Directions : In the following question more than one of the answers given may be correct. Select the correct answer and mark it according to the code:
The organs which have duel origin form embryonic layers : (1) hypophysis (2) adrenal gland (3) sense organs (4) pancreasA) 1, 2 and 3 are correct
B) 1 and 2 are correct
C) 1,2 and 4 are correct
D) 1 and 3 are correct
Correct Answer: A
Solution :
The pituitary gland or hypophysis is formed of two main lobes of different origin. These lobes are the much larger anterior lobe or adenohypophysis or pars disialis and the smaller posterior lobe or neurohypophysis or pars nervosa. Adenohypophysis originates as Rathke's pouch from dorsal wall of stomodaeum in the embryo, but later its connection with the stomodaeum disappears. The neurohypophysis originates as an outgrowth from the floor of the diencephalon. Thus the pituitary gland is dual in origin. It is partly ectodermal and partly endodermal. Adrenal gland has two parts external adrenal cortex and internal adrenal medulla. The adrenal cortex is derived from the mesoderm of the embryo. The adrenal medulla develops from the neuroectoderm of the embryo. Sense organs are derived from ectoderm and endoderm.
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