Respiratory System Lecture 3, Tishk International University, 2021-2022 PDF

Tishk International University Faculty of Nursing Physiology of Respiratory System Lecture - 3 1st Grade – Spring Semester 2021-2022 Objectives: 1. Study general organization of respiratory system (RS). 2. Explain the functions and parts of respiratory system. The Respiratory System Basic functions...

Tishk International University Faculty of Nursing Physiology of Respiratory System Lecture - 3 1st Grade – Spring Semester 2021-2022 Objectives: 1. Study general organization of respiratory system (RS). 2. Explain the functions and parts of respiratory system. The Respiratory System Basic functions of the respiratory system –Breathing (Pulmonary Ventilation) – movement of air in and out of the lungs Inhalation (inspiration) draws gases into the lungs. Exhalation (expiration) forces gases out of the lungs. Basic Functions , cont. –Gas Conditioning – as gases pass through the nasal cavity and paranasal sinuses, inhaled air becomes turbulent. The gases in the air are : warmed to body temperature humidified cleaned of particulate matter –Gas Exchange - respiration Supplies body with oxygen Disposes of carbon dioxide Remove CO2 - Produces Sounds - Protects respiratory surfaces - Site for olfactory sensation ((site of sense of smell)) or ((Site for olfactory sensation)) are both same thing you can use both of them Respiration Respiration – It is the process of gas exchange in the body. Three distinct processes must happen – Pulmonary ventilation – moving air into and out of the lungs – External respiration – gas exchange between the lungs and the blood – Internal respiration – gas exchange between systemic blood vessels and tissues Pressure Changes during Pulmonary Ventilation Air moves into the lungs when the air pressure inside the lungs is less than the air pressure in the atmosphere. Air moves out of the lungs when the air pressure inside the lungs is greater than the air pressure in the atmosphere. Inhalation Breathing in is called inhalation (inspiration). Just before each inhalation, the air pressure inside the lungs is equal to the air pressure of the atmosphere. For air to flow into the lungs, the pressure inside the alveoli must become lower than the atmospheric pressure. The pressure of a gas in a closed container is inversely proportional to the volume of the container. This means that if the size of a closed container is increased, the pressure of the gas inside the container decreases, and that if the size of the container is decreased, then the pressure inside it increases. This inverse relationship between volume and pressure, called Boyle’s law Boyle’s law The volume of a gas varies inversely with its pressure. Muscle contraction during inhalation The first step in expanding the lungs during normal quiet inhalation involves contraction of the main muscles of inhalation, the diaphragm and external intercostals. The most important muscle of inhalation is the diaphragm. Exhalation Breathing out, called exhalation (expiration), is also due to a pressure gradient, but in this case the gradient is in the opposite direction: The pressure in the lungs is greater than the pressure of the atmosphere. Normal exhalation during quiet breathing, unlike inhalation, is a passive process because no muscular contractions are involved. End