Edited by Dr. Luca Franzon
Breathing and Diaphragm
The respiratory system is made up of the lungs, which represent the site of gas exchanges, and the pump that serves to ventilate the lungs. The pump consists of the rib cage, the respiratory muscles that move it and the nerve centers that control its movements. Pump work is regulated by the respiratory centers located in the medulla oblongata. The muscles involved are the diaphragm and the external and internal intercostal muscles, the intercondral parasternal muscles, the scalenes, and the sternocleidomastoid.
The diaphragm consists of three parts:
the rib portion, consisting of the muscle fibers that are attached to the ribs around the bottom of the rib cage;
the crural portion, made up of the fibers that are attached to the ligaments along the vertebrae;
the tendon center, in which the rib and crural fibers are inserted. The latter, passing from each side of the esophagus, can compress it as they contract. The tendon center is also the lower part of the pericardium. The rib and crural portions are innervated by different parts of the phrenic nerve and can contract separately. For example, during vomiting and belching, intra-abdominal pressure is increased by the contraction of the rib fibers, but the crural fibers remain released, allowing material to pass from the stomach into the esophagus.
In addition to the diaphragm, the other major inspiratory muscles are the external intercostals, which run obliquely down and forward from each rib to the next. The ribs rotate by pivoting posteriorly on the costo-vertebral joint, and when the intercostal muscles contract, they, which are tilted down and forward, are lifted to a more horizontal position; the sternum is then pushed forward, and the antero-posterior diameter of the thorax increases. The transverse diameter also increases, but to a lesser extent. Both the diaphragm and the external intercostal muscles can, by themselves, maintain adequate ventilation in conditions of rest. The section of the spinal cord above the 3rd cervical segment is fatal without artificial respiration, while a section below the origin of the phrenic nerves (cervical segments 3-5) is not; on the other hand, in patients with paralysis bilateral of the phrenic, but with innervation of the intercostal muscles intact, breathing is a bit tiring but sufficient. The scalene they sternocleidomastoid they are accessory inspiratory muscles that help raise the rib cage in deep and labored breathing.
When the expiratory muscles contract, there is a decrease in intrathoracic volume and forced expiration. The internal intercostals they have this action because they run obliquely downwards and backwards, from one rib to the one below, so they pull the rib cage down when they contract. Contractions of the muscles of the anterior abdominal wall also help with exhalation, both because they pull the rib cage down and in, and because they increase intra-abdominal pressure, which pushes the diaphragm up.
Inspiration
It consists in the dilation of the thoracic cage which, thanks to the pleural system, involves the dilation of the lungs and the recall of air in the bronchial tree and in the alveoli. In normal breathing activity is almost exclusively borne by the diaphragm. With intense inspiratory effort, intra-pleural pressure can drop as low as -30 mmHg, producing much greater than normal expansion (inflation) of the lungs. When ventilation increases, the emptying (deflation) of the lungs also increases, due to the activity of the expiratory muscles which reduce the intra-thoracic volume.
Exhalation
The flow of air exiting the lungs is determined by the decrease in the volume of the chest. It is largely a passive phenomenon due to the elastic nature of the cartilagenic tissues, the lungs themselves and the abdominal walls. This allows the reduction without muscle intervention. Only forced exhalation requires considerable muscular effort. Ventilation maintains the normal concentration of O2 and CO2 in the alveolar blood, through a passage of these gases from the alveoli to the blood capillaries by diffusion. perfusion it corresponds to the pulmonary blood flow which is given by the heart rate for the systolic volume of the right atrium.The relationship between ventilation and perfusion should be the same throughout the lung. The difference between the respiratory gas partial pressures in exhaled gas and systemic arterial blood is a measure of the efficiency of lung function.
Breathing Exercises
Most of the exercises described below should be performed in a sufficiently heated and quiet place and require the use of one or more sandbags weighing 3 kg.
DIAPHRAGMATIC GYMNASTICS
Supine position with knees bent, place the hands on the abdomen at the height of the diaphragm. Inhale deeply while inflating the abdomen, hold the breath for a few seconds, then exhale completely by compressing the abdomen with your hands. Repeat the exercise slowly 20 times.
Supine position legs bent, place the sandbag on the abdomen. Inhale deeply while lifting the bag with the abdomen, hold the breath for a few seconds, then exhale completely while lowering the bag. Repeat the exercise 30 times.
Sitting position hands on the abdomen, inhaling inflate the abdomen, maintain the position for a few seconds then exhale deeply compressing the abdomen with the hands. Repeat the exercise 30 times.
Standing upright position hands placed on the abdomen, inhale deeply inflating the abdomen, hold the position for 10 seconds then exhale compressing the abdomen with the hands. Repeat the exercise 30 times.
On the side in the right lateral decubitus position, the right leg is bent, the hands placed on the abdomen inhale by inflating the abdominal cavity; hold the breath for a few seconds then exhale by compressing the abdomen with the hands. Repeat the exercise 25 times per side.
Exercise similar to the previous one with the addition of a sandbag on the abdomen. Repeat the exercise 30 times per side.
COSTAL GYMNASTICS
Supine legs bent, hands placed on the chest, inhale raising the chest as much as possible; hold your breath for a few seconds, then exhale by squeezing your chest with your hands. Repeat the exercise 30 times.
Exercise similar to the previous one with the addition of a sandbag on the chest. Repeat the exercise 30 times.
Variant to the previous exercise by adding the movement of the arms that in the inhalation phase are brought backwards, in the exhalation phase they return along the hips. Repeat the exercise 25 times.
On the right side with the bag placed on the same side, inhale by bringing the left arm to the back and lifting the sandbag; hold the breath for a few seconds then exhale by lowering the upper limb and the bag. Repeat the exercise 20 times on each side.
