11- Physiology Explains Flashcards
What are the effects of parathyroid hormone (PTH) on calcium and phosphate levels?
Increases calcium levels and decreases phosphate levels
What is the immediate action of PTH on osteoblasts?
Increases calcium in extracellular fluid
What do osteoblasts produce that activate osteoclasts?
Protein signaling molecules
What does PTH stimulate the synthesis of in the kidney?
1,25-dihydroxycholecalciferol (active form of vitamin D)
What is the effect of 1,25-dihydroxycholecalciferol on plasma calcium and phosphate levels?
Increases both calcium and phosphate levels
What is the role of PTH in renal tubular reabsorption?
Increases calcium reabsorption
What does 1,25-dihydroxycholecalciferol increase in terms of calcium absorption?
Renal tubular reabsorption and gut absorption
What is the effect of calcitonin on renal tubular absorption of calcium?
Inhibits it
What is the effect of calcitonin on intestinal calcium absorption?
Inhibits it
What is the effect of calcitonin on osteoclast activity?
Inhibits it
What are the stimulators of glucagon release?
Decreased plasma glucose, increased catecholamines, increased plasma amino acids, sympathetic nervous system, acetylcholine, cholecystokinin
What are the main components of the stress response?
Substrate mobilization, muscle protein loss, sodium and water retention, suppression of anabolic hormone secretion, activation of the sympathetic nervous system, immunological and hematological changes
What are the inhibitors of glucagon release?
Somatostatin, insulin, increased free fatty acids, keto acids, increased urea
What are the effects of the sympathetic nervous system on the body during the stress response?
Stimulates catecholamine release, causes tachycardia and hypertension
Which hormones are stimulated by the hypothalamic releasing factors CRF and somatotrophin during the stress response?
ACTH and growth hormone (GH)
What happens to prolactin secretion during the stress response?
It increases due to release of inhibitory control
Which hormones remain unchanged significantly during the stress response?
Thyroid stimulating hormone (TSH), luteinizing hormone (LH), and follicle stimulating hormone (FSH)
What is the effect of ACTH on cortisol production during surgery?
ACTH stimulates cortisol production within a few minutes of the start of surgery
What are the metabolic effects of cortisol during the stress response?
Skeletal muscle protein breakdown, stimulation of lipolysis, anti-insulin effect, mineralocorticoid effects, anti-inflammatory effects
What is the role of growth hormone in the stress response?
It prevents muscle protein breakdown and promotes tissue repair
Which hormone is important for vasopressor activity and enhances hemostasis?
Antidiuretic hormone (ADH)
What is the effect of insulin during the stress response?
Release of insulin is inhibited, leading to functional insulin deficiency
What happens to circulating concentrations of thyroxine (T4) and tri-iodothyronine (T3) during the stress response?
They are reduced initially due to sympathetic activity, but normalize over a few days
What are the effects of the stress response on carbohydrate metabolism?
Hyperglycemia due to increased glucose production and reduced glucose utilization