Oxygen and Carbon Dioxide Transport Lecture

This set of vocabulary flashcards covers concepts related to oxygen and carbon dioxide transport, hemoglobin properties, and the oxygen-hemoglobin dissociation curve as discussed in the lecture.

Dissolved in plasma

One of the two ways oxygen is carried in the blood, calculated by multiplying the partial pressure of oxygen by the constant $0.03$, resulting in $mils/deciliter$.

Bound to Hemoglobin

The primary method of oxygen transport in the blood, calculated using the formula: $\text{Hemoglobin} \times 1.34 \times SaO_2$.

Tissue oxygen extraction

The process where body tissues typically extract $25\%$ of the available oxygen, leaving a $75\%$ reserve for increased metabolic demand or emergencies.

Heart oxygen extraction

The high rate of oxygen removal by cardiac tissue, which extracts approximately $70\%$ to $90\%$ of oxygen because the heart is in a constant state of contracting and relaxing.

Heme portion

Also known as the iron portion, this is the specific part of the hemoglobin molecule where oxygen binds.

Globin portion

The protein portion of the hemoglobin molecule where $CO_2$ binds.

Hemoglobin capacity

Each individual hemoglobin molecule can bind to $4$ oxygen molecules, and each red blood cell contains approximately $300,000,000$ molecules of hemoglobin.

Fetal hemoglobin

A specialized type of hemoglobin that is stronger at pulling and binding oxygen compared to adult hemoglobin.

Cooperative binding

The process where the binding of one oxygen molecule changes the shape of the hemoglobin, making it more attractive for the remaining three molecules to bind.

Sigmoidal

The S-shaped curve that describes the relationship between the partial pressure of oxygen and hemoglobin saturation in the oxygen dissociation curve.

P50

The partial pressure of oxygen ($PO_2$) at which hemoglobin is $50\%$ saturated; the normal value is approximately $27\,mmHg$.

Sixty-ninety rule

A clinical guideline stating that under normal conditions, a $PaO_2$ of $60\,mmHg$ corresponds to an oxygen saturation of $90\%\text{.}$

Flat portion of the curve

The upper part of the oxygen dissociation curve where oxygen affinity is high, representing the loading of oxygen in the lungs.

Steep portion of the curve

The part of the dissociation curve where oxygen saturation drops rapidly when $PO_2$ falls below $60\,mmHg$, facilitating oxygen unloading to the tissues.

Left Shift

A shift in the curve indicating increased oxygen affinity (easier loading/harder unloading) caused by low $PCO_2$, high pH, low temperature, or low $2,3\text{-DPG}$.

Right Shift

A shift in the curve indicating decreased oxygen affinity (easier unloading/harder loading) caused by high $PCO_2$, low pH (acidity), high temperature, or high $2,3\text{-DPG}$.

Cyanosis

A clinical sign occurring when there is at least $5\,g/dL$ of deoxygenated hemoglobin.

Peripheral cyanosis

A bluish tint in the extremities often caused by low cardiac output, low perfusion, or excessive tissue oxygen extraction.

Central cyanosis

A bluish tint affecting mucous membranes, lips, and the tongue, typically caused by low arterial oxygen saturation ($SaO_2$).