In flies, frogs, and chicks, gradients of morphogens determine the future antero-posterior and dorso-ventral axes of the developing embryo. How is the antero-posterior axis determined in C. elegans?

#Question id: 11552

#Unit 7. System Physiology – Animal

Which of the following are properties of steroid hormones?

I) Steroid hormones are lipid soluble and easily cross the phospholipid bilayer.

II) Steroid hormones usually exert their effects on target cells through membrane receptor proteins.

III) Steroid hormones act on cells close to where they were produced.

IV) Steroid hormones regulate gene transcription by binding to intracellular receptor proteins.

#Question id: 11553

#Unit 7. System Physiology – Animal

Tadpoles must undergo a major metamorphosis to become frogs. This change includes reabsorption of the tail, growth of limbs, calcification of the skeleton, increase in rhodopsin in the eye, development of lungs, change in hemoglobin structure, and reformation of the gut from the long gut of an herbivore to the short gut of a carnivore. Amazingly, all of these changes are induced by thyroxine. What is the most likely explanation for such a wide array of effects of thyroxine?

#Question id: 11554

#Unit 7. System Physiology – Animal

What happens in a cell when adenylyl cyclase is activated?

#Question id: 11555

#Unit 7. System Physiology – Animal

Nitric oxide and epinephrine ________.

#Question id: 11556

#Unit 7. System Physiology – Animal

During mammalian labor and delivery, the contraction of uterine muscles is enhanced by oxytocin. This is an example of ________.

#Question id: 11557

#Unit 7. System Physiology – Animal

Which of the following has both endocrine and exocrine activity?