Determine which of the following relationships corresponds to the lcoation of the isthmus of the thyroid gland?
A. A line along the neck to the back of the toungue.
B. Ascends between the thyroid cartilage and carotid sheath
C. Croses over the 2nd and 3rd trachea rings
D. Lies anterior to the thyroid cartilage

Which of the following best describes a drug which is a noncompetitive antagonist?

A. drug binds reversibly to the active site of a receptor and competes with agonist binding to this site.

B. drug binds irreversibly to the active site of a receptor and prevents agonsit from binding to this site

C. drug binds to the active site of a receptor and partially activates this site

D. drugs bind to a receptor which generally exists in an active form and stabilizes the receptor into an inactive form

Which endocrine gland is capable of developing an invasive tumor that will create symptoms that affect peripheral vision?

A. Adrenal medulla

B. Anterior pituitary

C. Parathyroid

D. Thyroid