Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

JL Respiratory > Physiology > Flashcards

Physiology Flashcards

0
Q

What is external respiration?

A

the sequence of events that leads to the exchange of oxygen and carbon dioxide between the external environment and the cells of the body.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

What does internal respiration refer to?

A

The intracellular mechanisms which consume oxygen and produce carbon dioxide.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Name the four steps of external respiration

A

Ventilation, gas exchange between alveoli and blood, gas transport in the blood, gas exchange at tissue level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

State Boyle’s law

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

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

A
  1. intrapleural fluid cohesiveness: the water molecules in the intrapleural fluid are attracted to each other and resist being pulled apart. Hence the pleural membranes tend to stick together.
  2. negative intrapleural pressure: the sub-atmospheric intrapleural pressure creates a transmural pressure gradient across the lung wall and across the chest wall. So the lungs are forced to expand outwards while the chest is forced to squeeze inwards.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the typical values of: atmospheric pressure, intra alveolar pressure and intrapleural pressure?

A

760, 760, 755

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a pneumothorax?

A

Air in the pleural space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What causes lungs to recoil during expiration?

A

Elastic connective tissue and alveolar surface tension

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Explain the law of LaPlace in relation to small alveoli

A

the smaller alveoli have a higher tendency to collapse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is pulmonary surfactant?

A

A complex mixture of lipids and proteins secreted by type II alveoli. It lowers alveolar surface tension.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is alveolar interdependence?

A

if an alveolus starts to collapse the surrounding alveoli are stretched and then recoil exerting expanding forces in the collapsing alveolus to open it.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Name the accessory muscles of inspiration, the major muscles and the muscles of active expiration.

A

Scalenus and sternocleidomasteod, extenal intercostal muscles and diaphragm, abdominal muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Tidal volume volume

A

500ml

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Inspiratory reserve volume volume

A

3000ml

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Inspiratory capacity volume

A

3500ml

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

expiratory reserve volume volume

A

1000ml

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

residual volume volume

A

1200ml

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

functional residual capacity volume

A

2200ml

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

vital capacity volume

A

4500ml

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

total lung capacity volume

A

5700ml

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the tidal volume?

A

The volume of air entering and leaving the lungs during a single breath

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the inspiratory reserve volume?

A

The extra volume of air that can be maximally inspired over and above the typical resting tidal volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the inspiratory capacity?

A

The maximum volume of air that can be inspired at the end of a normal quiet expiration. IC = TV + IRV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the expiratory reserve volume?

A

The extra volume of air that can be actively expired by maximal contraction beyond the normal volume of air after a resting tidal volume.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the residual volume?

A

The minimum volume of air remaining in the lungs even after maximal expiration.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is functional residual capacity?

A

The volume of air in the lungs at the end of normal passive expiration (FRC = ERV + RV)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the vital capacity?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is total lung capacity?

A

The maximum volume of air that the lungs can hold (TLC = VC + RV)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is forced expiratory volume in one second (FEV1) ?

A

Th volume of air that can be expired during the first second of expiration in an FVC determination. A ration with a percentage above 75% is normal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What does parasympathetic stimulation do to the bronchioles?

A

Causes bronchoconstriction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What does sympathetic stimulation do to the bronchioles?

A

Causes bronchodilatation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is pulmonary compliance?

A

The measure of effort that has to go into stretching or distnding the lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Name five factors that decrease pulmonary compliance

A

pulmonary fibrosis, pulmonary oedema, lung collapse, pneumonia, absence of surfactant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

In what condition does increased compliance occur?

A

emphysema

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is anatomical dead space?

A

Inspired air that remains in the airways and is not available for gas exchange (150ml)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is pulmonary ventilation?

A

The volume of air breathed in and out per minute. TV + RR = 0.5 + 12 = 6 L/min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Why is alveolar ventilation less than pulmonary ventilation?

A

Because of the presence of anatomical dead space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is alveolar ventilation?

A

The volume of air exchanged between the atmosphere and alveoli per minute. It represents the new air available for gas exchange with blood. (TV - dead space) x RR = (0.5 - 0.15) x 12 = 4.2 L/min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What does decreased oxygen do to pulmonary arterioles?

A

Vasoconstriction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What does increased oxygen do to pulmonary arterioles?

A

Vasodilatation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What does decreased oxygen do to systemic arterioles?

A

Vasodilatation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What does increased oxygen do to systemic arterioles?

A

Vasoconstriction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

State Dalton’s law

A

the total pressure exerted by a gaseous mixture depends on the sum of the partisl pressures of each individual component in the gas mixture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

How much does watere vapour pressure contribute to the total pressure in the lungs?

A

47 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is the pressure of inspired air and how was it worked out?

A

atmospheric pressure - water vapour pressure = 760 - 47 = 713 mm Hg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What is the partial pressure of oxygen?

A

150 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Across pulmonary capillaries: what is the partial pressure gradient of oxygen from alveoli to blood?

A

60 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Across the pulmonary capillaries: what is the partial pressure gradient of carbon dioxide from blood to alveoli?

A

6 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Across systemic capillaries: what is the partial pressure gradient of oxygen from blood to tissue cell?

A

greater than 60 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Across systemic capillaries what is the partial pressure gradient of carbon dioxide from tissue cell to blood ?

A

greater than 6 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Which is more soluble in membranes - CO2 or oxygen?

A

CO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What is the solubility of gas in membranes known as?

A

The diffusion coefficient.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

How much greater is the diffusion coefficient for C02 compared to oxygen?

A

20 times greater

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What would a big gradient between PA02 and Pa02 indicate?

A

Problems with gas exchange in the lungs or a right to left shunt in the heart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

How much of the cardiac output does the pulmonary circulation receive?

A

The entire cardiac output

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What has a respiratory membrane?

A

Alveoli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

What do the walls of alveoli consist of?

A

Single layer of flattened type I alveolar cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

What encricles each alveolus?

A

Pulmonary capillaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Name 4 factors that influence the rate of gas exchange across alveolar membranes?

A
  1. Partial pressure gradients of O2 and CO2
  2. Surface area of alveolar membrane
  3. Thickness of blood/air barrier across membrane
  4. Diffusion coefficient (solubility of gas in membrane)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

In relation to the partial pressure gradients of O2 and CO2: what happens when the partial pressure increases?

A

Rate of transfer of gas exchange across alveolar membranes increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

In relation to hte surface area of alveolar membranes: what occurs when the surface area increases?

A

Rate of transfer increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

What does the surface area of alveolar membranes increase during and why?

A

During exercise as more pulmonary capillaries open up when the cardiac output increases and the alveoli expand as breathing deepens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

In relation to the thickness of blood/air barrier across membranes: what occurs as it thickens?

A

Rate of transfer decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What does thickness of blood/air barrier across membrane increase with?

A

Pathological conditions such as pulmonary oedma, pulmonary fibrosis and pneumonia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

In relation to the diffusion coefficient (solubility of gas in membrane): what occurs as the diffusion coefficient decreases?

A

Rate of transfer increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Where must oxygen that has been picked up by the blood be transported to?

A

Tissues for cellular use

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Where must CO2 produced at the tissues be transported to?

A

The lungs for removal from the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

What is the PO2 in atmospheric air?

A

160

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

What is the PCO2 in atmospheric air?

A

0.03

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

What is the PO2 in alveoli?

A

100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

What is the PCO2 in alveoli?

A

40

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

What is the PO2 in deoxygenated blood?

A

40

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

What is the PCO2 in deoxygenated blood?

A

46

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

What is the PO2 in oxygenated blood?

A

100

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

What is the PCO2 in oxygenated blood?

A

40

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

In the tissues what is the PO2?

A

<40

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

In the tissues what is the PCO2?

A

> 46

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

What law relates to the effect of partial pressure on gas solubility?

A

Henry’s law

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

What is Henry’s law?

A

The amount of a given gas dissolve in a given type and volume of liquid (e.g. blood)v at a constant temperature is: proportional to the partial pressure of the gas in equilibrium with the liquid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

If the partial pressure in the gas phase is increased, what happens to the concentration of the gas in the liquid phase?

A

It would increase proportionally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

What is the oxygen amount dissolved in blood proportional to?

A

The partial pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

How much oxygen is there per litre of blood at P02 of 13.3kPa?

A

3ml

82
Q

Under resting conditions - what is cardiac output?

A

5L/min

83
Q

Under resting conditions how much oxygen per minute is taken to tissues as dissolved O2?

A

15ml/min

84
Q

What is the cardiac output during strenuous exercise?

A

30L/min

85
Q

During srenuous exercise much much oxygen per minute would be taken to tissues as dissolved oxygen?

A

90ml/min

86
Q

What is the resting oxygen consumption of our body cells?

A

About 250ml/min

87
Q

How much may oxygen consumption increase during strenuous exericese?

A

25 folds

88
Q

How is most oxygen in the blood transported?

A

Bound to haemoglobin

89
Q

What is the normal oxygen concentration in the arterial blood at a normal arterial PO2 of 13.3kPa?

A

20ml/100ml (200ml per litre)

90
Q

What is the normal haemoglobin concentration at a normal arterial PO2 of 13.3kPa?

A

15g/100ml

91
Q

What is the percentage of oxygen carried bound to haemoglobin?

A

98.5%

92
Q

What is the percentage of oxygen carried in the dissolved form?

A

1.5% (3ml per litre at a PO2 of 13.3kPa

93
Q

What two forms is oxygen present in the blood in?

A

Bound to haemoglobin or physically dissolved

94
Q

What kind of combination does haemoglobin form with oxygen?

A

Reversible

95
Q

How many haem groups does a Hb molcule contain?

A

4 haem groups

96
Q

When is haemoglobin considered fully saturated?

A

When all the Hb present is carrying its maximum oxygen load

97
Q

What is the primary factor which determines the percent saturation of haemoglobin with oxygen?

A

PO2

98
Q

What is the equation for the oxygen delivery index? (DO2I)

A

DO2I = CaO2 x Cl

99
Q

What is CaO2?

A

Oxygen content of arterial blood (ml/L)

100
Q

What is CI?

A

Cardiac index (L/min/metre)

101
Q

What does the cardiac index relate to?

A

The cardiac output to the body surface area (i.e. size of the individual)

102
Q

What is the normal range for CL?

A

2.4 - 4.2 L/min/metre

103
Q

What is the oxygen delivery to the tissues a function of?

A

Oxygen content of arterial blood and the cardiac output

104
Q

What is the equation for the oxygen content of arterial blood (CaO2)?

A

CaO2 = 1.34 x [Hb] x SaO2

105
Q

How much oxygen does 1 gram of Hb carry when fully saturated?

A

1.34ml

106
Q

In the oxygen content of arterial blood (CaO2) equation: what is [Hb] and SaO2?

A 
[Hb] = haemoglobin concentration (gram/L)
SaO2 = %Hb saturated with O2 (remember this is determined by PO2)
107
Q

What is the oxygen content of arterial blood determined by?

A

Haemoglobin concentration [Hb] and the saturation of Hb with O2

108
Q

What three things can impair oxygen delivery to the tissues?

A

Respiratory disease
Heart failure
Anaemia

109
Q

What does the binding of one oxygen to Hb increase?

A

The affinity of Hb for oxygen

110
Q

What happens to haemoglobin where all the sites are becoming occupied?

A

Flattens

111
Q

What is co-operativity in relation to oxygen binding to haemoglobin?

A

Binding of one oxygen to Hb increaeses the affinity of Hb for oxygen

112
Q

What are heme group, beta chains and alpha chains all a part of?

A

Haemoglobin

113
Q

On a graph where the y axis is %haemoglobin saturation, x axis is blood PO2 (kPa) and the right axis is O2 concentration ml/100ml: What does the flat upper portions of a sigmoid curve mean?

A

Means that moderate fall in alveolar PO2 will not much affect oxygen loading.

114
Q

On a graph where the y axis is %haemoglobin saturation, x axis is blood PO2 (kPa) and the right axis is O2 concentration ml/100ml: What does the steep lower part of the sigmoid curve mean?

A

That the peripheral tissues get a lot of oxygen for a small drop in capillary PO2

115
Q

What is the Bohr effect - on a graph with y axis as % Hb saturation and x axis of PO2?

A

A shift of the curve to the right: The Bohr effect

116
Q

What 4 things increase to give the Bohr effect?

A
  1. PCO2
  2. [H+]
  3. Temperature
  4. 2,3-Bisphosphoglycerate
117
Q

The Bohr effect is a shift of the curve to the right, what does this mean?

A

Increased release of oxygen by conditions at the tissues

118
Q

What type of tension has 100 PO2 and 13.3kP?

A

Arterial O2 tension

119
Q

What type of tension has PO2 of 40 and 5.3kP?

A

Tissue oxygen tension

120
Q

On a graph with O2 content as the y-axis and PO2 (mm Hg, kP) as the x-axis: which curve is more left and finishes higher - curve in arterial conditions or curve in tissue conditions?

A

Curve in arterial conditions

121
Q

Where is myoglobin present?

A

In skeletal and cardiac muscles

122
Q

How many haem groups per myoglobin molecule?

A

one

123
Q

In relation to myoglobin is htere any cooperative binding of oxygen?

A

No

124
Q

On a graph with % saturation of myoglobin on y-axis and PO2 mmHg on x-axis, what is the curve like?

A

Dissociation curve hyperbolic

125
Q

At what level of PO2 does myoglobin release oxygen?

A

At very low PO2

126
Q

On a graph with %saturation on y-axis and PO2 mmHg on x-axis: which curve is more left - dissociation curve for myoglobin (1:1 binding) or dissociation curve for haemoglobin?

A

Dissociation curve for myoglobin (1:1 binding)

127
Q

What does myoglobin provide a short term storage of oxygen for?

A

Anaerobic conditions

128
Q

What does the presence of myglobin the the blood indicate?

A

Muscle damage

129
Q

Describe the 3 means of CO2 transport in the blood (including %)

A
  1. Solution (10%)
  2. As Bicarbonate (60%)
  3. As Carbamino compounds (30%)
130
Q

What law is associated with CO2 transportation in solution?

A

Henry’s law

131
Q

How is most CO2 transported in the blood?

A

As bicarbonate

132
Q

What is the equation for Bicarbonate being formed in the blood?

A

CO2 + H20 = H2CO3 = H+ + HCO3

133
Q

Where does carbonic anhydrase occur?

A

In red blood cells

134
Q

How are carbamino compounds formed?

A

By the combination of CO2 with terminal amine groups in blood proteins

135
Q

What gives carbamino-haemoglobin?

A

Globin of haemoglobin and CO2

136
Q

Can reduced Hb bind more CO2 than HbO2?

A

Yes

137
Q

What is the haldane effect?

A

Removing oxygen from Hb increases the ability of Hb to pick-up CO2 and CO2 generated H+

138
Q

What does the Haldane effect work in synchrony with?

A

The Boher effect

139
Q

What to effects work in synchrony to facilitate oxygen liberation and uptake of CO2 and CO2 generated H+ at tissues?

A

Boher effect and Haldane effect

140
Q

What is haemoglobin present in the red blood cells as?

A

Carbonic anhydrase

141
Q

What is the enzyme that caralyses the production of bicarbonate?

A

Carbonic anhydrase

142
Q

What does the H+ generated during the production of HCO3 bind to?

A

Hb

143
Q

How does bicarbonate move out of red blood cells and into the plasma?

A

By facilitated diffusion down its concentration gradient

144
Q

Name the 4 sections of the sagital brain stem from inner most to outer?

A
  1. Midpoint
  2. Pons
  3. Medulla oblongata
  4. Spinal cord
145
Q

What part of the brain stem is the major rythm generator?

A

Medulla

146
Q

What network of neurons generate the breathing rhythm?

A

Pre-Botzinger complex

147
Q

What kind of activity do Pre-Botzinger complex neurons display?

A

Pacemaker actiivty

148
Q

Where are the Pre-Botzinger complex neurons located?

A

Near the upper end of the medullary respiratory centre

149
Q

In the pons of the brainstem - what two centers are present?

A

Pneumotaxic center and apneustic center

150
Q

What respiratory group is the Pre-Botzinger complex above?

A

The ventral respiratory group

151
Q

Which respiratory group is posterior to the ventral respiratory group in the brain stem?

A

Dorsal respiratory group

152
Q

What two respiratory groups are in the medullary respiratory center?

A

Dorsal respiratory group

Ventral respiratory group

153
Q

What group of neurones in the brainstem give rise to inspiration?

A

The dorsal respiratory group neurones

154
Q

How do the dorsal respiratory group neurones fire?

A

In bursts

155
Q

What does firing of the dorsal respiratory group neurones lead to?

A

Contraction of inspiratory muscles - inspiration

156
Q

When firing of the dorsal respiratory group neurones stop - what happens?

A

Passive expiration

157
Q

During ‘active’ expiration during hyperventilation - what happens when there is increased firing of dorsal neruones?

A

They excite a second group called the ventral respiratory group neurones

158
Q

What do the ventral respiratory group neurones excite and what doesthis cause?

A

Excite internal intercostals, abdominals which leads to forceful expiration

159
Q

In normal quiet breathing, dp ventral neurones activate expiratory muscles?

A

No

160
Q

The rhythm generated in the medulla can be modified by what neurones?

A

In the pons

161
Q

What does stimulation of the pneumotaxic centre (PC) terminate?

A

Inspiration

162
Q

When is the pneumotaxic centre (PC) stimulated?

A

When the dorsal respiratory neurones fire

163
Q

When the PC is stimulated when dorsal respiratory neurones fire - what is inhibited?

A

Inspiration

164
Q

Without PC, breathing is prolonged inspiratory gasps with brief expiration - what is the name for this?

A

Apneusis

165
Q

What do impulses from the apneustic centre excite?

A

Inspiratory area of the medulla

166
Q

When the apneustic centre inpulses excite the respiratory area of the medulla what occurs?

A

Prolonged inspiration

167
Q

Where is the rythm generated and where can it be modified?

A

Generated in medulla and modified by inputs from pons

168
Q

Respiratory centres are influenced by stimuli received from what 7 receptors?

A
  1. Higher brain centres
  2. Stretch receptors
  3. Juxtapulmonary receptors
  4. Joint receptors
  5. Baroreceptors
  6. Central cehmoreceptors
  7. Peripheral chemoreceptors
169
Q

What are the 3 higher brain centres?

A

Cerebral cortex, limbic system, hypothalamus

170
Q

Where are stretch receptors located?

A

In the walls of the bronchi and bronchioles

171
Q

What does the inflation Hering-Breur reflex guard against?

A

Hyperinflation

172
Q

What 3 things stimulate the J receptors?

A

Pulmonary capillary congestion and pulmonary oedema, also pulmonary emboli

173
Q

What heart failure causes pulmonary oedema?

A

Left sided

174
Q

How are joint receptors stimulated?

A

Joint movement

175
Q

In relation to baroreceptors what causes increased ventilatory rate?

A

Decreased blood pressure

176
Q

Give 4 examples of involuntary modifications of breathing

A
  1. Pulmonary stretch receptors Hering-Breuer Reflex
  2. Joint receptors reflex in exercise
  3. Stimulation of respiratory centre by temperature, adrenaline, or impulses from cerebral cortex
  4. Cough refelx
177
Q

When are pulmonary stretch receptors activated and what do the afferent discharges inhibit?

A

Activated during inspiration, afferent discharge inhibits inspiration - Hering-Breur reflex

178
Q

At what level of tidal volumes are pulmonary stretch receptors activated?

A

At large&raquo_space; 1 litre tidal volumes

179
Q

What do impulses from moving limbs increase?

A

Breathing

180
Q

What 5 factors may increase ventilation during exercise?

A
  1. Reflexes originating from body movement
  2. Adrenaline release
  3. Impulses from the cerebral cortex
  4. Increase in body temperature
  5. Later: accumulation of CO2 and H+ generated by active muscles
181
Q

Where is the cough reflex control centre?

A

Centre in the medulla

182
Q

In relation to the cough reflex: what does afferent discharge stimulate?

A

Short intake of breath, followed by closeure of the larynx, then contraction of abdominal muscles (increases intra-alveolar pressure), and finally opening of the larynx and expulsin of air at a high speed

183
Q

What kind of feedback is chemical control of respiration an example pof?

A

Negative feedback

184
Q

In the chemical control of respiration: what are the controlled variables?

A

Blood gas tensions, especially carbon dioxide

185
Q

What do chemoreceptors sense the values of?

A

Gas tensions

186
Q

Where are the two peripheral chemoreceptors located?

A

Carotid bodies and aortic bodies

187
Q

What 3 things do the peripheral chemoreceptors sense?

A

Tension of oxygen, carbon dioxide and [H+] in the blood

188
Q

Where are the central chemoreceptors situated?

A

Near the surface of the medulla of the brainstem

189
Q

What do the central chemoreceptors respond to?

A

[H+] of the cerebrospinal fluid (CSF)

190
Q

What seperates the CSF from the blood?

A

The blood/brain barrier

191
Q

What is the blood-brain barrier relatively impermeable to and whayt diffuses readily across it?

A

Relatively impermeable to H+ and HCO3

CO2 diffuses readily

192
Q

Is CSF less buffered that blood?

A

Yes - contains less protein

193
Q

What is ventilation very responsive to?

A

PCO2

194
Q

In relation to the hypoxic drive of respiration: what is the effect via?

A

Peripheral chemoreceptors

195
Q

When is the hypoxic drive of respiration stimulated?

A

When arterial PO2 falls to low levels (<8.0 kPa)

196
Q

When may hypoxic drive of respiration become important?

A

In patients with chronic CO2 retention (patients with COPD)

At high altitudes

197
Q

What is hypoxia at high altitudes caused by?

A

Decreased partial pressure of inspired oxygen (PiO2)

198
Q

What are the 2 acute responses of jhypoxia at high altitudes?

A

Hyperventilation

Increased cardiac output

199
Q

What are the 5 chronic adaptions to high altitude hypoxia?

A
  1. Increased red blood cell production (polycythaemia) - O2 carrying capacity of blood increases
  2. 2,3 BPG produced within RBC - O2 offloaded more easily into tissues
  3. Increased number of capillaries - blood diffuses more easily
  4. Increased number of mitochondria - O2 can be used more efficiently
  5. Kidneys conserve acid - arteiral pH decreases
200
Q

What is the effect of the H+ drive of respiration?

A

Via the peripheral chemoreceptors

201
Q

Does H+ readily cross the blood brain barrier?

A

No (CO2 does)

202
Q

The peripheral chemoreceptors play a major role in adjusting for acidosis. What is the acidosis caused by?

A

The addition of non-carbonic acid H+ to the blood (e.g. lactic acid during exercise; and diabetic ketoacidosis)

203
Q

What does peripheral chemoreceptor stimulation by H+ cause?

A

Hyperventilation and increases elimination of CO2 from the body

(important in acid-base balance)
Remember CO2 can generate H+, so its increased elimination help reduce the load of H+ in the body)

JL Respiratory (27 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions