What is meant by “pastness of the past”
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Explanation:
- #When we breathe, we inhale oxygen and exhale carbon dioxide. The so-called exchange of gases is necessary for metabolic activities and can be considered a chemical process.
- Every organism, from an individual bacterial cell to a mighty blue whale, undergoes respiration. This respiration is carried out by a system of organs known as the Respiratory System and the respiration in humans is carried out by the human respiratory system.
- Let us explore respiratory system notes to have a detailed understanding of the human respiratory system, its parts, functions and the process of respiration in humans.
- Respiratory System Definition
- “Human Respiratory System is the organ system that involves inhaling of oxygen and exhaling of carbon dioxide to meet the energy requirements.”
- What is the Respiratory System?
- The human respiratory system consists of a group of organs and tissues that help us to breathe. Lungs are the primary organs of the respiratory system which help in the exchange of gases. The other main parts of this system include a series of airways for air passages, blood vessels and the muscles that facilitate breathing.
- #Features of the Human Respiratory System
- The respiratory system in humans has the following important features.
- The energy is generated by the breakdown of glucose molecules in all living cells of the human body.
- Oxygen is inhaled and is transported to various parts and are used in the process of burning food particles (breaking down of glucose molecules) at the cellular level in a series of chemical reactions.
- The obtained glucose molecules are used for discharging energy in the form of ATP- adenosine triphosphate molecules by the human body to fulfil essential life processes.
- #Respiratory System Parts and Functions
- Let us have a detailed look at the different parts of the respiratory system and their functions.
- Nose
- The nose possesses a couple of exterior nostrils, which are divided by a framework of cartilaginous structure termed as the septum. This is the structure that evenly separates the right nostril from the left nostril. Tiny hair follicles that cover the interior lining of nostrils acts as the body’s first line of defence against foreign pathogens. Furthermore, they provide additional humidity for inhaled air.
- Larynx
- Two cartilaginous chords lay the framework for the larynx. They are situated at the point of joining the pharynx and trachea. It is also termed as Adam’s apple or the voice box. It is the portion which rises and falls during swallowing of food particles. It generates sound as air passes through the hollow in the middle.
- Pharynx
- The nasal chambers open up into a wide hollow space termed as the pharynx. It is a common path for both air and food. It functions by preventing the entry of food particles into the windpipe. The epiglottis is an elastic cartilage, which serves as a switch between the larynx and the oesophagus by allowing the passage of air into the airway to the lungs, and food in the gastrointestinal tract.
- Talking while we eat or swallow results in incessant coughing. The reason behind this reaction is the epiglottis. It is forced to open for the air to exit outwards and the food to enter into the windpipe, triggering a cough.
- Trachea
- The trachea or the windpipe rises below the larynx and moves down to the neck. The walls of trachea comprise C-shaped cartilaginous rings which give hardness to the trachea and maintain it by completely expanding. The trachea extends further down into the breastbone and splits into two bronchi, one for each lung.
- Bronchi
- The trachea splits into two tubes termed as bronchi, which enter each lung individually. The bronchi divide into secondary, tertiary, and to bronchioles, which is again further divided into small air-sacs called the alveoli. The alveoli are minute sacs of air with thin walls and single-celled manner. It enables the exchange of oxygen and carbon dioxide molecules into or away from the bloodstream.
- Lungs
- Lungs are the chief centres of the respiration in humans and other vertebrates. They are located in the thoracic cavity of the chest near the backbone and on either side of the heart. They are the pair of large, spongy organs, mainly involved in the exchange of gases between the blood and the air. Compared to the left lung, the right lung is quite bigger and heavier.
