Physiology 2130 Lecture Notes - Lecture 10: Reversible Reaction, Cardiac Output, Baroreceptor
28 Mar 2017
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Document Summary
Transport of oxygen (from air into the blood) Removal of carbon dioxide (from blood into the air) Pharynx: where nasal cavity and mouth come together. Pulmonary artery: delivers deoxygenated blood to the lungs, branches to form a dense network of capillaries around each alveolus. Capillary characteristics: make it ideal site for gas exchange: thin endothelial wall, large total cross-sectional area, low blood velocity. 300 million alveoli in a healthy human lung: diameter = 0. 3 mm, alveolar wall is 1 cell thick, composed of alveolar epithelial cells (type i cells) Alveolar type ii cells: secrete a fluid called surfactant. Respiratory membrane: region between alveolar space and capillary lumen: can be as narrow as 0. 3 microns, made up of alveolar type ii cells and capillary endothelial cells. Macrophages and lymphocytes: present in the vicinity to protect the body from airborne particles. Elastin and collagen: around blood vessels and bronchi.
