The Parasympathetic System

Inspiratory muscles relax (diaphragm rises; rib cage descends)  Thoracic cavity volume decreases  Elastic lungs recoil and intrapulmonary volume decreases  pressure increases  Air flows out of lungs down its pressure gradient until Ppul = 0. (Marieb & Hoehn, 2013, p. 817-819)

• Decreased SOB, decreased crackles in the bases of the lungs, and possibly decreased O2

an increase in heart and respiration rates in order to increase oxygen levels in the body as part of

At higher altitudes respiration rate is increased which leads to increases in ventilation (possibly a five-fold increase from sea level). Chemoreceptors in the arterial blood vessels are stimulated to signal the brain to increase ventilation. The increase in ventilation is associated with increased breathing frequency and tidal volume.

Once oxygen is deposited into the bloodstream by the lungs, the body must also increase your heart rate to deliver oxygen to the cells to once again maintain homeostasis. The increase in

their relation to the above questions. Describe the role of the nervous system, adrenal glands, kidneys and

- opposite effect of the Sympathetic System. This system saves your energy by decreasing your heartbeat, lowering your blood sugar and so forth.

Breathing is known as ventilation; and the act of hyperventilation is over-breathing or taking more breaths in per minute than the normal rate. Hyperventilating is a demonstration of a person’s breathing control center, however it causes stress to a person’s body (Campbell et al, 2006). Blood picks up oxygen as it travels and when exercise is introduced the rate of respiration increases to introduce more blood to the oxygen, keeping up with a person’s lungs. The body still taking in breaths at a higher pace than normal, has a different effect on the respiratory rate and system than the act of hyperventilation. Hyperventilation is less controlled, which is the cause of damage due to rapid breathing that purges the blood of so much CO2 that the control center temporarily ceases to send signals to the rib muscles and diaphragm; breathing continues when the CO2 levels increase enough to switch the breathing center back on (Simon et al, 2006).

Bradycardia is a decrease of heart rate to less than 60 beats per minute (American Heart Association 2016). In humans, the heart rate could slow up to 50%. Peripheral vasoconstriction causes blood flow to reduce by narrowing the blood vessels or increasing resistance (Tandy 2016). Reduction of blood flow allows for the intrinsic oxygen stores to go to oxygen sensitive organs with highest priority like the heart and brain. Blood shift protects the lungs in high pressure such as preventing the lungs from collapsing by moving blood plasma to the blood vessels of the thoracic chest cavity and accumulating there (Breatheology). These three physiological responses work together to conserve oxygen activated by peripheral receptors. Age is also another factor that affects the diving reflex because older adults have increasing heart rate in comparison to children (Panneton 2013). Therefore, the diving reflex works better in

to flow through. There will be greater back pressure and heart will have to work harder to circulate

Control centers: the medulla oblongata and neural circuits establish a person’s breathing rhythm that gathers information from the internal environment to coordinate breathing based on the body’s need for oxygen. To accomplish this, the sensors in the medulla monitor the pH of the cerebrospinal fluid to indicate the concentration of carbon dioxide in the body. A normal pH is about ~7.4. When the blood pH falls below this range, the medulla’s sensors detect a low pH in the cerebrospinal fluid and blood. This cause the ribs and diaphragm to increase their rate of rate of ventilation, causing the carbon dioxide level in the blood to fall and raising the blood and cerebrospinal fluid pH once again. The higher the carbon dioxide level, the more hydrogens that are present in a substance, causing its pH to

Also, it affects the heart; the blood is stopped from reaching the heart and it regulates the volume of blood flow.

The first stage of shock the underlying disorder, such as a trauma, triggers a decrease in circulating blood volume resulting in hypotension (low blood pressure). The sympathetic nervous system (SNS) is quickly stimulated to try to compensate for the decrease in blood pressure. The signs caused by this stimulation include thirst, anxiety, restlessness, and tachycardia. There are also signs caused directly from the decrease in blood pressure and blood flow. These include dizziness, fainting, fatigue, and lack of

     The Parasympathetic nervous system is an antagonist to the sympathetic nervous system. Its primary function is to give you the ability to rest and relax, in times when you are tired or stressed. The parasympathetic nervous system works to save energy and allow your blood pressure to also decrease. Your heartbeat reduces becoming much slower, and digestion can start. Notice again in figure

in a reduction of baroreceptor activity to the brain. This causes the cardiovascular control center