Question

analyzing blood oxygen levels investigation rubric
focus question: how do o₂ concentrations in arterial and venous blood change from rest to exercise?
at rest:
what is the concentration of o₂ in arterial blood?
what is the concentration of o₂ in venous blood?
during increasing levels of exercise:
how does the concentration of o₂ in arterial blood change?
how does the concentration of o₂ in venous blood change?
key ideas
where do arterial blood samples come from, and what do they carry?
where do venous blood samples come from, and what do they carry?
arterial and venous blood samples were collected from the same person while they were resting and while they were exercising.
arterial blood comes from the arteries. it carries oxygen - rich blood from the lungs and heart out to the tissues of the body.
venous blood comes from the veins. it carries oxygen - depleted blood from the bodys muscles and organs back toward the heart and lungs.
these blood samples help show how different body systems work together to keep oxygen levels balanced. the respiratory system brings oxygen into the lungs, the circulatory system moves that oxygen through the blood, and the muscular system uses the oxygen during activity. comparing arterial and venous blood shows how cells, tissues, organs, and systems are organized and interact to carry out this important function.
connections
which body systems are involved in bringing oxygen into the body and transporting it?
how does the muscular system use the oxygen that is carried in the blood?
how do o₂ concentrations in arterial and venous blood change from rest to exercise? support your response with evidence from the graph and text

Explanation:

• At rest, arterial blood has a higher oxygen concentration (as shown in the graph and text).
• During exercise, the body's demand for oxygen increases. The muscular system uses more oxygen.
• The circulatory system (arteries and veins) and respiratory system work together. The respiratory system brings in oxygen, the circulatory system transports it.
• From the graph, during increasing levels of exercise, venous blood oxygen concentration may decrease (as the muscles use more oxygen) while arterial blood oxygen concentration may stay relatively stable (as the respiratory and circulatory systems work to supply oxygen).

Answer:

At rest, arterial blood has a higher oxygen concentration. During exercise, the muscular system uses the oxygen carried in the blood for energy - production (cellular respiration). The respiratory system brings oxygen into the body, and the circulatory system transports it. From rest to exercise, venous blood oxygen concentration likely decreases (as muscles consume more oxygen) and arterial blood oxygen concentration may remain relatively stable (as the body's oxygen - supply systems (respiratory and circulatory) try to meet the demand).