Arterial Blood Gases, Control of Respiration and Respiratory Adaptation at Altitude

Question 1

what conducts involuntary breathing

Answer 1

inspiratory and expiratory neurones

Question 2

where are inspiratory and expiratory neurones found

Answer 2

PONS
Medulla oblongata

Question 3

What nerves innervate the cerebral cortex and the hypothalamus

Answer 3

CN IX and X

Question 4

What inputs from the cerebral cortex and hypothalamus can change the respiratory rate

Answer 4

Poutine respiratory centre -> medulla

Question 5

What does the medulla stimulate or suppress

Answer 5

Voluntary control
Pain
Emotion
Temperature

Question 6

What do dorsal respiratory group control

Answer 6

Inspiration

Question 7

What do ventral respiratory group neurones control

Answer 7

Inspiration and expiration in active breathing

Question 8

What is the pacemaker in the medulla

Answer 8

Central pattern generator which is in the ventral respiratory group

Question 9

What does the central pattern generator do

Answer 9

Initiates breathing

Question 10

What are the 2 respiratory control Centres in the brain stem

Answer 10

PON respiratory centres and medullary respiratory centres

Question 11

What is the pons respiratory centres divided into

Answer 11

Pneomotaxic center
Apneustic center

Question 12

What is the medullary respiratory center divided into

Answer 12

Dorsal and ventral respiratory group

Question 13

What does the pontine respiratory center do

Answer 13

Inhibits and excited inspiration

Question 14

What does the pneumotaxic centre do

Answer 14

Inhibits inspiration to allow expiration

Question 15

What does the apneustic centre do

Answer 15

Excites inspiration to enhance breathing (gasps)

Question 16

What do central chemoreceptors detect

Answer 16

PCO2 and pH

Question 17

What does peripheral chemoreceptors detect

Answer 17

PCO2 pH and PO2

Question 18

Where are central chemoreceptors found

Answer 18

Lie near the venterolateral surface of the medulla near the exit of CN IX and X

Question 19

What is the blood brain barrier

Answer 19

Tight endothelial layer which separates the cerebrospinal fluid from blood

Question 20

What is the blood brain barrier impermeable to

Answer 20

Charged molecules (H+ and HCO3-)

Question 21

What is the blood brain barrier permeable to

Answer 21

CO2 so it can easily cross from blood to cerebral spinal fluid

Question 22

What is the pH of the cerebral spinal fluid determined by

Answer 22

Arterial PCO2

Question 23

is the pH of the cerebral spinal fluid affected by changes in blood pH

Answer 23

no

Question 24

why does the cerebral spinal fluid have low buffering capacity

Answer 24

little protein

Question 25

what are neurones in the central chemoreceptors sensitive to

Answer 25

CO2

Question 26

what are the neurones in the central chemoreceptors less sensitive to

Answer 26

H+

Question 27

what does an increase in CO2 in the cerebral spinal fluid cause

Answer 27

an increase in minute ventilation (VE)

Question 28

how does metabolic acidosis shift the CO2-ventilation curve

Answer 28

to the left

Question 29

how does metabolic alkilosis shift the CO2-ventilation curve

Answer 29

to the right

Question 30

where is the carotid body found

Answer 30

bifurcation of the common carotid artery just above the carotid sinus

Question 31

what is the carotid body innervated by

Answer 31

Carotid Sinus Nerve → Glossopharyngeal Nerve (CN IX)

Question 32

where is the aortic bodies found

Answer 32

around the aoritc arch

Question 33

what are the aoritc bodies innervated by

Answer 33

Vagus nerve (CNX)

Question 34

what do all the peripheral chemoreceptors respond to when there is a small change

Answer 34

PCO2, pH, pO2

Question 35

what happens to minute ventilation when there's an increase in PCO2

Answer 35

increase

Question 36

what happens to minute ventilation when there is an increase in pH

Answer 36

decrease

Question 37

what happens to minute ventilation when there is an increase in PO2

Answer 37

decrease

Question 38

what happens to the respiratory centre when there hyercapnoea

Answer 38

less sensitive to chronic PaCO2 elevations, and respiratory response becomes blunted

Question 39

what is the respiratory response to hypocapnoea

Answer 39

- Chronic respiratory acidosis with metabolic compensation - Hypoxaemia due to hypoventilation

Question 40

what happens to chemoreceptors in response to chronic lung disease

Answer 40

hypoventilation → prolonged hypercapnoea (high CO2)

Question 41

what happens to the cerebral spinal fluid pH in response to prolonged hypercapnoea

Answer 41

returns to normal due to adaptive and compensatory processes

Question 42

what do stretch receptors in smooth muscle of the bronchial walls do

Answer 42

Receive and send signals through Vagi → shallower inspiration, delaying next cycle of inspiration

Question 43

what do irritant receptors in smooth muscle do

Answer 43

Receive parasympathetic bronchoconstrictor nerve supply via Vagi which act via Acetylcholine and Muscarinic Type 3 receptors → deep sighs, prevent lungs from collapsing

Question 44

what do juxtapulmonary receptors do

Answer 44

Afferents are small, unmylelinated C-fibres or Vagi. Stimulation → apnoea, rapid shallow breathing, ↓ HR and BP

Question 45

where are juxtapulmonary receptors found

Answer 45

on alveolar and bronchial walls close to capillaries.

Question 46

what are juxtapulmonary receptors stimulated by

Answer 46

Stimulated by pulmonary congestion, pulmonary oedema, microemboli and inflammatory mediator.

Question 47

where are irritant receptors found

Answer 47

smooth muscle and trachea

Question 48

where are proprioceptors found

Answer 48

Golgi tendon organs, muscle spindles and joints of respiratory muscles (not diaphragm) → Spinal Cord

Question 49

what are proprioceptors stimulated by

Answer 49

Stimulated by shortening of the respiratory muscles → Respiratory Centre →↓ RR

Question 50

what are opioids

Answer 50

naturally occurring peptides used as analgesics (pain control)

Question 51

what do opioids do

Answer 51

Opioids → decrease in sensitivity of peripheral and central chemoreceptors → Respiratory Depression

Question 52

what is the treatment for opioid overdose

Answer 52

naloxone

Question 53

where are ABG's taken from

Answer 53

peripheral artery: Radial, Brachial, Femoral

Question 54

what does low PaO2 show

Answer 54

respiratory faliure

Question 55

what does low pH show

Answer 55

acidosis

Question 56

what does high pH show

Answer 56

alkilosis

Question 57

what does abnormal PaCO2 show

Answer 57

type 2 respiratory faliure

Question 58

what does a normal PaCO2 show

Answer 58

type 1 respiratory faliure

Question 59

what does this ABG show PaO2: 12.7 kPa (11 – 13 kPa) pH: 7.50 (7.35 – 7.45) PaCO2: 5.5 kPa (4.7 – 6.0 kPa) HCO3-: 29 (22 – 26 mEq/L) BE: +3 (-2 to +2)

Answer 59

metabolic alkalosis

Question 60

what does this ABG show PaO2: 9.1 kPa (11 – 13 kPa) pH: 7.30 (7.35 – 7.45) PaCO2: 8.4 kPa (4.7 – 6.0 kPa) HCO3-: 29 (22 – 26 mEq/L) BE: +4 (-2 to +2)

Answer 60

respiratory acidosis with metabolic compensation

Question 61

what does this ABG show PaO2: 7.9 kPa (11 – 13 kPa) pH: 7.31 (7.35 – 7.45) PaCO2: 7.1 (4.7 – 6.0 kPa) HCO3-: 22 (22 – 26 mEq/L) BE: +1 (-2 to +2)

Answer 61

type 2 respiratory falire respiratory acidosis

Question 62

what does this ABG show PaO2: 6 kPa (11 – 13 kPa) pH: 7.51 (7.35 – 7.45) PaCO2: 3.1 kPa (4.7 – 6.0 kPa) HCO3-: 21 (22 – 26 mEq/L) BE: 0 (-2 to +2)

Answer 62

Respiratory alkalosis and type 1 respiratory failure.

Question 63

what are causes of Type 1 RF

Answer 63

- Low inspired O2 (FIO2): high altitude, asphyxia - Hypoventilation: COPD - Diffusion impairment: pulmonary fibrosis - VQ mismatch: pulmonary emboli, pneumonia - R-L Shunt: includes congenital causes

Question 64

what are the causes of type 2 RF

Answer 64

- Failure of ventilation → alveolar hypoventilation - Chronic Lung Disease: - Musculoskeletal abnormalities: - Neuromuscular disease: - Central Nervous System:

Question 65

what is the anion gap

Answer 65

difference between primary measured Cations and Anions

Question 66

what are symotoms of acute mountain sickness

Answer 66

headache and disturbed sleep malaise, drowsiness loss of appetite and nausea

Question 67

what can acute ountain sickness cause

Answer 67

peripheral oadema

Question 68

what happens during high altitude pulmonary oedema

Answer 68

increase of capillary hydrostatic pressure

Question 69

what are symptoms of high altitute cerebral oedema

Answer 69

change in level of consciousness nausea vomiting hallucinations, seizures and paralysis