{ Topic 6.4 Gas Exchange Ventilation, alveoli structure & disease

VENTILATION 6.4.U1Ventilation maintains concentration gradients of O 2 & CO 2 between air in alveoli and blood flowing in adjacent capillaries. 6.4.S1Monitoring of ventilation in humans at rest & after mild & vigorous exercise. (Practical 6) 6.4.U4Air is carried to the lungs in the trachea & bronchi and then to the alveoli in bronchioles 6.4.U5Muscle contractions cause the pressure changes inside the thorax that force air in & out of the lungs to ventilate them. 6.4.U6Different muscles are required for inspiration & expiration because muscles only do work when they contract. 6.4.A3External and internal intercostal muscles, & diaphragm & abdominal muscles as examples of antagonistic muscle action.

1.Detail the pathway that air takes as it enters the body and makes its way to the pulmonary capillaries. 1.What is the name of the process that brings air in and out of the lungs?

Explain the process of ventilation.

VENTILATION PROCESS

Intra- pulmonary pressure = 763 mmHg Intra- pulmonary pressure = 758 mmHg Create a chart comparing inspiration and expiration

Antagonistic Muscles Work opposite each other. One contracts while the other relaxes. 1. Internal & External Intercoastal muscles 2. Diaphragm & abdominal muscles EXAMPLES INCLUDE:

Identify the different types of cells in the alveoli and explain their importance.

AVEOLI STRUCTURE Be able to draw a diagram of the structure of the alveoli and the adjacent capillary 6.4.U2 Type I pneumocytes are extremely thin alveolar cells that are adapted to carry out gas exchange. 6.4.U3 Type II pneumocytes secrete a solution containing surfactant that creates a moist surface inside the alveoli to prevent the sides of the alveolus adhering to each other by reducing surface tension.

Structure of Alveoli

Type II pneumocyteType I pneumocyte

Discuss the causes & consequences of emphysema & lung cancer.

DISEASES AFFECTING VENTILATION AND GAS EXCHANGE 6.4.A1Causes and consequences of lung cancer. 6.4.A2Causes and consequences of emphysema.

Lung Cancer Statistics Link Lung Cancer Risks Link

1.What muscles are involved in inspiration? 2. Why does air go out during expiration? 3. What is the main purpose of surfactant? 4. Where is surfactant produced? 5.What is a distinguishing feature between type I & II pneumocytes? 6.Define antagonistic muscles and give an example. 7.How are the consequences of lung cancer and emphysema different.