Explain the exchange of gases in tissues with a schematic representation.

(N/A) $1$. Oxygenated blood reaches the tissues through systemic circulation.
$2$. The partial pressure of oxygen $(PO_2)$ is higher in the blood than in the tissues, causing oxygen to diffuse from the blood into the tissues.
$3$. Cellular respiration in the tissues produces carbon dioxide $(CO_2)$, leading to a higher partial pressure of $CO_2$ $(PCO_2)$ in the tissues compared to the blood.
$4$. Consequently, $CO_2$ diffuses from the tissues into the blood.
$5$. The deoxygenated blood then carries $CO_2$ back to the lungs for exhalation.
Schematic: $\text{Blood (High } PO_2, \text{ Low } PCO_2) \rightarrow \text{Tissues (Low } PO_2, \text{ High } PCO_2) \rightarrow \text{Blood (Low } PO_2, \text{ High } PCO_2)$.