Key Functions of the Diaphragm in Human Physiology
All living organisms require energy to meet down their daily requirements. This energy is derived from the breakdown of nutrient molecules like glucose. Catabolic reactions are the reactions in which glucose is broken down into carbon dioxide and water in the presence of oxygen and energy is released in the form of ATP. Breathing is the process that helps us to get the oxygen we need and release out carbon dioxide. The diaphragm plays an important role in breathing. It helps in the contraction and relaxation of lungs that help them to increase their surface area. It is present at the base of the chest and is separated from the abdomen.
Diaphragm Definition
Here we will define diaphragm. The diaphragm in human body is a group of thin skeletal muscles that sits at the base of the chest. This diaphragm also separates the abdomen from the chest. When we inhale the diaphragm contracts and flattens. This in turn helps to create a vacuum. The vacuum effect then helps to pull the air into the lungs. When the diaphragm relaxes, the air from the lungs is pushed out and this helps us to exhale the carbon dioxide. This gives us an idea about the diaphragm meaning.
Diaphragm Anatomy
The diaphragm plays an important role in the expulsive actions of the body such as coughing, sneezing, crying. Thus, these are the functions that the diaphragm exhibits other than helping in respiration. The movement of the diaphragm is controlled by the phrenic nerve. The rubber arcing spring, coil spring, and flat spring, as well as the silicone wide seal rim15, are types of diaphragms.
The diaphragm has three openings and these openings help to provide a space from which certain structures can pass. These openings are:
Oesophagal Opening: Through this opening, the oesophagus and the vagus nerve passes. These structures control the digestive system.
Aortic Opening: Aorta is the main artery of the body that transports blood from the heart. Through this opening, the aorta and the thoracic duct pass.
Caval Opening: Through this opening, the inferior vena cava passes. It is the vein that transports blood to the heart.
This gives us an idea about the diaphragm anatomy. Now we will look for a diaphragm diagram.
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What is Diaphragm Function?
The diaphragm is the main part of the human respiratory system along with the lungs. Let’s learn about the human respiratory system and then about the role of diaphragm.
Respiratory passage: Through this passage, the air travels from outside to the lungs. The passage consists of nostrils, nasal passages, pharynx, larynx, trachea, bronchi and lungs. We will learn about the mechanism of breathing now.
Inspiration
In this process, fresh air enters the lungs. The inflow or inhalation of air is known as inhalation. A pressure gradient is created between the lungs and this helps in the movement of air in and out of the body. The pressure gradient is defined as the pressure that is created so that the gases flow from higher concentration to their lower concentration. As we know that the pressure of oxygen outside the body is high and inside the lungs is low, so the oxygen diffuses into the lungs that are from a higher concentration to its lower concentration. The diaphragm plays a great role in this process. The diaphragm muscles get contracted, due to this the diaphragm becomes flat and this helps to increase the volume of the thoracic cavity in the anteroposterior axis. This increase in the volume of the thoracic cavity leads to an increase in the pulmonary cavity. This then decreases the pressure within the pulmonary cavity and this causes the air from the atmosphere to enter the lungs as air moves from higher pressure to lower pressure. The external intercostal muscles are present between the ribs. When these muscles contract it increases the volume of the thoracic cavity by lifting the ribs and sternum up and outward.
Expiration
By this process, carbon dioxide is expelled outside the body through the lungs. It is also known as outflow or exhalation of air. When the pressure within the lungs is more than the atmospheric pressure, then the air moves out of the lungs. The diaphragm plays an important role here also. When the diaphragm relaxes, it returns to its original position and thus the volume of the thoracic cavity is decreased. The decrease in thoracic volume results in expelling out the air from the lungs. The decrease in volume of the thoracic cavity leads to the decrease in the pulmonary cavity and this causes the pressure in the pulmonary cavity to increase and thus creating a zone of high pressure as compared to the atmospheric pressure. So air moves from the lungs to the atmosphere.
Diaphragm Diseases
As we know the diaphragm in human body is a very important organ to the human body. It plays a major role in breathing. But some conditions can lead to dysfunctioning of the diaphragm. Some of these conditions are listed below.
Hiatal Hernia
This condition happens when the upper part of the stomach bulges out from the oesophagal opening of the diaphragm. These can be caused by age-related changes in the diaphragm. Some injuries or birth defects can also cause a hiatal hernia. It can also occur by straining, lifting heavy weights or from the chronic pressure created around the muscles from coughing. Obese people suffer more from this condition. Some symptoms of hiatal hernia are acid reflux, chest burn and sometimes chest pain that radiates to the back. Surgery is required for the larger Hiatal hernias.
Diaphragmatic Hernia
This happens when anyone's abdominal organ is bulged out from the chest through the opening of the diaphragm. When this condition is present from birth it is known as a congenital diaphragmatic hernia. Injuries from accidents can also cause this hernia. The symptoms may include rapid breathing or difficulty in breathing. The heart rate is also increased and the skin appears bluish.
Phrenic Nerve Damage
The phrenic nerve gets damaged due to surgery, spinal cord conditions and autoimmune diseases. Certain illnesses and neuromuscular disorders also result in this condition. Sometimes due to this the diaphragm can be paralyzed or dysfunctional.
Diaphragm Health
Hence, to protect our diaphragm from these diseases and to lead a life with a healthy diaphragm some points can be kept in mind:
To eat smaller portions of food. To properly chew the food.
To stretch and warm-up before exercising.
To avoid the food that may lead to heartburns or acid refluxes.
To exercise within our limits.
To do certain exercises that strengthen the diaphragm.
FAQs on Diaphragm Anatomy: Complete Guide for Students
1. What is the diaphragm and where is it located in the human body?
The diaphragm is a large, dome-shaped sheet of skeletal muscle that serves as the primary muscle for respiration. It is strategically located at the base of the thoracic (chest) cavity, physically separating it from the abdominal cavity below. Its position allows it to effectively increase and decrease the volume of the chest for breathing.
2. What is the main function of the diaphragm in the process of breathing?
The diaphragm's main function is to power breathing. During inhalation, it contracts and moves downward, flattening its dome shape. This action increases the vertical volume of the thoracic cavity, creating negative pressure that draws air into the lungs. During passive exhalation, the diaphragm relaxes and rises back to its dome shape, decreasing thoracic volume and pushing air out.
3. What are the major openings or apertures that pass through the diaphragm?
The diaphragm has three principal openings, known as hiatuses, that allow vital structures to pass between the thorax and the abdomen. These are:
- The Caval Opening: Allows passage for the inferior vena cava, the large vein that carries deoxygenated blood back to the heart.
- The Esophageal Hiatus: Allows the esophagus and the vagus nerves to pass through to the stomach.
- The Aortic Hiatus: Allows passage for the aorta (the body's main artery), the thoracic duct, and the azygos vein.
4. How does the diaphragm work with other muscles during forceful breathing, like during exercise?
While the diaphragm is the main muscle for quiet breathing, it works with accessory muscles during forceful respiration. For deep, forceful inhalation, the external intercostal muscles lift the rib cage to expand the chest. For forceful exhalation, the internal intercostal muscles and abdominal muscles (like the rectus abdominis) contract vigorously to compress the thoracic cavity and rapidly expel air.
5. What are the anatomical attachment points (origin and insertion) of the diaphragm?
The diaphragm has a complex origin, attaching to multiple structures along the inner wall of the lower chest. Its origins are:
- Sternal Part: Attaches to the back of the xiphoid process.
- Costal Part: Attaches to the inner surfaces of the lower six ribs and their cartilages.
- Lumbar Part: Attaches to the upper lumbar vertebrae via two muscular pillars called the right and left crura.
6. Why is the right side of the diaphragm typically positioned higher than the left side?
The right dome of the diaphragm is anatomically higher than the left dome. This asymmetry is not due to the muscle itself but because of the large liver situated directly beneath it on the right side of the abdominal cavity. The liver pushes the right hemidiaphragm upwards. The left side is slightly lower to accommodate the position of the heart and stomach.
7. What happens if the phrenic nerve, which controls the diaphragm, gets damaged?
The phrenic nerve is the sole motor nerve supply to the diaphragm. Damage to this nerve can have serious consequences. If one side is paralysed (unilateral paralysis), that side of the diaphragm fails to contract during inhalation and may move paradoxically upwards, leading to shortness of breath. Complete paralysis of both sides (bilateral paralysis) causes severe respiratory distress and often requires mechanical ventilation for survival. Irritation of the phrenic nerve is a common cause of hiccups.
8. Besides breathing, what other physiological functions involve the diaphragm?
The diaphragm's contractions are crucial for non-respiratory actions that involve changing intra-abdominal pressure. These include:
- Expulsive Acts: It assists in coughing, sneezing, vomiting, and expelling faeces (defecation) and urine (micturition) by increasing pressure within the abdomen.
- Circulatory Aid: By changing pressures in the chest and abdomen, it helps in returning venous blood to the heart.
- Sphincter Action: The part of the diaphragm surrounding the esophagus helps prevent acid reflux from the stomach.
