Problem 131 - Objective Biology for NEET

Question

Macula in man are present in (a) Semicircular canals (b) Utriculus (c) Sacculus (d) Both utriculus and sacculus

Step-by-Step Solution

Answer

(d) Both utriculus and sacculus.

Step 1: Understand the role of Macula

Maculae are sensory receptors that are present in the ear. They play a key role in detecting stable body position and linear movement with respect to gravitational and linear force.

Step 2: Indentifying the location of Macula

There are two macula in the ear, one in each of the two otolith organs called the utriculus and the sacculus. So macula are present in both parts.

Step 3: Select the answer

Given that macula are present in both the utriculus and the sacculus, the correct choice from the given options is '(d) Both utriculus and sacculus'.

Key Concepts

Macula

The maculae are tiny sensory structures found within the inner ear. Their primary function is to help our brain interpret signals about balance and spatial orientation.
These structures contain hair cells topped with otolithic membranes that contain small crystals called otoconia. When you move your head, the otoconia shift, causing the hair cells to bend. This bending generates nerve signals that are sent to the brain, providing information about the direction of movement and head position. Key roles of the macula:

• Detecting tilt and linear movements
• Helping perceive balance and spatial orientation

Utriculus

The utriculus is one of the two otolith organs in the inner ear, the other being the sacculus. Its macula, or sensory area, is positioned in a horizontal plane when a person is upright, making it particularly sensitive to changes in lateral (side to side) movement and head tilts.
It works by allowing the brain to understand forward and backward movements as well as sensing the position of the head in relation to gravity. Features of the utriculus include:

• Contains a horizontal macula
• Sensitive to linear acceleration and head tilts
• Critical for maintaining balance

Sacculus

The sacculus is the second otolith organ within the vestibular system of the inner ear, alongside the utriculus. The macula within the sacculus is oriented vertically, allowing it to detect up-and-down movements.
This helps in sensing vertical accelerations like when you jump or move in an elevator. The sacculus, together with the utriculus, provides essential feedback to the brain about head movements relative to gravity. Key aspects of the sacculus:

• Contains a vertical macula
• Responds to vertical acceleration
• Involved in sensing head position changes

Otolith Organs

Otolith organs include both the utriculus and the sacculus. Each contains a patch of sensory receptors known as a macula.
These structures are vital for detecting linear accelerations and gravitational forces. The otolith organs are located in the vestibular system of the inner ear and are crucial for maintaining equilibrium and spatial orientation. Functions of otolith organs:

• Detect acceleration and changes in head position
• Help distinguish between tilting and actual acceleration

Understanding otolith organs is essential for grasping how humans maintain balance and navigate their environment.