1. Nervous System

2. The Nervous System Body’s primary communication network.
Contains approximately 1 trillion neurons.
Subdivided in two components
Central Nervous System (CNS)
Peripheral Nervous System (PNS)

3. Subdivisions of the Nervous System

4. CNS in the center of the body PNS includes the rest of the body
Central nervous system
Peripheral nervous system

5. Central Nervous System (CNS)
Is central in location and function.
The brain is considered the “command center” as it controls most behavior.
The spinal cord carries messages to and from the brain.
So critical that it is encased in bone.
The brain is protected by the skull.
The spinal chord is protected by the vertebrae.

6. Peripheral Nervous System (PNS)
Periphery means “lying at the outer edges.”
Carries information to and from the CNS.
The PNS is subdivided further
Somatic Nervous System
Voluntary Muscle Movement (‘soma’ means body)
Autonomic Nervous System
Works independent of thought, self-governing
Usually it is involuntary… we’ll come back to this

7. For example,
You want to pick up your pen, turn your head to the right, or touch your toe.
All three of these movements require your brain to send the message via your spinal chord (CNS) to the motor neurons (PNS), which then are attached to the muscles and allow you to execute the movement.

8. The ANS controls: Heart rate Blood pressure Breathing Sweat
Pupil dilation
Orgasm
Digestion

9. The Somatic and Autonomic Nervous Systems work together
Suppose you decide to go on a run – your physical movement of running with legs moving at a faster pace and arms pumping harder falls under the somatic nervous system, because you are voluntarily moving your legs and arms.
As you are running, your heart beats faster, your breathing becomes more shallow, and you begin to sweat; these functions fall under the autonomic nervous system, because they are working involuntarily.

10. The Autonomic Nervous System is further subdivided into the following:

11. Depending on what you are doing (somatic), the involuntary functions (autonomic) follow suit.

12. Imagine you are camping in Yosemite and you see a bear…
What would happen to the ANS functions?
They would most likely increase
Heart rate up
Shortened breath
Start to sweat
Digestion turns off
Here we are discussing the Sympathetic Nervous System.

13. The Sympathetic Nervous System
Controls your ability to react in an “Emergency.”
This emergency can be any perceived threat or danger, which includes emotions such as anger and anxiety.
Action potential is fired down the axon more quickly.

14. The Sympathetic Nervous System
Associated with the 4 F’s
Fear
Flight
Fight
Fornicate (sex)
In each of these cases we have an increased level of arousal.
While most of the autonomic functions increase arousal, there is one that decrease. Anyone know which one?

15. Digestion!!
The purpose of digestion turning off while the other ANS functions turn on is to allow the nutrients (oxygen and glucose) to get to the places that need it most, the muscles (so that you can run away from the bear!!)

16. Once you escape the potential threat (real or perceived)
Digestion turns back on, which is why people may begin to feel hungry after sex or after a high stress time of not eating, one might finally be struck with immense hunger.
And, the other ANS functions turn way down.

17. Imagine yourself in a setting that feels very relaxing to you (your ‘happy place’).
Notice how your breathing is natural and relaxed.
Here, the Parasympathetic Nervous System is responsible for you feeling calm.

18. Parasympathetic Nervous System
Conserves and maintains energy.
Acts more slowly than the sympathetic nervous system (hence, why when you get angry at someone, you can feel a sudden adrenaline rush and tensing of your body, and calming down afterwards takes longer).
Most active after the sympathetic nervous system was turned on because the body tries to bring itself back to homeostasis (balance) by going to the other extreme.

19. Reacting vs. Responding
We went over earlier that the autonomic nervous system is primarily “automatic” in that you don’t have to tell your heart or sweat glands to work.
However, as students of psychology, we also have to address a main point and that is “Can we consciously influence to the degree our sympathetic or parasympathetic functions take over?”

20. For example,
Imagine you are sitting in traffic, do you begin to curse aloud and honk your horn out of frustration and annoyance?
Or, might you acknowledge your frustration and use this idle time to breathe, enjoy your surroundings, and practice being calm in stressful situations?

21. Another Example
Your partner just did something that upset you. Do you, cuss him or her out without holding back because your anger consumes you and you feel like you rightfully have the place to unload on him or her?
Or, do you still feel your anger, and perhaps, breathe through it, take some space, and then approach your partner in a manner that can gather more information instead of making her or him feel defensive?

22. In many cases, the choice is yours!
The critical point to understand is that while it is extremely beneficial that our ANS functions are for the most part self-governing, which frees up time to do more pleasurable and enjoyable activities;
We can consciously influence the ANS to some degree and begin to learn how to practice responding vs. reacting.

23. Remember the sympathetic nervous system kicks in even if it perceives a threat, however, perhaps we can shift our perception and what once appeared threatening can now be an opportunity for growth, self-understanding, and healing.

24. Responding instead of reacting is important because we can choose our behaviors and words that support the kind of person we want to be and create the lives we envision for ourselves instead of being a ball of reactivity that relives past, unhealed wounds in the present.

25. There is an important question in Buddhist psychology and that is, “Who is driving the cart? Is it you or the horse?”
We need to wake up to this present moment and become aware of the places we tend to react so that we can heal those areas, and cultivate more mindful responses that allow us to drive the cart, or direct our life, instead of the horses, or our past.