What is the Difference Between Medulla Oblongata and Spinal Cord

The main difference between medulla oblongata and spinal cord is that the medulla oblongata is the most posterior part of the brainstem merging with the spinal cord whereas the spinal cord is the cylindrical structure running through the center of the spine, from the brainstem to the low back.

The medulla oblongata and the spinal cord are two structures that occur in the central nervous system of humans.

Key Areas Covered

1. What is Medulla Oblongata
– Definition, Structure, Function
2. What is Spinal Cord
– Definition, Structure, Function
3. What are the Similarities Medulla Oblongata and Spinal Cord
– Outline of Common Features
4. What is the Difference Between Medulla Oblongata and Spinal Cord
– Comparison of Key Differences

Key Terms

Medulla Oblongata, Spinal Cord

What is Medulla Oblongata

The medulla oblongata is the bottommost part of the brain. It is located where the brain and spinal cord connect. It is connected to the pons by the midbrain. The medulla oblongata is a part of the brain stem. It is continuous posteriorly with the spinal cord, with which it merges at the opening (foramen magnum) at the base of the skull. The medulla generally has the shape of a funnel or tube and is at its widest at its top. It is beige or off-white in color with a slight tint of pink. Though the medulla has many functions, it is very small in structure. Its widest diameter is 0.78 inches and 1.1 inches long.

Figure 1: Medulla Oblongata

Furthermore, there are two main parts of the medulla oblongata: the ventral medulla and the dorsal medulla. The ventral medulla is known as the frontal portion, while the dorsal medulla is known as the rare portion or the tegmentum. The ventral medulla is comprised of a pair of structures called the pyramids, and it also contains paired structures known as the olivary bodies, which are located lateral to the pyramids. There is both white matter (myelinated fibers) and grey matter (unmyelinated) nerve fibers in the medulla oblongata. The medulla oblongata transmits signals between the spinal cord and the higher part of the brain. It also manages heart, circulation, and breathing, manages other autonomic processes, and acts as a crossover point.

What is Spinal Cord

The spinal cord is a long, thin, tubular structure that occurs inside the vertebral column or the spine. It starts at the medulla oblongata in the brainstem and extends to the level of the first or second lumbar vertebrae. The spinal cord is 40 to 50 cm long and its diameter reduces with the length. The spinal cord connects the body to the brain. Importantly, the brain sends motor messages through the spinal cord to the limbs in order to control movements. It sends sensory information from the body to the brain. Further, it contains many reflex arcs, which can control reflexes independently from the brain, resulting in unconscious muscular movements.

Figure 2: Spinal Cord

Moreover, the spinal cord is made up of both grey matter and white matter. Additionally, the three regions of the spinal cord are the cervical, thoracic, and lumbar region. On each side of the spinal cord, two consecutive nerve roots of spinal nerves emerge. 31 pairs of spinal nerves arise from the spinal cord. They include eight pairs of cervical nerves, twelve pairs of thoracic nerves, five pairs of lumbar nerves, five pairs of sacral nerves, and one pair of coccygeal nerves.

Similarities Between Medulla Oblongata and Spinal Cord

• The medulla oblongata and spinal cord are two types of structures that occur in the central nervous system of humans.
• Both structures occur on the posterior side of the brain.

Difference Between Medulla Oblongata and Spinal Cord

Definition

Medulla oblongata refers to the bottom-most part of the brain connecting the spinal cord to the brain while the spinal cord refers to a column of nerve tissue running from the base of the skull down the center of the back.

Belongs to

The medulla oblongata belongs to the hindbrain while along with the brain, the spinal cord is a part of the central nervous system.

Importance

The medulla oblongata is the most posterior part of the brainstem merging with the spinal cord while the spinal cord is the cylindrical structure running through the center of the spine, from the brainstem to the low back.

Structure

The medulla oblongata is the bottom-most part of the brain, connecting the spinal cord through the foramen magnum, opening at the bottom of the skull while the spinal cord is a long, cylindrical structure that connects the brain and the lower back.

Function

The medullar oblongata helps to control heartbeat, breathing, and blood pressure while the spinal cord sends motor commands from the brain to the body, sends sensory information to the brain, and coordinates refluxes.

Conclusion

In brief, the medulla oblongata and the spinal cord are two structures of the central nervous system of humans. Both occur posterior side of the brain. The medulla oblongata belongs to the hindbrain and it occurs in the posterior part of the brainstem, connecting the spinal cord to the brain. Also, the main function of the medulla oblongata is to control heartbeat, breathing, and blood pressure. In comparison, the spinal cord is the long, cylindrical structure that connects the brain and the lower back. The main function of the spinal cord is to send motor commands from the brain to the body, send sensory information to the brain, and coordinate refluxes. Therefore, the main difference between medulla oblongata and spinal cord is the structure and function.

References:

1. Medulla oblongata: What it is, Function & Anatomy. Cleveland Clinic. (n.d.-d). 
2. Harrow-Mortelliti M, Reddy V, Jimsheleishvili G. Physiology, Spinal Cord. [Updated 2023 Mar 17]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-

Image Courtesy:

1. “Diagram showing the brain stem which includes the medulla oblongata, the pons and the midbrain (2) CRUK 294” By Cancer Research UK – Own work (CC-BY SA 4.0) via Commons Wikimedia
2. “Spinal Cord Sectional Anatomy” By BruceBlaus – Own Work (CC-BY SA 4.0) via Commons Wikimedia