Brainscape's Knowledge GenomeTM

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


See full index

Medicine 1 Respiratory > Respiratory Physiology > Flashcards

Respiratory Physiology Flashcards

1
Q

The main function of the respiratory system is to maintain

A

normal arterial oxygen and carbon dioxide content

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

Are the mechanisms used to maintain normal arterial oxygen and carbon dioxide the same?

A

Most of them are but not all

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

True/False? Lung compliance alters ventilation?

A

True

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

List the functions of the respiratory System

A

Gas Exchange, Acid Base Balance, protection from infection, communication via speech

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

What is acid-base balance in the respiratory system?

A

acid base balance is the maintenance of the pH of extracellular fluid at a value of 7.4.

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

Which other system does the respiratory system work with in order to maintain the body pH?

A

Renal System

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

What percent of acid base balance is achieved through changes in the respiratory system?

A

50%

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

How does the respiratory system protect one from infections?

A

the respiratory epithelia has a dense concentration of immune tissue present within it that constantly scans the air we inhale looking for pathogens against which it would set up an immune response. The respiratory epithelia also has a dense cilia network that is responsible for beating any large inhaled particles up the respiratory tract and away from the deep lung tissues.

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

if you inhale smoke or very fine dust particles, then they will get trapped in

A

mucus

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

___________ beats mucus up the respiratory tract and away from the delicate alveolar tissues

A

cilia

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

How is the respiratory system involved in speech?

A

air moving through our vocal cords in our larynx, cause those vocal cords to vibrate

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

Do we speak on inhalation or exhalation?

A

Exhalation

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

Why do we need oxygen?

A

To produce energy

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

Can humans produce energy anaerobically? If so, is it sufficient to meet the resting energy demand of the body?

A

Yes, the body can produce energy anaerobically but however, it is not enough to meet the resting energy demand of the body.

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

Type of respiration that occurs out in the periphery is called?

A

Cellular/Internal respiration

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

External respiration is the movement of gases between

A

the air and the body’s cells

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

Name the 2 circulatory systems

A

Pulmonary and systemic circulations

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

When you’re exercising, you have an increase in energy demand of

A

your working skeletal muscle

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

Why is there an increase in the rate and depth of breathing when exercising?

A

To speed up substrate (oxygen) acquisition and expel carbon dioxide

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

net volume of gas exchanged in the lungs per minute

A

250 mLs oxygen and 200 mLs carbon dioxide

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

Why is it important that the amount of gas that we are exchanging at the lungs is equal to the volume of gas being exchanged at the tissues?

A

because it prevents gas build-up in the circulation that could hamper gas exchange or to maintain the concentration gradient difference between the lungs and the blood

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

Which one is higher? PCO2 in cells or PCO2 in systemic arterial blood?

A

PCO2 in cells

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

Why do we feel more comfortable breathing with our nose than with our mouth?

A

The nose has a larger surface area to volume ratio which is much better at warming and moistening the air.

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

Why does the air have to be moistened before reaching the lungs?

A

air we breathe has to be fairly saturated with water vapour because the air needs to be in solution in order to diffuse from the lungs into the blood.

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

What is the pharynx most commonly known as?

A

Throat

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

A tube that connects the back of your nose and the back of your mouth and joins with the larynx or splits to form the oesophagus

A

Pharynx

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

common conduit shared with the digestive system

A

Pharynx

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

What is the epiglottis?

A

A flap of cartilaginous tissue

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

When is the epiglottis open and when is it closed?

A

Open when breathing and closed when eating

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

How does the epiglottis close?

A

when we swallow small muscles around the larynx act to cause the epiglottis to close

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

The biggest Airway?

A

Trachea

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

Sternal angle location?

A

Between jugular notch and sternum

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

At which point does the trachea split?

A

From underneath the sternal angle

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

How many times does the left and right primary bronchi divide?

A

24 times

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

Where does the upper respiratory tract end?

A

Below the larynx, above the ribcage

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

Part of the upper respiratory system that isn’t also shared with the alimentary system?

A

Larynx

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

Which fissure can be found in both lungs?

A

Oblique

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

Oblique fissure in the right lung divides

A

Middle and inferior lobes

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

Horizontal fissure in the right lung divides

A

Superior and middle lobes

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

Oblique fissure in the left lung divides

A

Superior and inferior lobes

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

How many secondary bronchi can be found in the right lung?

A

3, one in each lobe

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

How many secondary bronchi can be found in the left lung?

A

2, one in each lobe

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

Secondary bronchi branch to give

A

tertiary bronchi

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

We have one tertiary bronchi or bronchus going to

A

each bronchial pulmonary segment of the lung

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

The lung as well as being split into lobes, is further split into

A

bronchial segments

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

What is the function of c-shaped, cartilaginous rings?

A

helps maintain patency of trachea and bronchi by giving some degree of rigidity that stops them from collapsing or compressing

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

What is patency?

A

by patency, we mean that the airway is open and air can flow freely along it.

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

Why is it important to maintain a patent or clear airway?

A

So that ventilation and movement of air to and from the lungs can take place unimpeded.

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

How many generations of branching do we have from the trachea to the level of alveoli?

A

24

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

How do we maintain the patency of bronchioles?

A

By the physical forces of the thorax

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

At any one time, how much air sits in the dead space?

A

150 mL

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

Compare the right and left primary bronchi

A

The right primary bronchi is slightly more wider than the left The right primary bronchi has a more vertical trajectory than the left primary bronchi making it easier for aspirated foreign bodies to get stuck in the right bronchi

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

Compared to the angle to the right lung, the angle to the left lung is more

A

acute

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

Compared to the angle to the left lung, the angle to the right lung is more

A

obtuse

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

The difference in angles to both the lungs is due to

A

the trachea being acute

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

Airways where no gaseous exchange occur fall under which zone?

A

Conducting zone

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

Airways where gaseous exchange occur fall under which zone?

A

Respiratory zone

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

Bronchioles split into how many generations?

A

12

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

First division within the respiratory tree

A

Primary bronchi

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

Second division within the respiratory tree

A

Secondary bronchi

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

Third division within the respiratory tree

A

Tertiary bronchi

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

As we move down our respiratory tree, the diameter of the airways

A

decreases

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

According to physics, what happens to resistance as diameter decreases?

A

increases

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

What happens to resistance as airway diameter decreases?

A

decreases

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

Why does airflow down the respiratory tree not obey the resistance laws in physics?

A

When looking at resistance and diameter in the respiratory tree, we look at the cross-sectional area instead of airway diameter. The cross-sectional area is much greater in the lower parts of the respiratory tree compared to the trachea or upper parts of the respiratory tree.

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

Why is there an increase in resistance as you go up the respiratory tree?

A

While diameter increases as you go up the respiratory tree, the increase in diameter is not proportional to the number of air molecules that are trying to move through it and as a result we get an increase in resistance.

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

In which zone of the respiratory tract, does the dead space occur?

A

Conducting zone

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

How can the diameter of the bronchial airways change?

A

The bronchial smooth muscle can relax or contract.

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

What would happen to resistance if the bronchial smooth muscle contracts (diameter decreases)?

A

Increase

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

Which nervous system acts on bronchial smooth muscles?

A

Sympathetic Nervous system

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

The sympathetic nervous system acts on _________ receptors

A

Beta receptors (Beta-2 because we have 2 lungs)

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

What happens to bronchial smooth muscle when adrenaline or noradrenaline binds to beta-2 receptors?

A

Relax (increase diameter of bronchiole)

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

When the sympathetic system kicks in, the bronchial smooth muscles relax causing the bronchioles to

A

Dilate

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

What happens to ventilation when bronchioles dilate?

A

Maximised

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

What accommdates the alveoli with inflation during inspiration?

A

Elastic fibres

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

When is energy stored in elastic fibres and how is it used?

A

Energy is stored in the elastic fibres during alveoli inflation and is used during expiration to squeeze the alveoli and force air out since expiration at rest is passive.

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

Which type of cells make up the bulk of the alveolar wall and what is its function?

A

Type 1 alveolar cells are responsible for gas exchange

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

Type 1 cells are studded with yellow ________ cells

A

Type 2

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

Type 2 cells are responsible for

A

Surfactant secretion

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

Do type 2 cells play a role in gas exchange?

A

No

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

Capillaries are directly abutted with

A

Type 1 cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

Why are capillaries never sitting adjacent to type 2 cells?

A

Because they are not responsible in gas exchange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

Why do elastic fibres never sit between type 1 cells and capillary cells?

A

To minimise the distance required for gases to travel and diffuse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

________are dotted all around the respiratory system to combat infections

A

Macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

To help boost the immune function of the lung, _____ are present in the connective tissue of the lungs

A

Alveolar macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

If you flatten out all the alveoli, it will cover about

A

80m^2 (size of a badminton court)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

Each lung has a capacity of about

A

3 L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

Thickness of the alveoli

A

one cell thick

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

At the end of a normal inspiration, our lungs contain ___ L of air

A

2.8

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

Normal amount of air we breathe in and out is ___ mL and is referred to as the _____ volume

A

500, tidal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

Amount of air left in the lungs at the end of a normal relaxed expiration is referred to as the _______

A

Functional residual capacity`

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

The biggest breath that we can take on top of our normal tidal volume is a volume of about __ L

A

3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

The extra air that we can breathe in is referred to as the

A

Inspiratory reserve volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
94
Q

Extra air that we can expire with a bit more effort is called the

A

expiratory reserve volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
95
Q

Expiratory reserve volume is about __ L

A

1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
96
Q

Maximum amount of air that we can expire after a maximum inspiration is known as the

A

vital capacity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
97
Q

Vital capacity manoeuvre is often used in

A

respiratory physiology and clinical respiratory physiology to measure lung function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
98
Q

Volume vs. Capacity

A

A capacity involves a number of different volumes added together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
99
Q

Vital capacity involves the volumes of

A

Inspiratory reserve volume, tidal volume and expiratory reserve volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
100
Q

_______ volume is the amount of air left in the lungs after a maximum expiratory effort and is usually about __ L

A

Residual, 1.2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
101
Q

Residual volume is important because

A

it stops the alveoli from collapsing even after the elastic fibres recoil and it provides a volume of air that can allow a gas exchange to take place between breaths

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
102
Q

What would happen if the alveoli completely collapsed?

A

It would take an awful lot of energy to inflate them again in the next breath

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
103
Q

The 150 mL of air in dead space is part of the

A

Tidal volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
104
Q

The _____ of the lungs is the point at which the lungs connect with the major airways or the airways are leaving or entering those lungs

A

hilum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
105
Q

How much fluid can be found in each pleural cavity?

A

3 mL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
106
Q

The pleural cavity is surrounded by the

A

Pleural membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
107
Q

Pleural membrane has 2 aspects named

A

Parietal and visceral membranes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
108
Q

The parietal pleural membrane is the membrane that is

A

closest to the ribs and attached to the superior surface of the diaphragm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
109
Q

The visceral pleural membrane is the membrane that is

A

attached to the outer surface of the lungs and goes into all the fissures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
110
Q

The pleural fluid creates a _____ force that allows the two pleural membranes to glide across each other

A

Cohesive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
111
Q

The cohesive force of the pleural fluid ensures the lungs are effectively stuck to the

A

ribcage and diaphragm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
112
Q

Visceral pleura is stuck to the parietal pleura through the

A

cohesive forces of the pleural fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
113
Q

Functions of pleural fluid

A
  • Stops the lungs from recoiling by limiting recoiling of the elastic fibres by cohesive forces of the pleural fluid - Allows friction free movement of lungs across the ribcage as we breathe in and out
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
114
Q

Why do we feel ‘comfortable’ at the end of a normal expiration?

A

Because an equilibrium is reached between the elastic fibres wanting to recoil and the chest wanting to expand further.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
115
Q

Pneumothoraxes commonly occur due to

A

penetrating wounds to the chest wall that allow air to enter the pleural cavity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
116
Q

What happens when air enters the pleural membrane?

A

we lose the cohesive force in the pleural fluid because the air forces them apart

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
117
Q

What happens to lung function in relation to chest wall in a pneumothorax?

A

Lung functions independently

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
118
Q

Boyle’s law states that

A

the pressure exerted by a gas is inversely proportional to its volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
119
Q

Dalton’s law states that

A

the total pressure of a gas mixture is the sum of the pressures of the individual gases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
120
Q

Charles’ law states that

A

the volume occupied by a gas is directly related to the absolute temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
121
Q

In vivo, Charles’ law is not applied as much because

A

the temperature in the human body is constant at 37 degree Celsius

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
122
Q

Any given volume will measure a greater amount in a warm room because

A

gas molecules move about more when they are hot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
123
Q

Henry’s Law states that

A

the amount of gas dissolved in a liquid is determined by the pressure of the gas and it’s solubility in the liquid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
124
Q

Which law governs the movement of air during inspiration and/or expiration?

A

Boyle’s Law

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
125
Q

Breathing happens because

A

the thoracic cavity changes volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
126
Q

What happens to the pressure inside the thoracic cavity when the volume inside the thoracic cavity increases?

A

Decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
127
Q

Which muscles are used upon inspiration?

A

External intercostals and diaphragm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
128
Q

Which muscles are used during severe respiratory load or forced expiration?

A

Internal intercostal muscles and abdominal muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
129
Q

Main muscle in respiration responsible for about 70 percent of the muscular activity of inspiration

A

Diaphragm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
130
Q

External intercostal muscles run between

A

the ribs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
131
Q

During normal relaxed inspiration, are the scalene and sternocleidomastoid muscles used?

A

Rarely

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
132
Q

When and how are scalene and sternocleidomastoid muscles used in respiration?

A

During severe respiratory load, these muscles act on the upper ribs and clavicle to lift them up for expiration. It also aids in chest wall expansion to get extra amounts of air into the thoracic cavity during inspiration.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
133
Q

True/False: When the abdominal muscles contract, they directly act on the thoracic cavity and not the abdominal cavity

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
134
Q

What happens to the volume of the abdominal cavity when the abdominal muscles contract?

A

Decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
135
Q

Where do the organs of the abdominal cavity go when the volume of the abdominal cavity decreases?

A

They get pushed up against the diaphragm which pushes up into the thoracic cavity (decreasing thoracic cavity volume)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
136
Q

When we start to inspire the _____ nerve innervates the diaphragm causing it to contract

A

phrenic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
137
Q

The diaphragm _________ at inspiration causing an increase in thoracic cavity volume

A

Flattens down

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
138
Q

The diaphragm _________ at expiration causing a decrease in thoracic cavity volume

A

relaxes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
139
Q

The diaphragm is aided by the

A

intercostal muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
140
Q

The external intercostal muscles act to

A

raise the sternum and expand the ribs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
141
Q

There is an increase in_________ dimensions of the thoracic cavity when the external intercostal muscles lift up the sternum and the ribs

A

posterior

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
142
Q

The external intercostal muscles increase thoracic cavity volume in which 3 dimensions?

A

Anterior, posterior and lateral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
143
Q

The internal intercostal muscles act to

A

push the sternum in and the ribs down

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
144
Q

The internal intercostal muscles lie at ___ degrees to the external intercostal muscles as they run between the ribs

A

90

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
145
Q

List the pressures of the thoracic cavity

A

Intra-thoracic (alveolar) pressure [PA] Intrapleural Pressure [Pip] Transpulmonary Pressure [PT]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
146
Q

What is Intra-thoracic (alveolar) pressure [PA]?

A

pressure inside the thoracic cavity, essentially pressure in the lungs. May be positive or negative compared to atmospheric pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
147
Q

When is alveolar pressure positive?

A

When the atmospheric pressure is less than alveolar pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
148
Q

What is Intrapleural Pressure [Pip]?

A

pressure inside the pleural cavity, typically megative compared to atmospheric pressure (at least in healthy lungs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
149
Q

What is Transpulmonary Pressure [PT]?

A

difference between alveolar and intrapleural pressures. Almost always positive.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
150
Q

True/False: In health. Intrapleural Pressure is always more negative than alveolar pressure?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
151
Q

What is the normal intrapleural pressure?

A

-3mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
152
Q

Why is intrapleural pressure negative?

A

pleural membranes are constantly being pulled apart ever so slightly by the recoil of the lungs and the expansion of the chest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
153
Q

What is surfactant?

A

Detergent-like fluid produced by type 2 alveolar cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
154
Q

How does surfactant help the alveoli?

A

It reduces surface tension on the alveolar surface membrane thus reducing the alveoli’s tendency to collapse.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
155
Q

When does surface tension occur?

A

It occurs wherever there is an air-water interface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
156
Q

Where does the air-water interface occur at the alveolar level?

A

Thin film of water on the surface of the alveoli to saturate the air in the alveolar sac before it can diffuse into the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
157
Q

How can the thin fluid film of water around the alveoli cause the alveoli to collapse?

A

The water molecules around the alveoli are attracted to each other thus creating a force or inwardly directed pressure that could cause the alveoli to collapse by pulling it into the middle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
158
Q

How does surfactant help the thin fluid film from causing the alveoli to collapse?

A

Surfactant reduces the attraction between the water molecules by sitting between them and therefore reducing the surface tension.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
159
Q

Surfactant increases

A

Lung compliance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
160
Q

What is Lung compliance?

A

It is a measure of lung distensibility/stretchibility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
161
Q

Increased lung distensibility makes it easier to get air

A

into the lungs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
162
Q

Surfactant is more effective in small/large alveoli?

A

Small

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
163
Q

Why is surfactant more effective in small alveoli?

A

Because surfactant molecules are more concentrated in small alveoli.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
164
Q

Surfactant and surface tension obey the law of

A

LaPlace

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
165
Q

Law of LaPlace states that the pressure required to keep an alveoli open is equal to

A

2T/r

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
166
Q

Does the surface tension differ between smaller and larger alveolus? Why?

A

No because the droplets of water are attracted to each other with the same attractive force

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
167
Q

Does surfactant equalize or create pressure differences among small and large alveolus?

A

Equalize

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
168
Q

When does surfactant production start in the womb?

A

25 weeks gestation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
169
Q

When is surfactant production complete in the womb?

A

36 weeks gestation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
170
Q

Full gestation period in a human is

A

40 weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
171
Q

Production of which hormones stimulate surfactant production?

A

Thyroid hormones and hormone cortisol (both of which are significantly increased towards the end of pregnancy)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
172
Q

Babies that are born before 36 weeks tend to have inadequate amounts of surfactant. This causes

A

Infant Respiratory Distress Syndrome (IRDS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
173
Q

IRDS causes _____ such that _________

A

breathing difficulties; premature babies have to overcome the surface tension and have to invest a big amount of energy to inflate their alveoli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
174
Q

IRDS can be treated with

A

synthetic surfactant aerosols

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
175
Q

Does it take more pressure to fill the lungs with saline or air?

A

Air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
176
Q

Just like us, babies in utero go through the same breathing cycle. What do they breathe in to fill their lungs given the fact that they are still incapable of putting the effort needed to breathe normally?

A

Uterine fluid (effectively saline)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
177
Q

Define compliance

A

Compliance is a term that defines a change in volume relative to a change in pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
178
Q

Compliance does not measure elasticity. It measures

A

stretchability, how easy it is to inflate the lungs (get air into the lungs NOT out)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
179
Q

High compliance refers to

A

healthy lungs where there is a large increase in lung volume for a small decrease in intrapleural pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
180
Q

A disease where patients have highly compliant lungs but lost elasticity

A

Emphysema

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
181
Q

Low compliance refers to

A

a small increase in lung volume for a large decrease in intrapleural pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
182
Q

A disease where the lungs have low compliance

A

Fibrosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
183
Q

Does anatomical dead space volume differ at different times?

A

Anatomical dead space volume is relatively fixed for any one individual

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
184
Q

Ventilation refers to

A

movement of air (not specified) in and out of lungs (Breathing)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
185
Q

Ventilation can be described in two ways, namely

A
  • Pulmonary (Minute) ventilation - Alveolar ventilation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
186
Q

Pulmonary (Minute) ventilation refers to

A

total air movement into/out of lungs (relatively insignificant in functional terms)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
187
Q

Alveolar ventilation refers to

A

fresh air getting to alveoli and therefore available for gas exchange (functionally much more significant)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
188
Q

Alveolar ventilation is very significantly impacted by

A

anatomical dead space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
189
Q

Both pulmonary and alveolar ventilation are measured in

A

litres per minute

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
190
Q

What percent of normal tidal breathing is efficient? Where does the rest go?

A

70%; stuck in dead space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
191
Q

Can alveolar ventilation change? If so, how?

A

Yes, alveolar ventilation can vary depending on our breathing pattern and this can be for the better or for the worse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
192
Q

Average normal respiratory rate of an ideal man is

A

12 breaths/min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
193
Q

`Tidal volume of an ideal man is

A

500 mL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
194
Q

What happens to our respiratory rate and tidal volume when we are anxious?

A

Respiratory rate increases (20 breaths/min) and tidal volume decreases (300mL) (fast, shallow breaths)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
195
Q

What happens to our respiratory rate and tidal volume when we are sleeping or in a chilled out state?

A

Respiratory rate drops (8 breaths/min) and tidal volume increases (750 mL)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
196
Q

Pulmonary ventilation (mL/min) =

A

Tidal volume (mL) * Respiratory rate (breaths/min)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
197
Q

Air to alveoli (mL) =

A

Tidal volume (mL) - Dead space volume (mL)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
198
Q

Alveolar Ventilation (mL/min) =

A

Air to alveoli (mL) * Respiratory rate (breaths/min)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
199
Q

Most efficient way of breathing is by

A

breathing deeply

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
200
Q

Best way to enhance alveolar ventilation

A

breathing deeply and rapidly (i.e. when you exercise)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
201
Q

What happens to alveolar ventilation if you increase respiratory rate but keep the tidal volume the same?

A

Increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
202
Q

Hypoventilation refers to

A

low alveolar ventilation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
203
Q

Hyperventilation refers to

A

high alveolar ventilation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
204
Q

What is the composition of the air we breathe in? Where does the carbon dioxide in our body come from?

A

79% nitrogen, 21% oxygen, and 0.03% Carbon dioxide The carbon dioxide found in our blood and cells is made by us and is a by-product of aerobic respiration.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
205
Q

Partial pressure can be defined as

A

the pressure of a gas in a mixture of gases is equivalent to the percentage of that particular gas in the entire mixture multiplied by the pressure of the whole gaseous mixture.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
206
Q

Partial pressure of the oxygen we breathe in =

A

21% * 760mmHg = 160mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
207
Q

True/False: All gas molecules exert the same pressure.

A

True

208
Q

What happens to partial pressure if there is an increase in concentration of gas mixture?

A

Increases

209
Q

Normal alveolar ventilation is about

A

4.2 L

210
Q

Partial pressure of oxygen at normal alveolar ventilation

A

100 mmHg / 13.3 kPa

211
Q

Partial pressure of carbon dioxide at normal alveolar ventilation

A

40 mmHg / 5.3 kPa

212
Q

What is the air that we breathe in diluted by?

A

Anatomical dead space, residual volume, and water vapour

213
Q

Are the partial pressure values in the alveoli the same as the partial pressure values in systemic arterial blood? If so why?

A

Yes, because both diffuse until equilibrium is reached.

214
Q

What happens to oxygen in hypoventilation?

A

It is metabolised by the peripheral tissues faster than it is being replenished

215
Q

What happens to partial pressure of oxygen in hyperventilation?

A

Increases

216
Q

What is our primary driving force for breathing?

A

Carbon dioxide

217
Q

Why is chronic hyperventilation difficult to keep up?

A

Because you have to consciously always overcome your brain

218
Q

As we breathe in, intrapleural pressure becomes (more/less) negative.

A

more

219
Q

The more negative intrapleural pressure becomes, the ______ the transpulmonary pressure becomes.

A

becomes

220
Q

True/False: For any given change in pressure, we get a bigger change at the base than at the apex of the lung.

A

True

221
Q

Alveolar pressure is the greatest at the (base/apex) of the lung

A

base

222
Q

As height increase (from base to apex), what happens to alveolar ventilation?

A

declines

223
Q

Why does alveolar ventilation decrease with height?

A

Because compliance is lower at the apex of the lung than it is at the base.

224
Q

When a patient is lying down, where do you expect to have more alveolar ventilation?

A

Back of the lung

225
Q

Branch of systemic circulation that delivers nutritive blood supply to the lungs is known as the

A

bronchial circulation

226
Q

What does the bronchial circulation supply and remove the lung tissue with/from?

A

Supplies with nutrients, enzymes, and hormones Removes waste products

227
Q

Bronchial circulation comprises about ___ % of left heart output

A

2

228
Q

Blood from bronchial veins drains to the ________ via the ___________

A

left atrium; pulmonary veins

229
Q

Bronchial circulation veins are

A

systemic veins

230
Q

____________ carries the entire cardiac output from the right ventricle

A

Pulmonary artery

231
Q

Pulmonary circulation is in _______ with systemic circulation

A

series

232
Q

What does “pulmonary circulation is in series with systemic circulation” mean?

A

The volume of blood that goes through the pulmonary circulation per minute is the same volume of blood that goes around the rest of the body in one minute

233
Q

Pulmonary circulation is a ____ flow, ____ pressure system

A

high, low

234
Q

Systolic over diastolic pressure in pulmonary circulation is

A

25/10

235
Q

Systolic over diastolic pressure in systemic circulation is

A

120/80

236
Q

There is a very ____ pressure gradient driving blood from the right side of the heart to the left side of the heart.

A

low

237
Q

Is the pressure gradient lower from the right side of the heart to the left or from the left side of the heart to the right?

A

Right side of the heart to the left

238
Q

PAo2 stands for

A

Alveolar Po2

239
Q

Value of Alveolar Po2

A

100 mmHg / 13.3 kPa

240
Q

PACO2 stands for

A

Partial pressure of Carbondioxide in alveoli (Alveolar PCO2)

241
Q

Value of Alveolar PCO2

A

40 mmHg / 5.3 kPa

242
Q

PaO2 stands for

A

Partial pressure of oxygen in arterial blood (Arterial PO2)

243
Q

Value of arterial PO2

A

100 mmHg / 13.3 kPa

244
Q

PaCO2 stands for

A

Arterial pressure of carbondiaoxide (Arterial PCO2)

245
Q

Value of arterial PCO2

A

40 mmHg / 5.3 kPa

246
Q

PVO2 stands for

A

Partial pressure of oxygen in mixed venous blood (Venous PO2)

247
Q

Value of Venous P02

A

40 mmHg / 5.3 kPa

248
Q

PVCO2 stands for

A

Partial pressure of carbondioxide in mixed venous blood (Venous PCO2)

249
Q

Value of Venous PCO2

A

46 mmHg / 6.2 kPa

250
Q

Arterial blood values reflect

A

lung values

251
Q

Mixed venous blood values reflect

A

tissue values

252
Q

Relationship between diffusion and partial pressure gradient

A

Directly proportional

253
Q

Relationship between diffusion and gas solubility

A

directly proportional

254
Q

Relationship between diffusion and available surface area

A

directly proportional

255
Q

Relationship between diffusion and membrane thickness

A

inversely proportional

256
Q

Relationship between diffusion and short distances

A

diffusion is rapid over short distances

257
Q

True/False: Oxygen is very soluble in water

A

False

258
Q

True/False: Carbondioxide is very soluble in water

A

True

259
Q

Why is it that when it comes to diffusion, the pressure difference between oxygen is much higher than that of carbondioxide?

A

Because carbondioxide is very soluble in water compared to oxygen

260
Q

What happens in emphysema?

A

Destruction of surface area available for gas exchange which then reduces the rate of diffusion needed for adequate gas exchange leading to less oxygen entering the blood (low PO2 in pulmonary vein and systemic arterial blood and low PCO2 in pulmonary artery)

261
Q

What happens in fibrosis?

A

Fibrous tissue is laid out alongside elastic tissue between Type 1 cell and capillary cell causing the lung’s connective tissue to end up with both fibrous and elastic tissue which then leads to a thick alveolar membrane slowing down gas exchange. The fibrous tissue impedes diffusion as well as resists stretch making lung expansion difficult lowering lung compliance and decreasing partial pressure gradient (less oxygen/carbondioxide goes into/out of the blood).

262
Q

What is pulmonary hypertension?

A

An increase in blood pressure in the pulmonary capillaries forcing plasma out of the capillaries to sit in the interstitial space.

263
Q

What happens in pulmonary edema?

A

Usually comes about as a result of pulmonary hypertension forcing plasma out of the capillaries and cools in the interstitial space increasing the distance between the alveoli and blood vessel. The fluid creates a pressure that resists inflation of the alveoli. Partial pressure of oxygen decreases since oxygen cannot easily dissolve in water while partial pressure of carbondioxide usually remains the same. It affects diffusion rather than compliance or ventilation.

264
Q

What happens in asthma?

A

Asthma affects ventilation rather than diffusion. In asthma, there is no diificulty in gases diffusing but however there is a low partial pressure of oxygen and this is because there is not enough oxygen available in the first place for diffusion. Asthma causes an inappropriate constriction of the bronchial smooth muscle or inflammation of the bronchioles thus impeding ventilation.

265
Q

Apart from asthma, what other diseases affect ventilation?

A

Emphysema and fibrosis

266
Q

The X-Ray of a patient with fibrosis would show

A

radiopaque fibres

267
Q

How does smoking cause emphysema?

A

Constituents within cigarette smoke activate an enzyme called elastase that break down elastic fibres and the alveolar wall resulting in a loss of surface area and elasticity

268
Q

Define Obstructive lung disease

A

Obstruction of airflow, especially during expiration

269
Q

Define Restrictive lung disease.

A

Restriction of lung expansion as a result of loss of lung compliance

270
Q

What happens in chronic bronchitis?

A

Inflammation of the bronchi that narrows the airways compromising airflow.

271
Q

Chronic bronchitis and emphysema fall under the umbrella

A

Chronic Obstructive Pulmonary Disease (COPD)

272
Q

COPD and Asthma are classified as

A

Obstructive lung diseases

273
Q

There is about _______ people worldwide estimated to have COPD in a moderate to severe form.

A

80 million

274
Q

About ___ percent of the UK’s population has moderate to severe COPD

A

1

275
Q

It is suspected that there is a high prevalance of COPD in individuals over the age of ___

A

75

276
Q

What is an idiopathic condition?

A

A condition where the origin of the disease is not specified or unknown.

277
Q

True/False: Fibrosis is an idiopathic condition

A

True

278
Q

For every 100,000 people, there is about ___ new cases of fibrosis every year in the UK

A

50

279
Q

Name and explain a class of fibrosis.

A

Asbestosis; occurs when exposed to asbestos dust for a long period of time

280
Q

What is spirometry?

A

Spirometry is a technique commonly used to measure lung function producing either static or dynamic measurements. It is a commonly used technique in the clinical respiratory physiology lab.

281
Q

Static spirometer measurements consider

A

exhaled/inhaled volume

282
Q

Dynamic spirometer measurements consider

A

the time taken to inhale/exhale a certain volume of what is being measured

283
Q

Most clinical respiratory lung function tests work with

A

expired air

284
Q

Name the lung volumes that can be measured by spirometry.

A

Any lung volume that does not involve residual volume (cannot be expired) can be measured by spirometry, i.e. tidal volume, inspiratory reserve volume, expiratory reserve volume, inspiratory capacity, and vital capacity

285
Q

Common lung function test carried out with spirometry

A

FEV1/FVC

286
Q

What is FEV1? What is its value in a fit, healthy, young male?

A

FEV1 refers to the forced expiratory volume in 1 second; 4 litres

287
Q

What is FVC? What is its value in a healthy, young, adult male?

A

The total amount of air that you can expire over whatever time (sees how fast you can push the air out); 5 litres

288
Q

What is the FEV1/FVC ratio in a healthy person regardless of age, gender, or sex?

A

80%

289
Q

What does an FEV1/FVC ratio of 80% mean?

A

A healthy person is able to expire about 80% of their vital capacity in the first second when an FVC maneuver is performed.

290
Q

Why is the FEV1 decreased in restrictive lung diseases when there is no problem expiring?

A

Because there is less air in the lungs in the first place.

291
Q

True/False: In restrictive lung diseases, FEV and FVC ratios are reduced in proportion to a much greater extent than in obstructive lung diseases

A

True

292
Q

Possible reasons for why expiring air can be challenging in obstructive lung diseases

A
  • Increase in resistance in the airways
  • Loss of pressure normally generated in the alveoli by contraction of elastic fibres
293
Q

What happens to functional residual capacity in patients with obstructive lung disease? Why?

A

Increases because they start retaining more air as they can’t expire most air out

294
Q

Is spirometry more useful in diagnosing restrictive or obstructive lung diseases? Why?

A

More useful to diagnose obstructive lung diseases

Little to no use to diagnose restrictive lung diseases as these patients could have a normal FEV1/FVC ratio

295
Q

At what point of inspiration is compliance low? How does it increase?

A

The start; it increases by big changes in intrapleural pressure in the beginning.

296
Q

At what point of expiration is compliance low? How does it increase?

A

The start; it increases when intrapleural pressure reaches about -0.4kPa towards the end end of expiration

297
Q

Why do the inspiratory and expiratory curves not superimpose?

A
  • During inspiration, we need to overcome lung inertia (the tissue’s reluctance to change shape )
  • Overcome surface tension that causes the alveoli to collapse

During expiration, pressure increases (making intrapleural pressure less negative) to push air out

298
Q

Decreased compliance curve looks

A

less steep than normal

299
Q

Perfusion refers to

A

blood flow through pulmonary circulation (or) local blood flow

300
Q

What does our body ideally want in terms of ventilation and perfusion? Do we get it?

A

Ideally, our body would like the amount of air getting into the lungs per minute to be equal to the amount of blood flowing past the lungs per minute.

We, however, do not get it as there is a ventilation-perfusion mismatch

301
Q

Ventilation and perfusion across all the lung_________. With height, ventilation and perfusion _____.

A

do not precisely match; decreases

302
Q

At the base of the lung, blood flow is ______ than ventilation because

A

higher; arterial/blood pressure exceeds alveolar pressure compressing the alveoli

303
Q

At the apex of the lung, blood flow is ______ than ventilation because

A

lower; arterial pressure is less than alveolar pressure compressing the arterioles

304
Q

At which part of the lung are ventilation and perfusion equal?

A

Rib 3 (V/Q ratio 1)

305
Q

At which part of the lung do we have the greatest ventilation-perfusion mismatch?

A

Apex

306
Q

With height, blood flow ______ faster than ventilation

A

declines

307
Q

In the upright position, the ventilation-perfusion ratio _______ with height

A

increases

308
Q

The base of the lung is normally poorly ventilated which is minimal. In what extreme cases is this poor ventilation beyond the minimum?

A
  • Blockage of an upper airway due to aspiration of a foreign body
  • Lung tumour compressing one of the upper airways, secondary or tertiary bronchi, or one of the upper bronchioles
309
Q

Poorly ventilated alveoli tend to have a build-up of

A

carbon dioxide

310
Q

What causes a fall in PO2 in poorly-ventilated alveoli?

A

Oxygen is used up faster in poorly-ventilated alveoli than being replenished leading to a fall in its partial pressure. Keep in mind that oxygen needs a big partial pressure gradient in order to diffuse.

311
Q

What happens when carbondioxide starts to build-up in the alveoli?

A

We will lose the partial pressure gradient that pulls carbon dioxide out of the blood and cannot replenish the blood with oxygen. We end up sending this blood back to the heart through the pulmonary vein diluting it with blood from better-ventilated alveoli.

312
Q

Blood flowing past the poorly ventilated alveoli is being ________ from the right side of the heart without undergoing gas exchange.

A

shunted

313
Q

How does the body minimize the effects of a shunt in pulmonary circulation?

A

In response to a decrease in PO2 or hypoxia, the smooth muscle in the blood vessels around poorly ventilated alveoli constrict redirecting the blood to better-ventilated regions of the lung.

314
Q

How does the body combat hypoxia in systemic circulation?

A

If there is a region in the periphery that is hypoxic, the systemic vessels dilate so that it can deliver oxygen to that region.

315
Q

Constriction in response to hypoxia is absolutely unique to _____ blood vessel

A

pulmonary

316
Q

What happens to ventilation and perfusion in poorly ventilated alveoli?

A

An increase in PCO2 causes the bronchial smooth muscle to dilate increasing ventilation while constriction of blood vessels reduces perfusion in an effort to bring the V/Q ratio close to 1.

317
Q

When ventilation exceeds blood flow, we get __________

A

alveolar dead space that cannot participate in gas exchange due to low perfusion

318
Q

‘Ventilation > perfusion’ normally occurs at the apex. It happens to a greater extent in pathological situations like

A

pulmonary embolism where there is a blood clot in one of the pulmonary vessels impeding blood flow

319
Q

What does it mean by alveolar dead space is opposite to shunt?

A

In shunt, perfusion exceeds ventilation while in alveolar dead space, ventilation exceeds perfusion

320
Q

Why do we get a decrease in PCO2 in alveolar dead space?

A

Because we are blowing off carbon dioxide faster than it is added to the alveoli due to a reduction in blood flow bringing a mild bronchial constriction

321
Q

An increase in PO2 leads to

A

pulmonary vasodilation

322
Q

The biggest contributor to physiologic dead space is

A

anatomical dead space

323
Q

In pulmonary embolism, anatomical dead space

A

increases

324
Q

Normal change in heart rate during the breathing cycle is known as

A

Respiratory Sinus Arrhythmia

325
Q

Borometry trace going up signifies

A

breathing in

326
Q

Borometry trace going down signifies

A

breathing out

327
Q

As you breathe in, heart rate

A

goes up

328
Q

True/False: dogs have a stronger sinus rhythm arrhythmia than humans

A

true

329
Q

Sinus arrhythmia is important because

A

it helps minimise ventilation-perfusion mismatch

330
Q

What would happen if heart rate stayed constant during inspiration? Why?

A

increased alveolar dead space due to increased ventilation than perfusion

331
Q

What would happen if heart rate stayed constant during expiration? Why?

A

increased shunt due to perfusion being greater than ventilation

332
Q

______________ innervates the heart

A

Parasympathetic vagus nerve

333
Q

What happens to vagal nerve activity when heart rate goes up?

A

Decreases

334
Q

______ slows down the heart rate

A

Vagal nerve

335
Q

Decrease in vagal nerve activity occurs when heart rate goes up. How?

A

Removing brake on heart rate

336
Q

What happens to vagal nerve activity when heart rate goes down? How?

A

Increases by outting the brakes on hearet rate

337
Q

Oxygen travels in 2 forms in the blood, namely:

A
  • In solution in plasma
  • Bound to haemoglobin within RBC
338
Q

How much and why does very little oxygen travel in plasma?

A

3 mL oxygen per litre of plasma; Because plasma is 95% water making it harder for oxygen to dissolve.

339
Q

How much oxygen is present in whole blood?

A

200 mL per litre

340
Q

How much oxygen is bound to haemoglobin?

A

197 mL

341
Q

Why is it important to have this little amount of oxygen inplasma?

A

Because it determines how much oxygen binds to haemoglobin

342
Q

How does carbon dioxide travel?

A

It travels in one form or the other in plasma since it is soluble in water

343
Q

The bulk of carbon dioxide travels in the form of

A

bicarbonate ions

344
Q

How much CO2 is transported in solution in plasma and how much is stored in haemoglobin?

A

77% in solution in plasma

23% stored in haemoglobin

345
Q

What does partial pressure in the alveoli reflect?

A

systemic arterial blood

346
Q

What does partial pressure in pulmonary arteries reflect?

A

Partial pressure at tissues

347
Q

What are the typical partial pressure values for oxygen and CO2 in alveoli?

A

100 mmHg Oxygen

40 mmHg Carbon dioxide

348
Q

What are the typical partial pressure values for oxygen and CO2 in the pulmonary arteries?

A

40 mmHg Oxygen

46 mmHg Carbon dioxide

349
Q

PO2 in plasma should be the same as PO2 in

A

alveoli

350
Q

How do values of partial pressure of gases in solution compare to the partial pressure in gaseous phase that is driving the gas into solution?

A

equal

351
Q

Our cardiac output at rest is

A

5 L per minute

352
Q

O2 delivery to tissues =

A

Arterial O2 content * Cardiac Output

353
Q

If the heart pumps 5 litres of blood per minute, how much oxygen would be delivered to our tissues given that there are no red blood cells or haemoglobin oresent?

A

Cardiac output = 5L/min

Arterial O2 content = 3mL/min

Oxygen delivered = 3*5 = 15 mL/min

354
Q

How much is the oxygen demand for resting tissues?

A

250 mL/min

355
Q

What percentage of arterial O2 is extracted by peripheral tissues at rest?

A

25%

356
Q

True/False: At rest, we are delivering way more oxygen than needed to the periphery

A

True

357
Q

98% of the oxygen carried in the blood is carried in

A

haemoglobin

358
Q

Most haemoglobin in adult blood is in the form of

A

Haemoglobin A

359
Q

Haemoglobin A contains

A

4 polypeptide chains, 2 alpha chains and 2 beta chains

All the chains are associated with a haem group

360
Q

Each molecule of haemoglobin has ___ haem groups

A

4

361
Q

In the centre of the haem group, an ______ atom can be found. Each of these atoms will associate with one oxygen molecule.

A

Iron

362
Q

True/False: Each red blood cell can only carry 4 molecules of oxygen.

A

False. Each red blood cell is jam-packed with hemoglobin.

363
Q

Association between oxygen and iron atom with the haem group is known as

A

oxygenation reaction

364
Q

Oxygenation reaction vs. oxidation reaction

A

Oxygenation reaction is weaker

365
Q

Oxygen binds to iron

A

weakly

366
Q

When oxygen binds to haemoglobin, it causes polypeptide chains to shuffle because

A

making it easier for other oxygen molecules to bind

367
Q

How does haemoglobin bind to oxygen?

A

Cooperatively binds to 4 oxygen molecules

368
Q

What is meant by cooperative binding in haemoglobin?

A

When one oxygen molecule starts to leave, it encourages the other oxygen molecules to leave.

369
Q

The major detriment of the degree to which haemoglobin binds or is saturated with oxygen is the

A

partial pressure of oxygen in the blood and amount of oxygen in plasma

370
Q

Partial pressure of oxygen is determined by

A

how much oxygen is in solution

371
Q

Partial pressure of oxygen in the plasma is the same as the partial pressure of oxygen in the

A

alveoli

372
Q

Partial pressure of oxygen in the alveoli is determined by

A

alveolar ventilation

373
Q

Why does the partial pressure of oxygen not change as hemoglobin binds to it?

A

It effectively hides it from the plasma, maintaining the partial pressure gradient that continues to suck O2 out of alveoli until Hb becomes saturated

374
Q

Haemoglobin binds to oxygen to form

A

oxyhemoglobin

375
Q

When is saturation of haemoglobin complete?

A

After 0.25 seconds of contact with alveoli

376
Q

What is the total contact time between haemoglobin and alveoli?

A

0.75 seconds

377
Q

The relationship between PO2 and the saturation of haemoglobin results in a

A

sigmoidal curve

378
Q

How saturated in haemoglobin at a PaO2 of 60 mmHg?

A

90%

379
Q

How saturated in haemoglobin at a PaO2 of 40 mmHg?

A

75%

380
Q

What is normal venous PO2?

A

40 mmHg

381
Q

What happens to the affinity of haem groups for oxygen when the partial pressure of oxygen drops below 60?

A

decreases

382
Q

What is anaemia?

A

Any condition where the oxygen carrying capacity of blood is compromised

383
Q

What are some examples of anaemia?

A

Iron deficiency

Hemorrhage

Vitamin B12 deficiency

384
Q

Vitamin B12 is necessary because

A

it produces red blood cells

385
Q

Is it possible for red blood cells to be fully saturated with oxygen in anaemia? Why?

A

Yes, because the major detriment of oxygen saturation of haemoglobin is partial pressure of oxygen.

386
Q

What factors affect the affinity of haemoglobin for oxygen?

A

pH

PCO2

Temperature

387
Q

How does pH affect affinity?

A

A decrease in pH decreases affinity

388
Q

How does PCO2 affect haemoglobin affinity for oxygen?

A

An increase in PCO2 decreases affinity

389
Q

How does temperature affect haemoglobin affinity for oxygen?

A
390
Q

How does an increase in affinity impact collecting and depositing oxygen?

A

Makes collecting easier but depositing harder

391
Q

What is the Bohr effect?

A

for any given partial pressure of oxygen, the haemoglobin becomes less saturated with oxygen when there is a decrease in pH or increase in PCO2.

It aids oxygen unloading at peripheral tissues.

392
Q

How does a decrease in pH affect extracellular fluid?

A

Makes it acidic

393
Q

In acidosis, the curve shifts to the right. How does this affect the normal 25% oxygen delivery to tissues?

A

Tissues get more than the usual 25%

394
Q

When the affinity of haemoglobin for oxygen decreases, oxygen delivery to tissues

A

increase

395
Q

A complication of hypothermia

A

peripheral tissues cannot access oxygen in the blood

396
Q

What can bind to haemoglobin to decrease its affinity for oxygen?

A

2, 3 - diphosphoglycerate (2,3 - DPG)

397
Q

Red blood cells start to produce more ___________ in situations of hypoxia.

A

2,3 diphosphoglycerate

398
Q

What synthesises 2,3 - diphosphoglycerate (2,3 - DPG)?

A

Erythrocytes

399
Q

When does 2,3 - diphosphoglycerate (2,3 - DPG) increase and why?

A

Situations associated with inadequate oxygen supply (such as heart or lung disease, living at a high altitude) to help maintain oxygen release in tissues

400
Q

Why does carbon monoxide cause problems?

A

It binds to haemoglobin with an affinity 250x greater than oxygen

401
Q

What does carbon monoxide form when it binds to haemoglobin?

A

Carboxyhaemoglobin

402
Q

When does carbon monoxide bocome problematic?

A

As soon as it dissolves in plasma

403
Q

What PCO causes progressive carboxyhaemoglobin formation?

A

0.4 mmHg

404
Q

What are the symptoms of too much carbon monoxide?

A

Hypoxia

Anaemia

Nausea

Headaches

Cherry red skin and red mucous membranes

Brain damage

Death

405
Q

What happens to respiration rate in patients with too much carbon monoxide?

A

unaffected

406
Q

What is hypoxia?

A

Deficiency in the amount of oxygen reaching tissues

407
Q

How is carbon dioxide transported in the blood?

A

7% remains dissolved in erythrocytes and plasma

23% combines in the erythrocytes with deoxyhaemoglobin to form carbamino compounds

70% combines in the erythrocytes with water to form carbonic acid which dissociates to yield bicarbonate and H+ ions

408
Q

What happens to most of the bicarbonate within red blood cells?

A

Moves out of the cell into the plasma in exchange for Cl- ions and excess H+ ions bind to deoxyhaemoglobin

409
Q

What is bicarbonate leaving erythrocytes for Cl- called?

A

Chloride shift

410
Q
A
411
Q

The partial pressure of oxygen refers to

A

oxygen in solution in plasma

412
Q

What happens to excess H+ ions after carbonic acid dissociates into bicarbonate and H+ ions?

A

Bind to deoxyhaemoglobin

413
Q

Where does carbon dioxide bond to compounds to be broken down, and where is it built up?

A

Dissolved and made into other substances in systmemic capillaries

Built up from these substances in pulmonary capillary to be diffused into the alveoli lumen

414
Q

Why is normal pH stable althoug carbon dioxide is broken down into H+?

A

All the carbon dioxide produced is eliminated in expired air

415
Q

When would the pH not be stable due to carbon dioxide?

A

During hypo/hyperventilation as it alters plasma PCO2 and plasma [H+] will vary

416
Q

What does hypoventilation do the the amount of carbon dioxide in the blood and [H+]?

A

CO2 retention

Increased [H+] bringing about respiratory acidosis

417
Q

What brings about respiratory acidosis?

A

Hypoventilation (retention of carbon dioxide)

418
Q

What does hyperventilation do to the amount of carbon dioxide in the blood and [H+]?

A

Blowing of more CO2

Decreased [H+] bringing about respiratory alkalosis

419
Q

What brings about respiratory alkalosis?

A

Hyperventilation (blowing of more CO2)

420
Q

How much oxygen dissolve in 1 litre of water?

A

0.03 mLs

421
Q

What is PaO2 determined by?

A

O2 solubility and the partial pressure of O2, in the gaseous phase that is driving O2 into solution

422
Q

How do values of partial pressure of gases in solution compare to the partial pressure in gaseous phase that is driving the gas into solution?

A

They are equal

423
Q

If 3ml of oxygen is present per litre of plasma, what is the partial pressure that is driving O2 into the loquid phase in plasma?

A

100mmHg

This is because solubility of water is 0.03ml/L/mmHg (3/0.03 = 100)

424
Q
A
425
Q

How many oxygen molecules are in 1 litre of gas?

A

30 times more than in 1 litre of plasma

426
Q

True/False: concentration of oxygen molecules per litre is different in the gaseous phase than the liquid phase

A

true

427
Q

True/False: partial pressure of oxygen molecules per litre is different in the gaseous phase than the liquid phase

A

false

428
Q

If we get gas in the blood, then we get

A

an air embolism

429
Q

What is the partial pressure of oxygen also known as?

A

oxygen tension

430
Q

How does PO2 in the liquid phase compare to that in the gaseous phase, and to the concentration in the liquid phase?

A

PO2 is the same in the liquid phase as the gas phase

PO2 in the liquid phase is different from the concentration as that varies depending on what phase the gas is in

431
Q

Why do some divers get air embolisms?

A

Sometimes divers ascend from depth too quickly causing more air to be pushed into the liquid phase (arterial bloodstream) than it normally would at sea level leading to nitrogen gas bubbles in their tissues and bloodstream.

432
Q

What percent of haemoglobin is not in adult form?

A

8%

433
Q

How much oxygen binds to each gram of haemoglobin?

A

1.34 mL

434
Q

How much oxygen can be found in 1L of systemic blood?

A

200 mL

435
Q

What are some forms of haemoglobin other than HbA?

A

HbA2 (δ chains replace β)

HbF (γ chains replace β)

Glycosylated Hb (HbA1a, HbA1b, HbA1c)

436
Q

What happens to beta chains in HbA2?

A

Replaced with delta chains

437
Q

What happens to beta chains in foetal haemoglobin (HbF)?

A

replaced with gamma chains

438
Q

Glycosylated Haemoglobin is really important

A

clinically

439
Q

What is glycosylated hemoglobin used for?

A

monitoring diabetes and blood glucose control in diabetes

440
Q

When does hemoglobin become glycosylated?

A

When it is exposed to high levels of glucose.

441
Q

Red blood cells have a life span of about

A

120 days

442
Q

Name the haemoglobin (not necessarily a type but a distant cousin!) found in skeletal and cardiac muscle.

A

Myoglobin

443
Q

When can myoglobin be found in the circulation?

A

When there is extensive muscle damage

444
Q

Compare and contrast between hemoglobin and myoglobin.

A

Both are oxygen-carrying molecules

Haemoglobin transports oxygen while myoglobin stores oxygen

445
Q

Which one has a higher affinity for oxygen; Haemoglobin or myoglobin?

A

Myoglobin

+ foetal haemoglobin

446
Q

Structurally, how do haemoglobin and myoglobin differ?

A

Both contain haem groups to which oxygen binds

Myoglobin contains 1 polypeptide chain while hemoglobin contains 4 polypeptide chains

447
Q

How does the affinity of foetal haemoglobin (HbF) and myoglobin for oxygen compare to HbA?

A

They are higher which is necessary for extracting oxygen from maternal arterial blood

448
Q

True/False: The affinity of the foetal haemoglobin is greater than the maternal haemoglobin

A

True

449
Q

Importance of foetal haemoglobin.

A

access maternal haemoglobin

450
Q

What are the 5 main types of hypoxia?

A

Hypoxaemic hypoxia

Anaemic hypoxia

Stagnant hypoxia

Histotoxic hypoxia

Metabolic hypoxia

451
Q

What is hypoxaemic hypoxia?

A

Reduction in oxygen diffusion at lungs either due to decreased PO2atmosphere or tissue pathology

452
Q

What is anaemic hypoxia?

A

Reduction in oxygen-carrying of blood due to anaemia, such as red blood cell loss or iron deficiency

453
Q

What is stagnant hypoxia?

A

Heart disease results in inefficient pumping of blood to lungs/around the body

454
Q

What is histotoxic hypoxia?

A

Poisoning prevents cells utilising oxygen delivered to them, such as carbon monoxide or cyanide

455
Q

What is metabolic hypoxia?

A

Oxygen delivery to the tissues does not meet increased oxygen demand by cells

456
Q

What stimulation does ventilatory control require?

A

Stimulation of skeletal muscles of respiration

457
Q

Skeletal muscles of inspiration are innervated by ________ nerve which supplies the diaphragm and the _________ nerves which supply the external intercostal muscles.

A

phrenic; intercostal

458
Q

Is there any neural input to muscles of expiration? Why or why not?

A

No because expiration is normally passive

459
Q

Where does ventilatory control reside?

A

With ill-defined centres (respiratory centres) found in the pons and medulla

460
Q

Ventilatory control is entirely dependent on

A

signalling from the brain

461
Q

The phrenic nerve is made up of cervical nerves

A

C3, C4, and C5

462
Q

What can you say about the conscious level required to breath?

A

In subconscious but can be voluntaraly modulated

463
Q

Where must the spinal cord be severed for breathing to stop?

A

Above the origin of the phrenic nerve (C3)

464
Q

Like the intrinsic rhythm to the heart, is there an intrinsic rhythm to the muscles of breathing?

A

no

465
Q

What would happen if you cut the nerve input to the heart?

A

It will continue to beat as long as there is a blood and nutrient supply.

466
Q

How are muscles of respiration activated?

A

Input of the somatic motor neuron

467
Q

What would happen if you cut the somatic motor neuron?

A

respiratory muscles will not contract therefore breathing ceases

468
Q

Which stimuli can alter the rhythm of respiratory centers in the brain stem?

A

emotions

469
Q

Which system does emotion reside in?

A

Limbic system

470
Q

In which part of the brain does voluntary, conscious thought originate?

A

Cortex

471
Q

What do respiratory centres have their rhythm modulated by?

A

Emotion (via limbic system of the brain)

Volunrary over ride (via higher centres in the brain)

Mechano-sensory input from thorax (such as stretch reflex)

Chemical composition of the blood detect by chemoreceptors (PCO2, PO2 and ph)

472
Q

Explain mechano-sensory input from the thorax.

A

Refers to stretch receptors that exist in the thoracic cage monitoring how much the thoracic wall is stretching. When a threshold is reached in terms of stretch, we get a reflex inhibition of ventilation (safety mechanism from overinflation of the alveoli)

473
Q

How does the chemical composition of blood alter respiratory rhythm?

A

Chemoreceptors detect PO2, PCO2, and pH of systemic arterial plasma

474
Q

Name the 2 group of neurons that can be found in the respiratory centers.

A

Dorsal Respiratory Group (DRG)

Ventral Respiratory Group (VRG)

475
Q

What do the dorsal respiratory group of neurons innervate?

A

Inspiratory muscles via the phrenic and intercostal nerves

476
Q

DRG neurons are involved in

A

setting up stimulation of inspiratory muscles, diaphragm, and external intercostal muscles

477
Q

What does the ventral respiratory group of neurons innervate?

A

Tongue

Pharynx

Larynx

Expiratory muscles

478
Q

VRG neurons are involved in

A

stimulating contraction or basal muscular tone of tongue, pharynx, larynx, and expiratory muscles

479
Q

Why is it important to have VRG neuron to maintain a basal tone?

A

Because it helps maintain a patent airway or the pharynx, larynx, tongue, and expiratory muscles would collapse

during normal expiration, the Ventral Respiratory Group maintains its basal tone in the tongue, pharynx and the larynx (EXPIRATORY MUSCLES ONLY DURING RESP. LOAD)

480
Q

What happens to DRG during expiration?

A

It switches off

481
Q

What happens to expiratory muscles during relaxed expiration?

A

Not being used but helps maintain basal tone

482
Q

Name the 2 types of chemoreceptors.

A

Central and peripheral

483
Q

Where are central chemoreceptors?

A

Medulla

484
Q

What do central chemoreceptors respond to?

A

Directly to H+ (directly reflects PCO2 by binding to H+)

Changes in [H+] in CSF

485
Q

What do central chemoreceptors provide?

A

Primary ventilatory drive

486
Q

Where are peripheral chemoreceptors?

A

Carotid and aortic bodies

487
Q

What do peripheral chemoreceptors respond to?

A

Changes in PO2 and changes in plasma [H+]

488
Q

What do peripheral chemoreceptors provide?

A

Secondary ventilatory drive

489
Q

How does the cerebrospinal fluid differ from interstitial fluid?

A

Cerebrospinal fluid has a much more tighter composition that interstitial fluid does elsewhere in the body

The brain is much less tolerant of changes in the composition of the fluid that bathes it than other tissues are.

490
Q

How is the composition of the cerebrospinal fluid regulated?

A

By the blood-brain barrier

491
Q

How do central chemoreceptors respond to changes in [H+] in the CSF around the brain?

A

Reflex stimulation of ventilation in response to an increase in [H+)

492
Q

What is hypercapnia?

A

Abnormally elevated levels of carbon dioxide in the blood

493
Q

What is the process of central chemoreceptor altering ventilation?

A

1) Arterial PCO2 increases and carbon dioxide crosses the blood-brain barrier (not H+)
2) Bicarbonate and H+ are formed and receptors respond to H+
3) Feedback via the respiratory centres increases ventilation in response to increased arterial PCO2
4) Decreased arterial PCO2 slows ventilation rate
5) This means that the central chemoreceptors monitor the PCO2 indirectly in the cerebrospinal fluid

494
Q

What type of feedback loop is the response to an increase in PCO2?

A

Leads to an increase in ventilation

Negative feedback loop

495
Q

Patients with chronic lung disease are on hypoxic drive rather than hypercapnia drive. What do these patients rely on?

A

Their central chemoreceptors become desensitized to the increased stimulation of PCO2. They then start to rely instead on their peripheral chemoreceptors and respond to changes in the partial pressure of oxygen and also to changes in hydrogen ion concentration.

496
Q

Why are peripheral chemoreceptors termed as peripheral?

A

Because they are found in the carotid artery and aorta

497
Q

Peripheral chemoreceptors don’t do much until your PO2 falls to

A

60 mmHg

498
Q

What is the process of peripheral chemoreceptors altering ventilation?

A

1) Arterial PO2 is low so no oxygen combines with an oxygen sensor
2) K+ channel closes so the cell depolarises
3) Exocytosis of dopamine-containing vesicles
4) Act on dopamine receptors on sensory neuron
5) Action potential generated that signals medullary centres to increase ventilation

499
Q

When would peripheral chemoreceptor stimulate ventilation?

A

Plasma pH falls ([H+] increases)

During acidosis

500
Q

When would peripheral chemoreceptor inhibit ventilation?

A

When pH rises ([H+] decreases)

During alkalosis or vomiting

501
Q

What can voluntary descending neural pathways from the cerebral cortex not override?

A

Involuntary stimuli such as arterial PCO2 or [H+]

502
Q

Why is respiration inhibited during swallowing?

A

Avoid aspiration of foods or fluids into the airways, followed by an expiration in order than any particles are dislodged outwards from the region of the glottis

503
Q

What are common drugs that affect respiratory centres?

A

Barbiturates and opioids

Gaseous anaesthetic agents

Nitrous oxide

504
Q

How do barbiturates and opioids affect respiratory centres?

A

Depress respiratory centres, overose often results in death as a result of respiratory failure

505
Q

How do gaseous anaesthetic agents affect respiratory rate?

A

Increase respiratory rate, but decreases tidal volume

506
Q

Hows does nitrous oxide affect respiratory centres?

A

Blunts peripheral chemoreceptor response to falling PaO2

507
Q

How safe is using nitrous oxide on respiratory centres?

A

Very safe in most people

Problematic in chronic lung disease cases where individual often on hypoxic drive and administering O2 to these patients aggravates situation

508
Q

What causes an increase of [H+] in the blood?

A

Rise in arterial PCO2

CO2 + H2O ↔ H2CO3 ↔ HCO3 + H+

509
Q

Difference between the peripheral chemoreceptors responding to hydrogen ions and the central chemoreceptors responding to hydrogen ions

A

peripheral chemoreceptors will respond to hydrogen ions that are generated by any means (i.e. lactic acid) so they don’t have to originate from carbon dioxide. Whereas the hydrogen ions that the central chemoreceptors are responding to always have to originate from carbon dioxide.

510
Q

As hydrogen ion concentration increases and our pH decreases, we will get a ______ increase in ventilation

A

Linear

511
Q

The muscles of inspiration and expiration are

A

All skeletal muscle and under voluntary control

512
Q
A
513
Q
A
514
Q
A
515
Q
A
516
Q
A
517
Q
A

Medicine 1 Respiratory (20 decks)

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