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20 Cards in this Set
- Front
- Back
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-each heme group has what -Hb two forms |
a porphyrin ring that contains an iron atom in the ferrous form (Fe2+) -deoxyhemoglobin, hemoglobin |
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O2 + Hb ↔ HbO2 can be explained by what |
oxygen dissociation curve |
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O2 capacity Hb saturation determinants of Hb saturation |
-max amount of O2 that can be bound to Hb -amount of Hb binding sites bound to O2 -arterial pO2 (most important) and cooperative binding (results in a sigmoidal dissociation curve) also pH, temp, PCO2 |
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cooperative binding |
-When O2 binds to heme, it deforms the shape of the heme whichchanges the shape of its associated globin chain from tense (T) to relaxed (R) state -The change in the shape of one globin chain deforms the others, exposing the ironin their hemes and facilitates binding of additional O2 molecules. -This action produces the characteristic sigmoidal oxygenbinding curve of Hb. |
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sigmoidal dissociation curve -plateau meaning -steep slope meaning |
- many conditions result inreduced alveolar PO2 and thereforearterial PO2 (pulmonary diseases,altitude). Due to the plateau,saturation stays high over a widerange of alveolar PO2 - Because PO2 in the capillary ofperipheral tissue is on steep portion, small changes in shape ofdissociation curve due tocompounds produced in tissues (pH, temperature) enhance O2 unloading |
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change to the right and left in dissociation curve -an increase in DPG means what for the curve and what is it |
-right- O2 affinity for Hb reduced= more unloading left-opposite -shifts it to the right, an end product in RBC metabolism |
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CO2 in peripheral tissue CO2 at respiratory membrane |
- remain in plasma as dissolved CO2, enter RBC and remain as dissolved CO2, bind to deoxyHb, or react with water and produce HCo3- and H+ -dissolved co2 in blood diffuses to alveoli, |
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Hb has a key role in buffering H+ production in periphery, how |
deoxyHb higher affinity for H+ than oxyHb most H will bind to Hb, so keeps it less acidic |
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-hypoventilation -hyperventilation -metabolic alkalosis -metabolic acidosis |
- Co2 production > co2 elimination. PCO2/H+ increase= respiratory acidosis - opposite, respiratory alkalosis - higher H+ in blood, independant of PCO2 - opposite |
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breathing is initiated in.. modified in... |
-medulla - higher structuresof the CNS & inputs from central& peripheral chemoreceptors &mechanoceptors in the lung andchest wall |
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neuronal networks must adjust breathing rhythm to accommodate changes in |
-metabolic demands (changes in PO2, PCO2, pH) -mechanical conditions (posture) -non ventilatory behaviours (speaking) -pulmonary and non-pulmonary diseases |
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-chemical control of ventilation |
- Hypoxia (low PO2), hypercapnia(high PCO2), and acidosis (low pH in blood) all cause an increase inventilation, which tends to raise PO2, to lower PCO2, and to raise pH |
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PERIPHERAL CHEMORECEPTORS:CAROTID AND AORTIC BODIES. |
sense hypoxia, but also pH |
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carotid bodies physical structure two types of cells |
-small, chemosensitive, highly vascularized, high metabolic rate -pO2, pCO2, pH same as systemic arteries - type I: chemosensitive, glomus -type II: sustentacular, for support |
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-carotid bodies neuron characteristics - how to stimulate it |
-voltage gates ion channels, depolarization triggers AP, vesicles that have neurotransmitters -low arterial PO2, below 60 mmHg (also CO2 and pH though)= higher firing rate |
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central chemoreceptors responsible for what |
70% hypercapnia (at dorsal and ventral respiratorygroup) |
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peripheral chemoreceptors |
H+ because it does notcross easily bbb (as CO2does). |
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groups of respiratory neurons |
-pontine, ventral, dorsal |
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-in ventral respiratory group, the preBotC responsible for what -pFRG for what |
-excitatory inspiratory rhythmic activity -excitatory active expiratory rhythmic activity |
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-Rhythm of breathing isgenerated in the____. -________ and _______ neurons drive activity inpremotor neurons, which _______. |
-VRG -preBOTc, pFRG -excite motoneurons thatactivate rhythmicallyrespiratory muscles |
