Adrenal Medulla
This division of the autonomic nervous system, known as "fight or flight," activates the adrenal medulla.
What is the sympathetic division
This is the largest single body fluid compartment, typically containing about two-thirds of the total body water.
What is the Intracellular Fluid (ICF) compartment
This anatomical zone of the hypothalamus is a cell-rich region lying between the Lateral and Periventricular zones and is involved in osmoregulation, thermoregulation, and feeding.
What is medial zone
This hypothalamic hormone, transported via the hypophyseal portal system, stimulates the release of GH from its target cells.
What is GHRH (Growth Hormone Releasing Hormone)?
The functional unit of the thyroid gland is this spherical structure, which consists of a single layer of epithelial cells surrounding a lumen filled with colloid.
What is the thyroid follicle?
This is the amino acid precursor for the synthesis of all catecholamines, including epinephrine and norepinephrine.
What is Tyrosine
These specialized cells in the hypothalamus are primarily responsible for monitoring and detecting the concentration of solutes in the extracellular fluids.
What is osmoreceptors
This large-celled neurosecretory system secretes Arginine Vasopressin (AVP) and Oxytocin directly into the posterior pituitary
What is the Magnocellular system (or Supraopticohypophysial Tract)
GH action on longitudinal growth is primarily indirect, being mediated by this key peptide produced mainly by the liver.
What is IGF-1 (Insulin-like Growth Factor-1)?
The essential mineral required for the synthesis of thyroxine (T4) and triiodothyronine (T3), which is transported into the follicular cells by the Na/I symporter (NIS).
What is Iodine?
This enzyme, enhanced by cortisol from the adrenal cortex, is responsible for converting norepinephrine to epinephrine in the chromaffin cells.
What is PNMT
ADH binds to this specific type of receptor on the principal cells of the renal collecting ducts to initiate the insertion of water channels.
What is V2 (Vasopressin 2) receptor
The Parvocellular system regulates the anterior pituitary by secreting hormones into this specialized vascular network that connects the hypothalamus to the pituitary gland.
What is the Hypophyseal Portal System (or Tuberoinfundibular Tract)?
This is a key metabolic and direct action of GH on adipose tissue, which helps conserve blood glucose by mobilizing fatty acids.
What is Lipolysis (fat breakdown)?
This critical enzyme, located at the apical membrane of the follicular cell, catalyzes the oxidation of iodide and the organification/iodination of tyrosine residues on thyroglobulin.
What is TPO (Thyroid Peroxidase)?
Released acetylcholine from preganglionic sympathetic neurons stimulates chromaffin cells via this type of receptor, leading to catecholamine release.
What is Nicotinic type 2 (N2) receptor
This condition, caused by a lack of ADH effect, can be classified as either neurogenic (central) or nephrogenic.
What is Diabetes Insipidus (DI)
This specific nucleus, located in the Supraoptic region, functions as the body's primary pacemaker, coordinating circadian rhythms.
What is the the Suprachiasmatic Nucleus (SCN)?
Hypersecretion of GH that occurs in adulthood, after the closure of the epiphyses, resulting in the enlargement of hands, feet, and facial features, is known by this name.
What is Acromegaly?
The conversion of T4 (the prohormone) to the highly active T3 in peripheral tissues, like the liver and kidney, is primarily catalyzed by these two types of deiodinase enzymes.
What is Deiodinases D1 and D2?
While both are potent agonists for B1 receptors in the heart, epinephrine has a significantly greater potency than norepinephrine for this specific receptor subtype, which mediates effects like glycogenolysis and bronchodilation.
What is B2 adrenergic receptor
In this pathological state, plasma ADH is inappropriately high, leading to hyponatremia and hyper-osmotic urine.
What is Syndrome of Inappropriate ADH Release (SIADH)
This group of orexin (or hypocretin) containing neurons in the Lateral hypothalamic area is referred to as the "feeding center" and is also crucial for stabilizing wakefulness.
What is the Hypocretin (Orexin) cells?
This severe metabolic complication, caused by chronically elevated GH (e.g., in Acromegaly), results from GH's counter-regulatory effects leading to insulin insensitivity in tissues and potential "burn-out" of pancreatic beta-islet cells.
What is Pituitary Diabetes?
T3 exerts its major physiological effects through this mechanism, where it binds to nuclear receptors TR alpha and TR beta to regulate gene transcription.
What is Genomic actions?