Respiratory Flashcards
1
Q
What are the four groups of sinuses?
A
Frontal
Maxillary
Ethmoid
Sphenoid
2
Q
Where do the frontal sinuses drain into?
A
Middle meatus through infundibulum
3
Q
Where do the maxillary sinuses drain into?
A
Middle meatus through hiatus semilunaris
4
Q
Where do the ethmoid sinuses drain into?
A
Anterior - infundibulum of middle meatus
Middle - Middle meatus
Posterior - superior meatus
5
Q
Where do the sphenoid sinuses drain into?
A
The sphenoethmoidal recess (this lies above the superior concha)
6
Q
What are the contents of the carotid sheaths?
A
Common carotid artery
Internal jugular vein
Vagus nerve
Cervical lymph nodes
7
Q
What is the name of the part of the nasal cavity that is just inside the nostrils?
A
Nasal vestibule
8
Q
What are the names of the three bones located in the nose?
A
Superior, middle and inferior conchae
9
Q
What is the area beneath each of the conchae called?
A
Meatus (superior, middle & inferior)
10
Q
What is the area superior to the superior conchae called?
A
Sphenoethmoidal recess
11
Q
What is the nerve supply to the nasal cavity?
A
Smell - olfactory nerves
Sensation - Branches of V1 and V2 of trigeminal nerve
12
Q
What is the arterial supply to the nasal cavity?
A
Branches of the maxillary artery (a branch of the external carotid artery)
13
Q
What is the lymph drainage of the nasal cavity?
A
Vestibule end - submandibular nodes
Remainder - Upper cervical nodes
14
Q
What are the paranasal sinuses lined by?
A
Mucoperiosteum - compound structure of mucous membrane and underlying periosteum (membrane that lines all bones)
15
Q
How is the mucous in the sinuses drained?
A
1) Through cillary action of columnar cells
2) Siphon action through blowing of the nose
16
Q
What are the functions of the paranasal sinuses?
A
1) They act as resonators to the voice
2) They reduce the weight of the skull
17
Q
What are the three parts of the pharynx?
A
Nasopharynx
Oropharynx
Laryngopharynx
18
Q
What is the location of the nasopharynx?
A
Above the soft palate and behind the nasal cavity
19
Q
What is the name for the opening between the sodt palate and the posterior pharyngeal wall?
A
Pharyngeal isthmus
20
Q
Where is the oropharynx located?
A
Behind the oral cavity down to the epiglottis - it is formed by the posterior third of the tongue
21
Q
What are the two arches located on the lateral walls of the oropharynx?
A
Palatoglossal and palatopharyngeal arches (or folds)
22
Q
What lies between the arches in the oropharynx?
A
Palatine tonsils
23
Q
What is the name for the boundary between the mouth and the pharynx?
A
Oropharyngeal isthmus - this is the section between the two arches
24
Q
Where is the laryngopharynx located?
A
Behind the opening of the larynx
25
What is the name for the depression either side of the laryngeal inlet?
Piriform fossa
26
What is the innervation of the nasopharynx?
Maxillary nerve (V2)
27
What is the innervation of the oropharynx?
Glossopharyngeal nerve
28
What is the innervation of the laryngopharynx?
Internal laryngeal branch of the vagus nerve
29
What are the pharyngeal constrictor muscles?
Superior, middle and inferior
30
What is the inferior pharyngeal constrictor muscle split into?
Thyropharyngeus (superior section)
| Cricopharyngeus (inferior section)
31
What are the three paired cartilages in the larynx?
Arytenoid cartilages
Corniculate cartilages
Cuneiform cartilages
32
What are the single (unpaired) cartilages in the larynx?
Thyroid cartilage
Cricoid cartilage
Epiglottis
33
What is the epiglottis made of?
Elastic cartilage
34
The epiglottis has attachments at its side, what are they?
Aryepiglottic folds - they attach the epiglottis to the arytenoid cartilages
35
Where is the stalk of the epiglottis attached to?
Thyroid cartilage
36
What are the membranes and ligaments of the larynx?
```
Thyrohyoid membrane
Hyo-epiglottic ligament
Cricotracheal ligament
Cricothyroid ligament
Quadrangular membrane
```
37
What are the attachments of the quadrangular membrane?
Spans between the antereolateral arytenoid cartilage and the lateral aspect of the epiglottis
Note: Lower margin becomes thickened - vestibular ligament
38
What are the vestibular folds also known as?
False vocal cords
39
Are the vestibular folds located above or below the true vocal cords?
Above
40
what is the role of the false vocal cords?
To provide protection to the larynx
41
What is the epithelial lining of the larynx?
Respiratory epithelium (except for the true vocal cords)
42
What is the epithelial lining of the true vocal cords?
Non-keratinised stratified squamous epithelium
43
What is the structure of the true vocal cords (folds)?
```
Superficial to deep:
Epithelium
Reinke's space - water layer
Vocal ligament
Vocalis muscle
```
44
What do the vestibular folds consist of?
The vestibular ligament
45
What are the two groups of extrinsic muscles that act of the larynx?
Suprahyoid and infrahyoid muscles
46
What (as a general rule) do the suprahyoid muscles do?
Elevate the larynx
47
What (as a general rule) do the infrahyoid muscles do?
Depress the larynx
48
What are the intrinsic muscles of the larynx?
```
Cricothyroid
Thyroarytenoid
Posterior cricoarytenoid
Lateral cricoarytenoid
Transverse and oblique arytenoids
```
49
What does the cricothyroid muscle do?
Stretches and tenses the vocal ligament
50
What does the thyroarytenoid muscle do?
Relaxes the vocal ligament
51
What does the posterior cricoaryntenoid muscle do?
Abducts the vocal folds
52
What does the lateral cricoarytenoid muscle do?
Adducts the vocal folds
53
What do the transverse and oblique arytenoids do?
Adduct the arytenoid cartilages
54
What vertebra does the larynx span?
C3-C6
55
What are the three divisions of the larynx?
Supra glottis
Glottis
Subglottis
56
What is the location of the supraglottis?
Inferior surface of epiglottis to vestibular folds
57
What is the location of the glottis?
Below vestibular folds and contains vocal cords and 1 cm below
58
What is the location of the subglottis?
Inferior border of the glottis to the inferior border of the cricoid cartilage
59
What is the space between the vocal cords called?
Rima glottidis
60
What is the arterial supply to the larynx?
Superior laryngeal and inferior laryngeal arteries
61
What is the superior laryngeal artery a branch of?
Superior thyroid artery
62
What is the inferior laryngeal artery a branch of?
Inferior thyroid artery
63
Where does the superior laryngeal vein drain to?
Internal jugualr vein via the superior thyroid vein
64
Where does the inferior laryngeal vein drain?
To the left brachiocephalic vein via the inferior thyroid vein
65
What provides sensory innervation to the infraglottis?
Recurrent laryngeal nerve
66
What supplies sensory innervation to the supraglottis?
Internal branch of the superior laryngeal nerve
67
What innervates the internal muscles of the larynx?
Recurrent laryngeal nerve (except cricothyroid)
68
What innervates the cricothyroid muscle?
External branch of the superior laryngeal nerve
69
What is the thyroid gland composed of in terms of structures?
Two lobes
| An isthmus connecting the two lobes
70
Where would the pyramidal lobe be located if it is present?
As an upwards projection from the isthmus
71
What is the arterial supply of the thyroid gland?
Superior and inferior thyroid arteries
72
What additional artery can be present to supply the thyroid gland?
Thyoidea ima
73
What is the superior thyroid artery a branch of?
External carotid artery
74
What is the inferior thyroid artery a branch of?
Thyrocervical trunk - a branch of the subclavian artery
75
Where can the thyroidea ima arise from?
Brachiocephalic artery or arch of the aorta
76
What are the veins that drain the thyroid artery?
Superior, middle and inferior thyroid veins
77
Where does the superior thyroid vein drain?
Into the internal jugular vein
78
Where does the middle thyroid vein drain?
Internal jugular vein
79
Where does the inferior thyroid vein drain?
Brachiocephalic vein
80
What are the main hormones produced by the thyroid gland?
Thyroxine (T4)
Triiodothyronine (T3)
Calcentonin
81
What cells in the thyroid gland produce calcetonin?
C-cells (aka Parafollicular cells)
82
What vertebra does the thyroid gland span?
C5-T1
83
Why is the thyroid gland so highly vascularised?
It secretes its hormones directly into the blood, a good vasuclar supply means the hormones can be quickly flushed from the gland and be taken around the body
84
What is the first stage of swallowing? is it voluntary?
It is a volutary process.
The bolus of food is pushed to the roof of the mouth and then backwards by he tongue against the hard palate.
This involves the styloglossus muscle
85
What is the second stage in swallowing? is it voluntary?
It is involuntary.
The soft palate elevates (contraction of the palatoparyngeus) and the posterior wall of the pharynx moves forward (contraction of superior constrictor).
The larynx is then elevated causing the epiglottis to shut off the larynx (contraction of stylopharyngeus, salpingopharyngeus, thyrohyoid & palatopharyngeus)
86
What is the third stage of swallowing? is it voluntary?
It is involuntary.
The bolus of food moves down over the epiglottis into the oesophagus through successive constriction of the constrictor muscles.
87
Where does the azygous vein drain into?
Superior vena cava
88
What does the accessory hemiazygous vein drain?
Superior left hemithorax
89
What does the hemiazygous vein drain?
9th-11th posterior intercostal veins and left subcostal vein (plus some oesophageal veins)
90
What are the three groups of ribs?
True ribs
False ribs
Floating ribs
91
How many true ribs are there? Which ones?
7 (1-7)
92
How many false ribs are there? Which ones?
3 (8-10)
93
How many floating ribs are there? Which ones?
2 (11 and 12)
94
What is the angle of louis?
AKA sternal angle
Formed between the junction of the manubrium and the body of the sternum
95
What is the midsternal line?
A line running down the middle of the sternum
96
What is the midclavicular line?
A line running fro the midpoint of the clavicle.
This is also described as: midway between the jugular notch and the acromioclavicular joint.
97
What is the lateral sternal line?
A line running along the sternal margin
98
What is the midaxillary line?
A vertical line from the apex of the axilla
99
What is the scapula line?
A vertical line running from the inferior angle of the scapula
100
At what level does the trachea bifurcate?
T4/T5
101
At what level does the arch of the aorta end?
T4/T5
102
At what level is the horizontal fissure of the right lung?
4th intercostal cartilage
103
At what level is the oblique fissue of both lungs found?
6th rib anteriorly up to 4th rib at the back
104
How many bronchi are there?
10 on each side
105
How many terminal brochioles are there?
Approx. 40 million
106
How many alveoli are there>
Approx. 300 million
107
What are the fissures of the right lung?
Horizontal
| Oblique
108
What are the fissures of the left lung?
Oblique - theres only one
109
What is the arterial supply to the lungs?
```
Bronchial artery (arises from thoracic aorta)
2 Pulmonary arteries (from right ventricle)
```
110
What is the venous drainage of the lungs?
```
Bronchial veins (drain to azygous vein)
4 Pulmonary veins (drain to left atrium)
```
111
What is the pleura called that lines the internal chest wall?
Parietal
112
What is the pleura called that lines the lungs?
Visceral
113
What are the five embryonic stages of lung formation?
```
Embryonic
Pseudoglandular
Canalicular
Terminal sac
Alveolar
```
114
What happens in the embryonic stage of lung development? when is it?
0-5 weeks.
1) Trachea and secondary (lobar) buds form
2) Right and left lungs begin to develop with left and right bronchi
115
What happens in the pseudoglandular stage of lung development? when does it occur?
5-16 weeks
| Branching occurs to form terminal bronchioles
116
What happens in the canalicular stage of lung development? when does it occur?
16-26 weeks
1) Each terminal bronchiole divides into two or more respiratory bronchioles
2) each respiratory bronchiole divides into 3-6 alveolar ducts
117
What happens in the terminal sac stage of lung development? when does it occur?
26 weeks-birth
Terminal sacs (primative alveoli) form and capillaries establish close contact
118
What happens in the alveolar stage of lung development? when does it occur?
8 months- childhood
1) Alveoli mature
2) Endothelial (capillary) contacts are developed
119
Where does the respiratory diverticulum arise from?
The anterior of the foregut
120
What is the difference in vasoconstrictors and dilators for the systemmic and pulmonary blood vessels?
Systemic:
Oxygen - Vasoconstrictor
CO2 - Vasodilator
Pulmonary:
Oxygen - Vasodilator
CO2 - Vasoconstrictor
121
Briefly describe the events following the first breath
1) Fluid removed form lungs
2) Adrenaline released - increases surfactant production
3) Air inhaled - oxygen causes pulmonary vessels to dilate and umbilical cord arteries and ductus arteriosis to constrict
4) Decreased in pulmonary pressure occurs - pressure in left atrium exceeds right
5 Pressure change = closing of foramen ovale by fusion of septum primum and secundum
122
When does the ductus venosus close?
Within the first week after birth
123
What does LaPlace's law state?
The larger the vessel radius the larger the wall tension required to withstand the given internal fluid pressure.
This means that if one alveoli was larger than another it would get larger and the small one would get smaller
124
What is the role of surfactant?
1) Removes surface tension
2) allows homogenous aeration
3) Stops alveoli collapsing - maintains residual capacity
125
What can surfactant deficiency lead to?
1) Respiratory distress syndrome
2) Loss of lung volume
3) Non-compliant lungs
4) Uneven aeration
126
What can increase surfactant production?
1) Distention of alveoli
2) Steroids
3) Adrenaline
127
What epithelium lines the nose?
Start of nose - keratinising and non-keratinising squamous epithelium
Rest of nose - Respiratory epithelium
128
Where is the olfactory part of the nose?
Roof of the nasal cavity and extends down the septum
129
What part of the airways does not have cartilagenous rings?
Bronchioles
130
What part of the airways is not lined by respiratory epithelium?
Bronchioles
131
What epithelium lines the bronchioles?
Ciliated columnar epithelium
132
What cells are present in the bronchioles and not in the rest of the airways?
Clara cells
133
What is the function of clara cells?
It is relatively unknown
134
What two cells are the alveoli made up of?
Type I and type II pneumocytes
135
Which out of type I and type II pneumocytes have the greatest number?
Type II (60%)
| type I - 40%
136
Which out of type I and type II pneuomcytes have the majority of the surface area?
```
Type I (90%)
Type II (10%)
```
137
What are the 7 layers of gas diffusion?
1) Type I pneumocyte
2) Type I pneumocyte cytoplasm
3) Type I pnumocyte cell membrane
4) Basement membrane (Type IV collagen)
5) Endothelial cell membrane
6) Endothelial cytoplasm
7) Endothelial cell membrane
138
What is the thickness of air-blood barrier?
200-800nm
139
What does the intersitium of the alveoli?
```
Collagen
Elastic fibers
Fibroblasts
Macrophages
Pores of Kohn
```
140
What is dead space?
The volume of the parts of the lungs where gas exchange is not taking place
141
What is the volume of dead space in the lungs?
175mls:
| 150mls anatomic, 35mls alveolar
142
What does perfusion depend on?
Pulmonary artery pressure
Pulmonary venous pressure
Alveoli pressure
143
What does the V and the Q stand for in V/Q ratio?
V - Ventilation
| Q - Perfusion
144
Where is the V/Q ratio lowest?
Base of the lung
145
What is an area with perfusion but no ventialtion called?
Shunt
146
What is an area with ventilation but no perfusion called?
Dead space
147
What is a cause for a low V/Q ratio?
Pulmonary oedema
148
What is a cause for a high V/Q ratio?
Pulmonary embolism
149
What is type 1 hypersensitivity called?
Intermediate/anaphylatic
150
What is type 2 hypersensitivity called?
Antigen dependent/cytotoxic
151
What is type 3 hypersensitivity called?
Immune complex
152
What is type 4 hypersensitivity called?
Delayed type/cell mediated
153
What happens in type 1 hypersensitivity?
Antigens interact with IgE bound to mast cells - leads to histamine release
e.g. Eczema, hayfever
154
What happens in type 2 hypersensitivity?
IgM/IgG bind to foreign antigens
| e.g. Haemolytic anaemia (RBC mistaken for antigen)
155
What happens in type 3 hypersensitivity?
Immune complexes form from antibodies (mainly IgG) and these target and get deposited in organs
e.g. rheumatoid arthritis
156
What happens in type 4 hypersensitivity?
T-lymphocytes interact with antigens, t-helpers release cytokines which activate T-killer cells and recruit macrophages that cause damage
e.g. Tuberculosis, contact dermatitis
157
What are the two main effects of histamine release in an immune response?
1) Vasodilation
| 2) Bronchoconstriction
158
What is type I respiratory failure?
This is where oxygen levels are low (hypoxia) but carbon dioxide levels are normal or slightly low.
O2 =
159
What is type II respiratory failure?
Where oxygen levels are low (hypoxia) and carbon dioxide levels are high (hypercapnia).
O2 = 50mmHg
160
What is the common causes of type I respiratory failure?
```
Pneumonia
Pulmonary embolism
Pulmonary oedema
Pulmonary hypertension
COPD
```
161
What is the most common cause of type II respiratory failure?
Drug overdose
162
What affect does the parasympathetic innervation have on the lungs?
1) Vasodilation
| 2) Bronchoconstriction
163
What affect does the sympathetic innervation have on the lungs?
1) Vasoconstriction
Note: There is little or no effect on the smooth muscle of the airways
164
What are nicotinic receptors?
1) Cholinergic - acetylcholine receptors
2) Receptor that signals for muscle contraction
3) Form ligand-gated ion channels pre and post synaptic membrane of neuromuscular junction
165
What are muscarinic receptors?
1) Cholinergic - acetylcholine receptors
2) Located in cell membrane of certain neurones and other cells
3) Main role is main end receptor in parasympathetic nervous system
166
Why are nicotinic receptors named the way they arre?
They are sensitive to nicotine - are opened by it
167
Why are muscarinic receptors named the way they are?
They are more sensitive to muscarine than to nicotine
168
What is the definition of a neurotransmitter?
A chemical substance that is released by the end of a nerve fiber by the arrival of a nerve impulse, and by diffusing across the synapse, it effects the transfer of the impulse to another nerve fibre, muscle fibre or some other structure
169
What is the definition of an autacoid?
A biological factor which acts like a local hormone, has brief duration and acts near the site of synthesis
170
What is the definition of a hormone?
A regulatory substance that is produced in an organism and transported in tissue fluids such as blood to stimulate specific cells of tissues into action
171
What are the three main types of receptors?
1) G-protein coupled
2) Ligand-gated channels
3) Nuclear
172
What is the function of G-protein coupled receptors?
They are able to sense a molecule outside the cell and activate a process within the cell (signal transduction)
173
What is the function of ligand-gated channels?
They are involved in synaptic signalling. The binding of hormones or neurotransmitters allows passage of ions, changing the charge across the memebrane.
174
What is the function of nuclear receptors?
These are ligand-regulated transcription factors that are activated by steroid hormones
175
What are the two types of receptor ligand?
1) Agonist
| 2) Antagonist
176
How is it determined whether a molecule is an agonist or antagonist?
By:
1) Affinity
2) Efficacy
177
What does affinity mean?
How well a ligand binds
178
What does efficacy mean?
How well a ligand activates a receptor
179
If a ligand has a high efficacy what is it?
High efficacy AGONIST
180
If a ligand has a low efficacy what is it?
Low efficacy AGONIST
181
If a ligand has no efficacy what is it?
ANTAGONIST
182
What neurotransmitter is used by the parasympathetic nervous system in the lungs? whats the receptor? whats the effect?
Acetylcholine
M3 receptor
Bronchoconstriction
183
What neurotransmitter is used by the sympathetic nervous system in the lungs? what is the receptor? what is its effect?
Noradrenaline
Beta-2
Bronchodilation
184
Where does the nasolacrimal duct drain into?
Inferior meatus
185
What is the bifurcation of the trachea called?
Carina
186
What is the role of typeI pneumocytes?
Pavement cells
187
What is the role of type II pneumocytes?
Surfactant production
188
What epithelial defence mechanisms do the lungs have?
1) antiproteinases
2) anti-fungal peptides
3) anti-microbal peptides
4) surfactant - opsonize pathogens
189
What does opsonize mean?
Make (pathogens) more susceptible to phagocytosis
190
Is coughing voluntary or reflexive?
Both
191
What afferent pathways are involved in coughing?
Trigeminal
Glossopharyngeal
Superior laryngeal nerve
Vagus nerve
192
What efferent pathways are involved in coughing?
Recurrent laryngeal nerve
| Spinal nerves
193
What is meant by plasticity in terms of epithelium?
This is where the epithelium has the ability to repair itself and change its phenotype in response to damage e.g. in response to viral infections
194
Whoa is meant by extrinsic asthma?
Asthma caused by response to an inhaled antigen
195
What is meant by intrinsic asthma?
Asthma that is caused by a non-immune mechanism e.g. cold, exercise or aspirin
196
What is asthma?
A chronic inflammatory disorder characterized by hyperactive airways leading to episodic reversible bronchoconstriction
197
What are the macrophages found in the lungs?
Alveolar macrophages
198
What does PAMPs stand for?
Pathogen-associated molecular patterns
199
What does DAMPs stand for?
Damage-associated molecular patterns
200
What are TLRs?
Toll-like receptors: They a receptors on macrophages and dendritic cells - they recognise molecules derived from microbes
201
What are NLRs?
NOD-like receptos: These co=operate with TLRs and help regulate the immune system - they are found on macrophages, lymphocytes and dendritic cells as well as non-immune cells
202
What is the structure of an antibody?
Composed of four polypeptide chains - two heavy chains and two light chains joined together in a Y shape.
The amino acids at the tips of the Y vary greatly and this gives them their specificity
203
What is atopy?
Inherited tendency to have an exaggerated IgE response to an antigen - 25% have it, only half develop atopic disease.
204
Where is the Inspiratory center located?
Dorsal portion of the medulla
205
Where is the expiratory center located?
Antero-lateral part of the medulla
206
Where is the pneumotaxic center located?
Upper pons
207
Where is the Apneustic center located?
Lower part of pons
208
What is the function of the pneumotaxic center?
Controls both rate and pattern of breathing, inhibits inspiration
209
What is the function of the apneustic center?
1) it sends stimulatory impulses to the inspiratory center causing inspiration
2) It receives inhibitory impulses from the pneumotaxic center and from stretch receptors in the lung
3) It discharges inhibatory impulses to the expiratory center
210
What are J receptors?
They are receptors innervated by the vagus nerve that lead to increased ventilation
211
What are the two types of stretch receptors in the lungs?
SASR - Slow adapting strecth receptors
| RASR - Rapid adapting stretch receptors
212
List the structural and functional changes that occur to the lungs in old age?
1) Decreased chest wall compliance
2) Decreased respiratory muscle strength
3) Decreased elastic recoil
4) Decreased response to hypercapnia and hypoxia
5) Impaired gas exchange
6) Decreased immune system function
213
How does the chest wall change in old age?
1) Increased Kyphosis - Curvature of the spine
| 2) Costal cartilage calcification and stiffness
214
What happens to skeletal muscles in old age (this includes the intercostal muscles)?
1) Reduction in type IIA (fast - fatigue resistant) muscle fibres
2) Decrease in muscle mass
3) Denervation of type II fibres
215
What happens to the lung parenchyma in old age?
1) increased cross-linking of collagen and elastin fibers
| 2) Degeneration and rupture of
216
What happens to gas exchange in old age?
1) Ventilation perfusion mismatch increases
2) Reduction in alveolar surface area
3) Reduced lung capillaries and blood flow
217
Why is their impaired immunity in old age?
1) Decrease in glandular epithelial cells - less protective mucus
2) Decreased septum clearance
3) Small airways collapse
4) Immunosenescence - Natural deterioration in the immune system with age
218
What are the reasons for underdiagnosis of respiratory disease in older patients?
1) Patient-related reasons: Less physically active, different perceptions of breathlessness
2) Physican-related reasons: Co-morbidity may mask symptoms, broader differential diagnosis, heard to reach groups
219
What is the normal response to increased altitude by the lungs?
1) Hyperventilation - due to hypoxia
2) Lowered PaCO2
3) Initial alkalosis
4) Tachycardia
5) Renal compensation for alkalosis
220
What is the alveolar gas equation?
PAO2 = PiO2 - PaCO2/R
```
A = alveolar
a = arterial
R = 0.8 (normal diet)
```
221
What does PiO2 stand for?
Pressure of inspired oxygen
222
What does FiO2 stand for?
Fraction of inspired oxygen
223
What is the usual FiO2?
0.21
224
What is V'A?
Alveolar ventilation
225
What is V'CO2
CO2 production
226
What does ATA stand for?
Atmosphere absolute
227
What does MSW stand for?
Metres of sea water
228
What is 1 bar in atmosphere absolute?
1 atmosphere absolute
229
What is 1 bar in metres of sea water?
10 metres of sea water
230
How do you calculate volume of lungs at depth?
P1 V1 = P2 V2
231
If total lung capacity is 8 litres at the surface what is the volume at 160m?
470mls
P1 V1 = P2 V2
1 x 8 = 17 x V2
V2 = 8/17 = 0.470
Pressure is 17 as it increases by 1 for every 10m
232
What is boyle's law?
At a constant temperature and pressure the absolute pressure of a fixed mass of gas is inversely proportional to its volume
233
What is Henry's Law?
The amount of a gas dissolved in a liquid at a given temperature is directly proportional to the partial pressure of the gas
234
what is the negative effect of Henry's law in diving?
Proportionally more gas dissolves in the bodys tissues at depth.
If you ascend to fast the body is unable to clear the gas and bubbles form in the tissues - decompression illness
235
What is Dalton's law?
Total pressure exerted by a mixture of gases equals the sum of the pressures that would be exerted by each of the individual gases if they were alone and occupied the same volume
236
What are the effects of oxygen toxicity?
```
Common final (and first sign) is convulsion
Vision - tunnel vision
Ears - tinitus
Nausea
Twitching
Irritability
Dizziness
```
Remember: conVENTID
237
How is total lung capacity calculated?
Vital capacity + residual volume
238
What is the difference between residual volume and functional residual capacity?
Residual volume is the volume left in the lungs following full expiration
Functional residual volume is the volume left in the lungs after a normal breath
