Part One: Understanding Nervous System The Easy Way

Would you be interested to learn about the nervous system?

No worries, you don't need to become a neuroscientist to understand it perfectly. Let's discuss it thoroughly and learn how to take good care of it.

To begin with, let's recall what we had learned way back in our early school days. We knew that our body is composed of billions of the smaller structures of four major kinds such as the cells, tissues, organs, and systems.

With a little bit more backtrack, we were taught that cells form into tissues, tissues into organs, and organs into body systems. 

Talking about the body systems, we learned that a human body is made up of 10 major systems: skeletal, muscular, nervous, endocrine, cardiovascular, lymphatic, respiratory, digestive, urinary, and the reproductive system. But the most vital one is our nervous system. Well, no doubt because brain is the main part of it being the central command center of the body.

Do you still remember what makes up our nervous system? It is the most complex masterpiece in nature and quite an extensive topic for a discussion. 

Firstly, it is compartmentalized in two ways as the following:

1. Central Nervous System (CNS) - composed of brain and spinal cord.
2. Peripheral Nervous System (PNS)- made up of nerves that branch off from the spinal cord and extend vastly all throughout the body parts.

 The Four Basic Functions of the Nervous System

1. Voluntary Movement - means that everything we do driven by the brain is completely volitional and emotional. The type of neuron responsible for this function is motor neurons, the special type of neuron found in the spinal cord (bodily movement) and brain stem (facial movement, speech, and swallowing).
   

2. Perception - means you consciously appreciates about sensation which includes  the  vision, smell, taste, and sense of balance. The type of neuron responsible for this funciton is sensory neurons that take place in the forebrain (note: all sensory inputs are regulated by cerebral cortex).
   

3. Homeostasis - refers to our physiological limits such as having our body enough supply of oxygen,body temperature,rhythm, wake & sleep, digestion, staying warm in Chicago winter, cycle of life, and among others that keep us alive. It a process that largely depends on the forebrain (hormonal), brain stem (automatic and conscious movement), and spinal cord.
   

4. Higher Abstract Function - perception, language, interaction, motivation, memory, thinking, feelings, and others that are parts of our being human. It entirely depends on the forebrain.
   

The Central Nervous System

The brain & Spinal Cord 

 Key terms: neuron, action potential, synapse, axon,dendrites

The basic unit of nervous system is a nerve cell called neuron. There is about 100 billions of neurons in the matured human brain.

A neuron has a cell body made up of cell nucleus (organelles & genetic information), axons, and dendrites. Neurons are called  information messengers of the body using electrical and chemical signals. They communicate between the different parts of the brains brain, spinal cord, and whole body parts. 

Dendrites: Signal receivers 

They have leaf-like structure called spine and are responsible for receiving data or signals from another neurons. Also, they collect and store incoming information transmitted in the axons' terminals.

Cell Body: Metabolic Center

It contains genetic information, maintains the neuron's structure, and provides energy to drive activities.

 

Axon: Signal Transmitter

They are a bundle of nerves responsible for signal transmission through the neurotransmitters, the chemical messengers. 

The Synapses

Synapses are the locations where neurons pass chemical and electrical signals between them. They consist of presynaptic ending, a synaptic cleft, and a postsynaptic ending. 

Chemical Synapse

It is an activity which a neuron releases chemical messengers known as neurotransmitters. They cross the synaptic cleft and bind to the receptoprs postsynaptic ending of a dendrite which  trigger a response.

Electrical Synapse

It is the resulting effect of two neurons connected by a gap junction which is smaller than chemical synapse. It contains ion channels that aid in transmitting positive electrical signals. These signals move faster across electric synapses than chemical synapse. The odd thing is they tend to diminish from one neuron to another making them less effective in the repetitive cycles of signal transmission.

The Basic Structures of a  Neuron    

• Dendrites: Signal Receivers

  Nucleus: Genetic Storage

  Cell Body: Nerve Center

  Axon: Signal Transmitter 

  Myelin Sheath: Speed Booster

  Nodes of Ranvier: Impulse Amplifiers

  Axon Terminal: Transmission Points

  Synapse: Connection site 

Photo credit: nichd.nih.gov

 Neuron's Structures and Types

 

Photo credit: kenhub.com

1. Cell Body (Soma): The central part of the neuron. It contains the neuron's nucleus and controls all of its metabolic activities including the processing of nutrients and protein synthesis.

2. Nucleus: Contains the neuron's DNA and regulates the cell's functions and growth.

3. Dendrites: Branch-like structures that receive signals from other neurons and transmit them to the cell body.

4. Axon: A long, tail-like structure that transmits signals from the cell body to other neurons, muscles, or glands. 

5. Myelin Sheath: A fatty coating that covers the axon to insulate it and improve the speed and efficiency of electrical signal transmission.

6. Nodes of Ranvier: Small gaps in the myelin sheath where the axon membrane is exposed, they play a crucial role in conducting electrical signals along the neuron.

7. Axon Terminal: The endpoint of the axon where neurotransmitters are stored. These neurotransmitters are released into the synapse to transmit the signal to the next neuron.

8. Synapse: The small gap between neurons where signals are transmitted from one neuron to the next.

9. Schwann Cells: Specialized cells that produce the myelin sheath around the axons.

10. Nerve Impulse: An electrical signal that travels along the neuron, initiated by changes in electrical properties of the neuron's cell membrane.

11. Neurotransmitters: Chemical messengers released from the axon terminal that transmit signals across the synapse to the next neuron.

Keynote: Neurons differ in location, appearance, excitability, neurotransmitters, and connectivity

 

Major Types of Neuron

Essentially, there are various types of neurons that carry distinctive roles in the body, and perhaps about thousands of them exist within us. But we can classify them into three major types such as motor neurons, sensory neurons, and interneurons.

Motor neurons- transmit messages from the brain to the muscles to initiate bodily movements.

Sensory neurons - detect light, sound, odor, taste, pressure, and heat

Interneurons - the most common type which form into complex circuits to help the body reacts to stimuli.

All these types of neurons send messages to the brain through action potential. It is generated by the flow of the charged particles in and out of the neuron's membrane. Action potentials trigger both chemical and electrical signals in the synapse. 

The Peripheral Nervous System (PNS)

This is a part of the nervous system composed of a network of nerves that spread throughout the parts of the body: head,neck,and body. These nerves carry messages emanating from the central nervous system (brain and spinal cord). Briefly speaking, it's a network of nerves outside the brain and spinal cord. However, it connects the central nervous system to the various parts of the body allowing them to communicate and function properly.

The PNS is divided into two main parts: the autonomic and somatic nervous systems.

• Autonomic nervous system (ANS): Controls involuntary bodily functions and regulates glands.
• Somatic nervous system (SNS): Controls muscle movement and relays information from ears, eyes and skin to the central nervous

Nerves In the Peripheral Nervous System (43 paired nerves)

• Brachial plexus (radial nerve, median nerve, ulnar nerves)
• Peroneal nerve (foot drop)
• Femoral nerve
• Lateral femoral cutaneous nerve
• Sciatic nerve
• Spinal accessory nerve
• Tibial nerve 
• Others

 Two Classifications of PNS Nerves

1) Cranial nerves - they come from cranium brain/brainstem and in 12 pairs.

Afferent/ Sensory Neurons - PNS nerves that send information toward the CNS.

2) Spinal nerves - leave the CNS through spinal the cord and they are in 31 pairs.

 Efferent/ Motor Neurons - PNS nerves that send information from the CNS.

Takeaways

• The Central Nervous System (CNS) consists of the brain and the spinal cord. It is the main control center of the body, regulating and coordinating body activities. The CNS processes and sends out signals, influencing all body movements, thoughts, feelings, and automatic responses like breathing and heartbeat. Damage or disorders within the CNS can significantly affect physical and mental functioning.
  

•  The peripheral nervous system (PNS) is the division of the nervous system containing all the nerves outside the brain and spinal cord. It connects the central nervous system to the rest of the body, enabling it to communicate and function. It's subdivided into the autonomic nervous system (controls involuntary actions like heart rate) and the somatic nervous system (controls voluntary movements like muscle movement). It also involves sensory neurons (responsible for receiving sensation) and motor neurons (responsible for motion).
  

• Neurons, also known as nerve cells, are the primary components of the nervous system that transmit information to other nerve cells, muscle, or gland cells. Most neurons have a cell body, an axon, and dendrites. The cell body contains the nucleus and cytoplasm, the axon extends from the cell body and often gives rise to many smaller branches before ending at nerve terminals, and dendrites branch from the cell body and receive messages from other neurons. The process of transmitting messages occurs through an electrochemical process called an action potential. There are different types of neurons that serve specific functions such as sensory neurons, motor neurons, and interneurons. Neurons also generate electrical signals known as nerve impulses which allow them to rapidly transmit information over long distances.

  
  

  
  

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FAQ: The History of Asylum for Mental Illness

Do you want to learn a little bit of the history of Asylum? You're in the right place as in this post we show to you an overview of it.

Perhaps, you are one of those who think that people with mental illness should be isolated. You believe that they are dangerous and they should have a suitable place. Well, that is where asylum began to emerge.

However, over time it earned a reputation that was quite morally questionable. In fact, a few times asylum carried a bad rap. The patients didn't receive much of the acceptance from the society. But time has evolved that people begin to understand the condition of these people suffering from brain diseases deserve treatment and cure. 

So get a decent view about asylum historically by looking into the list shown below. It is a set of questions and answers for your quicker understanding.

Q: What is an asylum in the context of mental illness?

A: An asylum in the context of mental illness is a residential institution that was initially built to house people suffering from mental illnesses. It was used as a place to confine, treat, and care for the mentally ill, but over time many of these institutions became notorious for their poor living conditions, inhumane treatments, and neglect of patients.

 

Q: What is the history of asylums in treating mental illnesses?

A: Asylums for people with mental illnesses have a long history dating back to at least the Middle Ages, although the approach to care was more custodial than therapeutic. 

 

In the late 18th and early 19th century, asylums began to adopt a more humanitarian approach towards mental illness under the guidance of pioneers like Philippe Pinel and Dorothea Dix. They believed mental illness was a medical condition and should be treated with kindness and care. However, by the late 19th century, asylums had become overcrowded and conditions had deteriorated, leading to inhumane treatment. The mid-20th century saw a move away from institutional care towards community-based care and medication.

 

Q: Who was Dorothea Dix and what role did she play in the asylum history?

A: Dorothea Dix was an American activist in the 19th century who was a staunch advocate for better, more compassionate care for people with mental illnesses. She campaigned vigorously for reforms in the treatment of people with mental illnesses and was instrumental in the creation of the first mental asylums in the United States that provided decent conditions and proper medical care for the patients.

Q: When was the first mental asylum established?

A: The first mental asylum, as per recorded history, was established in 792 AD in Baghdad. In the Western world, Bethlem Royal Hospital in London, founded in 1247, is considered the first dedicated institution for the mentally ill.

Q: What was the purpose of mental asylums?

A: Initially, mental asylums were created as safe places to house individuals with mental illness. The aim was to provide patients with treatment and care, to rehabilitate them back into society. However, with the advent of the asylum era in the 19th century, these institutions became more of a place to confine those deemed 'mad' or 'insane', keeping them away from society.

Q: What was the condition of early mental asylums?

A: Many early mental asylums, particularly those in the 18th and 19th centuries, were notoriously bad. Patients were often confined in horrific conditions, subjected to cruel and unusual treatments, and experienced gross neglect. These practices reflected a lack of understanding of mental illness at the time and the prevailing stigma attached to it.

Q: What were some treatments used in asylums?

A: In the 18th and 19th centuries, treatment methods ranged from hydrotherapy, electroconvulsive therapy (ECT), and insulin shock therapy to more brutal forms like physical restraints, lobotomies, and in some instances, even physical and psychological abuse. The choice of treatment often depended on the prevailing theories about mental illness and the facilities available in the institution.

Q: When did asylums start to close?

A: The closure of mental asylums began around the mid-20th century, particularly after World War II. This was driven by multiple factors such as advancements in psychiatric medications, realization of the poor living conditions and treatments in asylums, changes in societal attitudes towards mental illness, and an increasing preference for community-based treatment and care. 

Q: What replaced mental asylums?

A: Deinstitutionalization, the process of replacing long-stay psychiatric hospitals with less segregated community mental health services, became widespread in the mid to late 20th century. Psychiatric treatments started focusing more on outpatient care, community-based support services, psychopharmacological treatment, new laws promoting patient rights, and integration of mental health care with general healthcare services. 

Q: How did the asylum era impact the perception and treatment of mental health?

A: The asylum era had a profound impact on the perception and treatment of mental health. While it initially reinforced negative stereotypes and stigma towards mental illness, the closure of asylums and the shift towards community-based care heralded a change in perspective. It helped increase awareness of the importance of mental health and paved the way for more humane, compassionate, and patient-centric approaches to mental health care.

 

 

Insights:

It hurts to know that the patients during asylum era suffered more from the malpractices than their own diseases. Not only they were isolated, their families felt ashamed of them too. It's like they were the living-dead people with nobody else to go to.