respiratory physiology 2

Question 1

ventilation control

Answer 1

inspiration is aided by muscles that are stimulated by the intercostal nerves an dthe phrenic nerve.
expiration is a passive process

Question 2

factors that stimulate the respiratory centres in the brain

Answer 2

emotion that is via limbic system in the brain.
voluntary over -ride that is through higher centres in the brain.( example is cerebral cortex)
mechanosensory input form the thorax that is the stretch reflex.
chemical composition of the blood that is pco2 and po2 and pH

Question 3

dorsal respiratory group of muscles

Answer 3

they control the inspiratory muscles that is through the phrenic and the intercostal nerves .

Question 4

ventral respiratory group of neurons

Answer 4

that is the toup , pharynx , larynx and the expiratory muscles ( that is the internal intercostal muscles )

Question 5

chemoreceptors in the brain

Answer 5

central chemoreceptors and peripheral chemoreceptors

Question 6

examples of central chemoreceptors

Answer 6

medulla - that measure strictly the amount of hydrogen ions in the CSF which is as a result of carbon dioxide since carbon dioxide is a gas it can pass through the blood brain barrier.

Question 7

primary ventilatory drive

Answer 7

central chemoreceptors

Question 8

secondary ventilatory drive

Answer 8

peripheral chemoreceptors

Question 9

peripheral chemoreceptors

Answer 9

carotid and aortic bodies
they respond to both PO2 ( primarily ) and PCO2 in the plasma .
in this case the hydrogen ions are not an accurate measure as they could be from anything else that is not failure of the respiratory system.

Question 10

central chemoreceptors in the medulla

Answer 10

the receptors detect changes in hydrogen ions in the CSF and causes reflex stimulation of ventilation following the rise in hydrogen ions

Question 11

decrease of hydrogen ions in the CSF

Answer 11

leads to a decrease in the rate of ventilation
( there is less carbon dioxide )

Question 12

chronic lung disease and paCO2

Answer 12

with chronic lung disease there is always elevated levels of carbon dioxide ; they become desensitised to the increased levels in the carbon dioxide they therefore rely on oxygen pressure

Question 13

hypoxic drive

Answer 13

reliant of oxygen for ventilation control

Question 14

peripheral chemoreceptors

Answer 14

they are the carotid and aortic bodies

Question 15

carotid and aortic bodies

Answer 15

changes in the arterial PO2 and Hydrogen ions

Question 16

peripheral chemoreceptors

Answer 16

they cause reflex stimulation of ventilation following significant fall in arterial PO2

Question 17

changes in oxygen partial pressure

Answer 17

changes upto 60 can lead to the changes in ventilation

Question 18

what does the peripheral chemoreceptors detect

Answer 18

Respond to arterial PO2 not oxygen content ​

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Question 19

anaesthesia and ventilatory control

Answer 19

Most gaseous anaesthetic agents increase RR but decrease TV so decrease AV.

Question 20

opioids and barbiturates

Answer 20

an overdose results in a decrease to the sensitivity of pH and therefore response to pCO2 .

Question 21

nitrous oxide

Answer 21

common sedative/light anaesthetic agent, blunts peripheral chemoreceptor response to falling PaO2. Very safe in most individuals, problematic in chronic lung disease cases where individual often on “hypoxic drive”. Administering O2 to these patients aggravates situation.​

Question 22

how changes in plasma alter ventilation via the peripheral chemoreceptor pathways

Answer 22

if plasma pH falls ventilation will be stimulated
if plasma ph increases there will be decreased ventilation

Question 23

hypoventilation

Answer 23

Hypoventilation, causing CO2 retention, leads to increased [H+] bringing about respiratory acidosis.​

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Question 24

hyperventilation

Answer 24

Hyperventilation, blowing off more CO2, lead to decreased [H+] bringing about respiratory alkalosis​

Question 25

important chemical equation

Answer 25

pH is directly proportional to the bicarbonate ions
pH is indirectly proportional to carbon dioxide produced

Question 26

ventilation during exercise

Answer 26

ventilation occurs more than metabolism the arterial hydrogen ions will increase because of the increase in the lactic acid concentration hence the hyperventilation