Respiration Exam 3 Review - Part A

This set of vocabulary flashcards covers the fundamental concepts of respiratory physiology, including gas laws, neural regulation, transport mechanisms, and related clinical pathologies based on the Exam 3 Study Guide.

Pulmonary Ventilation

The physical movement of air into and out of the respiratory tract (breathing).

External Respiration

The exchange of oxygen ($O_2$) and carbon dioxide ($CO_2$) between the interstitial fluid and the external environment, specifically occurring at the alveoli.

Internal Respiration

The absorption of oxygen ($O_2$) and release of carbon dioxide ($CO_2$) by those cells in the body's tissues.

Compliance

An indication of the expandability of the lungs; lower compliance requires more force to fill the lungs, while higher compliance makes it easier.

Boyle’s Law

A gas law stating that for a fixed amount of an ideal gas kept at a fixed temperature, pressure and volume are inversely proportional ($P \times V = \text{k}$).

Henry’s Law

A gas law stating that at a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.

Surfactant

An oily secretion produced by septal cells (Type II pneumocytes) that reduces surface tension in the liquid coating the alveolar surface to prevent collapse.

Normal Inspiration Muscles

The primary muscles involved in non-forced inhalation, which are the diaphragm and the external intercostal muscles.

Normal Expiration

A passive process that occurs due to elastic recoil of the lungs and thoracic cage, as well as surface tension within the alveoli, rather than muscle contraction.

Tidal Volume ($TV$)

The amount of air moved into or out of the lungs during a single respiratory cycle during quiet breathing; typically amounts to approximately $500\text{ ml}$.

Hemoglobin ($Hb$)

The substance responsible for transporting the majority of oxygen ($O_2$) and a portion of carbon dioxide ($CO_2$) in the blood.

Oxygen-Hemoglobin Saturation Curve

A graph relating the saturation of hemoglobin to changes in the partial pressure of oxygen ($P_{O_2}$).

Fetal Hemoglobin

A form of hemoglobin found in fetuses that has a higher affinity for oxygen than maternal hemoglobin, allowing it to "strip" oxygen from the mother's blood.

Respiratory Rhythmicity Center

The center located in the medulla oblongata that sets the basic pace and rhythm of respiration, consisting of the Dorsal Respiratory Group ($DRG$) and Ventral Respiratory Group ($VRG$).

Dorsal Respiratory Group ($DRG$)

A nuclei in the medulla oblongata primarily responsible for inspiration by controlling the lower motor neurons that innervate the external intercostals and diaphragm.

Ventral Respiratory Group ($VRG$)

A nuclei in the medulla oblongata that functions only during forced breathing to assist in maximum inhalation and exhalation.

Apneustic and Pneumotaxic Centers

Nuclei located in the pons that adjust the output of the respiratory rhythmicity center to modify the pace and depth of breathing.

Central Chemoreceptors

Sensors located in the medulla oblongata that respond to changes in the $pH$ and $P_{CO_2}$ of the cerebrospinal fluid ($CSF$).

Peripheral Chemoreceptors

Sensors located in the carotid and aortic bodies that monitor the $P_{O_2}$, $P_{CO_2}$, and $pH$ of the circulating blood.

Hypercapnia

An increase in the partial pressure of carbon dioxide ($P_{CO_2}$) in arterial blood.

The Bends

A condition formally known as decompression sickness, caused by nitrogen gas coming out of solution and forming bubbles in the blood when a diver ascends too rapidly.

Emphysema

A type of Chronic Obstructive Pulmonary Disorder ($COPD$) characterized by the destruction of alveolar surfaces, resulting in decreased surface area for gas exchange and difficulty breathing (often called "pink puffers").

Erythropoietin ($EPO$)

A hormone produced by the kidneys in response to low oxygen levels (hypoxia) that stimulates the production of red blood cells in the bone marrow.