Anatomy and Physiology of Breathing

Overview
The main function of the respiratory system is to bring oxygen into the body and deliver it to the bloodstream, which will transport it to the cells of the body. Every cell in the body requires oxygen to function. Oxygen, also known as O2, is responsible for creating energy in the cells of the body. Once oxygen is delivered to the cells of the body, a waste product called carbon dioxide or CO2, is created, CO2 is exhaled out of the lungs.

The basic structure of the respiratory system, for our understanding of breath work is, lungs, protective ribs, trachea and a muscle called the diaphragm. The diaphragm is referenced often during breath work, it is a long muscle that is situated below the lungs, it is a large dome shaped muscle. When we inhale, this large muscle contracts and flattens, creating more space in the chest for air to enter the body. As we exhale, the diaphragm relaxes, moving upwards, decreasing the volume in the chest and pushing air out of the lungs.

Inhalation
As we inhale, air will travel through the nose or the mouth, down the trachea and into the lungs. On the inhalation, the diaphragm contracts, pulls itself flat and the external, intercostal muscles between the ribs contract, these lift the ribs up and out, causing the chest cavity to expand, this makes the pressure inside your lungs lower than the air outside your body, since fluids like gases move from areas of high pressure to lower pressure, the lungs fill up with outside air.  Now that we have taken a breath in, we are in the respiratory zone, this is where gas exchange occurs..

Gas Exchange
From the lungs our blood will transport oxygen to the cells of the body.  Oxygen is carried in the blood in two ways, firstly, oxygen will attach to hemoglobin is a protein molecule that is found in red blood cells, the oxygen that we breathe in will attach to this molecule and travel around the body through the blood stream, being delivered to the cells of the body.  The rest of the oxygen is dissolved in the plasma.

Plasma is a liquid base for the entire body, it carries water, salts and enzymes and transports nutrients, hormones and proteins to parts of the body that require it.
As you can see, the respiratory system and the circulatory system must work well together for optimal oxygen delivery to the cells of the body.  Once hemoglobin is fully saturated with oxygen, it is ready to be delivered to the cells of the body via the bloodstream, active tissue such as the brain, heart and muscles are always hungry for oxygen and they burn through it quickly. 

As oxygen rich blood arrives on the scene, hemoglobin releases the oxygen to the cells, this causes the oxygen levels in the blood to drop.  All of this activity is also producing other triggers in the form of waste products, specifically heat and carbon dioxide, also known as CO2.

Carbon dioxide is a waste product that is created as a by product of metabolic activity but carbon dioxide also plays a vital role in the body as it helps to maintain the respiratory drive and it helps to maintain the blood pH levels. An imbalance in CO2 levels can affect blood pressure, heart rate, affect energy levels, heighten the nervous system and affect our ability to relax or focus.

Now that oxygen has been delivered and red blood cells are loaded up with carbon dioxide, the blood will be transported back towards the lungs for the CO2 to be breathed out.  Here in the lungs a new wave of freshly inhaled oxygen is breathed into the lungs where the oxygen can bind to hemoglobin and get delivered to the cells of the body once again.

The Nervous System
One of the most powerful effects of regulated breathing is its ability to switch off the stress response in the body and to switch on the relaxation response, also know as the parasympathetic nervous system.

When we are feeling stressed or anxious our sympathetic nervous system has been switched on, one of the most noticeable signs of a person being in an SNS state is that their breathing is short, fast and shallow, when we consciously slow down the breath, extend the exhalation and regulate our breathing, this can have a profound effect on the body’s stress response, slow or regulated breathing sends the signal to our body that we are safe, from here, our parasympathetic nervous system switches on, this will help us to feel calm, relaxed, peaceful and clear minded.

In the PNS state, our body can use all of its internal resources to heal and balance our body and mind.  When we are calm and relaxed there is better oxygen delivery to all of the cells of our body, including the brain, this is one of the reasons students may notice a reduction in brain fog and will notice clearer thinking.

The calming of the nervous system can help to switch off the fear centers in the brain and to switch on the parts of our brain that are designed with more complex thought.  We will now take a brief look at the nervous system so that you are familiar with it. The autonomic nervous system or ANS is a branch of the peripheral NS.

The ANS is involved in either amping you up or calming you down, it controls many of the body’s processes including heart rate, digestion, saliva, body temperature, metabolism and the stress response which is also known as the fight, flight or freeze response.

The ANS can be broken down into two systems:
• The Sympathetic Nervous System
• The Parasympathetic Nervous System

The Sympathetic Nervous System or SNS is designed to amp you up and to trigger the stress response in the body.  The Parasympathetic Nervous System or PNS is designed to calm you down and to trigger the rest and digest response, this is the system that is often triggered during a yoga or meditation practice.

The Sympathetic Nervous System
The SNS is responsible for amping you up and for triggering the fight or flight response.  When a dangerous or stressful situation is perceived the SNS sends signals to the adrenal glands.  Adrenaline and cortisol, which are stress hormones are released and a host of processes take place, these processes are a safety system designed to keep you alive, to help you to run from danger or fight for your life, some of the processes that take place are:
• Pupils will dilate
• Heart rate increases
• The body releases glucose from storage, this will go into the blood stream and will be used as
energy by the muscles and organs
• The vessels of the lungs dilate to increase oxygen uptake
• Blood is directed away from digestive organs and redirected to extremities in order to help you
fight or run away

Once the immediate or acute danger has passed adrenaline drops but cortisol is released, it keeps the stress response on guard but not in full motion. This incredible system is designed to keep you safe from danger, in our modern world the danger is often more psychological, it is often more a condition of our minds, thoughts and perceptions as a thought is enough to switch on the body’s stress response.

While this stress response system is amazing, when constantly switched on, it uses up all of our internal resources, leaving us feeling depleted and unhealthy in body and mind.  Just as a thought is powerful enough to switch on the body’s stress response, it is also powerful enough to switch off the body’s stress response, when the stress response is switched off, the PNS takes over.

The Parasympathetic Nervous System
The PNS when activated slows down our heart beat, it stimulates digestion, it stimulates activity of the intestines and saliva, it allows the body to rest and digest, we essentially feel good and well nourished when the body is in this state.  If our life is not in danger we essentially want the PNS to be our dominant state, it helps our body to maintain homeostasis, this is where the body and it’s systems are essentially balanced.

Homeostasis comes from the Greek word same or steady, when our PNS is activated it allows the systems of our body to maintain homeostasis and our bodies perform optimally. A stressor or a perceived stressor is any stimulus that upsets or threatens our homeostatic processes.

Yoga, mindfulness and meditation are all practices that can signal to our nervous system that we are safe and all is well, deep breathing and slow movements signal to our brain and body that we are safe, this will trigger a PNS state and this allows our body to use it’s resources to create health and well-being, a state of inner healing.

It is important to note that there are three types of breathwork, each will have a different effect on the nervous system, they are:
1. Shamvat/Calming – these practices will calm and settle the nervous system, leaving you feeling relaxed and peaceful

2. Sampad/Balancing – these practices are designed to bring balance to the systems of the body on both a physical and an energetic level, for example, these practices are said to balance the right and left hemispheres of the brain on a physical level and to balance the solar and lunar energy in the body

3. Uttejack/Exciting – these practices will amp up or excite the nervous system bringing energy to the systems of the body.
You will learn breathwork practices from each of these categories during this course.