In ear, the membranous labyrinth is filled with fluid called

Options

A. Endolymph
B. Perilymph
C. Plasma
D. Haemolymph

Answer

**Step-by-Step Solution:**

1. **Understanding the Membranous Labyrinth**: The membranous labyrinth is a crucial structure located within the inner ear. It is surrounded by the bony labyrinth and plays a significant role in the auditory and vestibular systems.

2. **Components of the Membranous Labyrinth**: The membranous labyrinth consists of several parts, including the cochlear duct (scala media), semicircular ducts, utricle, and saccule. Each of these components is essential for hearing and balance.

3. **Identifying the Fluid**: The question asks about the fluid that fills the membranous labyrinth. The correct fluid is known as endolymph.

4. **Evaluating Other Options**:
- **Endolymph**: This is the correct answer, as it specifically fills the membranous labyrinth.
- **Perilymph**: This fluid is found in the spaces between the bony labyrinth and the membranous labyrinth (in the scala tympani and scala vestibuli) and is not the correct answer.
- **Plasma**: This is a component of blood and is not related to the ear's anatomy, making it an incorrect option.
- **Hemolymph**: This is a fluid found in invertebrates, which is not applicable to the structure of the ear in vertebrates, thus also incorrect.

5. **Conclusion**: After evaluating all the options, the fluid that fills the membranous labyrinth is indeed **endolymph**.

**Final Answer**: The membranous labyrinth is filled with fluid called **endolymph**.

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