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| Five functions of respiratory system | 1)Gas exchange for cellular respiration 2)Sound production 3)assistance in abdominal compression during micturition, defecation, and parturition 4)route for water and heat loss 5)coughing and sneezing out inhaled foreign matter |
| Internal respiration | process by which gases are exchanged between the blood and the cells |
| External respiration | gas exchange between the air in the alveoli and blood |
| Cellular respiration | cells use )2 for metabolism and give off CO2 as a waste product |
| Bronchial tree | trachea>right and left primary bronchi>secondary bronchi>tertiary bronchi>bronchioles>terminal bronchioles>alveolar ducts>alveolar sacs |
| Pulmonary alveoli | alveolar sacs are formed of many microscopic pulmonary alveoli |
| How many pulmonary alveoli are there | 300 million with 6 times the surface area of the body |
| Type II alveolar cells secrete what and for what | secrete surfactant to lower the surface tension inside the alveolus |
| What remove dust particles and other debris from the pulmonary alveolus? | alveolar macrophages |
| External intercostals muscles | elevate during inspiration |
| Internal intercostals muscles | contract during expiration |
| Hypoxia | a deprivation of O2 in tissues and organs |
| Eupnea | normal breathing |
| Dyspnea | difficult or labored breathing |
| Apnea | temporary cessation of respiration that may follow hyperventilation |
| Cheyne-strokes | periods of dyspnea followed by periods of apnea (leads to death if not stopped) |
| Respiration rate | 12-15 times per minute |
| O2 consumption | 250 ml O2 per minute at rest |
| Bronchoconstriction | decreased radius, and increased resistance to flow. Allergy induced spasm of the airways-maybe from histamine release or from parasympathetic stimulation |
| Bronchodilation | increased radius, and decreased resistance to airflow. Sympathetic stimulation controlled through epinephrine and norepinephrine |
| Asthma | a disease characterized by recurrent attacks of dyspnea. Often an allergic response to plants, animals, or food products resulting in contraction of the bronchial muscles |
| Pneumonia | acute infection and inflammation of the lungs with exudation (accumulation of fluid) |
| Chronic bronchitis | a long term inflammatory condition of the lower respiratory airways, generally triggered by frequent exposure to irritating cigarette smoke, polluted air, or allergens. |
| Emphysema | collapse of the smaller airways and a breakdown of alveolar walls. Caused by excessive release of destruction enzymes such as trypsin from alveolar macrophages as a defense mechanism in response to chronic exposure to inhaled cigarette smoke or other irr |
| TV | tidal volume-volume of air moved into or out of the lungs during normal breathing 400-500ml |
| IRV | Inspiratory reserve volume-max volume beyond the tidal volume that can be inspired in one deep breath- 3000ml |
| ERV | expiratory reserve volume-max volume beyond the tidal volume that can be forcefully exhaled following a normal expiration- 1100 ml |
| RV | residual volume-air that remains in the lungs follwing a forceful expiration- 1200 ml |
| MRV | minute respiratory volume-volume of air moved in normal ventilation in one minute- 6000ml/min |
| AVV | alveolar ventilation volume-volume of air that actually ventilates the alveoli. A portion of inspired iar does not take part in gas exchange b/c it fills the air passageways (dead air). Dead air makes up about 30% of the tidal volume |
| How much of the tidal volume does dead air contribute | 30% |
| TLC | total lung coapacity-sum of the four lung volumes TV+ERV+IRV+RV=TLV=5700ml |
| VC | vital capacity- total amount of air that can be exchanged by the lungs- sum of the TV+IRV+ERV=4600 ml |
| Spirogram | record of pulmonary volumes and capacities |
| 6 Layers of the respiratory membrane | 1)surfactant 2)thin layer of fluid-water 3)alveolar epithelium 4)interstitial space 5)capillary basement membrane 6)capillary endothelium |
| surfactant | phospholipid protein decreases the surface tenstion of the fluids lining the alveoli and respiratory passages (Hyaline membrane disease or Respiratory distress syndrome) |
| Four factors affecting gaseous diffusion across the respiratory membrane | 1)thickness of the respiratory membrane 2)surface area of the membrane 3)diffusion coefficient of each gas 4)pressure difference across the membrane |
| Changes in the thickness of the respiratory membrane | edema in the lungs (left heart failure), pneumonia (edema in membrane and fluid in the lungs) |
| Changes in surface area of the membrane | emphysema-decrease in overall surface area |
| Changes in diffusion coefficient of each gas | O2 has a coefficient value of 1 (it’s the standard), CO2 has a coefficient of 20 (20 times more soluble than water) |
| Changes in pressure difference across the membrane | Pressure in Alveolus (O2=104, CO2=40) in capillary (O2=40 and goes to 104, CO2=45 and goes to 40) |
| Composition of atmospheric Air | N2=78.6, O2=20.8, CO2=0.04, H2O=0.5 |
| Composition of Alveolar air | N2=74.9, O2=13.6, CO2=5.3, H2O=6.2 |
| Composition of expired air | N2=74, O2=15.7, CO2=3.6, H2O=6.2 |
| Percent of O2 dissolved in blood | 1-3% |
| Percent of O2 carried by hemoglobin | 97-99% |
| What determines whether oxygen is bound or released from hemoglobin? | partial pressure of O2 |
| PO2 of O2 in atmospheric air | 21% of 760 mmHg=160mmHg |
| Alveolar PO2 and PCO2 | PO2=104mmHg, PCO2=40mmHg at sea level |
| Grams of Hb per 100 ml of blood | 15 grams |
| Ml of O2 per 1 gram of Hb | 1.34ml |
| Ml of O2 per 100 ml of blood | 20ml |
| Arterial blood is how saturated with O2 | 97% |
| Venous blood is how saturated with O2 | 75% |
| During exercise how saturated is arterial blood with O2 | 97% |
| During exercise how saturated is venous blood with O2 | 25% |
| the most important factor determing the % Hb saturation of O2 is what? | PO2 of the blood |
| factors affecting the O2-Hb dissociation curve | pH, PCO2, temperature, and 2,3-DPG |
| bohr effect | the O2-Hg dissociation curve shifting to the right from increased acidity, PCO2, temp, or 2,3-DPG |
| three major ways CO2 is transported | dissolved in blood (7-8%), carried by Hg forming carbaminohemoglobin(23-25%), as bicorbonate ion (65-70%) |
| two types of respiration control | neural and chemical |
| basic rhythm of repiration is controlled by what | medullary respiratory center in the brain stem |
| two subgroups in medullary respiratory center | dorsal and ventral |
| two other repiratory control centers in the pons | apneustic and pneumotaxic |
| dorsal respiratory group consits mainly of what | inspiratory neurons whose descending fibers stimulate inspiratory muscles. Serves as the major rhythm regulators |
| the ventral respiratory group contains | both inspiratory and expiratory neurons, which are inactive during quiet breathing, but become active during periods in whcih demands on ventailation are increased |
| pneumotaxic center functions | sends impulses to the dorsal neurons that help "switch off" the inspiratory neurons, thereby limiting hte duration of inspiration |
| apneustic center function | prevents the inpiratory neurons from being switched off, thus providing an extra boost to the inspiratory drive |
| herring-breuer reflex | triggered to prevent overinflation of the lungs. Stretch receptors in the lungs are activated by the stretching of the lungs at large tidal volumes |
| two types of receptors in chemical control of respiration | peripheral and central |
| peripheral chemoreceptors | located in the carotid bodies of the aortic bodies and are stimulated by decreased PO2 and increased H+ concentrations |
| central chemoreceptors | located in the medulla and respond to changes in brain extracellular fluid levels of PCO2. Increased PCO2 stimulates respiration. |
