Question

What are some controls on breathing? Think critically if one of those is affected and how that would influence breathing. For example, how is breathing influenced if aortic carbon dioxide concentration goes up?

Understand the definitions of each of the ”volumes of air” in a breath. Which one is associated with deep breathing? How are these volumes altered if lung tissue is damaged or destroyed? What affect does that have on breathing? How are volumes affected with an asthma attack?

1. What is the affect of smoking on the lungs? Be able to identify ”big picture” changes and “small picture” changes.

Answer 1

1)Breathing, called ventilation consists of two phases, inspiration and expiration.It is voluntary or involuntary.The cerebral cortex of the brain controls voluntary respiration.Involuntary respiration is controlled by the respiratory centers of the upper brainstem.
The motor cortex within the cerebral cortex of the brain controls voluntary respiration.The phrenic nerves, vagus nerves, and posterior thoracic nerves are the major nerves involved in respiration.
The medulla oblongata is the primary respiratory control center. Its main function is to send signals to the muscles that control respiration to cause breathing to occur. There are two regions in the medulla that control respiration:The ventral respiratory group stimulates expiratory movements and the dorsal respiratory group stimulates inspiratory movements. The pons is the other respiratory center and is located underneath the medulla. Its main function is to control the rate or speed of involuntary respiration. The respiratory centers contain chemoreceptors that detect pH levels in the blood and send signals to the respiratory centers of the brain to adjust the ventilation rate to change acidity by increasing or decreasing the removal of carbon dioxide.
For example if a person with severe diarrhea loses a lot of bicarbonate in the intestinal tract, which decreases bicarbonate levels in the plasma. As bicarbonate levels decrease while hydrogen ion concentrations stays the same, blood pH will decrease (as bicarbonate is a buffer) and become more acidic.In cases of acidosis, the chemoreceptors detect this change, and send a signal to the medulla, which signals the respiratory muscles to increase the ventilation rate so carbon dioxide levels and pH can return to normal levels.

2)Respiratory volume is the term used for various volumes of air moved by or associated with the lungs at a given point in the respiratory cycle. There are four major types of respiratory volumes: tidal, residual, inspiratory reserve, and expiratory reserve. Tidal volume (TV) is the amount of air that normally enters the lungs during quiet breathing, which is about 500 milliliters. Residual volume (RV) is the air left in the lungs if you exhale as much air as possible Inspiratory reserve volume (IRV) , is the extra volume that can be brought into the lungs during a forced inspiration. Expiratory reserve volume (ERV) is the amount of air you can forcefully exhale past a normal tidal expiration.

Inspiratory reserve volume (IRV) is associated with deep breathing.

When lungs tissue is damaged it causes Chronic obstructive pulmonary disease (COPD) that prevent proper breathing. Volume of air inhaled will be affected as the damaged lung will not be able to move oxygen to blood and thus it decreases the tidal volume of air.It leads to shortness of breath.

Asthma is a disease in which inflammation is triggered by environmental factors, obstructing the airways. The obstruction may be due to edema, smooth muscle spasms in the walls of the bronchioles, increased mucus secretion, damage to the epithelia of the airways, or a combination of these events. Those with asthma experience blockage of the airways from increased inflammation preventing the proper movement of gases. So large volumes of air istrapped after exhalation. They breathe at a very high lung volume to compensate for the lack of airway recruitment.

3)When you smoke, the cells that produce mucus in your lungs and airways grow in size and number. As a result, the amount of mucus increases and thickens.The toxins from inhaled cigarette smoke break the thin walls of alveoli, leaving larger, less efficient air sacs. The sacs also begin to lose their bounce, making it harder to bring in the oxygen and expel carbon dioxide. Both can become partially trapped in the lungs.Smoking inflames and irritates the lungs.The lungs are lined in broom-like hairs called cilia, which clean the lungs.A few seconds after you light a cigarette, cilia slow down in movement and cleaning of lungs..All these leads to coughing,infection,damage to lung tissue etc. Lungs can be very badly affected by smoking. Coughs, colds, wheezing and asthma are just the start. Also it can cause fatal diseases such as pneumonia, emphysema and lung cancer. Smoking causes 84% of deaths from lung cancer and 83% of deaths from chronic obstructive pulmonary disease.The risk of lung cancer is 20% more than a non-smoker.