Respiration in Organisms

Respiration in Human

Respiration takes place in humans in the two sets of processes. In one set glucose is broken down in cells, and in another set exchange of gases for respiration occurs.

We take oxygen in for respiration and release out carbon dioxide at the end of respiration.

Our body has a very good mechanism for exchanges of gases. This mechanism is composed of two processes. In the first step, we take oxygen in, which is mixed in blood. After that carbon dioxide is removed from the blood and expelled out of the body as the second process.

For this we need breathing. Breathing is a part of respiration.

Breathing

The taking oxygen in and expelling out carbon dioxide is called breathing. We take air in and give air out through our nostrils. All living organism need breathing to keep them survive. It continues till life, without breathing none can survive.

Breathing is taken place by our respiratory organs. Breathing is taken place in two stages. In the first stage air rich in oxygen is taken in, and in the second stage carbon dioxide is expelled out.

Figure¹ : Exchange of gases in human lungs (See below for reference)

Inhalation and Exhalation

The taking the air rich in oxygen in is called inhalation or inspiration and giving out of carbon dioxide is called exhalation or expiration.

The one inhalation and exhalation completes one breathe.

Breathing is a continuous process, which is carried on throughout the life of an organism.

Breathing rate

The number times a person breathes in one minute is called the breathing rate. One breath means one inhalation and one exhalation. One can calculate his breathing rate by counting the number of breath in one minute.

We need extra energy after running, doing exercise, fast cycling, fast walking, etc. In these conditions we do extra work than normal, so our body needs extra energy. To fulfill this extra energy, our body needs more oxygen for respiration consequently we start breathing fast.

This means in the condition of need of extra energy our breathing rate increases. Similarly, when we feel drowsy, in sleeping, or in rest, our body require less energy. In that condition our breathing rate decreases.

Normal Breathing Rate

On an average, an adult human being at rest breathes in and out 15–18 times in a minute.

During heavy exercise, the breathing rate can increase up to 25 times per minute. While we exercise, not only do we breathe fast, we also take deep breaths and thus inhale more oxygen.

How Do We Breathe?

Human Respiratory System

We respire through our lungs. Besides lungs some other organs also help in respiration. These all together forms a system called Respiratory System. Our Respiratory System is composed of organs named nasal cavity, pharynx, larynx, trachea, bronchi and lungs

Nasal Cavity

Respiration starts from our nose. We breathe in air and breathe out air through our nose. Our nose has two hollow spaces at both side. The hollow space inside the nose is called nasal cavity.

Our nasal cavity has many hairs inside it. These hairs trap dust in the course of inspiration and prevent them from entering further. The nasal cavity secretes mucus to keep itself wet. Mucus helps in trapping dust further by keeping the hairs and cavity wet. Hairs and mucus work together like a filter. This filtering system ensures sending clean air inside the lungs.

Figure² : Respiratory System Human (Please See below for reference)

Pharynx

The pharynx is positioned after nasal cavity. The pharynx and buccal cavity has common opening. This common opening works as a type of safety mechanism. Whenever there is a blockade in nasal cavity, this common opening allows breathing. But sometimes food can accidently enter in the pharynx because of common opening. So you should always be careful while eating. We should not speak while eating to prevent any such happening.

The entering of food in pharynx can be a cause of little discomfort.

Larynx

The larynx comes after pharynx. The air we take in through nasal cavity is advanced in through this larynx.

Trachea

Trachea has a tube like structure. It starts from throat and is composed of cartilage rings. These cartilage rings keep trachea spread. Because of cartilage, trachea does not collapse in the absence of air in it. Trachea is also known as the wind pipe.

Bronchi

Trachea is further branched into two parts which are known as bronchi. Bronchus is singular form of bronchi. Each bronchus goes to a lung. These carry air which we breathe in to the lungs, and carry air to the nasal cavity which we breathe out.

Lungs

There are two lungs present in humans. One is the right lung and the other is the left lung. The structure of the lung is like a big sac. The lung is pink in colour. Each bronchus is further branched into many small parts called bronchioles inside the lungs. At the end of each bronchiole, air sacs similar to bulbs are found. These air sacs are called Alveoli. Alveoli are made of a very thin membrane. These thin membranes of alveoli carry oxygen readily to blood and carry carbon dioxide from the blood to the alveoli.

Diaphragm

The diaphragm is like a big membrane. Diaphragm separates thoracic cavity from abdominal cavity. Thoracic cavity is the chamber which contains heart and lungs. The chamber which contains stomach, intestines, etc. is called the abdominal cavity.

Process of Breathing

Diaphragm helps in breathing by moving up and down.

During taking air in, i.e. in inhalation, diaphragm goes down, with this rib case also expands. This facilitate lungs to be expanded and air goes inside the lungs.

During expelling air, i.e. in exhalation, diaphragm goes up along with contraction of rib case. This creates a high pressure zone inside lungs and air expels out.

Figure³ : Breathing in Human (Please See below for reference)

We release carbon dioxide when we exhale air during breathing. Air which we breathe out contains moisture also along with carbon dioxide.

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Reference:

Figure¹ : Exchange of gases in human lungs By domdomegg - Own work, CC BY 4.0, Link

Figure² : Respiratory System Human Reference: By Lord Akryl, Jmarchn - Vectorized version of File:Illu conducting passages.jpg, which was in the public domain as a work of the US Government, Public Domain, Link

Figure³ : Breathing in Human By John Pierce - Own work, CC0, Link