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It is important to note that a single neuron does not act alone—neuronal communication depends on the connections that neurons make with one another (as well as with other cells, like muscle cells). Dendrites from a single neuron may receive synaptic contact from many other neurons. For example, dendrites from a Purkinje cell in the cerebellum are thought to receive contact from as many as 200,000 other neurons.

Art connection

Illustration shows a neuron. The main part of the cell body, called the soma, contains the nucleus. Branch-like dendrites project from three sides of the soma. A long, thin axon projects from the fourth side. The axon branches at the end. The tip of the axon is in close proximity to dendrites of an adjacent nerve cell. The narrow space between the axon and dendrites is called the synapse. Cells called oligodendrocytes are located next to the axon. Projections from the oligodendrocytes wrap around the axon, forming a myelin sheath. The myelin sheath is not continuous, and gaps where the axon is exposed are called nodes of Ranvier.
Neurons contain organelles common to many other cells, such as a nucleus and mitochondria. They also have more specialized structures, including dendrites and axons.

Which of the following statements is false?

  1. The soma is the cell body of a nerve cell.
  2. Myelin sheath provides an insulating layer to the dendrites.
  3. Axons carry the signal from the soma to the target.
  4. Dendrites carry the signal to the soma.

Types of neurons

There are different types of neurons, and the functional role of a given neuron is intimately dependent on its structure. There is an amazing diversity of neuron shapes and sizes found in different parts of the nervous system (and across species), as illustrated by the neurons shown in [link] .

Part A shows a pyramidal cell with two long, branched projections on either end of the soma. Dendrites branch from either side. Part B shows a Purkinje cell with highly branched dendrites opposite the axon. Part C shows cells with long, thin axons. The dendrites are less branched than in pyramidal or Purkinje cells.
There is great diversity in the size and shape of neurons throughout the nervous system. Examples include (a) a pyramidal cell from the cerebral cortex, (b) a Purkinje cell from the cerebellar cortex, and (c) olfactory cells from the olfactory epithelium and olfactory bulb.

While there are many defined neuron cell subtypes, neurons are broadly divided into four basic types: unipolar, bipolar, multipolar, and pseudounipolar. [link] illustrates these four basic neuron types. Unipolar neurons have only one structure that extends away from the soma. These neurons are not found in vertebrates but are found in insects where they stimulate muscles or glands. A bipolar neuron has one axon and one dendrite extending from the soma. An example of a bipolar neuron is a retinal bipolar cell, which receives signals from photoreceptor cells that are sensitive to light and transmits these signals to ganglion cells that carry the signal to the brain. Multipolar neurons are the most common type of neuron. Each multipolar neuron contains one axon and multiple dendrites. Multipolar neurons can be found in the central nervous system (brain and spinal cord). An example of a multipolar neuron is a Purkinje cell in the cerebellum, which has many branching dendrites but only one axon. Pseudounipolar cells share characteristics with both unipolar and bipolar cells. A pseudounipolar cell has a single process that extends from the soma, like a unipolar cell, but this process later branches into two distinct structures, like a bipolar cell. Most sensory neurons are pseudounipolar and have an axon that branches into two extensions: one connected to dendrites that receive sensory information and another that transmits this information to the spinal cord.

The unipolar cell has a single, long axon extending from the cell body. The bipolar neuron has two axons projecting from opposite sides of the cell body. The multipolar neuron has one long axon and several short, highly branched axons extending in all directions. The pseudounipolar neuron has one axon that forms two branches a short distance from the cell body, each of which extends in a different direction.
Neurons are broadly divided into four main types based on the number and placement of axons: (1) unipolar, (2) bipolar, (3) multipolar, and (4) pseudounipolar.

Questions & Answers

what is ecology
Odion Reply
what is cell
Odion
what is cell
Odion
What is a cell
Awal Reply
What are tissues
Awal
A cell is the smallest unit of living organisms.
hamidat
Tissues are group of similar cells performing a particular function.
hamidat
how to pronounce the word cyanobacteria
siva Reply
Cyano then bacteria. look that "cyano" is just like "ciyano".
hamidat
explain the term transpiration pull
Tank Reply
water is mainly " pulled" through the plant and that the driving force for this process is transpiration from the leaves .This is also referred to as the cohesion- tension -transpiration pull model transport.
Vanessa
explain TRANSIOCATION and GUTATION
Tank
what Is corona
INGIEBE Reply
My brother go and ask GOOGLE😷😷😷
hamidat
Google it for the right answer. Corona is a virus which causes Novel Covid-19 disease that has been declared by WHO as a global or world pandemic.
Katlholo
Why is it called Covid-19?
Katlholo
jjwhat is. condinative system
Odion
joy
Odion
condinative system is the system that harmonize all the. different. part. of. the. body and make. them function as a. specific unit
Odion
Describe the process of protein sythesis?
Kizito Reply
Ribosomes are responsible for protein synthesis in animals.
hamidat
What is a ploidy level
Francis Reply
Ploidy refers to the number of chromosomes. We have 23 pairs of chromosomes in somatic cells. Sex cells are haploid thus 23 chromosomes vs. 46 Chromosomes.
Eric
Evolution is evolvement according to one's environment. Let's use humidity as an example. A person from a very cold environment would not be used to hot humid weather. But over time their body would slowly, slowly adapt.
Eric
Give me (3) types of biodiversity
Jay
Hi guys 🇧🇪
Namutebi
hello boy
Tedi
hi
INGIEBE
yes
amani
what do you guys understand about evolution?
Kiana Reply
it's a process or analayzing some program
Fahamia
but am not sure if some know plz let share
Fahamia
is a study of
Sarah
unfolding or unrolling hence the process of development of growth
Sarah
is the periodic change of the structural features of an organism
Rahim
I think
Rahim
process of developing
Nikita
hi guiz
Mohammed
hello guys
Safuna
hi
Kaniki
Evolution ~ Is the gradual change of development over time in which a new species are formed
amani
Evolution is the sum total of adaptive changes that has existed before.
hamidat
odionjimoh
Odion
hi
Odion
why are diagrams not available
Evans Reply
How can nucleotide molecules of DNA be constructed?construct a six molecules of DNA?
Julia Reply
You take a Deoxyribose sugar. The Deoxyribose sugar has a hydrogen on the second carbon vs. an OH group. The nitrogenous base binds to the #1 Carbon and a phosphate binds to the 5'. When the 2nd NBase bonds, it does so on the 3' Carbon. Thus you have 5' to 3' directional growth.
Eric
what is the explanation of local biomes in Nigeria
Kabir
It would be savanna, tropical grassland.
Eric
describe the breathing mechanism in the body fish.
Jackson Reply
what is genetics.
Jackson
the study of hereditary
Julia
state the importance of biodiversity of organisms in an area?
Chris Reply
Let's compare The Brazilian Rain Forest to Antarctica. There many, many types of flora and fona in The Rain Forest. So many that we are still discovering them vs. the variety in Antarctica.
Eric
it boosts the ecosystem where each species has an important tole
Kizito
what is biology
Adam Reply
Biology is the study of living things.
Patrick
what are some of the branches of biology?
Jackson
anatomy,genetics,parasitology
Evans
Botany
Kizito
Botany and zoology.
hamidat
what is meosis
Mabatho Reply
did you mean meiosis? meiosis this is the type of cell division where one diploid parent cell produces two daughter cells that are haploid and genetically different from the parent cell.
Patrick
thankyou
Mabatho
I'm struggling to understand genetics
Mabatho
Am also struggling as well
Patrick
nothing comes on a silver platter, you need to put effort in everything you are doing not forgetting God. study as if there is no tomorrow. "Suffer now and enjoy the future"
Patrick
true bro
Patrick
exactly brother
Odhiambo
Glory to God
Patrick
Thanks Pat🙏
Mabatho
you're welcome
Patrick
thanks
Odion
can anybody tell me what is cell
Odion
what's a nervous system
tessy Reply
what's the human brain
tessy
The human brain consist of the cerebrum, cerebellum and brain stem. The cerebral cortex is composed of neuronal cell bodies, which is the gray matter. The white matter is composed of neuronal axons. The brain is the motherboard of our system.
Eric
The nervous system brings about coordination of body activities.
hamidat
The human brain is protected by the skull and cranium and it is divided into three: the forebrain, the midbrain and the hindbrain.
hamidat
nervous system are the most specialize organs of .the body
Odion

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Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
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