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Respiratory Homeostasis And Abnormalities Notes

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This is an extract of our Respiratory Homeostasis And Abnormalities document, which we sell as part of our Respiratory System Notes collection written by the top tier of Bristol University students.

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Lecture 9 Respiratory homeostasis and abnormalities

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Apply Fick's principle to solve problems involving CO and oxygen consumption o Blood flow to organ can be calculated using marker substance if following is known
? Amount of marker substance taken up by the organ per unit time
? Concentration of marker substance in arterial blood supplying the

organ Concentration of marker substance in venous blood leaving the organ

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*o Oxygen Consumption Rate (Vo2)
? Measured using spirometer or calculated using Fick principle:

* Vo2 = Cardiac output x (CaO2 - CvO2)
? Depends upon cardiac function (ETT) andability of tissues to extract oxygen. Describe & explain changes in respiratory rate, tidal volume, CO, oxygen consumption & CO2 that occur during exercise o PAO2, PaO2, CO2 & oxygen saturation all unchanged o Increased ventilation (tidal volume, respiratory rate, CO & O2 consumption increase) Outline theories regarding alteration to control of ventilation during exercise o Chemoreceptors in veins that haven't been found yet o Increase in body temperature (not much evidence) o Activity in motor cortex= increased respiratory centre activity o Receptors in muscle spindles and joints (tandem bike test, one pedalling but both ventilation goes up) o Chemoreceptors more sensitive in exercise so sense small changes Define and explain VO2 max. Using Fick principle to explain determining factors o Maximum capacity of an individual's body to transport and use oxygen during incremental exercise, which reflects the physical fitness of the individual o Factors affecting VO2 are often divided into supply and demand factors
? Supply (usually limiting one)

* Transport of oxygen from the lungs to the mitochondria

* Lung diffusion, stroke volume, blood volume, & capillary density of muscle
? Demand

* Rate at which the mitochondria can reduce O2 in the process of oxidative phosphorylation Describe and explain anaerobic threshold stating the effect upon plasma lactate concentration and minute ventilation o Calculate the rate of oxygen delivery to systemic tissues o Greater delivery than consumption o So, if arterial levels drop, there is no real danger o Factors that determine oxygen delivery to tissue
? Blood flow (in terms of CO)
? Oxygen content in arterial blood (amount of O2 dissolved & bound to haemoglobin can be calculated) List the symptoms and signs of acute hypoxia

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