Question

Number of cranial nerves in Frog is
A. 8
B. 10
C. 12
D. 14

Answer 1

Hint: Cranial nerves arise from the brain and pass information to different parts of the body.

Complete Answer:
Frogs belong to the class Amphibia of phylum Chordata. They can live on both land and water. Frogs are cold blooded animals and have camouflage property. They are short-bodied and tailless amphibians and are distributed widely, ranging from tropics to subarctic regions, the greatest being in tropical rainforest.

The 10 pairs of cranial nerves in frog are:
1. Olfactory – its origin is at the Olfactory lobes and is distributed in the lining of the nose. It acts as a sensory nerve for smell.
2. Optic- Origin at Diencephalon and distributed in the retina of the eye. Nature is sensory (Vision).
3. Oculomotor- they originate from midbrain ventrally and present in four muscles of eyes. It is a motor nerve.
4. Trochlear- Originate from midbrain dorsally and its nature is also motor. Present in the superior oblique muscle of the eye.
5. Trigeminal- It is divided into three: Ophthalmic (somatic sensory), Maxillary (somatic sensory) and Mandibular (visceral motor). Origin is at medulla. The ophthalmic nerve is present at the skin of snout, maxillary at the skin of upper jaw and mandibular at the muscle of lower jaw and tongue.
6. Abducens- It is a motor nerve present in the external rectus of the eye. Origin is at medulla ventrally.
7. Facial- origin is from medulla laterally. There are 2 types: Palatinus, distributed at the roof of buccal cavity and Il Mandibularis, at the tympanum, skin of lower jaw, and tongue. Both are visceral.
8. Auditory- Present in the internal ear and aids in hearing. Origin is from medulla laterally.
9. Glossopharyngeal- Present in tongue, hyoid and pharynx. Originate from medulla laterally.
10. Vagus- Originate from medulla laterally. There are four types with different distributions: Laryngeal (present in laryngotracheal chamber), gastric (stomach), pulmonary (lung), and cardiac (heart).

Hence the correct option is B, ‘10’. Frogs have 10 pairs of cranial nerves.

Note: Cranial nerves are the nerves that emerge directly from the brain and carry information between the brain and different parts of the body. In adult frogs, ten pairs of cranial nerves are found that emerge from the brain through various foramina of the cranium to supply the different organs of the body.