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.

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.