Question

Choose the correct statements regarding frog's anatomy.
A. Hepatic portal system is the special venous connection between liver and intestine.
B. There are twelve pairs of cranial nerves arising from the brain.
C. The ureters and oviducts open separately into the cloaca in female frogs.
D. Hind-brain consists of cerebellum, medulla oblongata and optic lobes.
E. Sinus venosus joins the right atrium of heart.
Choose the correct answer from the options given below:

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

Hint:

Logic Tip: A quick way to eliminate options is remembering that amphibians only have 10 pairs of cranial nerves. Knowing Statement B is false immediately eliminates options 1, 2, and 4, leaving option 3 as the only possible correct answer!

Answer 1

The Correct Option is C

Step 1 : Understanding the Question:
This question evaluates various aspects of the anatomy of the frog ({Rana tigrina}). We must identify which statements regarding its circulatory, nervous, and reproductive systems are factually accurate for amphibians as opposed to higher vertebrates.
Step 2 : Key Formulas and Approach:
The approach involves distinguishing between amphibian and mammalian anatomy:
1. Portal Systems: Presence of specialized venous connections.
2. Nervous System: Identifying the correct number of cranial nerves and parts of the brain.
3. Reproduction: Comparing the duct systems in male vs. female frogs.
4. Cardiac Anatomy: Identifying specialized heart chambers unique to lower vertebrates.
Step 3 : Detailed Explanation:

Statement A: Like many vertebrates, frogs have a hepatic portal system. This is a specialized venous arrangement that collects blood from the digestive tract (intestines) and delivers it to the liver for processing before it enters the systemic circulation. This statement is correct.

Statement B: Amphibians, including frogs, possess only ten pairs of cranial nerves. The presence of twelve pairs is a trait found in reptiles, birds, and mammals. Thus, this statement is incorrect.

Statement C: In female frogs, the excretory and reproductive tracts are distinct. The ureters (from kidneys) and the oviducts (from ovaries) lead to the cloaca independently and open through separate apertures. In males, however, the ureter also functions as a urinogenital duct. This statement is correct.

Statement D: The frog's brain is divided into forebrain, midbrain, and hindbrain. While the hindbrain includes the cerebellum and medulla oblongata, the optic lobes are located in the midbrain. Thus, this statement is incorrect.

Statement E: The frog's heart has three chambers but is supplemented by accessory structures. The sinus venosus is a triangular chamber on the dorsal surface that receives deoxygenated blood and empties it into the right atrium. This statement is correct.

Step 4 : Final Answer:
Based on the anatomical evaluation of the frog, statements A, C, and E are the only correct ones. Therefore, the correct combination is option (C).