signaling is _________ One ligand generates a diverse set of responses.
pleiotropic.
Acetylcholine receptor is a __________, Beta-adrenergic and serotonin receptors are examples of __________
Acetylcholine receptor is a ligand gated cation channel (Na, K, Ca), Beta-adrenergic and serotonin receptors are examples of 7-TM receptors
Confirm the presence of a functional endocrine tumor ______ the diagnosis has been made on biochemical testing
after
assessment of endocrine disease functional imaging (2)
- benign hyperfunction
2. presence of functionan endocrine malignancy
Endocrine Disease Structural Imaging goals (2)
- to confirm the presence of an endocrine tumor
2. to assess structural damage
___________ play an essential role in homeostasis
Feedback loops
Random Hormone Levels not always helpful
yep
origin:
adrenal medulla, paraganglia
ectoderm
origin:
adrenal cortex
mesoderm
origin:
GI tract, bronchi, pancreas and thyroid C-cells
endoderm
Arranged in anatomically discrete glands
Specific messenger from each cell type
Glands have NO DUCTS, secretion into the blood stream
classes endocrine cells
Organized in classic glands (e.g., pituitary, pancreatic islets, adrenal medulla) or dispersed (e.g., in gut or bronchi, or within the ducts of exocrine secretory organs)
neuroendocrine cells
neuroendocrine cells messengers (2)
- tissue specific messengers
2. generic messengers (granin proteins)
Most neuroendocrine cells cancers occurs in the
GI tract and bronchopulmonary system
Neuroendocrine cells _____ their secretory products in dense core secretory granules; _________________ is the most abundant secretory granule protein and most widely utilized generic neuroendocrine marker
Neuroendocrine cells store their secretory products in dense core secretory granules; “Chromogranin A” is the most abundant secretory granule protein and most widely utilized generic neuroendocrine marker
Chromogranin A was isolated from secretory granules in adrenal medullary __________cells
chromaffin
Endocrine cells with neuroendocrine features:
The hormonal secretory products of these cells are (2)
peptides and monoamines
Endocrine cells NOT considered neuroendocrine include: (2)
- Adrenal cortex
secretes steroids - Thyroid follicular cells
secretes modified amino acid
Islets of Langerhans:
a classic endocrine organ composed of ‘neuroendocrine” cells
____________________ is important for normal neuroendocrine function
Tissue microarchitecture
Prevalence ~1/40,000-1/200,000
Principally parathyroid, pancreatic islets, pituitary. Also carcinoids
Germline loss of function mutations of MEN1 tumor suppressor
MEN 1
Prevalence ~1/30,000
2A adrenal medulla C-cell, parathyroid
2B adrenal medulla, C-cell, mucosal neuromas
Germline gain of function mutations of RET proto-oncogene
MEN 2
secondary hypofunction
Primary hypofunction of pituitary causing secondary hypofunction of multiple end-organs
Polypeptide hormones and catecholamines bind to _________ receptors whereas steroid hormones, thyroid hormones, and vitamin D function through _____________ receptors
Polypeptide hormones and catecholamines bind to cell surface receptors whereas steroid hormones, thyroid hormones, and vitamin D function through intracellular receptors
When heterotrimeric G proteins are bound to GTP, the alpha subunit separates from the beta-gamma subunit where it is free to activate or inhibit effector molecules such as (2)
adenyl cyclase and phospholipase C
Integrated feedback loops are characteristic of the endocrine system and critical in maintaining normal hormonal function. Two major types of control exist: the hypothalamic-pituitary-peripheral organ unit and the free standing endocrine gland.
yep
To accurately assess endocrine function, measurement of basal hormone levels and/or dynamic testing are needed. Endocrine biochemical testing should be done _______ to endocrine imaging. Endocrine imaging can be either functional or structural.
prior
______________ cells are amine and/or peptide hormone- producing cells that have shared morphological and functional characteristics. They store their specific hormones in secretory granules that also contain chromogranin proteins and other generic markers. They can be dispersed (e.g. GI tract) or organized into classic endocrine glands (e.g. pituitary). ___________ tumors can produce eutopic or ectopic hormones.
“Neuroendocrine”
