Biomaterial Database

Decay of inspiratory muscle pressure during expiration in conscious humans. 1985

C D Shee, and Y Ploy-Song-Sang, and J Milic-Emili

In eight conscious spontaneously breathing adults we studied the decay of pressure developed by the inspiratory muscles during expiration (PmusI). PmusI was obtained according to the following equation: PmusI(t) = Ers X V(t) - Rrs X V(t), where V is volume and V is flow at any instant t during spontaneous expiration, and Ers and Rrs are, respectively, the passive elastance and resistance of the total respiratory system. Ers was determined with the relaxation method, and resistance with the interrupter method. All subjects showed marked braking of expiratory flow by PmusI. The mean time for PmusI to reduce to 50 and 0% amounted, respectively, to 23 and 79% of expiratory time. During expiration, 24-55% of the elastic energy stored during inspiration was used as resistive work and the remainder (45-76%) as negative work.

UI	MeSH Term	Description	Entries
D007366	Intercostal Muscles	Respiratory muscles that arise from the lower border of one rib and insert into the upper border of the adjoining rib, and contract during inspiration or respiration. (From Stedman, 25th ed)	Intercostal Muscle,Muscle, Intercostal,Muscles, Intercostal
D008176	Lung Volume Measurements	Measurement of the amount of air that the lungs may contain at various points in the respiratory cycle.	Lung Capacities,Lung Volumes,Capacity, Lung,Lung Capacity,Lung Volume,Lung Volume Measurement,Measurement, Lung Volume,Volume, Lung
D008297	Male		Males
D010369	Pectoralis Muscles	The pectoralis major and pectoralis minor muscles that make up the upper and fore part of the chest in front of the AXILLA.	Pectoralis Major,Pectoralis Major Muscle,Pectoralis Minor,Pectoralis Minor Muscle,Pectoral Muscle,Muscle, Pectoral,Muscle, Pectoralis,Muscle, Pectoralis Major,Muscle, Pectoralis Minor,Muscles, Pectoralis Major,Pectoral Muscles,Pectoralis Major Muscles,Pectoralis Majors,Pectoralis Minor Muscles,Pectoralis Minors,Pectoralis Muscle
D011312	Pressure	A type of stress exerted uniformly in all directions. Its measure is the force exerted per unit area. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Pressures
D012119	Respiration	The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (	Breathing
D012123	Pulmonary Ventilation	The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.	Respiratory Airflow,Ventilation Tests,Ventilation, Pulmonary,Expiratory Airflow,Airflow, Expiratory,Airflow, Respiratory,Test, Ventilation,Tests, Ventilation,Ventilation Test
D003243	Consciousness	Sense of awareness of self and of the environment.	Consciousnesses
D003964	Diaphragm	The musculofibrous partition that separates the THORACIC CAVITY from the ABDOMINAL CAVITY. Contraction of the diaphragm increases the volume of the thoracic cavity aiding INHALATION.	Respiratory Diaphragm,Diaphragm, Respiratory,Diaphragms,Diaphragms, Respiratory,Respiratory Diaphragms
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man