Respiration is the act of breathing.It includes the intake of oxygen and the output of carbon dioxide.External respiration refers to the interchange of oxygen and carbon dioxide between the alveoli of the lungs and pulmonary blood.There are two phases of external respiration namely:
- Inspiration or breathing-in phase, wherein the diaphragm and external intercostals muscles contract enlarging the chest cavity, causing the person to take in air.
- Expiration or the breathing-out phase, wherein the diaphragm and external intercostals muscles relax thereby decreasing the size of the chest cavity and forcing air out of the lungs.
Internal respiration is the interchange of oxygen and carbon dioxide between the circulating blood and the cells of the body.The alveoli are exchange of gases takes place.To a limited extent, regulation or respiration is under voluntary control when swallowing food or fluids, it is necessary to exercise some control over respiration since the entrance for both the respiratory and digestive systems is a common part of the throat.
The respiratory center in the brain, which lies in the medulla oblongata, the nerve fibers of the automatic nervous system and the chemical composition of the blood are factors that help regulate respiration.The respiratory center automatically sends out motor nerve impulses to cause the contraction of the chest muscles which is necessary for respiration.Sensory impulses travel to the respiratory center through the vagus nerve from the lungs and larynx.The Chemical composition of the blood also regulates the rate and depth or respiration.If the blood contains a small amount of carbon dioxide and a greater amount of oxygen, respiration will be weak and slow in rate.The opposite effect occurs when there is a greater amount of carbon dioxide and a lesser amount of oxygen.
Variation in Respiration
The rate of respiration for healthy adults ranges from 16-20 per minute.Respiration is said to be deep when the amount of air inspired is more than 500 ml and shallow, if it is less than 500 ml.However, many factors influence the rate and depth of respiration.They are: age, sex, emotions, disease process, exposure to extremes of temperature, ingestion of toxins, caffeine and stimulants, change in latitude, ingestion of food and exercise.
- Age. In the newborn, respiratory rate is higher while in old age, rate tends to decrease slightly.
- Sex. The female tends to have a slightly rapid respiration and males. It is noticed that increased respiration rate causes the breathing to become shallow. If it is decreased, the depth becomes greater.
- Strong Emotions. During rage, excitement, and anger, the respiration rate tends to go up because of the influence of hormones which are secreted in large amount.
- Disease Process. Diseases especially of the respiratory system have marked effects on the respiration. Pain and fever tend to make respiration feast as a compensatory mechanism to lessen and hasten dissipation or loss. Lessened blood vessels hemorrhage and subsequent decrease in oxygen content supplied into the will increase respiration.
- Exposure to extremes of temperature. Breathing becomes fuller and application of cold. The application may increase respiration temporarily that will cause the breathing to be shallower.
- Ingestion of toxins, caffeine and stimulants, these substances will cause the respiration to be generally faster and deepen. These are the drugs that will stimulate the respiratory system; there are also drugs that if taken in large amount will cause respiratory depression.
- Ingestion of food and exercise. These activities increase body metabolism therefore, increasing the oxygen, thus respiratory rate is increased.
Types of Respiration
Normally, respiration is automatic process.It is regular, even, and accomplished without effort.Some types of breathing are associated with disease and have become their characteristics symptoms.You must observe the rate and depth of respiration. There are many terms that you should know in the course of your study.These are commonly used when describing the respiration of an individual:
- Apnea = refers to the temporary cessation of breathing
- Eupnea = refers to normal respiration.
- Hyperventilation = refers to a very deep, rapid and slow respiration.
- Hypoventilation = refers to shallow and slow respiration.
- Dyspnea = refers to difficult breathing.
- Hyperpnea = refers to an increase rate and depth respiration.
- Hypoxemia = refers to decreased in blood; cyanosis is the bluish discoloration of the skin.
- Hypoxia = refers to the term used when there is decreased oxygen in the tissue.
- Othopnea = refers to the inability to breath when in lying or horizontal position.
- Bradypnea = refers to the abnormal decrease in the respiratory rate.
- Tachypnea = refers to the abnormal increase in the respiratory rate
Normal breathing is silent, however, in certain conditions abnormal sounds is observed or noted especially with the use of the stethoscope.Wheezing occurs when the airway is constricted like in persons with asthma.Stridor is a harsh crowning sound heard on inspirational caused by acute constriction of the trachea.Rales or rhonchi are bubbling or crackling or fizzing sounds that are evident with respiration in lung diseases.
Other types of breathing include abdominal breathing which involves chiefly the muscles of the abdomen and diaphragm; costal breathing which is accomplished chiefly by the diaphragm.
Kussmaul’s breathing or respiration is performed with difficulty, occurring in paroxysm and often preceding diabetic come.Stertorus breathing is noisy breathing that resembles snores.Cheyne-strokes respiration refers to respiration with alternating periods of hyperpnea and apnea.