11 Respiratory System

11 Respiratory System - Respiratory System I. Lung...

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Respiratory System I. Lung Functions a. Perfusion - deliver of oxygen to the tissues b. Ventilation - remove oxygen from the blood and exchange it through our lungs and from the atmosphere c. Defense mechanisms : c.i. As we age the defense mechanisms become affected and eventually become inadequate c.ii. COPD- true aging disease. May be brought on prematurely by smoking with c.iii. Emphysema- Due to failure of the defense mechanisms of the lungs d. Decline in lunch function early in life d.i. Age 20- peak lunch function d.ii. After age 20- gradual decline in lung function d.iii. 50’s 60’s- changes start to be significant II. Anatomy a. Lie in thoracic cavity a.i. Ribs a.ii. Sternum a.iii. Vertebral column a.iv. Diaphragm b. Tremendous elasticity b.i. Every time we inhale and expand the inflate and deflate c. Trachea - branches of into 2 primary bronchi c.i. Largest c.ii. Surrounded by cartilaginous rings c.ii.1. Help give structure and protection and help keep it from collapsing d. We have 23 branches of bronchi found from trachea all the way to alveoli d.i. As you go down the lumen of these divisions get smaller and smaller e. Bronchioles e.i. Small threadlike structures that get smaller as they go down f. Alveolar ducts f.i. Sacs are made of many individual alveoli g. Alveoli g.i. Interact with pulmonary capillaries to bring O 2 into the blood stream and CO2 out of blood stream g.ii. Total number in lungs = 8 million (around age 8) h. Less cartilage, more smooth muscle as you move down the branches III. Structural changes as we age a. Senile barrel chest - occurs in everyone, especially older individuals a.i. May occur in younger life in individuals with emphysema (just called “barrel Chest”) a.ii. Due to calcification of cartilage of ribs a.iii. Due to increase in spinal curvature- kyphosis a.iii.1. Cause decrease in volume of thoracic cavity increase pressure make lungs harder to expand a.iv. Increase in anterior-posterior thoracic diameter b. Trachea and bronchus b.i. Cartilage becomes calcified rigidity harder to expand/contract c. Bronchioles c.i. Because of sarcopenia the smooth muscle fibers will be replaced by CT
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c.ii. If you replace smooth muscles they become hardened harder to vasodilate and vasoconstrict c.iii. Asthma c.iii.1. Become overactive and bronchioles may strip because no proper air is going through c.iii.2. Use epinephrine to have bronchioles vasodilate d. Vital Capacity d.i. The amount of air you breathe normally. d.ii. Vital capacity = tidal volume + max expiratory volume + max inhalation volume d.iii. Normal = 5L d.iii.1. Tidal volume = 500ml d.iv. Important measurement of lung function d.v. By the time we reach age 70, the vital capacity will be decreased by about 60% d.vi. Number of alveoli found in lungs does not change as we age d.vii. Primarily due to structural changes seen in membranes that hold alveoli together d.vii.1. Break down as we age decrease surface area decrease in gas exchange
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This note was uploaded on 02/25/2012 for the course CHEM 1341 taught by Professor Compton during the Fall '08 term at Texas State.

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11 Respiratory System - Respiratory System I. Lung...

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