HPT Axis Team 12
Hypothalamus (TRß2 Receptors)
Anterior Pituitary (TRß2 Receptors)
Thyroid
T3: Triiodothyronine
Brain (TRß1 Receptors)
Regulates gene expression during fetal development
Stimulates appetite
Bone
Increases growth of cartilage/bone turnover and aids in skeletal development
Heart (TRa1 Receptors)
Decreased systemic vascular resistance (SVR) by a direct effect on the arteriolar smooth muscle cells
Chronotropic and ionotropic
Increases ß-adrenergic receptors
TRH Neuron
Stimulates Ca2+ and PLC
TSH Synthesis and Secretion
TSH Receptor on Thyroid
Stimulates AC
All aspects of thyroid hormone synthesis and secretion occur as well as cell growth
T4: Thyroxine
Skeletal Muscle (TRa1 Receptors)
Increases motor neuron stimulation by rapidly signaling for the activity for the sodium-potassium pump
Increases protein breakdown
Auditory
Role in the mechanism of hearing
Liver (TRß1 Receptors)
Regulates the basal metabolic rate of all cells, including hepatocytes; liver metabolizes the thyroid hormones and regulates their systemic endocrine effects
Aids in the formation of LDL receptors