John Has Aged Gracefully Now at the Age of 75

question 25

Essay

John has aged gracefully now at the age of 75 with distinguished gray hair and beard, unfortunately his SA node has failed and his heart rate is down to 40 beats per minute. An ECG shows bradycardia and his stroke volume is calculated to be 80 mL. John is short of breath and has low blood pressure and is feeling quite unwell. John's brother Jim is 78 years old and was a triathlete for many years and still swims and bikes five days a week. Jim's resting heart rate is 50 beats per minute and he feels great. His stroke volume has been calculated to be 120 mL per beat. Calculate the cardiac output for both John and Jim and explain why Jim feels so much better than
John.

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Definitions:

Host Population

A group of organisms that serve as a habitat or source of food for a parasite or pathogen.

Strain

In biology, a genetic variant or subtype of microorganisms, such as viruses or bacteria. In physics, it refers to deformation resulting from stress.

Swap Genes

The process of exchanging genetic material between two chromosomes or fragments, leading to genetic recombination or horizontal gene transfer.

Cetaceans

A group of marine mammals that includes whales, dolphins, and porpoises, characterized by their fully aquatic lifestyle and adaptations such as flippers and blowholes.