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.
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
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.
Give an example of a hormone that has negative feedback to both the anterior pituitary and the
ventral hypothalamus. ___________________________________________________________
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.
Page 1 of 2 BIO1014 Anatomy and Physiology II Lab
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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
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
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
Page 2 of 2 BIO1014 Anatomy and Physiology II Lab