PhysiologyLesson 3 of 6 in the course The Body’s Systems

Respiratory Gas Exchange, Circulation, and the Cardiac Cycle

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

Breathing, or ventilation, moves air between the atmosphere and the lungs. At rest, humans breathe about 15 times per minute on average. Each inhalation brings oxygen-containing air into the lungs; each exhalation removes air containing carbon dioxide.

Breathing has both involuntary and voluntary aspects. A respiratory center in the brain adjusts the rate and depth of breathing in response to information about blood carbon dioxide levels. A person can temporarily override automatic breathing to speak, sing, or swim underwater, but automatic regulation normally resumes.

All flashcards

Ventilation
Movement of air between the atmosphere and the lungs through inhalation and exhalation.
Double circulation
A complete blood circuit in which blood passes through the heart twice.
Alveolus
A thin-walled air sac where gases diffuse between air and nearby capillary blood.
Cardiomyocyte
A specialized heart muscle cell that contracts rhythmically and involuntarily.
Intercalated disks
Connections between neighboring cardiomyocytes that help electrical signals pass from cell to cell.

Quiz questions

  1. Which route does blood take from the right ventricle to the lungs?Answer: It travels through the pulmonary arteries to the lungs.
  2. Why do pulmonary arteries carry oxygen-poor blood?Answer: They carry blood away from the heart toward the lungs for oxygenation.
  3. Why is the left ventricle more muscular than the right ventricle?Answer: It pumps blood through the systemic circuit to the body.
  4. What produces the first familiar heart sound, “lub”?Answer: Closure of the valves between the atria and ventricles as the ventricles contract.
  5. What does an electrocardiogram (ECG) record?Answer: Electrical activity generated by the heart.

Based on Concepts of Biology by Samantha Fowler, Rebecca Roush, James Wise (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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