Which of these statements about the human ear is true ?

Options

A. Th Crista and macula are the specific receptors of the vestibular apparatus responsible for maintenance of balance of the body and posture .
B. The fluid between bony labyrinth and membranous labyrinth is endolymph
C. The lateral most ear ossicle is stapes while the medial most ear ossicles is malleus
D. A large number of processes called stereo cilia are projected from the basal part of each hair cell of organ of corti

Answer

To determine which statement about the human ear is true, we will evaluate each statement one by one.

### Step-by-Step Solution:

1. **Evaluate the First Statement:**
- The first statement claims that "cristae and macula are specific receptors of the vestibular apparatus responsible for maintenance of balance of the body and posture."
- The vestibular apparatus includes structures such as the semicircular canals, utricle, and saccule, which are indeed responsible for balance and posture.
- Cristae (found in the semicircular canals) and maculae (found in the utricle and saccule) are specialized sensory structures that detect changes in head position and motion.
- Therefore, this statement is **true**.

2. **Evaluate the Second Statement:**
- The second statement says, "fluid between bony labyrinth and membranous labyrinth is endolymph."
- In reality, the fluid that fills the space between the bony labyrinth and the membranous labyrinth is called **perilymph**, while endolymph is found within the membranous labyrinth itself.
- Thus, this statement is **false**.

3. **Evaluate the Third Statement:**
- The third statement claims, "lateral most ear ossicle is tapes while the medial most ear ossicle is malice."
- This is incorrect. The lateral most ossicle is the **malleus**, and the medial most ossicle is the **stapes**.
- Therefore, this statement is also **false**.

4. **Evaluate the Fourth Statement:**
- The fourth statement states, "large number of processes called stereocilia are projected from the basal part of each hair cell of organ of Corti."
- This statement is incorrect because stereocilia are actually found on the **apical** part of the hair cells in the organ of Corti, not the basal part.
- Hence, this statement is **false**.

### Conclusion:
After evaluating all the statements, we find that only the **first statement** is true.

### Final Answer:
The true statement about the human ear is: "Cristae and macula are specific receptors of vestibular apparatus responsible for maintenance of balance of the body and posture."

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