Breathing and Exchange of Gases - Key Vocabulary

Flashcards about breathing and exchange of gases in humans and animals.

Breathing (Respiration)

Exchange of O2 from the atmosphere with CO2 produced by the cells.

Gills (branchial respiration)

Vascularised structures used by most of the aquatic arthropods and molluscs for the exchange of gases.

Lungs (pulmonary respiration)

Vascularised bags used by the terrestrial forms for the exchange of gases.

Pharynx

The common passage for food and air.

Larynx

A cartilaginous box which helps in sound production and hence called the sound box.

Epiglottis

A thin elastic cartilaginous flap that covers the glottis during swallowing to prevent the entry of food into the larynx.

Conducting Part vs. Exchange Part (Respiratory System)

The conducting part transports the atmospheric air to the alveoli, clears it from foreign particles, humidifies and also brings the air to body temperature; the exchange part is the site of actual diffusion of O2 and CO2 between blood and atmospheric air.

Respiration Steps

Breathing or pulmonary ventilation by which atmospheric air is drawn in and CO2 rich alveolar air is released out; Diffusion of gases (O2 and CO2) across alveolar membrane; Transport of gases by the blood; Diffusion of O2 and CO2 between blood and tissues; Utilisation of O2 by the cells for catabolic reactions and resultant release of CO2 (cellular respiration).

Inspiration vs. Expiration

Inspiration during which atmospheric air is drawn in and expiration by which the alveolar air is released out.

Tidal Volume (TV)

Volume of air inspired or expired during a normal respiration (approx. 500 mL).

Inspiratory Reserve Volume (IRV)

The additional volume of air a person can inspire by a forcible inspiration (averages 2500 mL to 3000 mL).

Expiratory Reserve Volume (ERV)

The additional volume of air a person can expire by a forcible expiration (averages 1000 mL to 1100 mL).

Residual Volume (RV)

Volume of air remaining in the lungs even after a forcible expiration (averages 1100 mL to 1200 mL).

Inspiratory Capacity (IC)

Total volume of air a person can inspire after a normal expiration (TV+IRV).

Expiratory Capacity (EC)

Total volume of air a person can expire after a normal inspiration (TV+ERV).

Functional Residual Capacity (FRC)

Volume of air that will remain in the lungs after a normal expiration (ERV+RV).

Vital Capacity (VC)

The maximum volume of air a person can breathe in after a forced expiration (ERV+TV+IRV) or the maximum volume of air a person can breathe out after a forced inspiration.

Total Lung Capacity (TLC)

Total volume of air accommodated in the lungs at the end of a forced inspiration (RV+ERV+TV+IRV or VC+RV).

Partial Pressure

Pressure contributed by an individual gas in a mixture of gases; pO2 for oxygen and pCO2 for carbon dioxide.

Hemoglobin

A red colored iron containing pigment present in the RBCs.

Oxygen Dissociation Curve

A sigmoid curve obtained when percentage saturation of hemoglobin with O2 is plotted against the pO2.

Carbamino-hemoglobin

CO2 is carried by hemoglobin.

Carbonic Anhydrase

Enzyme in RBCs that facilitates the conversion of CO2 and H2O into carbonic acid and bicarbonate ions.

Respiratory Rhythm Center

Specialized center in the medulla region of the brain primarily responsible for regulating respiration.

Pneumotaxic Center

Center present in the pons region of the brain that can moderate the functions of the respiratory rhythm center, reducing the duration of inspiration and altering the respiratory rate.

Chemosensitive Area

Area situated adjacent to the rhythm center, highly sensitive to CO2 and hydrogen ions, activating the rhythm center to make necessary adjustments in the respiratory process for eliminating these substances.

Asthma

Difficulty in breathing causing wheezing due to inflammation of bronchi and bronchioles.

Emphysema

A chronic disorder in which alveolar walls are damaged due to which respiratory surface is decreased; one of the major causes of this is cigarette smoking.