Endocrine System PhysioEX (Activity 1)
How would you treat a thyroidectomized animal so that it functions like a "normal" animal?
Provide the animal T4 supplements
Thyroid Stimulating Hormone (TSH)
causes the thyroid gland to increase in size and secrete thyroxine in to the general circulation
As a result of the missing hormone(s) in the hypophysectimized rat, what would be some expected symptoms?
decreased basal metabolic rate
Thyrotropin-Releasing Hormone (TRH)
from the hypothalamus and stimulates the anterior pituitary to produce TSH, which then stimulates they thyroid to produce thyroxine
An injection of TSH to an otherwise normal animal will cause what?
goiter development
An injection of propylthiouracil to an otherwise normal animal will cause what?
goiter development
Tropic Hormones
hormones from the hypothalamus which stimulate the secretion of other hormones
An injection of thyroxine to an otherwise normal rat will cause what?
hyperthyroidism
Why didn't any of the rats develop a goiter after thyroxine injection?
in all cases, TSH leels were not elevated by the thyroxine injection
Thyroid-Stimulating Hormone (TSH) is:
produced in the pituitary gland
Thyrotropin releasing hormone (TRH) is:
secreted by the hypothalamus
Hypothalamic- Pituitary Portal System
system that transports hormones from the hypothalamus to the pituitary gland
Why did the normal rate develop a palpable goiter with the TSH injection?
the TSH receptors on the thyroid gland were excessively stimulated
Catabolism
the breakdown of large, complex molecules into smaller molecules via enzymatic reactions
Metabolism
the broad range of biochemical reactions occurring in the body
Anabolism
the building up of small molecules into larger, more- complex molecules via enzymatic reactions
Goiter
the glandular swelling in the neck due to high TSH levels
Why did the normal rat develop a palpable goiter with the propylthiouracil injection?
the injection decreased the negative feedback mechanism on TSH
Thyroxine (Thyroid Hormone)
the most important hormone for maintaining metabolism and body heat
Thyroxine is:
the most important hormone for maintaining the metabolic rate and body temperature
What does the hypothalamus primarily secret?
tropic hormones that stimulate the secretion of other hormones