Physiology Flashcards Preview

Y1 Respiratory > Physiology > Flashcards

Flashcards in Physiology Deck (188):
1

The pneumotaxic centre is stimulated when...

a. ventral respiratory neurons fire

b. ventral respiratory neurons stop firing

c. dorsal respiratory neurons fire

c. the pneumotaxic centre is stimualted when dorsal respiratory neurons fire. 

2

The ventral respiratory group neurons...

a. are activated during normal breathing

b. are activated during hyperventilation

c. are activated during apnoea

b. are activated during hyperventilation

3

FEV1/FVC ratio is less than 75% in restrictive lung diseases - true or false?

false as both the FVC and FEV1 both fall, the ratio of remains at a normal level

4

What higher centres in the brain influence respiratory centres?

cerebral cortex, limbic system, hypothalamus

5

A measure of effort that has to go into stretching or distending the lungs

Compliance

6

what is PAO2 at sea level approx?

100mmHg

7

If there is a decrease in blood pressure, the is a(n) _______ in ventilation

increase

8

During inspiration, which neurons are excited?

dorsal respiratory group neurons

9

What is a peak flow meter?

a device which the patient gives a sharp fast blow after maximal inspiration gives an estimate of airway function best of 3

10

Conditions where the Bohr Effect might come into play?

  1. increased PCO2
  2. increased H+
  3. increased temperature
  4. increased 2,3-biphosphoglycerate

11

Three pressures important for ventilation

Atmospheric Intra-alveolar Intra-pleural

12

the proportion of the FVC expired in first second

FEV1/FVC ratio

13

Why is the Bohr Effect useful?

allows oxygen offloading without the need for a drop in PO2

14

According to La Place's law...

smaller alveoli with a smaller radius have a higher tendency to collapse as there is a greater inwardly directed collapsing pressure

15

Afferent discharge from irritated airwasy stimulates what reaction from the medulla...(4)

  1. short intake of breath
  2. closure of larynx
  3. contraction of abdominal muscles 
  4. opening of larynx and expulsion of air at high speed

16

FEV1/FVC ratio is less than 75% in obstructive lung diseases - true or false

true

17

What are the 4 stages of External Respiration?

  1. Ventilation
  2. Gas Exchange between Alveoli and blood Gas
  3. Transport in the blood
  4. Gas Exchange in the tissues

18

What is the difference in oxygen dissociation in myoglobin?

hyperbolic curve as only dissociates at very low PO2

19

What is a pneumothorax?

air in the pleural space

20

The transfer of gases between the body and atmosphere depends upon....

ventilation perfusion

21

Normal CI

2.4-.42L/min/m2

22

At a normal PaCO2 of around 40mmHg, PAO2 =

100mmHg

23

How do we work out the partial pressure of O2 in the atmosphere?

21% of 760mmHg = 160mmHg which is breathed in

24

What is the body's normal response to acute hypoxia?

hyperventilation and increased CO

25

How is the Oxygen dissociation curve affected in HbF?

shifted to the left

26

Other non-respiratory functions of the resp. system (7)

- water loss and heat elimination - enhanced venous return - normal acid-base balance maintenance - speech, singing, vocalisations - defence against inhaled foreign matter - modification and removal of materials passing through - nose as an organ of smell

27

At the lungs, O2 binding Hb ______ the ability of Hb to bind CO2 and H+

Weakens

28

The flat upper portion of the oxygen dissociation curve is important as it means a _______ fall in O2 will not affect oxygen _____ onto _______

moderate, loading, haemoglobin

29

Alveolar ventilation (L) =

(tidal volume - dead space) x resp. rate

30

In systemic arterioles, a decrease in O2 will cause vasodilation to...

promote offloading of oxygen to the tissues

31

Where are central chemoreceptors located?

near the surface of the medulla

32

The aortic and carotid bodies sense the _____ of ______ and _____ and the concentration of ___ in the blood

tension, oxygen, carbon dioxide, H

33

What does the Haldane effect work in tandem with?

The Bohr Effect 

34

Residual Volume

minimum volumes of air remaining in the lungs even after a maximal expiration 1200ml

35

Average intra-pleural pressure at rest

756mmHg

36

Parasympathetic stimulation causes bronchodilation and and decreased resistance - true or false?

false PS stimulation causes bronchoconstriction and increased resistance

37

CO2 has a smaller partial pressure gradient, how is this offset so that CO2 still moves freely between the blood and alveoli?

it is 20x more soluble in membranes as it has a higher diffusion coefficient

38

What is external respiration?

sequence of events that leads to exchange of O2 and CO2 between the external environment and the cells of the body

39

Which particular gas is very regulated in respiration?

CO2

40

Why is alveolar ventilation more important?

it represents the new air available for gas exchange with blood.

41

What might a large difference between alveolar and arterial O2 partial pressure indicate?

issues with gas exchange or a right to left cardiac shunt

42

H+ dissociates from CO3- to join

Hb --> HbH

43

How much oxygen is carried by 1g of Hb when fully saturated?

1.34ml

44

Average intra-alveolar pressure during inspiration

759mmHg

45

What are the muscles of active expiration?

internal intercostals abdominal muscles

46

H+ drive of respiration is driven by the _______ chemoreceptors

peripheral

47

Anatomical dead space

where some inspired air remains in the airways and is not available for gas exchange

48

Why is CSF less able to buffer H+?

because there are less proteins

49

What allows the conversion of CO2 to bicarbonate to remain favourable?

chloride shift

50

What cannot pass through to the CSF via the blood brain barrier?

a. CO2

b. H

c. HCO3

H and HCO3

The CO2 diffuses easily and can generate H ions in the CSF as it is not so well buffered

51

The peripheral chemoreceptors are...

aortic and carotid bodies

52

In which situations is the hypoxic drive of respiration important?

  1. in patients with chronic CO2 retention
  2. at high altitudes

53

Inspiratory Capacity

The total volume of air that can be inspired 3500ml

54

Normally the work of breathing is ____% of total energy expenditure

3

55

apneusis

inspiration prolonged with brief expiration

56

How does binding of one O2 molecule affect haemoglobin?

increases its affinity for oxygen in a co-operative manner

57

What does Ficks Law of Diffusion tell us in respect to the movement of gases?

a large surface area and thin membrane is important for gas exchange

58

FEV1/FVC ratio

the proportion of the FVC expired in first second

59

alveolar pKa?

13.3kPa

60

PAO2 = PiO2 - [PaCO2/0.8]

partial pressure of O2 in alveoli

61

Active expiration during hyperventilation causes the dorsal neurons to...

excite the ventral respiratory group neurons

62

During inspiration the ______ and ______ expand as a result of contraction of _________ muscles

thorax, lungs, inspiratory

63

Atmospheric pKa?

21kPa

64

Where can rhythm of breathing be modified?

The Pons

65

Factors affecting rate of gas exchange (4)

- partial pressure gradient of O2 and CO2 - Diffusion coefficient for O2 and CO2 - Surface area of alveolar membrane - Thickness of alveolar membrane

66

H+ drive of respiration is important in...

acid base balance

67

Surfactant _______ the surface tension of smaller alveoli preventing them from ________

lowers, collapsing into larger alveoli

68

where reduced Hb can bind more CO2 than HbO2 removing the O2 from Hb increases its ability to bind CO2 and CO2 generated H+

Haldane Effect

69

What are carbamino compounds?

when CO2 combines with a terminal amine group in blood proteins

70

Inspiratory Reserve Volume

Volume of air that can be breathed in if required during active breathing 3000ml

71

Accumulation of CO2 in the alveoli as a result of increased perfusion _______ airway resistance leading to ______ airflow

decreases, increased

72

Joint receptors in exercise cause...

an increase in ventilation

73

Factors that may increase ventilation during exercise (5)

  1. Reflexes from body movement (joint receptors)
  2. Adrenaline release
  3. Impulses from cerebral cortex
  4. Increase in body temperature
  5. accumulation of CO2 and H+ generated by muscles

74

What body systems are involved in external respiration? (4)

  1. Respiratory
  2. Cardiovascular
  3. Haematology
  4. Nervous System

75

The ventral respiratory group neurons stimulate...

the internal intercostals and abdominals leading to forceful expiration 

76

Total Lung Capacity

maximum volume of air that the lungs can hold TLC = VC + RV 5700ml approx.

77

tissues pKa?

5kPa

78

The presence of myoglobin in the blood is of no concern - true or false?

false it indicates muscle damage

79

What are the differences between HbF and HbA?

HbF has higher affinity for O2 and interacts less with 2,3-biphosphoglycerate

80

What is physiological dead space?

alveolar dead space + anatomical dead space

81

Residual volume ________ when the elastic recoil of the lungs is lost as it becomes difficult to get the air out i.e. in ________

increases, emphysema

82

Normal O2 concentration in arterial blood at rest

200ml/L

83

What is the primary determinant of oxygen saturation of haemoglobin with O2?

PO2

84

Surfactant acts to intersperse the water molecules lining the alveoli - true or false?

true

85

Work of breathing is increased by...(4)

decrease in pulmonary compliance airway resistance increase elastic recoil is decreased a need for increased ventilation

86

Sectioning where causes ventilation to cease?

below the medulla

87

Why does it not matter how much haemoglobin there is, if partial pressure is normal?

it will become saturated

88

A local tissue increase in O2 will cause systemic arterioles to ....

constrict - this avoids too much oxygen being offloaded where it is no longer needed

89

Forces keeping the alveoli open

Transmural pressure gradient Pulmonary surfactant Alveolar interdependence

90

Percentage of CO2 carried as carbamino compounds in the blood?

30%

91

Which particular blood protein forms a carbamino compound?

globulin

92

What is the average distance of interstitial space between the capillaries and alveolus?

0.5µm

93

What two forces hold the thoracic wall and lungs in close opposition?

  1. Intrapleural fluid cohesiveness
  2. Negative intrapleural pressure

94

Why does HbF have a higher affinity for O2 than HbA?

to allow foetus to hijack O2 from mother

95

the rate at which blood is passing through the lungs

Perfusion

96

How does foetal Hb differ from adult haemoglobin in structure?

has two gamma subunits instead

97

Cells that produce pulmonary surfactant

Type II alveoli

98

If the partial pressure in a gas phase is increased, the concentration of the gas in the liquid phase would decrease proportionally - true or false?

false According to Henry's Law it would increase proportionally

99

Dynamic airway compression causes no problems in normal people. The _______ airway resistance causes an increase in airway pressure _______. This helps open the ______ by increasing the driving pressure between the ______ and _____.

increased, upstream, airways, alveolus, airway

100

Sectioning above the medulla

a. retains fairly normal ventilation

b. causes ventilation ceases

c. causes an abnormal breathing pattern

a - it retains fairly normal ventilation 

 

 

101

Percentage of O2 bound to haemoglobin?

98.5%

102

The Pre-Botzinger complex, a group of neurons that display _______ activity near the upper end of the _______ respiratory centre

pacemaker, medullary 

103

pulmonary compliance is reduced by factors such as...(5)

pulmonary fibrosis pulmonary oedema lung collapse pneumonia absence of surfactant

104

As gas volume increases, the pressure increases - True or False?

False

As gas volume increases, the pressure decreases allowing the air to move into the lungs as the intra-alveolar pressure decreases below that of the atmosphere

105

Why is alveolar ventilation less than pulmonary ventilation?

because of the anatomical dead space

106

What is the most important force for linking the lungs and the thorax?

negative intrapleural pressure

107

Functional Residual Capacity

Volume of the air in the lungs at the end of normal passive expiration 2200ml FRC = ERV + RV

108

Expiratory Reserve Volume

Extra volume of air that can be expired during forced expiration 1000ml

109

Oxygen content of arterial blood can be calculated as...

CaO2 = 1.34 x Hb x SaO2

110

Stimulation of peripheral chemoreceptors by H+ causes (2)

  1. hyperventilation
  2. increased elimination of CO2

111

Innervation of diaphragm

Phrenic nerve; C3,4,5

112

Henrys Law

the amount of a given gas dissolved in a given type and volume of liquid at a constant temperature is proportional to the partial pressure of the gas in equilibrium with the liquid

113

What adaptations do the lungs have to promote gas exchange?

large surface area promoted further by extensive alveoli and bronchial trees Extensive pulmonary capillary network

114

Amount of O2 dissolved in the blood at rest?

3ml/L

115

Main muscle of inspiration at rest

Diaphragm

116

Which effect does the Bohr Effect pair up with?

Haldane effect

117

Average intra-pleural pressure during inspiration

754mmHg

118

Where does the reaction that converts CO2 to bicarbonate occur?

in the red blood cells

119

PiO2

partial pressure of inspired air

120

What are the major muscles of inspiration?

external intercostal muscles diaphragm

121

How can respiratory distress syndrome of the New Born be prevented?

if prematurity is anticipated - provide mother with steroids to try and mature baby's lungs

122

PaCO2

partial pressure of arterial CO2

123

Increased pulmonary compliance occurs in...

emphysema

124

What is internal respiration?

the intracellular mechanisms that consume oxygen and produces CO2

125

Average intra-alveolar pressure during expiration

761mmHg

126

Definition of alveolar ventilation

the volume of air exchanged between the alveoli and atmosphere per minute

127

difference between myoglobin and haemoglobin?

haemoglobin has 4 haem groups, myoglobin has one

128

Haemoglobin can for a _____ combination with O2 where each Hb molecule contains __ haem groups each of which can bind ____ molecule

reversible, four, one

129

The cough reflex is activated by...

irritation of the airways or tight airways in asthma

130

What is the cause of alveolar dead space?

when the ventilated alveoli are not adequately perfused with blood

131

What are the accessory muscles of inspiration?

sternocleidomastoid scalenus

132

the rate at which gas is passing through the lungs

Ventilation

133

Neurons from the apneustic centre excite...

the inspiratory area of the medulla and prolong inspiration 

134

O2 consumption of our cells at rest

250ml/min

135

DO2I =

CaO2 x CI oxygen delivery index where CI is just CO accounting for body surface area

136

Why is negative intrapleural pressure so important for linking the lungs and thorax?

the sub-atmospheric intrapleural pressure creates a transmural gradient forcing the lungs to expand outwards.

137

Forces promoting alveolar collapse

Elasticity of stretched pulmonary connective tissue Alveolar surface tension

138

Compliance

A measure of effort that has to go into stretching or distending the lungs

139

What is ventilation?

the mechanical process of moving air between the atmosphere and alveolar sacs

140

If an alveolus starts to collapse, the surrounding alveoli are ______ and then ______ exerting expanding forces on the collapsing alveolus to ______ it

stretched, recoil, open

141

Daltons Law of Partial Pressures

The total pressure exerted by a gaseous mixture = the sum of the partial pressures of each individual component in gas mixture

142

Vital Capacity

maximum volume of air that can be moved out during a single breath following a maximal inspiration 4500ml VC = IRV + TV + ERV

143

the amount of a given gas dissolved in a given type and volume of liquid at a constant temperature is proportional to the partial pressure of the gas in equilibrium with the liquid

Henrys Law

144

Dorsal respiratory group neurons excites which muscles?

Inspiratory muscles 

Diaphragm

External Intercostals

145

Dynamic Airway Compression Pressure applied to the _______ helps to push air out of the lungs, whereas pressure applied to the ______ is not desirable as it tends to compress it. The rising pleural pressure during _____ expiration compresses the _______ and _______ which is known as dynamic airway compression

alveolus, airway, active, alveolus, airway

146

What is chloride shift?

the switching of Cl and CO3- so that the bicarbonate is moved to the blood

147

Stimulation the _______ _____ terminates inspiration

Pneumotaxic centre

148

Tidal Volume

Volume of air inspired and expired during normal passive breathing 500ml

149

Why are diseases airways not able to cope with dynamic airway compression?

the driving pressure is lost over the obstructed segment. This causes a fall in airway pressure downstream resulting in airway compression by the rising pleural pressure.

150

Sympathetic stimulation causes ________ and ________ resistance

bronchodilation and decreased

151

Definition of pulmonary ventilation

the volume of air breathed in and out per minute

152

The majority of CO2 is carried in solution in the blood - true or false?

false the majority is carried in bicarbonate

153

The less compliant the lungs are, the more work is required to produce a degree of inflation - true or false

true

154

To increase pulmonary ventilation, both the depth (_____ _____) and rate of breathing increase. Because of dead space, it is more advantageous to increase the _______.

tidal volume, depth

155

Hering-Breur Reflex

Stretch receptors in the walls of the bronchi/bronchioles that reflex guards against hyperinflation 

156

Patients with Heart Failure will get SOB before....

pulmonary oedema occurs

157

Perfusion

the rate at which blood is passing through the lungs

158

What is Respiratory Distress Syndrome of the New Born?

where newborn lungs are unable to produce the pulmonary surfactant to reduce the alveolar surface tension and thus have to make strenuous inspiratory efforts

159

Gases move across cell membranes by....

pressure gradients

160

Where is myoglobin present?

skeletal and cardiac muscles

161

What allows the lungs to relax and recoil?

elastic connective tissue alveolar surface tension

162

The graph for oxygen dissociation curve is....

sigmoidal

163

The hypoxic drive of respiration is completely through central chemoreceptors - true or false?

false 

it is entirely through peripheral chemoreceptors

164

What is the Haldane Effect?

where reduced Hb can bind more CO2 than HbO2 removing the O2 from Hb increases its ability to bind CO2 and CO2 generated H+

165

Muscles of active inspiration

external intercostals - contraction lifts ribs and moves out sternum

166

Chronic adaptations to hypoxia (5)

  1. increase in RBC production
  2. Increase 2,3BPG produced within RBC - increases O2 offloading
  3. Increase no, of capillaries
  4. Increase no, of mitochondria - use O2 more efficiently
  5. Kidneys conserve acid - decrease arterial pH

167

Oxygen delivery to the tissues can be impaired by... (3)

respiratory disease Anemia Heart Failure

168

Partial pressure of inspired O2 depends on total pressure and proportion of CO2 in the gas mixture - true or false?

false proportion of O2 - around 21% in atmosphere

169

Pulmonary ventilation (L) =

tidal volume x resp. rate

170

Increased _________ ___ as a result of increased ventilation causes pulmonary _______ which increases blood flow to match a larger airflow

alveolar O2, vasodilation

171

Boyle's Law

At any constant temperature, the pressure exerted by a gas varies inversely with the volume of the gas

172

What is the primary determinant of airway resistance?

the radius of the conducting airway

173

when are pulmonary stretch receptors likely to be activated?

during active inspiration where tidal volumes are >1L

174

The Bohr Effect causes a left shift in the oxygen-dissociation curve - true or false?

false it causes a right shift as it becomes easier for O2 to dissociate even at higher PO2s

175

Hypoxia at high altitudes is caused by...

a decreased partial pressure of inspired oxygen (PiO2)

176

What can increased pulmonary compliance be a result of?

elastic recoil loss

177

The steeper lower part of the oxygen dissociation curve is important as it allows _______ ______ to get a lot of oxygen for a _____ drop in PO2

peripheral tissues, small

178

Influence the respiratory centres (6)

Higher brain centres

Stretch receptors in the bronchi/bronchioles

Juxtapulmonary receptors

Joint receptors

Baroceptors

Central and Peripheral Chemoreceptors 

179

Pre-Botzinger complex

a network of neurons which controls rhythms 

180

In healthy people, alveolar dead space is of great importance - true or false?

false alveolar dead space should be minimal in a healthy individual

181

Ventilation

the rate at which gas is passing through the lungs

182

What types of pneumothorax can occur?

traumatic (wound to chest wall) spontaneous (lung side)

183

Rhythm for inspiration followed by expiration is generated by the _______

medulla oblongata

184

Surfactant is a mixture of proteins and carbohydrates - true or false?

False Surfactant is a mixture of proteins and lipids

185

Decreased pulmonary compliance may cause a _______ pattern of lung volumes in spirometry

restrictive

186

Enzyme that converts CO2 and H2O to carbonic acid

carbonic anhydrase

187

Average intra-alveolar pressure at rest

760mmHg

188

Pneumothorax abolishes the ___________ and causes the lung to ______

transmural gradient, collapse