Diagram of Human Lungs

Diagram of Human Lungs shows that the lungs begin at the bottom of our trachea. The trachea is a tube that carries the air in and out of our lungs. Each lung has a tube known as a bronchus that connects to the trachea. The trachea and bronchi airways form an upside-down “Y” in our chest which is known as the bronchial tree. The bronchi branch off into smaller bronchi and even smaller tubes called bronchioles. Each bronchiole tube ends with a cluster of small air sacs called alveoli where the gaseous exchange takes place. In this section, we will explain the diagram of the human lung in detail.

Human Lungs

Human lungs are the organs of respiration, which are located in the thorax on either side of the breastbone or mediastinum in the chest cavity. They are a vital part of the respiratory system. They are a group of organs and tissues that work together to help us breathe. Lungs are enclosed within the pleura which is a thin membranous sac. In addition to the lungs, the respiratory system comprises the airways which are responsible for carrying air in and out of our lungs, blood vessels that surround our lungs, and the muscles that help us breathe.

Lungs are very light, soft, spongy, and elastic organs that always contain some air. Healthy lungs float in water and crackle if squeezed whereas diseased lungs sink. The primary role of the lungs is to remove carbon dioxide from the blood and to add oxygen to it. To do this, the heart and lungs work together. Different parts of the lung are described below.

Lobes

The lungs are divided into five main sections termed as lobes separated from one another by a tissue fissure. The right lung is divided into three lobes, which are just like a balloon filled with sponge-like tissue. Air moves in and out through one opening—a branch of the bronchial tube. The left lung is divided into two lobes and is slightly smaller in size due to the asymmetrical placement of the heart. Internally, each lobe is further subdivided into hundreds of lobules.

Pleura

Each lung is enclosed in a thin membranous sac called the pleura, that surround each lobe of the lungs and isolate our lungs from our chest wall.

Cilia

Our bronchial tubes are lined with very small hairs known as cilia which move like waves. This wave like motion carries mucus i.e., a sticky phlegm or liquid upward and out into our throat, where it can be either swallowed or coughed up. The role of mucus is to catch and hold dust, germs, and other undesired materials that has entered our lungs. We usually get rid of such unwanted matter when we cough, sneeze or swallow.

Bronchioles

The smallest branches of the bronchial tubes are termed as Bronchioles. Air sacs or alveoli are located at the end of bronchioles.

Alveoli

The lungs consist of thousands of thin tubes which end in bunches of tiny air sacs called alveoli, where the actual gaseous exchange takes place i.e., exchange of oxygen and carbon dioxide. Each alveolus is covered with blood vessels that forms a connection to a system of veins and arteries that move blood through our body. When we take a breath, the pulmonary artery and its branches bring blood containing loads of carbon dioxide and no oxygen into these vessels. Carbon dioxide leaves the blood and enters the air, and oxygen leaves the air and enters the blood. This is called “Gas exchange”. Once the blood has sufficient oxygen and no carbon dioxide, it is returned to the heart and pumped to the rest of the body.

Hilum

The pulmonary arteries and veins, lymphatic vessels, nerves, and bronchi all enter the lung at the point called hilum, which is located in the inner side of each lung around two-thirds of the way from the base to the apex of the lung. After the main bronchus enters the lung, it repeatedly divides, creating an inverted tree-like network of tubules.

Diagram of Human Lung

The diagram of lung representing its different parts is shown below.

The Human Respiratory Pathway

In order to understand the mechanism of respiration in humans, we must know the human respiratory pathway completely which comprises of :

Nose/mouth → Pharynx → Larynx → Trachea → Bronchi → Bronchioles → Alveoli

Airways

Our body uses numerous channels to bring oxygen-rich air into the lungs and release carbon dioxide (a waste gas) out of the lungs. The body’s airways include:

Sinuses

These are little apertures that connect the hollow regions in our head’s bones above and below our eyes to our nose. The temperature and humidity of air that is inhaled are controlled by them.

Nose

The preferred orifice through which outside air enters the respiratory system is the nose. The air-cleaning system includes the hairs that line the wall of the nose.

Mouth

Air also enters through the mouth, especially for those who have a mouth-breathing habit, whose nasal passages may be temporarily blocked by a cold, or during heavy exercise.

Throat

Its function is to collect the incoming air from our nose and mouth and then pass it down to the windpipe (trachea). A thin flap of tissue, the epiglottis, blocks our windpipe when we swallow to stop food and liquid from entering.

Trachea

The passageway that connects our throat to our lungs is called the trachea, or WINDPIPE. It divides into the two main Bronchial Tubes, one for each lung, which further divides into each lobe of our lungs. They, in turn, further split into bronchioles.

When we breathe out, the air leaves our body through these airways.

Blood Vessels of the Lungs

Capillaries are the blood vessels in the walls of the alveoli. Blood passes through the capillaries, enters through our pulmonary artery and leaving via our pulmonary vein. When blood is in the capillaries, it gives off carbon dioxide through the capillary wall into the alveoli and takes up oxygen from air in the alveoli.

Muscles and Bones of the Lungs

Many muscles are needed in order to help lungs to expand and contract during breathing:

Diaphragm

The diaphragm is located below the lungs. It is the strong wall of muscle that separates our chest cavity from the abdominal cavity and is the main muscle required for breathing. By moving downward, it creates suction in our chest, which helps in drawing in of air and expanding of lungs.

Intercostal muscles

They are located between the ribs and provide space for the lungs to breathe by expanding and contracting the chest cavity.

Abdominal muscles

These muscles provide space for the lungs to breathe by compressing the internal organs in the abdomen.

Neck and upper chest muscles

These muscles help us to breathe in times of difficult breathing in case of lung disease or damage to other muscles.

Ribs

Ribs are the bones that support and protect our chest cavity. They move slightly in order to help our lungs to expand and contract.

Significance of the Human Lungs

Each cell of our body requires oxygen for survival. The air we breathe in contains oxygen and some gases. The primary job of our respiratory system is to transfer fresh air into our body as well as to remove waste gases from our body. As soon as the oxygen reaches our lungs, it is taken into the bloodstream and carried through our body. In each cell of our body, oxygen is exchanged for a waste gas known as carbon dioxide. This waste gas is taken back to our lungs by the bloodstream, where it is removed from the bloodstream and then exhaled. This essential phenomenon is known as gas exchange, which human lungs and respiratory system perform automatically.

Apart from gas exchange, our respiratory system performs some others roles as well which are essential for breathing such as:

1. Adjusting the air’s temperature to the proper body temperature and adjusting its moisture content.
2. Shielding our body from dangerous materials which is accomplished by sneezing, coughing, filtering, or ingesting them.
3. Enhancing our olfactory perception i.e., our sense of smell.

Apart from breathing, the lungs carry out various other physiological functions. They allow for the absorption and excretion of pharmaceutical drugs, alcohol, and water. They can absorb and eliminate anesthetic gases like nitrous oxide and ether. Furthermore, the lung is a real metabolic organ. It is involved in the synthesis, storage, transformation, and breakdown of a wide range of compounds, such as histamine, prostaglandins, as well as pulmonary surfactant.

FAQ on Human Lungs

1. Which Lung is Bigger?

The right lung is typically larger than the left lung. The human right lung is divided into three lobes (upper, middle, and lower lobes), while the left lung has only two lobes (upper and lower lobes).

2. What is Lung Made of?

The lungs are complex organs primarily involved in the respiratory system. The main components of lungs are tissues, blood vessels, alveoli and pleura.

3. Where is Lung Located?

The lungs are located in the thoracic cavity of the chest. They flank the heart and are enclosed by the ribcage.

4. What Disease Affects the Lungs?

Disease that affect the lungs include Asthma, COPD, Lung infections like pneumonia, Lung cancer, Bronchitis, Pulmonary edema, etc.

5. What are the Human Lungs?

The human lungs are complex organs made up of various tissues and structures that facilitate the process of breathing and gas exchange. The main components found in the human lungs are: Bronchi and Bronchioles, Alveoli, TIssues, Blood vessels, Pleura and Diaphragm.