Notes in 2. Respiratory Physiology (4-5)

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Published	02/10/2024	72. Describe ventilation and perfusion in the lungs at the base and at the apex.Why are the arterioles more compressed in the apex of the lungs, …
Published	02/10/2024	73. Describe the relationship between perfusion and ventilation in the optimal condition.
Published	02/10/2024	74. Describe the mismatch condition in the lungs where ventilation is less than perfusion, and how autoregulation occurs.
Published	02/10/2024	75. Describe the mismatch condition in the lungs where ventilation is more than perfusion, and how autoregulation occurs.
Published	02/10/2024	In the upright position the ratio of ventilation to perfusion within the lung {{c1::increases}} from the base of the lung (bottom) to the apex (top) o…
Published	02/10/2024	Over 75% of the height of a healthy lung performs quite well in matching ventilation and perfusion. The majority of the mismatch in the lung take…
Published	02/10/2024	Pulmonary arteries {{c1::constrict}} in response to hypoxia  Systemic arteries {{c1::dilate}} in response to hypoxia
Published	02/10/2024	76. Define the following terms:[1] Shunt[2] Alveolar dead space[3] Anatomical dead space[4] Physiologic dead space
Published	02/10/2024	{{c1::Shunt}} describes alveoli that are perfused but under-ventilated {{c1::Alveolar dead space}} describes alveoli that are ventilated but under-per…
Published	02/10/2024	Ventilation varies with height due to changes in {{c1::compliance}} across the lung
Published	02/10/2024	The ventilation-perfusion mismatch is compensated by local regulation of blood flow controlled by local {{c1::PO2}}
Published	02/10/2024	77. What is Respiratory Sinus Arrhythmia (RSA) and what role does it play during the breath cycle?
Published	02/10/2024	When the person breathes in, their heart rate {{c1::increases}}, and when they breathe out, the rate {{c1::decreases}}.This describes: {{c1::Resp…
Published	02/10/2024	78. Describe O2 and CO2 transport through the blood in general terms
Published	02/10/2024	Each litre of systemic arterial blood normally contains 200 ml of oxygen, more than {{c1::98}} percent of which is bound to haemoglobin.
Published	02/10/2024	Each haemoglobin molecule contains {{c1::4 haeme}} groups, each of which contains one Fe2+ which binds one O2 molecule. Each haemoglobin molecule…
Published	02/10/2024	The major determinant of the degree to which haemoglobin is saturated with oxygen is {{c1::partial pressure of oxygen}} in the blood.
Published	02/10/2024	80. Describe the role of haemoglobin in the movement of O2 from the alveoli to the capillaries.
Published	02/10/2024	Haemoglobin-O2 Saturation is complete after {{c1::0.25s}} contact with alveoli (total contact time ~0.75s)
Published	02/10/2024	81. Explain the Oxygen-haemoglobin dissociation curve
Published	02/10/2024	{{c1::Anaemia}} is defined as any condition where the oxygen carrying capacity of the blood is compromised    (e.g. iron deficiency, haemorr…
Published	02/10/2024	82. Explain what happens to PaO2 in anaemia and why?
Published	02/10/2024	83. Explain the relationship between PaO2 and total blood O2 content.
Published	02/10/2024	84. Is it possible for red blood cells to be fully saturated with O2 in anaemia?
Published	02/10/2024	85. Describe the factors that increase the O2 saturation of hemoglobin (increase affinity & decrease O2 unloading)What direction would t…
Published	02/10/2024	86. Describe the factors that decrease the O2 saturation of hemoglobin (decrease affinity & increase O2 unloading)What direction would t…
Published	02/10/2024	87. Explain why the shape of the oxyhemoglobin dissociation curve aids O2 loading in the lungs and unloading in the tissues.
Published	02/10/2024	#1 Revision purpose: (Open up)
Published	02/10/2024	Carbon monoxide (CO) binds to haemoglobin to form {{c1::carboxyhaemoglobin}} with an affinity 250 times greater than O2 PCO of only 0.4 mmHg caus…
Published	02/10/2024	88. Identify the forms in which CO2 is carried in the blood.
Published	02/10/2024	89. Explain the action of carbonic anhydrase in CO2 transport.
Published	02/10/2024	90. Identify the factors which favor CO2 unloading to the alveoli at the lungs.
Published	02/10/2024	{{c1::Oxygen in solution}} is the sole determinant of arterial partial pressure of oxygen (PaO2) and in health is in equilibrium with alveol…
Published	02/10/2024	91. Why is the PaO2 not the same as arterial O2 concentration/content?
Published	02/10/2024	Values assigned to the Pgas in solution are equal to the Pgas in gaseous phase that is driving that gas into solution at {{c1::equilibrium}}
Published	02/10/2024	92. Compare myoglobin, foetal hemoglobin, adult hemoglobin, in terms of their affinity and how it relates to their roles.
Published	02/10/2024	93. Define the following terms:[1] Hypoxaemic Hypoxia[2] Anaemic Hypoxia[3] Stagnant Hypoxia[4] Histotoxic Hypoxia[5] Metabolic Hypoxia
Published	02/10/2024	94. Explain how respiratory motor movements are affected by the central nervous system
Published	02/10/2024	Normally, ventilatory control is subconscious/autonomous with areas located in {{c1::pons}} and {{c1::medulla}}, but it can be voluntary.
Published	02/10/2024	95. How do we know that ventilatory control is entirely dependent on signalling from the brain (somatic motor neuron input)?
Published	02/10/2024	96. What are the stimuli that modulate the rhythm of the Respiratory Centres?List the factors involved in changing ‘respiratory drive’ i.e., the …
Published	02/10/2024	Within the respiratory centres there are two nerve groups:[1] {{c1::Dorsal Respiratory Group of neurons (DRG)}}→ Stimulation of inspiratory muscles (d…
Published	02/10/2024	97. Describe the location of the two classes of chemoreceptors that modulate respiratory centres and identify the stimuli which activate them.
Published	02/10/2024	98. Describe the role of Central Chemoreceptors in regulating PaCO2
Published	02/10/2024	Central chemoreceptors only respond to changes in {{c1::CSF}} [H+] and not to direct changes in {{c1::plasma}} [H+]→ because of the blood-brain barrie…
Published	02/10/2024	99. Explain the negative feedback loop that occurs when PCO2 increases in the CSF.
Published	02/10/2024	A 10% increase in PaCO2 = {{c1::100%}} increase in ventilation
Published	02/10/2024	101. Describe the role of Peripheral Chemoreceptors in regulating PaO2
Published	02/10/2024	A {{c1::40%}} decrease in PaO2 (from 100 mmHg to 60 mmHg) leads to a significant increase in ventilation
Published	02/10/2024	Peripheral Chemoreceptors respond to changes in {{c1::arterial PO2}} i.e. oxygen in solution in plasma, not total oxygen content.They also respon…
Published	02/10/2024	Most gaseous anaesthetic agents increase {{c1::respiratory rate}} but decrease {{c1::tidal volume}} and so they decrease alveolar ventilation.
Published	02/10/2024	102. Describe the effect of Barbiturates and Opioids on respiratory centres.
Published	02/10/2024	103. Why is usage of Nitrous Oxide very problematic in chronic lung disease cases?
Published	02/10/2024	Total blood oxygen content can fall very low (anaemia) but will have little impact on {{c1::ventilation}} if PaO2 (oxygen in solution in the plas…
Published	02/10/2024	{{c1::Central}} chemoreceptors respond only to H+ which originates from CO2{{c1::Peripheral}} chemoreceptors respond to H+ that originates f…
Published	02/10/2024	104. How do Peripheral Chemoreceptors regulate plasma pH levels (H+ conc)?Explain how Peripheral Chemoreceptors become important during hyp…
Published	02/10/2024	105. How does the change in [CO2] affect acid-base balance in the case of hypo/hyperventilation.
Published	02/10/2024	#2 Revision purpose: (Open up)
Published	02/10/2024	During {{c1::moderate}} exercise, ventilation increases in exact proportion to metabolism, but the signals causing this are unknown. The proportional…
Published	02/10/2024	During {{c1::strenuous}} exercise, ventilation increases more than metabolism. Arterial [H+] increases because of a rise in {{c1::lactic acid}} p…
Published	02/10/2024	106. Explain situations where we cannot override involuntary stimuli voluntarily such as PCO2 or [H+]
Published	02/10/2024	107. Why does increasing PCO2 in a chamber cause unpleasant and distressing feelings to the subject?
Published	02/10/2024	{{c1::Respiration}} is inhibited during swallowing to avoid aspiration of food or fluids into the airways. Swallowing is followed by an {{c1::exp…
Published	02/10/2024	Increasing [H+] in the plasma {{c1::stimulates}} ventilation Decreasing [H+] in the plasma {{c1::depresses}} ventilation
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