Breathing is usually automatic, controlled subconsciously by the respiratory center at the base of the brain. Breathing continues during sleep and usually even when a person is unconscious. People can also control their breathing when they wish, for example during speech, singing, or voluntary breath holding. Sensory organs in the brain and in the aorta and carotid arteries monitor the blood and sense oxygen and carbon dioxide levels. Normally, an increased concentration of carbon dioxide is the strongest stimulus to breathe more deeply and more frequently. Conversely, when the carbon dioxide concentration in the blood is low, the brain decreases the frequency and depth of breaths. During breathing at rest, the average adult inhales and exhales about 15 times a minute.
(See also Overview of the Respiratory System.)
Respiratory muscles
The lungs have no skeletal muscles of their own. The work of breathing is done by the
The diaphragm, a dome-shaped sheet of muscle that separates the chest cavity from the abdomen, is the most important muscle used for breathing in (called inhalation or inspiration). The diaphragm is attached to the base of the sternum, the lower parts of the rib cage, and the spine. As the diaphragm contracts, it increases the length and diameter of the chest cavity and thus expands the lungs.
The intercostal muscles and neck muscles help move the rib cage and thus assist in breathing.
Abdominal muscles are sometimes involved in breathing out. The process of breathing out (called exhalation or expiration) is usually passive when a person is not exercising. The elasticity of the lungs and chest wall, which are actively stretched during inhalation, causes them to return to their resting shape and to expel air out of the lungs when inspiratory muscles are relaxed. Therefore, when a person is at rest, no effort is needed to breathe out. During vigorous exercise, however, a number of muscles participate in exhalation. The abdominal muscles are the most important of these. Abdominal muscles contract, raise abdominal pressure, and push a relaxed diaphragm against the lungs, causing air to be pushed out.
The muscles used in breathing can contract only if the nerves connecting them to the brain are intact. In some neck and back injuries, the spinal cord can be severed, which breaks the nervous system connection between the brain and the muscles, and the person will die unless artificially ventilated.
Diaphragm’s Role in Breathing
When the diaphragm contracts and moves lower, the chest cavity enlarges, reducing the pressure inside the lungs. To equalize the pressure, air enters the lungs. When the diaphragm relaxes and moves back up, the elasticity of the lungs and chest wall pushes air out of the lungs.
FAQs
Common disorders associated with impaired cardiorespiratory control include brainstem stroke or compression, syringobulbia, Chiari malformation, high cervical spinal cord injuries, and multiple system atrophy.
What are the control mechanisms of breathing key terms? ›
Key Terms. The Phrenic Nerves: A set of two nerves that brings nerve impulses from the spinal cord to the diaphragm. primary motor cortex: The region in the brain that initiates all voluntary muscular movement, including those for respiration.
What controls breathing in the lungs? ›
Your breathing usually does not require any thought, because it is controlled by the autonomic nervous system, also called the involuntary nervous system. The parasympathetic system slows your breathing rate. It causes your bronchial tubes to narrow and the pulmonary blood vessels to widen.
What is breathing regulated by _____? ›
Breathing occurs due to repeated contractions of a large muscle called the diaphragm. The rate of breathing is regulated by the brain stem.
What drink is good for shortness of breath? ›
Eating fresh ginger or adding some to hot water may help reduce shortness of breath due to respiratory infections and asthma.
What are the disorders of the airway and breathing? ›
Chronic respiratory diseases (CRDs) affect the airways and other structures of the lungs. Some of the most common are chronic obstructive pulmonary disease (COPD), asthma, occupational lung diseases and pulmonary hypertension.
What are controlled breathing techniques? ›
BASIC INSTRUCTIONS FOR CONTROLLED BREATHING
- Begin by breathing at your current rate and depth.
- Inhale through the nose.
- Exhale through pursed lips (almost like whistling, but without the sound).
- Find the rhythm of your current breathing and count it to yourself.
First, take a normal breath. Then try a deep breath: Breathe in slowly through your nose, allowing your chest and lower belly to rise as you fill your lungs. Let your abdomen expand fully. Now breathe out slowly through your mouth (or your nose, if that feels more natural).
What is the mechanics and control of breathing? ›
Breathing is an automatic and rhythmic act produced by networks of neurons in the hindbrain (the pons and medulla). The neural networks direct muscles that form the walls of the thorax and abdomen and produce pressure gradients that move air into and out of the lungs.
What is the most powerful respiratory stimulant in a healthy person? ›
Carbon dioxide is one of the most powerful stimulants of breathing. As the partial pressure of carbon dioxide in arterial blood rises, ventilation increases nearly linearly.
Inhale slowly through your nose for 2 counts. Feel your belly get larger as you breathe in. Pucker your lips, as if you were going to whistle or blow out a candle. Exhale slowly through your lips for 4 or more counts.
What controls breathing and respiration? ›
Breathing is usually automatic, controlled subconsciously by the respiratory center at the base of the brain. Breathing continues during sleep and usually even when a person is unconscious. People can also control their breathing when they wish, for example during speech, singing, or voluntary breath holding.
What is controlled breathing called? ›
Diaphragmatic Breathing
Diaphragmatic exercises help to make people feel relaxed and rested. This breathing exercise is also sometimes called belly breathing or abdominal breathing.
What is breathing controlled by answer? ›
The medulla oblongata regulates the pace of breathing in humans. It's a major respiratory control facility. It transmits impulses to the muscles in the lungs that control breathing. 12 to 25 breaths per minute is the average breathing rate.
Which of the following controls breathing? ›
The medulla oblongata is responsible for controlling the respiratory activity of the body. This means that the level of inspiration and expiration is controlled with the help of the actions of the medulla oblongata. The respiratory rate is the number of times breathing occurs every minute.
What are the 5 diseases that affect breathing? ›
Respiratory disorders, or lung diseases, are disorders such as asthma, cystic fibrosis, emphysema, lung cancer, mesothelioma, pulmonary hypertension, and tuberculosis. If left untreated, lung disease can produce health complications, problematic symptoms, and life-threatening conditions.
Why am I always controlling my breathing? ›
Being in tune with your body can be a very positive thing. So a heightened awareness of bodily functions, such as blinking or breathing, is normal—and it's especially common if you're experiencing anxiety or panic.
What is it called when you can't control your breathing? ›
Hyperventilation syndrome happens when you hyperventilate frequently with no underlying physical cause. Episodes can happen due to stress or anxiety or for no apparent reason. Treatment involves breathing retraining to prevent future episodes.
What can cause disordered control of breathing? ›
Specific causes of disordered control of breathing include increased intracranial pressure (ICP), poisoning or drug overdose, and neuromuscular diseases.
