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16 Cards in this Set
- Front
- Back
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Direct effects of thyroid hormone (TH) |
-Increase basal metabolic rate (BMR) & heat production -Increased mito & Na/K pump expression - Sympathomimetic: increases sympathoexcitation by upregulating catecholamine receptors - Increases heart rate & force of heart contraction |
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Indirect effects of thyroid hormone (TH) |
- Essential for growth (permissive effect on GH stimulating secretion) - Development of CNS - Directs GH-dependent metamorphasis in amphibians |
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What is the HPT loop? |
Negative feedback loop involving HPT axis - elevated T3 & T4 inhibit TSH secretion by thyrotrophs of anterior pituitary - TSH, can lead to hyperplasia and hypertrophy of follicular cells (goiter) |
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Regulation of TRH secretion |
-Physiological or Psychological stress inhibits TRH secretion -cold stimulates TRH secretion (infants) |
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Hypothyroidism (causes) |
-Primary or secondary TH hyposecretion (tumors or autoimmune disease -Inadequate dietary supply of iodine and/or tyrosine (symptoms): Caused by reduced metabolic activity -weight gain, fatigue, cold intolerance, depression, confusion |
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Hyperthyroidism (causes) |
- Primary or secondary hypersecretion (symptoms): Caused by increased metabolic activity - Weight loss, heat intolerance, anxiety, paranoia, exopthalmos, arrythmia, muscle atrophy/weakness |
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Physiology of Macronutrient cycling |
Metabolism broadly refers to all chemical reactions that occur within body cells |
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Anabolism |
Synthesis of energy-rich nutrients from smaller subunits -requires energy (atp) -building blocks for tissues/organs/systems -storage of energy |
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Catabolism |
Breakdown of macronutrients into smaller subunits - Provides energy in the form of atp - Hydrolysis of large macromolecules and oxidation |
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dietary intake is |
usually intermittent (evolutionary advantage) |
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Absorptive nutritive state |
-Feasting & post-prandial state -after a meal -glucose is plentiful & used as the major energy source - excesses are stored as glycogen or triglycerides |
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Postabsorptive nutritive state |
- fasting - between meals - endogenous energy stores are mobilized to provide energy - fatty acids are the major energy source for most states |
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gluconeogenesis? |
- |
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Regulation of blood glucose |
- Pancreas regulates glucose flux b/w states -composed of both exocrine & endocrine tissues - exocrine portion secretes digestive enzymes - islets of langerhans are integrators of endocrine regulatory responses and secrete hormones |
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pancreatic islet hormones |
the dominant hormonal regulator of blood glucose homeostasis beta cells secrete insulin alpha cells secrete glucagon |
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Insulin (the hypoglycemic hormone) |
- Lowers blood glucose and promotes glycogenesis |
