Anatomy of the Respiratory Anatomy of the Respiratory SystemSystem

Every cell in the body must breathe by taking in Oxygen, generating

energy, and expelling Carbon Dioxide.

Flow of Oxygen through the Flow of Oxygen through the Respiratory SystemRespiratory System Oxygen from the

atmosphere enters through the nose during inhalation.

It crosses the hard and soft palates, then turns 90 degrees downward into the throat.

The Glottis in the throat blocks the Esophagus and sends the air into the Trachea, where it continues its journey to the lungs.

The Trachea branches into the left and right Bronchial Passages, and the air flows into the lungs.

The Bronchial Passages branch into secondary and tertiary bronchi, which lead to tiny sacs in the lungs called Alveoli.

It is in the Alveoli where Oxygen enters the bloodstream and is transported to the heart by way of the Pulmonary Arteries.

From the heart, Oxygen travels to the rest of body through the arteries in Systemic Circulation.

Carbon Dioxide travels the opposite direction, exiting the cells of the body and traveling back to the heart through the veins in Systemic Circulation.

Finally, CO2 travels from the heart back to the Alveoli in the lungs in Pulmonary Circulation, where it eventually exits through the respiratory system.

Pressure in the BodyPressure in the Body

Oxygen and Carbon Dioxide are moved in and out of our system through by means of pressure. How?

A gas moves from a region of high concentration to one of low concentration.

There is much concentration of (or pressure from) oxygen in the atmosphere, less in the alveoli, less still in the arterial blood and even less in the cells of the body.

It is just the reverse with Carbon Dioxide. There is the most in the cells and the least in the atmosphere.

Measuring PressureMeasuring Pressure

Atmospheric pressure is measured in Millimeters of Mercury (MMHG)

To derive the MMHG, create a tube of diameter X and extend it to the very end of the atmosphere. Now measure the weight of the air captured by that cylinder. Next, fill up a tube of diameter X with mercury until the two tubes weight the same. The millimeters of mercury it takes to achieve the weight of the tube of air is the MMHG.

ChemoreceptorsChemoreceptors

A key link between the autonomic and somatic nervous systems

Chemoreceptor’s sensitivity and the signals they send (via the autonomic nervous system) can be willfully altered by breath exercises.

Chemoreceptors Cont.Chemoreceptors Cont.

Chemoreceptors are nerve endings in the autonomic nervous system which detect fluctuations in the levels of oxygen and carbon dioxide in the body.

With this information they send the appropriate signals to the muscles of respiration (diaphragm, intercostal, and abdominal muscles).

2 Types of Chemoreceptors2 Types of Chemoreceptors

1. Peripheral chemorecptors are found in the arteries and react to substantial changes in oxygen. They cannot be reconditioned.

2. Central chemoreceptors are found in the brain and react to minute fluctuations of Carbon Dioxide. When Carbon Dioxide is high, the chemoreceptors assume oxygen is low and sends signals to increase the breathing rate. When Carbon Dioxide drops, the breathing rate slows. Central chemoreceptors can eventually adapt to lower levels of Carbon Dioxide with breathing exercises.

Identifying Your Lung Volumes Identifying Your Lung Volumes (Coulter page 93)(Coulter page 93) Tidal volume: Inhale and exhale normally (500ml) Expiratory Reserve volume: Exhale normally. Now

exhale all the rest of the air out. You have just emptied your expiratory reserve (1000ml)

Residual volume: Having emptied your expiratory reserve note that there is still some air left in the lungs keeping them inflated. This is the residual volume (1200ml)

Inspiratory reserve volume: Inhale normally. When you reach the peak of your tidal volume continue filling up any remaining space in your lungs. That additional space is your inspiratory reserve (3300ml)

Identifying Your Lung CapacitiesIdentifying Your Lung Capacities

Functional residual capacity: Exhale normally. The total amount of air left in your lungs is the functional residual capacity (expiratory reserve volume + residual volume) 2200ml

Inspiratory capacity: Exhale normally. The total amount of air you can inhale is your inspiratory capacity (tidal volume + inspiratory reserve volume) 3800ml

Vital capacity: Exhale completely, emptying your expiratory reserve volume. Now inhale filling up to the top of your inspiratory reserve volume (expiratory reserve + tidal + inspiratory reserve) 4800ml

Total lung capacity: Is the vital capacity + the residual volume (all the volumes added together) 6000ml

Minute VentilationMinute Ventilation

Defined as the amount of air we breathe in and out normally (Tidal volume) in a 60 second period.

Assuming a normal Tidal volume of 500 ml and an average of 12 breaths per minute, MV=500x12=6,000 ml per minute.

Minute ventilation measures the air flow that passes in and out of the nostrils.

Alveolar VentilationAlveolar Ventilation

Similar to Minute Ventilation but takes into account the Anatomic Dead Space (air that enters the breathing passages but that doesn’t reach the lungs).

AV=(500-150)x12 breaths per minute; =350x12=4,200 ml per minute.

In Bhastrika breathing, we take far more than 12 breaths per minute, but we also breathe below tidal capacity.

In meditation, we often try to fill the lungs to full capacity, but we slow the breath to only a few breaths per minute.

HypoventilationHypoventilation

Defined as too little Alveolar Ventilation or undersupply of oxygen.

Brain damage can occur after only one minute of severe oxygen deprivation.

For yoga teachers, we should be aware of students who have respiratory problems… Especially when teaching Pranayama.

HyperventilationHyperventilation

Also known as an oversupply of oxygen, it is sometimes necessary during vigorous exercise such as aerobic yoga.

When there is too much oxygen in the arteries, the level of carbon dioxide gets pushed down too low. Central chemoreceptors assume there is too much oxygen and constrict arterioles, restricting the supply of oxygen to the brain.

Hyperventilation, continued…Hyperventilation, continued…

“As carbon dioxide in the blood is reduced [chemoreceptors cause] the arterioles to clamp down and the blood supply to the tissue is restricted until there is so little blood flowing to the brain that it doesn’t matter how well it is oxygenated.”(Coulter, 98)

Bhastrika breathing induces controlled hyperventilation, training us (our central chemoreceptors) to cope with reduced levels of arterial carbon dioxide.

Three Hold Breath also enriches the blood with oxygen which reduces carbon dioxide and the slow exhalation engages the parasympathetic nervous system for a calming effect.