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21 Cards in this Set
- Front
- Back
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Functions of respiratory system (5) |
1. Gas exchange between blood and air 2. Move air to and from gas-exchange surfaces of lungs 3. Protect respiratory surfaces from environmental variations and pathogens 4. Produce sound 5. Detect olfactory stimuli |
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Larynx |
aka Voice box: made of 9 cartilages including epiglottis (covers larynx during swallowing.) Air passes through glottis. Exhaled air passes through true vocal cords, vibrates them to make sound. |
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Trachea |
aka Windpipe: Supported by "c-shaped" tracheal cartilages- open part faces posterior where esophagus is, allows distortion so food can pass. |
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Bronchi |
From trachea: right and left primary bronchi, to secondary bronchi, to tertiary bronchi, which continue to branch. As bronchi branch they become smaller, have less cartilage and more smooth muscle. |
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Bronchioles |
When bronchi narrow to 1 mm in diameter they are bronchioles. Cartilage is absent. Smooth muscle under control of ANS: parasympathetic= contraction/ bronchoconstriction; sympathetic= relaxation/ bronchodilation; Excess bronchoconstriction causes asthma. |
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terminal and respiratory bronchioles |
When bronchioles narrow to 0.3-0.5mm in diameter they are terminal bronchioles that deliver air to a single lobule of lung tissue. Within a lobule they branch into respiratory bronchioles, which open into alveolar ducts and deliver air to alveoli (gas-exchange surfaces.) |
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Cells in an alveolus (3 types) |
1. Respiratory cells/ pneumocytes type I: simple squamous epithelium, 90-95% of lung tissue; make up alveolar epithelium. 2. Septal cells/ pneumocytes type II: produce surfactant: oily secretion that reduces surface tension and keeps alveoli open. 3. Alveolar Macrophages: "dust cells," engulf foreign particles. |
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3 integrated processes of respiration |
1. Pulmonary ventilation- moving air in and out/ breathing 2. Gas exchange- diffusion between alveoli and circulating blood, blood and interstitial fluids 3. gas transport- movement of oxygen from alveoli to cells and CO2 from cells to alveoli |
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The pleural cavities and the pressure gradient |
Pressure gradient: Air flows from high to low pressure. Decrease in volume= increase in pressure, causes air to flow out of lungs (exhalation) Pleural cavity pressure= -3mmHg; Negative pressure and pleural fluid binds outer/inner pleura together. A puncture that breaks this fluid bond causes pneumothorax- a collapsed lung. |
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respiratory cycle |
one breath, (inhalation and exhalation) |
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respiratory rate |
breaths per minute (normal adult= 12-18; child= 18-20) |
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alveolar ventilation |
movement of air into and out of alveoli |
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tidal volume |
amount of air moved in and out during one resting respiratory cycle |
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Expiratory reserve volume (ERV) |
amount of air you can force out after one normal cycle (including one normal exhalation) |
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Inspiratory reserve volume (IRV) |
Amount of air you can suck in over and above tidal volume (after normal inhalation) |
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Vital capacity |
Max amount of air that can be moved in and out in one cycle= Tidal volume + ERV + IRV |
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Residual volume |
amount of air that remains in lungs after maximum exhalation |
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minimal volume |
amount of air that would remain in respiratory system if lungs collapsed |
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oxygen transport |
Blood entering capillaries delivers O2- the lower the O2 levels in tissues (or PO2- "partial pressure" of O2 in plasma,) the more O2 is released by hemoglobin. Binding affinity of hemoglobin increases in high O2 environment. pH also effects hemoglobin release of O2: active tissues generate acids- lower pH-- hemoglobin releases more O2. |
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Carbon dioxide transport |
-Aerobic metabolism produces CO2 -7% disolves in plasma -23% diffuses into RBCs, binds to hemoglobin (forms carbaminohemoglobin,) -70% converted to carbonic acid (H2CO3)-- dissociates into one hydrogen ion and one bicarbonate ion (HCO3) -Most of hydrogen ions bind to hemoglobin, preventing release from RBC or change of pH. |
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Control by respiratory centers of the brain |
-two pairs of nuclei in pons: adjust respiratory rate and depth of response -one pair in medulla oblongata- set pace -apneustic nuclei- promote inhalation -pneumotaxic nuclei- inhibit inhalation -When CO2 levels are high, the brain's respiratory centers force breathing. |
