29 C
Lagos
Saturday, February 22, 2020
Advertisement

What is the Nervous System?

Featured

How to Look After Your Dentures in 5 Easy Steps

Dentures offer many benefits to those who no longer have the use of their natural teeth. They help restore the ability to eat a...

Hackers Could Still Hold Health Records of 15M Canadians

LifeLabs — Canada’s major provider of lab diagnostics and testing services — announced on Dec. 17 that hackers had potentially accessed computer systems with...

Cat Scratch Disease: Causes, Symptoms, and Diagnosis

Do you love cats and have them as pets? Then you probably should know more about Cat scratch disease. Cat scratch disease also known...

Five Reasons your Disability Shouldn’t Bring you Down

Disability can be one of the most discouraging, frightening, and frustrating things in human life. The actual word is made up of the root...

Tooth Decay in Children – is It Time to Put the Needle and Drill Away?

Nearly half of all British adults and just over one in five Australian adults fear the dentist. Research shows that having dental treatment as...

A List of 7 Healthy Foods for the Women of All Ages!

In this hectic lifestyle, women do not take care of their health and stay busy constantly in accomplishing their daily life tasks. As they...

Infographic: Preventing Vision Problems

When the solar eclipse last month was all said and done, there were folks in the hospital for putting sunscreen in their eyes, folks...

Sickle Cell Anemia – Types, Causes, Symptoms and Treatment

Sickle cell anemia or SS hemoglobinopathy is an inherited form of anemia; it is a blood disorder that is characterized by fewer amounts of...

Find a Reason to Smile Again With All on 4 Dental Implants

As you know tooth loss is one of the common problems among adults as they age. A large number of adult populations in Australia...

How to Cope with and Manage Skin Conditions?

When it comes to the myriad of health concerns that exist in the modern age, skin complaints are not always at the top of...
Avatar
Victor Anunobi
Victor Anunobi is an environmentalist, writer and movie enthusiast living in the city of Lagos, Nigeria. He enjoys long walks, food and alternative music.

Imagine billions of messengers transferring information from one point to another with each messenger varying in structure and function and existing in a complex system in which information is exchanged.

Advertisement

The messenger and the system in which they exist and transfer information is known as the nervous system.  The nervous system is a very complex system of an animal that dictates its actions and response to stimulus by transmitting signals around different parts of its body.

It detects sensory information from the environment and works together with the endocrine system to respond to such information.

There are two main parts of the nervous system, the central nervous system (CNS), which consists of the brain and spinal cord, and the peripheral nervous system (PNS) which are all the numerous nerves that connect the central nervous system to the rest of the body.

The nerves which transmit signals from the brain are known as the efferent or motor nerves, while those that transmit signals and impulses from the body to the central nervous system are the sensory or afferent nerves.

The peripheral nervous system is further subdivided into the somatic nerves which control voluntary movement; the enteric nerves that control gastrointestinal activity; and the autonomic nerves that control the nervous system when its in a relaxed or excited state.

The unit of the nervous system is called a nerve cell or neuron. There are about 100 billion neurons in the brain. The neuron consists of a cell body that includes a nucleus and specialized parts known as axons and dendrites. These enable communication between neurons even across long distances.

When sending messages to each other, an electrical signal is sent down the length of its axon. Here it changes to a chemical signal and is released with chemical messengers known as neurotransmitters into the space between the end of one axon and the tip of the dendrite of another neuron.

This space is called the synapse. On reaching the other neuron, the signals are converted from chemical to electrical signals. This same process is repeated over and over again across the nervous system.

Nervous systems exist in most multicellular animals with sponges, mesozoans, and placozoans being the exceptions due to how simple their bodies are.

Advertisement

All animal species except certain species of worms have a nervous system consisting of a brain and central cords with nerves radiating from it.

The Central Nervous System

The central nervous system consists of two major parts; the brain and spinal cord

The Brain

The brain is contained within the skull and weighs approximately 1.3 to 1.4kg. It contains the neurons and supporting cells known as glia.

Two types of matter make up the brain – the grey matter which receives and stores impulses and the white matter which transports signals to and from the grey matter. The brain consists four primary parts. They are:

  • The Brainstem: Also known as the medulla oblongata. It is located between the pons and spinal cord and is about an inch long. The brainstem is responsible for the flow of messages between the brain and the rest of the body and controls basic body functions like breathing, swallowing, blood pressure, heart rate, and consciousness.
  • The Cerebrum: This makes up the majority of the brain and is supported by the brain stem. It is divided into two hemispheres, with each hemisphere controlling the activities of the side of the body opposite that hemisphere. The hemispheres are further divided into the frontal lobe, temporal lobe, parietal lobe, and occipital lobe. The cerebrum controls speech, emotional response, memory, and the senses.
  • The Cerebellum: It is located behind and beneath the cerebrum. The cerebellum is responsible for controlling voluntary movements like posture, balance, coordination, and speech.
  • The Diencephalon: This is made up of the thalamus, epithalamus, subthalamus, and hypothalamus. The diencephalon is responsible for connecting the endocrine system with the nervous system. It also manages the memory and emotions.

Other parts of the brain include the midbrain, which provides pathways from the upper and lower parts of the brain; and the pons which provide pathways between the medulla and higher brain centers.

The Spinal Cord

The spinal cord is contained inside a tube-like structure made of bones and known as the vertebral column. The column extends from the brain and is composed of 31 sections with a pair of spinal nerves coming out of each section.

Both sensory and motor nerves are located in the spinal cord. The spinal cord is about 43 cm long in women and 45 cm long in men.

The Peripheral Nervous System

Nervous System

The Peripheral nervous system is made up of two parts:

Advertisement

Somatic nervous system

This system consists of peripheral nerve fibers that pick up signals from the peripheral or distant organs such as the limbs and carry them to the central nervous system.

They also consist of motor nerve fibers that come out of the brain and take the sensory information for movement and necessary action to the skeletal muscles in response to the impulses received by the brain.

For example, when a hot object is touched, the sensory nerves carry information about the heat to the brain, which in turn, through the motor nerves, tells the muscles of the hand to withdraw it immediately. The entire process takes less than a second to occur.

Autonomic nervous system

This is divided into three parts. They are the sympathetic nervous system, the parasympathetic nervous system, and the enteric nervous system

The sympathetic nervous system controls how the body reacts in stressful situations. For example, filling the body with hormones that increases the body’s alertness, heart rate, and sending extra blood to the muscles. It is often referred to as the flight-or-fight response.

The parasympathetic nervous system is the exact opposite of the sympathetic nervous system. It relaxes the body and conserves energy, slowing down heart rate, and increasing intestinal and gland activity.

The Enteric nervous system which is the third part of the autonomic nervous system is responsible for controlling gastrointestinal activity.

Functions of the Nervous System

Sensation

One of the essential functions of the nervous system is sensation—receiving information about the environment to understand what is happening outside or within the body.

The senses are taste, touch, sight, smell, and hearing. The stimuli for taste and smell are both chemical substances, while that of touch is physical or mechanical stimuli that interact with the skin.

Light stimuli are responsible for how we see the world, and hearing is the perception of sound, which is also a physical stimulus akin to that of touch. These five senses enable us to process stimuli from the external environment

Advertisement

Response

The most common response produced by the nervous system upon receiving sensory information via sensory structures is the movement of muscles such as withdrawing from a hot stove or the sour and smacking sensation in the mouth when licking lime.

The responses also include the production of and secretion of sweat by the sweat glands to lower body temperature.

Responses can be divided into voluntary response which includes the movement of skeletal muscles, and involuntary response such as heartbeat, breathing, and the digestion of food.

More articles

LEAVE A REPLY

Please enter your comment!
Please enter your name here

Trending now

Eating Vaginal Discharge and It’s Health Benefits

For many people, vaginal discharge is a sign that a woman is ready and willing to have sex. Vaginal fluid is a whitish fluid...

Genital Warts: Do They Go Away Naturally? What to Expect?

Human Papilloma Virus is the causative organism for genital warts. The virus is available in various strains, and it can be contacted by many...

Cold Water Vs Warm Water: One of Them is Damaging to Your Health

Most people reach for a cup of coffee or a cold cup of water right upon waking up. But, it turns out that in...

9 Diseases That Lemon Can Destroy!

Lemon is one of nature’s many wonders. The citrus fruit has numerous health and beauty benefits – it can reinforce the immune system, improve...

Anklet Charms and Hot Wives What Do They Mean?

Women all over the world love to accessorise. From putting on necklaces to wearing makeup and buying the latest trending clothes, women are ready...

10 Male Celebs Who Love to Give Oral Sex

Eating the vagina, giving head, or doing it the southern style. However, you choose to call "eating the cake" as some rappers tag it,...

Kinky Sex Punishment Ideas You Should Try

Is your submissive being a spoilt little brat? Are you noticing some unwanted behaviour? Do not be dismayed. Sometimes subs can be naughty, and...

Fun Foods for Camping

Cooking can be the biggest part of the fun you have while out camping. Your appetite will absolutely open up once you are in...

7 Standing Sex Positions

Sex is more appealing when you do it in various ways and in many different places altogether. The best way to achieve his is...

Is Zobo Drink Healthy for Pregnant Women?

Zobo drink is a popular drink in Nigeria and it is loved by many; this common drink is made with hibiscus flower and it...

Friends