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16 Cards in this Set
- Front
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1) What happens to O2 and CO2 levels in hyper and hypoventilation 2) What is the relationship between ventilation and CO2 levels s4, 5 |
1) Hyperventilate, will increase O2 blood level. But reach a max level. CO2 goes down, O2 goes up. If hypoventilate, vice versa. CO2 is main determining factor, oxygen and plasma pH have smaller roles. 2) CO2 chemosensitivity natural increases ventilation, linear relationship.If metabolic hyperbola, increase ventilation and CO2 going down. |
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1) What happens to respiratory rate and tidal volume when CO2 increases and then back to normal? 2) What happens in hypoxia? s7 |
1) Both increase, then gradually decrease, since takes time until going back to normal 2) You have have lower O2, even higher CO2 accumulates and even higher ventilation. Lower O2 also stimulates higher ventilation |
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1) Where are the central and the peripheral CO2 chemoreceptors, and what do each measure? s9 |
1) -> Central ones located in the medulla and some brain tissue. monitor H+ in cerebro-spinal fluid and arterial circulation. Raphé neurons important. -> Peripheral ones in carotid and aortic bodies, monitor arterial levels of oxygen and CO2/H+ |
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1) Describe the mechanism of the central chemoreceptors. 2) Which area of the medulla is important in the chemoreception? s12 |
1) CO2 going from cerebral capillary into the CSF, forming H+ ions, detected by the chemoreceptors on the medulla, which act on respiratory control centers to increase ventilation. 2) The retrotrapezoid nucleus in the ventral part of medulla. Applying CO2 to this region, increased activity. Shows that these cells are responsive to CO2. |
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1) What are the CO2 chemoreceptors and where are they? what did the experiments show? 2) What is the neuron group expressed and where, why important for chemosensitivity? s14 |
1) Proton-sensing G-protein-coupled receptor 4 (GPR4) found in the retrotrapezoid nucleus. Responds to pH lower than 7. 2) The Medullary raphe, collections of neurons. There are mini capillaries in this area. The neurons are serotoninergic, chemosensitive. The neurons and capillaries are active in same regions, neurons quick to respond. |
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1) What is sleep apnea and what are some of the diffrent types. s16 |
1) Cessation of airflow without respiratory effort, brain can't activate diaphragm. They won't respond to CO2 levels. Cheyne-Strokes: decrease in ventilation, can stop breathing idiopathic central: newborns can experience Narcotic: Low breathing due to overdose Hypoventilation syndrome (Ondine's curse): mutation making insensitive to CO2 levels. less than 1% of pop'n, 25-40% of patients with heart failure |
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1) What cycles happens in Cheyne-stokes? s17 |
1) Nasal pressure is nonexistent for a while and then suddenly increases, and there is a cycle. Same with abdomen and rib cage activity. O2 blood saturation going down, CO2 high and stimulates chemosensors. O2 goes up in the periods of ventilation. |
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1) Why does apnea only occur in sleep? Describe breathing in sleep. s18, 19 |
1) When awake, have stimulation from cortical areas, stimulating respiratory neurons. When patients fall sleep, behavioural control systems are removed (non-REM sleep). Only thing breathing is CO2, O2 levels and some input from vagus nerves, some stretch receptors in the lunch. These are the only feedback systems in sleep (non rem). Can't ventilate voluntary either cause sleeping. even lower in REM. So basically, less sensitive to CO2 in sleep and ventilation goes down. Total lung ventilation going down = Tidal volume decreasing (upper airway muscles relaxing) |
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1) What happens in congenital central hypoventilation syndrome? Treatments? s21,22 |
1) Don't sleep during sleeping, they dont respond to CO2, and dont wake up when they have levels. mutation of Phox2B gene (transcription factor): gene encoding for transcription factor in autonomic nervous system (in Raphe area). Mechanical ventilation is required at least during sleep. Positive pressure ventilation (PPV) during first years of life. Later bi-level positive airway pressure ventilation (BiPAP), continuous negative extrathoracic pressure ventilation (CNEP) and diaphragm pacing. |
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1) What did they discover in Phox2B KO mice? s23 |
1) Abolished CO2 sensitivity in constitutive and conditional Phox2B mice. |
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1) Describe stimulus of lower O2 levels to ventilation. 2) Where are the central and peripheral O2 chemoreceptors. s24 |
1) If really low O2 levels (hypocania), stimulates ventilation, though not as sensitive to high CO2 levels. 2) Peripheral: Carotid and aortic bodies. Monitor arterial level of oxygen and CO2/H+ Central: Less important. Locus coeruleus, thalamus, preBotzinger complex |
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1) Where are the carotic and aortic bodies and how do they connect to the brainstem respiratory area. s26 |
1) Carotic arteries close to blood vessels near brain. Highest blood flow of the whole body around here. Accurate measure of O2. Also detect high CO2, low pH. Connect through Carotic sinus nerve to brainstem. carotic body nerve activity in response to O2 changes. Aortic bodies more on the bottom, vagus nerve to brainstem. |
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1) What are the 2 types of the glomus cells of the carotid bodies? 2) What are the 3 types of carotid tumours s28 |
1) Type 1: Chemosensitive cells Type 2: support cells 2) -> Familiar (10-50% of patients) -> Sporadic (85%) -> Hyperplastic (link to chronic hypoxia in altitude or in patients in COPD) |
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1) What happens when you breath in high altitudes. O2 level, CO2 level, ventilation, pH. s32,33 |
1) Low partial pressure of O2 in high levels, low levels of oxygen in blood. Arterial pressure of O2 goes down. O2 chemoreceptors increasing ventilation, and CO2 goes down (40 mmHg normal pressure, going down). pH going higher. Reduction in pCO2 reduces O2 chemosensitivity. |
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1) What are chronic changes to breathing in high altitude. s34 |
1) Ventilation going higher, but reaches max volume. Erythropoietin stimulates RBC production. Increase of hematocrit by 50%. Synthesis of 2,3 DPG in RBC. Muscle size decreases, loss of appetite. After years: Don't respond to O2 changes well at all. |
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1) What happens to 2,3-DPG in high altitude? 2) What happens to ventilation, PCO2, pH at very high altitude s36 |
1) More, increases level of O2 to tissue level. 2) Very high hyperventilation, PCO2 very low, pH very high, Oxygenation-Hb dissociation shift to left. |
