Longest cell in the human body is

(a) Nerve cell

(b) Leg muscle cell

(c) Bone cell

(d) Heart muscle cell

• Neurons (nerve cells) are the functional units of the nervous system and can grow to be the longest cells in the human body, reaching up to 3 feet (about 1 meter) in length.
• They connect the central nervous system (brain and spinal cord) to other parts of the body, enabling communication through electrical impulses.

Structure of a Neuron

Each neuron consists of three main parts:

1. Cell body (soma): Contains the nucleus and other organelles.
2. Axon: A long, fiber-like extension that carries signals away from the cell body. Some axons can extend up to 1 meter.
3. Dendrites: Numerous short, branching fibers that receive signals from other neurons.

Myelin Sheath

• Many axons are covered by a myelin sheath, a fatty insulating layer.
• It protects the axon, improves signal transmission, and ensures that messages travel quickly and efficiently between the brain, spinal cord, and the rest of the body.

Hence, the correct answer is, ‘Nerve cell’.