While a Runner Rests Before a Race, the Hemoglobin in the Blood

question 98

Multiple Choice

While a runner rests before a race, the hemoglobin in the blood returning to her heart is 75% saturated with oxygen.While she is running, this percentage

• A) stays the same because hemoglobin is usually 75% saturated with oxygen.
• B) increases because she is breathing harder.
• C) increases because her muscles need more oxygen.
• D) decreases because the decreased PO₂ in her muscles makes it easier for additional oxygen to be released from the hemoglobin.
• E) decreases because the partial pressure of oxygen in her alveoli is reduced below 40 mm Hg.

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Definitions:

Optic Nerve

A nerve located in the skull that is essential for transferring visual signals from the retina to the brain.

Synapse

The junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The tiny gap at this junction is called the synaptic gap or synaptic cleft.

Visual Cortex

The part of the brain responsible for processing visual information, located in the occipital lobe.

Color Receptors

Specialized types of cells in the eyes, primarily cones, that respond to and process color.