Key Difference – Nerve vs Vein
Our body has networks that are responsible for transporting certain things from one place to another. Although these components have the similar purpose in the biological system, their structures are different due to their variable functions. Nerves and veins are two components of such networks that transport nerve impulses and blood respectively. The key difference between nerve and vein is that the network of the nervous system is made by nerves while that of the circulatory system is composed of veins. There are other differences too between nerve and vein in terms of their structure, functions, etc., which are discussed here in detail.
What is a Nerve?
A nerve is made up of several thousand nerve fibers enclosed in a connective outer sheath. Nerves are connected via nerve cells known as neurons. A nerve fiber is either a long axon or dendrite of a neuron. Depending on the presence or absence of myelin sheath, there are two types of nerve fibers; namely, myelinated nerve fibers and nonmyelinated nerve fibers. Nerves transfer electro-chemical signals throughout the nerve network and is responsible for sensory actions/responses in the body. Not all nerves are interconnected. Nerve network starts mainly from the brain and spinal cord. Based on the nature of nerve impulse, nerves are divided into three types; sensory nerves, motor nerves, and mixed nerves.
Sensory nerves are composed of only sensory nerve fibers and conduct nerve impulses from peripheral tissues to the central nervous system in order to produce sensation. Motor neurons contain only motor fibers and are responsible for conducting nerve impulses from central nervous system to muscles or glands. Mixed nerves contain both sensory and motor nerve fibers, and carry out sensory and motor functions.
Nervous System
What is a Vein?
Veins are tube-like structures that carry blood towards the heart from all over the body. Unlike the nervous system, the human circulatory system is a closed network and all the veins are interconnected. Main veins found in the human body include jugular vein, renal vein, subclavian vein, hepatic portal vein, and femoral vein. Most veins carry deoxygenated blood with the exception of the pulmonary vein and umbilical vein.
The wall of the veins are less muscular and often found closer to the skin. Generally, the outermost wall of the vein is composed of connective tissue, called tunica adventitia. The middle layer is called tunica media, which contains smooth muscle. The inner layer is called tunica intima. Unlike the arteries, most veins have a lot of anatomical variations. Some veins have valves that prevent regurgitation.
Venous System
What is the difference between Nerve and Vein?
Connected System:
Nerve: Nerves make the nerve net of the nervous system.
Vein: Veins make the venous system of the circulatory system.
Structure:
Nerve: Nerves are made up of axons and dendrites.
Vein: Veins are made up of outer tunica adventitia, middle tunica media, and inner tunica intima.
Function:
Nerve: Nerves are important to carry out sensory functions.
Vein: Veins carry deoxygenated blood towards the heart.
Material Transported:
Nerve: Nerves transport electrochemical pulses.
Vein: Veins transport deoxygenated blood.
Interconnection:
Nerve: Most nerves are not interconnected.
Vein: All veins are interconnected.
Images Courtesy:
- Nervous System by CFCF (CC BY 3.0)
- Venous System via Wikicommons (Public Domain)
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