Interactive Physiology Worksheet:
Endocrine System: The Hypothalamic–Pituitary Axis
1. The anterior pituitary is composed of _____________________ tissue. Name the six classic hormones whose functions are well known.
1. _____________________________
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2. _____________________________
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3. _____________________________
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4. _____________________________
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5. _____________________________
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6. _____________________________
__________________________
2. TRH, GNRH, CRH, etc., are known as ________________________ hypothalamic hormones that regulate the function of the ________________ pituitary. These hormones are released into capillary beds and carried directly to the pituitary by the _________________ ______________ _______________, located in the _________________________.
3. ____________________ and ____________________, the posterior pituitary hormones, are synthesized in the ________________ and ______________________ nuclei of the hypothalamus. They are stored in the axon terminals located in the _______________ pituitary. Similar to neurotransmitters, a/an ____________ ________________ in the neuron causes their release.
4. In negative feedback, the target hormone feeds back to alter the release of the anterior or hypothalamic hormones, thus _______________________ its own release.
5. Give an example of a hormone that has negative feedback mainly to the anterior pituitary. _____________________________
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Give an example of a hormone that has negative feedback to both the anterior pituitary and the ventral hypothalamus. _____________________________
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6. Prolactin is unique in that the main ventral hypothalamic hormone regulating its secretion, _____________________________
_, inhibits its release. _______________________ (hormone) increases prolactin release. Very high levels of this hormone during pregnancy actually block the effect of prolactin on milk production. IPage 1 of 2
BO1014 and PAnatomy hysiology II Lab
7. _______________________ hormones are necessary for the release of ____________________ hormone. This is an example of modulation of a hormone by a target hormone of another series.
8. Suckling of an infant causes milk letdown by stimulating what hormone? ___________________
Changes in osmolarity detected by chemically sensitive neurons in the hypothalamus will alter what hormone’s level? _____________________________
_____
9. Cortisol release is synchronized by the light/dark cycle and has a 24-hour pattern of secretion known as a ____________________________ rhythm. Levels are highest at what part of the day? _____________________________
___
10. Besides controlling levels of T3 and T4, TSH also promotes ______________________ of the thyroid gland. T3 and T4 are carried in the bloodstream bound to ______________ ___________ because they are ___________________________ .
11. T3 and T4 enter the target cells by _____________________ and bind to receptors located _____________________________
__. T3 and T4 are synthesized from ________________ and ____________.
12. Which of the following would be symptoms of hypothyroidism, also known as __________________________?
_____________________________
______
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13. Lack of dietary iodine would cause _______________________ hypothyroidism and the patient would probably get an iodine-deficient _________________________.
14. Graves’ disease is the most common cause of primary __________________________. The body secretes ________________ _______________ _____________________, which mimics the action of TSH and thus may cause a ______________________ as well as high levels of thyroid hormone
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