Question

Arrange the following endocrine organs of a teleost based on location starting from anterior to posterior end
A. Corpuscle of Stannius
B. Chromaffin tissue
C. Uropyhophysis
D. Thyroid
E. Pineal
Choose the correct answer from the options given below:

• A. D, A, C, E, B
• B. A, C, B, E, D
• C. D, E, B, A, C
• D. E, D, B, A, C

Hint:

Urophypophysis is always located at the posterior tip of the spinal cord (caudal neurosecretory system), so "C" must be the last element in the sequence, which leaves only options (C) and (D). Pineal is in the brain (anterior-most), so "E" is first. This uniquely points to option (D).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Endocrine organs are distributed throughout the body of teleost fishes, ranging from the head and pharyngeal region to the caudal peduncle.

Step 2: Detailed Explanation:
Let us locate each endocrine organ from anterior to posterior:
- E. Pineal organ: Situated on the dorsal surface of the brain (Most anterior).
- D. Thyroid gland: Located in the pharyngeal region, near the ventral aorta.
- B. Chromaffin tissue: Embedded in the anterior kidney (head kidney) region.
- A. Corpuscles of Stannius: Located in the posterior kidney.
- C. Urophysics (Caudal neurosecretory system): Found at the extreme posterior end of the spinal cord (caudal peduncle region) (Most posterior).
The correct sequence from anterior to posterior is: E \(\rightarrow\) D \(\rightarrow\) B \(\rightarrow\) A \(\rightarrow\) C.

Step 3: Final Answer:
This sequence corresponds to option (D).