Increasing stimulation of the parasympathetic nervous system decreases heart rate and blood pressure as well as the size of the pupil. At the same time, it increases digestion, urination, defecation and sexual arousal. The parasympathetic nervous system governs activities that involve relaxation.Know More
The parasympathetic nervous system controls body functions that do not require immediate action. These include digestion and sexual arousal. It also promotes urination by moving urine down the tubes that connect the kidneys to the bladder, and causes the bladder to contract and relaxes the sphincter that allows urination. Defecation is aided by the movement of feces along the intestine and relaxation of the anal sphincter. Sexual arousal is dependent on the engorgement of sexual organs by blood, and stimulation of the PNS allows this to occur. In the female, PSN stimulation assists the movement of eggs from the fallopian tube to the uterus.
The PSN increases secretions, such as saliva, and this aids digestion. Mucous production is increased while the muscles of respiration relax.
Stimulation of the PSN decreases heart rate. It decreases blood pressure by causing dilation of the blood vessels. This is often seen in athletes who have a low resting heart rate and a fast recovery time. Runners and bicyclists are good examples of this.Learn more about Biology
Respiratory drive, or respiratory control, refers to the process by which detected changes in the body's pH and PCO2 levels are responded to by the central nervous system's corrective stimulation of the rhythm, effort and rate of breathing. The control and response of the respiratory system takes place within the medulla of the brain stem. The spinal cord serves as the conduit through which the appropriate neural signals are conveyed to the muscles of respiration.Full Answer >
Caffeine functions by stimulating the central nervous system, which affects the heart and blood pressure, by blocking adenosine, a natural chemical found in the brain that regulates sleep. Adenosine connects to receptors in the brain and slows down the activity of the cells; drowsiness results. Caffeine works to keep an individual alert by taking over the receptors and increasing their speed, which has the opposite effect of adenosine.Full Answer >
According to the National Institutes of Health, Medline Plus, the normal resting heart rate or cardiac rate for children, who are three to four years old, ranges from 80 to 120 beats per minute. Any major deviations from the normal heart rate can indicate a medical condition.Full Answer >
Holding your breath after breathing in causes the heart rate to slightly decrease as it stimulates the parasympathetic nervous system, explains Ricky Cheng for CurioCity. However without breathing in, holding your breath has very little effect on your heart rate.Full Answer >