How Do Our Lungs Work?

The lungs are one of the most vital components of the human body. They are used every second of the day and without them, we would die in 4-6 minutes. The lungs are located in the thoracic cavity behind your pectoral muscles and behind your ribs. Within the Thoracic cavity, there are two pleural cavities. Each pleural cavity contains one lung. The pleural cavity is created by two membranes and a fluid called pleural fluid. Combined, these structures make it easier for the lungs to expand and contract during inhalation and exhalation.

Within the lungs, there is a combination of many structures that carry air from your oral and nasal airways. These include the bronchi, bronchioles, and alveoli (the major ones). The bronchi is one major airway that brings air to both lungs. The bronchioles are tree-like structures that branch from the bronchi. Finally, the alveoli are the tiny ball-like structures at the end of the bronchioles that oxygen and carbon dioxide transfer through its membrane.

So, we all know how to breathe but, do you know what is actually going on in your body? Breathing is a combination of multiple muscles contracting and relaxing. When breathing in your diaphragm will contract. This increases the volume of the thoracic cavity and thus decreases the pressure of the lungs. When this occurs, the pressure outside of your mouth is higher than in your body. The difference in pressures causes a rush of air through your nasal and oral cavities and into your lungs to try and make the pressures the same. Other muscles that aid in this decrease of pressure include the ribs and intercostal muscles.

When exhaling, the same muscles relaxed and the muscles between the ribs contract, making the volume of the thoracic cavity decrease. This decreased volume causes an increase in pressure and for the same reason air enters your lungs, it will now leave your lungs.

Blood Pressure: What Is It?

Anytime you head into the doctor’s office you get your blood pressure taken. It is a very normal practice, but do you know what the two numbers mean? Blood pressure is represented by two numbers, the systolic and diastolic pressures. The systolic pressure is the first of the two numbers or the number depicted on top of the other. The bottom number or the second number is called the diastolic pressure. These two numbers represent drastically different things.

The systolic pressure represents the maximum pressure that your arterial walls are feeling at the time of contraction of your heart (contraction of the left ventricle). A healthy pressure is about 120 mm Hg (millimeters of mercury). If the systolic pressure begins to rise higher than 130 mm Hg then we can start to consider this hypertension. Hypertension is the term used to describe high blood pressure. Things such as being overweight, not getting enough exercise, eating too much salt, and being over the age of 65 are common reasons to have hypertension. If your blood pressure drops below 110 mm Hg then you are considered to have hypotension or low blood pressure. Things such as significant loss of blood or body fluid can cause this.

The diastolic blood pressure is the opposite of systolic blood pressure. It represents the pressure on the arteries during the relaxation of the heart (filling of the left ventricle). This is considered to be the lowest blood pressure on your arteries. Very similar reasons that cause an increase and decrease in systolic blood pressure will result in a decrease and increase of diastolic blood pressure.