Midbrain: Definition, Meaning, Anatomy, Function, Treatment
The midbrain (mesencephalon) is the smallest region of the brainstem and plays key roles in visual and auditory reflexes, motor coordination, arousal, and sleep regulation. It contains major structures such as the tectum, tegmentum, and cerebral peduncles. Despite its size, it serves as a crucial relay centre for sensory and motor pathways.
This Story also Contains
- What Is The Midbrain?
- Structure of the Midbrain
- Functions Of The Midbrain
- Interactions With Other Parts Of The Brain
- Midbrain NEET MCQs (With Answers & Explanations)
- Recommended video on "Midbrain"
What Is The Midbrain?
The midbrain is a very small region in the brainstem. It is the third region of that matter. Usually, the midbrain is a more developed part of the developing brain. The midbrain is associated with vision, hearing, and motor control.
Structure of the Midbrain
The components of the midbrain are:
Tectum
The tectum is that part of the back side of the midbrain which consists of 4 round hills 2 of them are superior and the others are inferior.
The superior colliculus is connected with the visual and reflex activity, and the inferior colliculus is involved in the processing of auditory information
Tegmentum
The tegmentum makes up the ventral part of the brain. It is composed of several nuclei and pathways.
It has the red nucleus and the substantia nigra that is involved in motor control.
Cerebral Peduncles
Cerebral pedestrians are bunches of nerve fibres connecting
Functions Of The Midbrain
The functions of the midbrain are:
Visual & Auditory Integration
It connects the midbrain up to the cerebrum, for motor and sensory information shipping to and from the cerebral cortex and the spinal cord.
It collates sensory information, and they form subprocesses of visual and auditory perceptions as mentioned above using the superior and inferior colliculi in the midbrain.
It contributes to a reflex in response to auditory and visual inputs.
Motor System Role
The midbrain possesses structures, such as the red nucleus and substantia nigra, which are included in the composition of the motor system.
These structures are implicated in the anatomisation of voluntary actions and coordination.
Control Of Arousal & Sleep
The midbrain keeps an individual in a state of alertness and controls the cyclical patterns of sleeping and waking.
It makes the ability for alertness and also controls the patterns of sleep.
Interactions With Other Parts Of The Brain
Interactions of midbrain with other parts of the brain:
Cerebral Cortex
The cerebral cortex interacts with the midbrain for the most part, in that information is passed on to it by the cerebral peduncles.
It is the region where this information is dealt with, being of a sensory and motor nature.
Brainstem
The midbrain is among the three most basic divisions of the brainstem: others are pons and medulla oblongata.
This processing works to control the heart, respiration, and reflexes.
Midbrain NEET MCQs (With Answers & Explanations)
Important questions asked in NEET from this topic are:
Structure of midbrain
Functions of the midbrain
Practice Questions for NEET
Q1. Which of the following is a part of our brain?
Corpora allata
Corpora adiposa
Corpora cardiaca
Corpora quadrigemina
Correct answer: 4) Corpora quadrigemina
Explanation:
The corpora quadrigemina, located in the dorsal midbrain, consists of four rounded lobes—the superior colliculi, which process visual information and control reflexive eye movements, and the inferior colliculi, which handle auditory processing and reflexes. These structures are crucial for sensory integration, wherein the midbrain, along with the hindbrain (pons and medulla oblongata), forms the brainstem, a vital structure that connects the brain to the spinal cord and regulates essential functions like breathing, heartbeat, and reflex actions.
Hence the correct answer is option 4) Corpora quadrigemina.
Q2. The cerebral aqueduct, which is surrounded by grey matter, separates the
tegmentum from the crus cerebri
tegmentum from the tectum
brainstem and spinal cord.
crus cerebri from the tectum
Correct answer: 4) Regulation of body temperature.
Explanation:
The tectum (dorsal part) and tegmentum (ventral part) are the two divisions of the midbrain that are separated by the grey matter-enclosed cerebral aqueduct. It permits the flow of cerebrospinal fluid between the third ventricle, which is situated in the diencephalon, and the fourth ventricle, which is situated in the hindbrain.
Hence, the correct answer is option 2)tegmentum from the tectum
Q3. The ventral part of midbrain is referred to as the
Cerebral aqueduct,
Tectum
Crus cerebri
Cri cerebro
Correct answer: 3) Crus cerebri
Explanation:
The cerebral hemispheres are connected with the cerebellum with the help of the midbrain which lies between the pons and forebrain. The most dorsal part of the midbrain is called the rectum and the ventral part is referred to as the crus cerebri.
Hence, the correct answer is option 3) Crus cerebri.
Also Read:
Recommended video on "Midbrain"
Frequently Asked Questions (FAQs)
The midbrain contains some important structures, including superior and inferior colliculi, which are involved in processing visual and auditory information, respectively, as well as the substantia nigra, which is critical for the control of movements.
The midbrain houses the red nucleus and substantia nigra, which are centres for the solicitation of increased voluntary motion and general coordination of the body.
It further plays a role in the regulation of sleep-wake cycles and forms part of maintaining alertness and sleep coordination.
The midbrain communicates with the cerebral cortex through the cerebral peduncles, which correlate sensory and motor information.
The midbrain controls many of the eye movements, processing of auditory information, and coordination of muscles.