Exam 27: B: Physiology of the Respiratory System
The apneustic center is located in what part of the nervous system?
A
Explain the diving reflex.
The diving reflex, also known as the mammalian diving response, is a physiological response to immersion in water, particularly cold water, that occurs in mammals, including humans. This reflex is an evolutionary adaptation that allows the body to conserve oxygen and prioritize its delivery to vital organs during periods of submersion, enabling longer periods of breath-holding underwater.
When a mammal's face is submerged in cold water, several automatic responses are triggered:
1. Bradycardia: The heart rate slows down significantly. This is the most notable aspect of the diving reflex. The reduction in heart rate decreases the body's overall oxygen consumption, ensuring that the limited oxygen reserves last longer.
2. Peripheral vasoconstriction: The blood vessels in the extremities (arms and legs) constrict, which reduces blood flow to these non-essential areas. This helps to redirect blood to the core of the body and vital organs such as the brain and heart, which are more critical for survival.
3. Blood shift: As the pressure increases with depth during a dive, the body responds by shifting blood from the thoracic cavity to the pulmonary vessels to prevent the lungs from collapsing under pressure. This also contributes to protecting the organs from the effects of increased external pressure.
4. Splenic contraction: In some mammals, the spleen contracts during the diving reflex, releasing a reserve of red blood cells into the bloodstream. This increases the oxygen-carrying capacity of the blood, providing an additional oxygen boost.
The diving reflex is more pronounced in aquatic mammals, such as seals and dolphins, which have evolved to maximize their ability to dive deep and stay underwater for extended periods. In humans, the reflex is less pronounced but still present and can be observed in free divers who train to enhance their breath-holding capabilities.
The diving reflex can also have practical applications in medicine, such as in the treatment of certain types of abnormal heart rhythms, where inducing the reflex can help to reset the heart's rhythm. Additionally, it has been studied for its potential protective effects during incidents of accidental submersion in water, particularly in young children, who may exhibit a stronger diving reflex compared to adults.
If a person were skiing high up in the mountains,she might feel that she is having trouble breathing (getting enough oxygen in her blood).This is because the:
B
George,a heavy smoker for 30 years,has developed a decreased expiratory reserve volume and a large,barrel-shaped chest cavity.What is his probable diagnosis?
If the tidal volume were 600 ml,the alveolar ventilation would be about _____ ml.
Steve used a spirometer to analyze his respiratory capacities.He found the following results:
A. After normal inspiration,a normal expiration was 500 ml.
B. After a normal expiration,he was able to expel an additional 1000 ml.
C. Taking as deep a breath as possible,then forcefully exhaling all the air possible,he yielded an output of 4500 ml.
Based on the outcome of these measurements,what is Steve's inspiratory reserve?
Match each pulmonary volume with its corresponding description or definition.
-largest additional volume of air that can be expired after tidal volume
The approximate partial pressure of oxygen at standard atmospheric pressure is about _____ mm Hg.
The tendency of the thorax and lungs to return to the pre-inspiration volume is called:
Which of the following is not a regulated process associated with the functioning of the respiratory system?
Which explains the relationship between the gas pressure gradient of the atmosphere and the alveolar air that allows inhalation?
Which of the following is not a means of transporting oxygen in the blood?
Which of the following combinations in arterial blood could cause an increase in the respiratory rate?
A type of breathing characterized by gradually increasing tidal volume for several breaths followed by several breaths with gradually decreasing tidal volume is:
Match each type of breathing with its corresponding definition.
-cessation of breathing in the inspiratory position
By the time the blood leaves the lung capillaries to return to the heart,what percentage of the blood's hemoglobin has united with oxygen?
Which gas law deals with the solubility of gases in solution?
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