What is the difference between the air we inhale and exhale

They also carry the waste gas carbon dioxide out of your lungs. The airways include these parts of your body:. Breathing air into your lungs. The windpipe divides into two bronchial tubes, or bronchi, then branches into smaller bronchioles.

The bronchioles end in tiny air sacs, called alveoli. Here the oxygen you inhale passes into the bloodstream, and carbon dioxide from your body passes out of the bloodstream into the air in your lungs. The carbon dioxide is expelled from your body when you exhale. Air first enters your body through your nose or mouth, which moistens and warms the air since cold, dry air can irritate your lungs. The air then travels past your voice box and down your windpipe.

Rings of tough tissue, called cartilage, acts as a support to keep the bronchial tubes open. Inside your lungs, the bronchial tubes branch into thousands of thinner tubes called bronchioles.

The bronchioles end in clusters of tiny air sacs called alveoli. Your lungs have about million alveoli. Normally, your alveoli are elastic, meaning that their size and shape can change easily. Alveoli are able to easily expand and contract, because their insides are coated with a substance called surfactant. Surfactant reduces the work it takes to breathe by helping the lungs inflate more easily when you breathe in and preventing the lungs from collapsing when you breath out.

Each of these alveoli is made up of a mesh of tiny blood vessels called capillaries. The capillaries connect to a network of arteries and veins that move blood through your body. The pulmonary artery and its branches deliver blood to the capillaries that surround the alveoli. This blood is rich in carbon dioxide and low in oxygen.

Carbon dioxide moves from the blood into the air inside the alveoli. At the same time, oxygen moves from the air into the blood in the capillaries. How does my body protect the airways from food or bacteria? When you swallow, a thin flap of tissue called the epiglottis covers your windpipe. Along with coughing and gag reflexes, the epiglottis prevents food and drink from entering the airway. The epiglottis also helps direct food into your esophagus, which is the pipe that goes to your stomach.

Except for the mouth and some parts of the nose, the airways have cells that make mucus, a sticky substance that coats the walls of the airways. Other cells in the airways have hairlike structures called cilia. The cilia and mucus trap germs and other particles that enter your airways when you breathe in air.

The cilia then sweep the mucus-coated germs up to the nose or mouth. From there, the germs are swallowed, coughed, or sneezed out of the body. The lungs are surrounded by the pleura, a membrane with two layers.

The space between these two layers is called the pleural cavity. A slippery liquid called pleural fluid acts as a lubricant to reduce friction during breathing.

The lungs are like sponges; they cannot expand get bigger on their own. Muscles in your chest and abdomen contract tighten to create a slight vacuum around your lungs. This causes air to flow in. When you exhale, the muscles relax and the lungs deflate on their own, much like an elastic balloon will deflate if left open to the air. Damage to the nerves in the upper spinal cord can interfere with the movement of your diaphragm and other muscles in your chest, neck, and abdomen.

This can happen due to a spinal cord injury, a stroke, or a degenerative disease such as muscular dystrophy. The damage can cause respiratory failure. Ventilator support or oxygen therapy may be necessary to maintain oxygen levels in the body and protect the organs from damage.

Your breathing usually does not require any thought, because it is controlled by the autonomic nervous system, also called the involuntary nervous system. Your breathing changes depending on how active you are and the condition of the air around you. For example, you need to breathe more often when you do physical activity. At times, you can control your breathing pattern, such as when you hold your breath or sing.

To help adjust your breathing to changing needs, your body has sensors that send signals to the breathing centers in the brain. In central sleep apnea, the brain temporarily stops sending signals to the muscles needed to breathe.

Learn more at our Sleep Apnea Health Topic. Breathing involves two phases: breathing in and breathing out. If you have problems breathing, gas exchange may be impaired, which can be a serious health problem.

When you breathe in, or inhale, your diaphragm contracts and moves downward. This increases the space in your chest cavity, and your lungs expand into it. The muscles between your ribs also help enlarge the chest cavity.

They contract to pull your rib cage both upward and outward when you inhale. As your lungs expand, air is sucked in through your nose or mouth. The air travels down your windpipe and into your lungs. After passing through your bronchial tubes, the air travels to the alveoli, or air sacs. Gas exchange in your lungs. Here one breath involves the one complete inhalation and exhalation.

So breathing rate varies from person to person and different kind of activity they perform in a day. Though on an average, the breathing rate of an adult is times a minute, however, it may increase up to 25 times per minute in case of heavy exercises, while running or fast walking. There is a lot of confusion between breathing and respiration, so it can be simply understood by saying that breathing involves the process of exchanging of gases like oxygen and carbon dioxide from the lungs with the help of various respiratory organs.

While respiration is a complete biochemical process, where the cells of organisms gain energy by combining oxygen and glucose, which results in giving out carbon dioxide, ATP adenosine triphosphate and water. As this article is focused on the breathing processes, which are inhalation and exhalation. Thus, we will consider the basic difference between the two with the brief description. Basis for Comparison Inhalation Exhalation Meaning Inhalation is the process of intake of air into lungs. Exhalation is the process of letting air out from lungs.

Type of process Inhalation is an active process. Exhalation is a passive process. The role of diaphragm They contract during the inhalation and get flattens by moving down. They relax during exhalation and turned into dome-shaped by moving up. The role of intercostal muscle Internal intercostal muscles relaxes and external costal muscles contract. Internal intercostal muscles contract and external intercostal muscles relax.

The volume of lungs It increases during inhalation means it get inflated. It decreases during exhalation means it gets deflated. The size of chest cavity Increases. It results Air rich in oxygen is taken into the blood. Types of breathing in humans include eupnea, hyperpnea, diaphragmatic, and costal breathing; each requires slightly different processes. There are different types, or modes, of breathing that require a slightly different process to allow inspiration and expiration.

All mammals have lungs that are the main organs for breathing. During exhalation, the lungs expel air and lung volume decreases. The various types of breathing, specifically in humans, include:. During eupnea, also referred to as quiet breathing, the diaphragm and external intercostals must contract. As the diaphragm relaxes, air passively leaves the lungs. This type of breathing is also known as deep breathing. Diaphragmatic breathing : Animation of a diaphragm exhaling and inhaling, demonstrating diaphragmatic breathing.

During inhalation, the diaphragm is contracted which increases the volume of the lung cavity. During exhalation, the diaphragm is relaxed which decreases the volume of the lung cavity. As the intercostal muscles relax, air passively leaves the lungs. This type of breathing is also known as shallow breathing.

During hyperpnea, also known as forced breathing, inspiration and expiration both occur due to muscle contractions. In addition to the contraction of the diaphragm and intercostal muscles, other accessory muscles must also contract. During forced inspiration, muscles of the neck, including the scalenes, contract and lift the thoracic wall, increasing lung volume. During forced expiration, accessory muscles of the abdomen, including the obliques, contract, forcing abdominal organs upward against the diaphragm.

This helps to push the diaphragm further into the thorax, pushing more air out. In addition, accessory muscles primarily the internal intercostals help to compress the rib cage, which also reduces the volume of the thoracic cavity. In animals such as amphibians, there have been multiple ways of breathing that have evolved.

In young amphibians, such as tadpoles that do not leave the water, gills are used to breathe. There are some amphibians that retain gills for life. As the tadpole grows, the gills disappear and lungs grow. These lungs are primitive and not as evolved as mammalian lungs. Adult amphibians are lacking or have a reduced diaphragm, so breathing via lungs is forced. The other means of breathing for amphibians is diffusion across the skin. To aid this diffusion, amphibian skin must remain moist.

Other animals, such as birds, must face a unique challenge with respect to breathing, which is that they fly. Flying consumes a large amount of energy; therefore, birds require a lot of oxygen to aid their metabolic processes. They have evolved a respiratory system that supplies them with the oxygen needed to enable flying. Similar to mammals, birds have lungs, which are organs specialized for gas exchange.

Oxygenated air, taken in during inhalation, diffuses across the surface of the lungs into the bloodstream, while carbon dioxide diffuses from the blood into the lungs and is expelled during exhalation.

However, the details of breathing between birds and mammals differ substantially. In addition to lungs, birds have air sacs inside their body that are attached to the lungs. Air flows in one direction from the posterior air sacs to the lungs and out of the anterior air sacs.

The flow of air is in the opposite direction from blood flow, which allows efficient gas exchange. This type of breathing enables birds to obtain the requisite oxygen, even at higher altitudes where the oxygen concentration is low. This directionality of airflow requires two cycles of air intake and exhalation to completely remove the air from the lungs.

Avian respiratory system : a Birds have a flow-through respiratory system in which air flows unidirectionally from the posterior sacs into the lungs, then into the anterior air sacs. The foods we eat such as carbohydrates and proteins are digested in our gastrointestinal tract into molecules such as sugars and amino acids that are small enough to pass into the blood.

The blood transports the sugars to the cells, where the mitochondria break up their chemical bonds to release the energy they contain. Cells need oxygen to be able to carry out that process. As every cell in our body needs energy, every one of them needs oxygen.

The energy released is stored in a chemical compound called adenosine triphosphate ATP , which contains three phosphate groups. When we need energy to carry out an activity, ATP is broken down into adenosine diphosphate ADP , containing only two phosphate groups. Breaking the chemical bond between the third phosphate group and ATP releases a high amount of energy. Our lungs supply oxygen from the outside air to the cells via the blood and cardiovascular system to enable us to obtain energy.

As we breathe in, oxygen enters the lungs and diffuses into the blood. It is taken to the heart and pumped into the cells. At the same time, the carbon dioxide waste from the breakdown of sugars in the cells of the body diffuses into the blood and then diffuses from the blood into the lungs and is expelled as we breathe out.

One gas oxygen is exchanged for another carbon dioxide. This exchange of gases takes places both in the lungs external respiration and in the cells internal respiration. Fig 1 summarises gas exchange in humans. Our respiratory system comprises a conduction zone and a respiratory zone. The conduction zone brings air from the external environment to the lungs via a series of tubes through which the air travels.

These are the:. The nasal cavity has a large number of tiny capillaries that bring warm blood to the cold nose. The warmth from the blood diffuses into the cold air entering the nose and warms it. The lining of the pharynx and larynx which form the upper respiratory tract and the lining of the trachea lower respiratory tract have small cells with little hairs or cilia. These hairs trap small airborne particles, such as dust, and prevent them from reaching the lungs.

The lining of the nasal cavity, upper respiratory tract and lower respiratory tract contains goblet cells that secrete mucus. It also traps particles, which the cilia then sweep upwards and away from the lungs so they are swallowed into the stomach for digestion, rather than getting trapped in the lungs.

This mechanism of moving trapped particles in this way is known as the mucociliary escalator. The lungs are a little like balloons: they do not inflate by themselves, but only do so if air is blown into them.

We can blow into the lungs and inflate them — which is one of the two techniques used for cardiopulmonary resuscitation — but that does not happen in the normal daily life of healthy people. We have to inhale and exhale air by ourselves. How do we do that?

We have two lungs right and left contained in the thoracic cavity chest. Surrounding the lungs are ribs, which not only protect them from damage but also serve as anchors for the intercostal muscles.

Beneath the lungs is a very large dome-shaped muscle, the diaphragm. All these muscles are attached to the lungs by the parietal and visceral membranes also called parietal and visceral pleura. The parietal membrane is attached to the muscles and the visceral membrane is attached to the lungs. The liquid between these two membranes, pleural fluid, sticks them together just as panes of glass become stuck together when wet.

As the visceral membrane covers, and is part of, the lungs and is stuck by pleural fluid to the parietal membrane, when the muscles in the thorax move, the lungs move with them. If air gets between the membranes, they become unstuck and, although the muscles can still contract and relax, they are no longer attached to the lung — as a result, the lung collapses.

This abnormal collection of air in the pleural space is called a pneumothorax. If the pleural fluid liquid becomes infected, the person develops pleurisy. When the intercostal muscles contract, they move up and away from the thoracic cavity.