Nervous system

1. “The nervous system is a complex
collection of nerves and specialised cells
known as neurons that transmit signals
between different parts of the body. It is
essentially the body’s electrical wiring”
Nervous system

2. Nervous system
• Central
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• Peripheral
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• Somatic
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• Autonomic:
Sympathetic
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Parasympathetic

3. • Central - Brain, spinal cord and retina
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• Peripheral - sensory neurons, ganglia and nerves that connect the
extremities to the CN
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• somatic - is the part of the peripheral nervous system associated
with skeletal muscle voluntary control of body movements
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• Autonomic - regulates the functions of our internal organs (the
viscera) such as the heart, stomach and intestines

4. The autonomic nervous system controls internal body processes such as the following:!
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• Blood pressure
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• Heart and breathing rates
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• Body temperature
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• Digestion
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• Metabolism (thus affecting body weight)
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• The balance of water and electrolytes (such as sodium and calcium)
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• The production of body fluids (saliva, sweat, and tears)
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• Urination

5. Autonomic two main divisions
• Sympathetic
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Flight, fight, freeze
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Prepares the body for stressful or emergency situations
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• Parasympathetic
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Rest and digest (savasana)
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Controls body process during ordinary situations

6. Many organs are controlled primarily by either the
sympathetic or the parasympathetic division
The two divisions have opposite effects on the
same organ
For example, the sympathetic division increases
blood pressure, and the parasympathetic division
decreases it
The two divisions work together to ensure that the
body responds appropriately to different situations

7. Signs of stress!
• blood pressure (pressure in your blood vessels is needed to
circulate the blood)
• Heart rate (number of times a person's heart beats per minute)
• Pupils dilate for better vision
• Immune system shuts down
• Digestion shuts down
• Muscle tone
• Clammy hands and feet
• Excess sweating
• Mental stress
• Dry mouth

8. How yoga breathing and relaxation can affect the
autonomic nervous system

9. • The SNS, in conjunction with such stress hormones as adrenaline and cortisol,
initiate a series of changes in the body, including raising blood pressure, heart
rate, and blood sugar levels. These changes help a person deal with a crisis
situation. They mean more energy and more blood and oxygen flowing to the
large muscles of the trunk, arms, and legs, allowing the person to run from
danger or do battle (the so-called “fight-or-flight” response).
• The PNS, in contrast, tends to slow the heart and lower the blood pressure,
allowing recovery after a stressful event. Blood flow that was diverted away
from the intestines and reproductive organs, whose function isn’t essential in an
emergency, returns. In contrast to fight or flight, these more restorative
functions can be thought of as “rest and digest.” They are also sometimes
dubbed the relaxation response.
• Many yoga practices, including quiet asana, slow breathing, meditation, and
guided imagery, increase activation of the PNS and lead to mental relaxation.
• Yoga techniques are more than just relaxation, however. Practices like vigorous
sun salutations, kaphalabhati breathing, and breath retentions actually activate
the SNS. One of yoga’s secrets, documented in research from the Swami
Vivekananda Yoga Research Foundation near Bangalore, is that more active
practices followed by relaxing ones lead to deeper relaxation than relaxing
practices alone. - YOGA JOURNAL

10. High blood pressure
‘High blood pressure (hypertension) rarely has noticeable symptoms,
but if untreated it increases your risk of heart attack, heart failure,
kidney disease, stroke or dementia’ NHS
‘Your heart pumps blood around your body to deliver energy and
oxygen. A certain amount of pressure in your blood vessels is needed
to do this. However, if there is too much pressure in your blood
vessels, it puts extra strain on your arteries and heart, which can lead
to serious conditions such as heart attack, heart failure, kidney
disease, stroke, or dementia’ - NHS
Medication is used to treat this condition
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11. • Inversions affect blood pressure
• In an inverted posture, gravity causes pressure to increase inside the blood
vessels (arteries, veins, and capillaries) of the head and neck.
• How far above the head is the heart?
• Mildly inverted posture like Adho Mukha Svanasana (Downward-Facing Dog),
which lifts the heart only a little above the head and does not elevate the legs,
only increases pressure in the head a little.
• Salamba Sarvangasana (Shoulderstand) increases pressure in the head still
more, because the legs and trunk are raised to their maximum vertical position
above the heart.
• Sirsasana (Headstand) increases blood pressure in the head the most, because
the legs and trunk are maximally elevated and the head is as far below
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