Structure and Function of the Lung Lecture 1 Flashcards

Question

Identify the mechansim responsible for maintaining patency of generations 5-11

Answer 1

Patency relies partially on some cartilage in walls and postive transmural pressure gradient * pressure gradient must exist between pleural space and airway or airway collapse occurs.

Answer 2

Generations 17-18 * Transition from conduction to gas exchange occurs here * gradual increase in nubmer of alveoli in walls of bronchioles * tremendous increase in cross- sectional area.

Answer 3

Total number 2 million to 8 million, depending on height

Answer 4

On one side of the alveolar wall the capillary endothelium and alveolar epithelium are closely opposed * Total distance from gas to blood is 0.3 micrometers, where gas exchange is more efficient * This is known as the active side.

Answer 5

* Small holes in the walls of adjoining alveoli (Alveolar septa) * Between 3 to 14 u in diameter * Formation of pores may be due to * Dequamation due to disease * Normal degeneration due to aging * Movement of macrophages leaving holes

Answer 6

* The other side of the capillary "service side" is usually more than 1-2 mm thick * Sizeable interstitial space containing elastin, collagen, nerve endings, and macrophages * Service side is more affected by edema and firbous tissue

Answer 7

One side of alveolar wall where capillary endothelium and alveolar epithelium are closely opposed * Total distance form gas to blood is 0.3 mm, where gas exhagne is more efficient.

Answer 8

* Alveolar Type 1 * 95% of the alveolar surface is made up of squamous pneumocyte cells * Between 0.1 U and 0.5 U thick * major site of gas exchange * Alveolar Type 2 * 5% of surface of alveoli composed of granular pneumocyte cells * cubodal in shape with microvilli * primary source of pulmonary surfactant * involved with reabsorption of fluid in the dry, alveolar spaces.

Answer 9

* Acts as a detergent to decrease surface tension * Pulmonary compliance is increased and work of breathing is reduced * Permits alveolar stability by keeping smaller alveoli from collapsing into large alveoli

Answer 10

1. Allow oxygen and carbon dioxide exhange 2. Maintain/ regulate pH 3. Metabolizes/ synthesizes/ converts compounds 4. Filters unwanted materials from the circulation 5. Acts as a reservoir for blood 6. Defense against environment.

Answer 11

* Parietal pleura lines the thoracic wall * Visceral pleura covers the lung surface

Answer 12

* Parasympatetic motor fibers (predominate) * constrict the bronchi * affected by medication, mechanical * Sympathetic (weak) * dilate the bronchi * affected by medication, agents.

Answer 13

* *Muscles of pharynx and larynx control upper airway resistance* * *Diaphragm, ribcage, spine, and neck muscles control inspiration* * *Muscles of the abdominal wall, ribcage and spine are utilized for active expiration* * The most important muscle of inspiration is the diaphragm (75%) * Innervation is solely from the phrenic nerves (C3, C4, C5)

Answer 14

1. Conversion of angiotensin I to angiotensin II 2. Complete or partial inactivation of vasoactive substances (bradykinin, serotonin, prostaglandins) 3. Metabolism of several vasoactive and bronchoactive compounds such as arachidonic acid metabolites (Leukotrienes, prostaglandins, prostacyclin) 4. Plays a major role in clotting mechanism (mast cells contain heparin) and immune system (IgA production)