A nerve cell has several adaptations that allow it to carry out needed functions, such as its myelin sheath, projections and divisions, and its extremely long length. Nerve cells are also known as neurons. There are billions of nerve cells inside the human body.Know More
There are three types of neurons: sensory, motor and relay. Projections from the cell membranes are called dendrons, which have even smaller protruding extensions known as dendrites. Dendrites between nerve cells overlap, transmitting signals and communication from neuron to neuron at locations known as synapses.
Some neurons have a dendrite known as an axon. This dendrite is the longest projection of the cell and occasionally has a myelin sheath. This sheath surrounds the axon with cells that contain a fatty chemical known as myelin to protect it and speed up impulses traveling through the nerves. The myelin sheath is comparable to the plastic covering of an electric wire.
Receptors are specially adapted nerve cells that respond to certain stimuli. Nerve receptors within the eye, for example, respond to light stimuli. Nerve receptors within the ear are adapted to respond to audio stimuli, whereas nerve receptors in the skin respond to touch stimuli. Reflexes are automatic responses to stimulus that do not require the nervous system to communicate with the brain before they are carried out. Reflexes protect the body from harm.Learn more about Cells
According to the Encyclopedia Brittanica, the cell membrane has two main functions: regulating which molecules go in and out of the cell and separating incompatible processes occurring within organelles. Without the cell membrane, toxins would inevitably enter the cell and cause damage.Full Answer >
Some cells, including euglenas and various bacterial species, use tail-like projections called flagella to move across a surface. Other cells, including paramecia, use numerous hair-like projections called cilia for locomotion.Full Answer >
The cell membrane’s primary purpose is to contain the contents of the cell and provide structural integrity to the entire unit. Additionally, the cell membrane must allow resources, such as water and oxygen, to permeate the membrane while excluding harmful objects from entering the cell. The cell membrane is made up of a phospholipid bilayer. Additionally, the cell membrane serves as the attachment site for some cell components.Full Answer >
Centrioles are tiny cylindrical tubes found in animal cells, and their job is to help organize the structure of microtubules during cell division. Centrioles are located near the cell’s nucleus and are arranged in such a way that they form a “9+3” pattern.Full Answer >