Exam 2 Endocrine Lab Flashcards
______ feedback mechanisms are important in regulating hormone secretion, synthesis and effectiveness at target cells. It ensures that, if the bdy needs a particular hormone that hormone will be produced until there is too much of it. When there is too much of the hormone its release is inhibited
negative
positive feedback mechanism was
oxytocin from the posterior pituitary
The broad range of biochemical reactions ocurring in the body is
metabolism
swelling of the thyroid in the neck is called a _____
goiter
the type of hormones, often secreted by the hypothalamus or pituitary that stimulate the release of other hormones are referred to as _______ hormones
tropic
TRH travels to the pituitary via the_____
hypothalamic pituitary portal system
TRH is released from the
hypothalamus
If a rat used 5 ml of oxyen per minute that rat’s oxygen consumption/hour was
____ in ml or cc/hour
300
if a rat used 5 ml of oxyen per minute
and the same rat weighed 300 grams
that rat’s metabolic rate in ml oxygen/Kg/hr would be
____ in ml or cc/hour
1000
the basal metabolic rate of the hypophsectomized rat (rat 3-no pituitary gland) and the thyroidectomized rat (rat 2, no thyroid) compared with the BMR of a normal rat
both the rat without a thyroid and the rat without a pituitary had slower BMR than that of a normal rat
Prior to injecting thyroxine into the 3 subject rats (normal, without thyroid, without pituitary) you were asked to predict what would happen if you injected thyroxine into each rat
the normal rat became hyperthyroid but did not develop a goiter
what would happen after you injected TSH into the 3 rats
the normal rat became hyperthyroid and developed a goiter
Prior to injecting PTU, a medicine that inhibits production of thyroxine, thyroid hormone, into the 3 subject rats (normal, without thyroid, without pituitary) you were asked to predict what would happen if you injected PTU into each rat.
the normal rat became hypothyroid and developed a goiter
how would you treat an animal without a pituitary galnd so that it’s metabolic rate functions like a “normal” animal
supplement with TSH
how would you treat an animal without a thyroid so that it functions like a “normal” animal
supplement with T4
the hormone that most directly stimulates the release of TRH is deficiency of______________ hormone
thyroid (T3, T4)
Due to the missing hormone a rat without a pituitary would expect to have which symptome RELATED TO the thyroid system
decreased BMR
an injection of thyroxine to an otherwise normal rat should cause
decrease TSH
decrease TRH
the rat with the fastest BMR was
the normal rat after the thyroxine injection
what difference in levels of TRH, TSH, and T4 , if any, that you would see
between a normal rat
and
a rat without a pituitary gland
A rat without a pituitary would have High TRH low TSH (absent) Low T4 relative to the normal rat
in this experiment the normal rat developed a palpable goiter after the supraphysiologic TSH injection
TSH receptors on the thyroid gland were excessively stimulated
what effect does TSH have on a animal that has no thyroid on T4 level?
What about on TRH levels?
No effect on the thyroid, it may lower TRH from the hypothalamus
TSH is a tropic hormone it has no effect on body cells. The only receptors for TSH, that we know of are on the hypothalamus and the thyroid. TSH should stimulate T4 release but decrease TRH release. How much it affects TRH is affected by the amount of T4 present
An injection of large amounts PTU to an otherwise normal animal will cause which of the following
hypothyroidism and goiter development
A TSH injection was given to an animal without a pituitary
What affect does this have on T4 levels?
What about on TRH levels?
TSH injection will replace the missing hormone in an animal without a pituitary
So T4 should rise
TRH should fall both due to the T4 and the TSH
