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Department of medical physiology4th week
Semester: winterStudy program: Dental medicineLecture: RNDr. Soňa Grešová, PhD.Department of medical physiologyFaculty of Medicine PJŠU
Department of medical physiology4th, week
1. Meaning and functions of respiratory system
2. Functional morphology of respiratory system
3. Ventilation – mechanisms and determinatingparameters
Basic Atmospheric conditions
• Basic Atmospheric conditions (Dalton´s law)
–Pressure is typically measured in mm Hg
–Atmospheric pressure is 760 mm Hg
–Atmospheric components
–Nitrogen = 78% of our atmosphere
–Oxygen = 21% of our atmosphere
–Carbon Dioxide =0.033% of our atmosphere
–Water vapor, krypton, argon, ….
• With increasing altitude the air pressure decreases, thus the number of components in a given volume
0 m.n.m.= 101kPa(760mmHg) O2= 21% (21kPa)
2000 m.n.m. = 80kPa(605mmHg) O2 = 21% (16kPa, 20mmHg)
8800 m.n.m. =33kPa(255mmHg) O2 = 21% (7kPa, 50mmHg)
1. Meaning and functions of respiratory system
• 1) pulmonary ventilation,
• 2) diffusion of oxygen and carbon dioxide between the alveoli and the blood,
• 3) transport of oxygen and carbon dioxide in the blood and body fluids,
• 4) regulation of ventilation
1. Meaning and functions of respiratory system
External Respiration
Internal Respiration
1. Functions of respiratory passageways
Copyright: Hall, J. E., & Guyton, A. C. (2006). Guyton and Hall textbook of medical physiology. Philadelphia, PA: Saunders Elsevier.
• Functions of the nose• the air is warmed• the air is almost completely humidified• the air is partially filtered
• Vocalization• Phonation
• larynx• Articulation
• lips, tongue, soft palate• Resonance
• mouth, nose, associated nasal sinuses, chest cavity
• Keep the respiratory passageways open and allow easy passage• Trachea (cartilage rings)• The bronchioles and alveoli (Tpl
pressure)
1. Functions of respiratory passageways
Copyright: Hall, J. E., & Guyton, A. C. (2006). Guyton and Hall textbook of medical physiology. Philadelphia, PA: Saunders Elsevier.
• Nervous and local control of the bronchiolar musculature• dilation of the bronchioles
• Sympathetic• NO• VIP• epinephrine
• constriction of the bronchioles• Parasympathetic• Histamine• thromboxane A2
• Substance P (responder to most noxious/extreme stimuli)
• Bradykinin (inflammatory mediator)
• Leukotrienes (inflammatorymediators)
1. Functions of respiratory passageways
Copyright: Hall, J. E., & Guyton, A. C. (2006). Guyton and Hall textbook of medical physiology. Philadelphia, PA: Saunders Elsevier.
• Protection
• Mucus (goblet cells)
• Cilia• to clear the passageways
• the nose and in the lower passages down as far as theterminal bronchioles
• Alveolar macrophages
• Synthesis
• Surfactant (type II alveolar epithelial cells) plays role in protection
1. Functions of respiratory passageways
Copyright: Hall, J. E., & Guyton, A. C. (2006). Guyton and Hall textbook of medical physiology. Philadelphia, PA: Saunders Elsevier.
• Exchange of gases• External respiration
• Surface area 80-100m2
• Perfusion (network of pulmonary capillaries)
• thickness of the respiratory membrane (0,2-0,6 micrometer)
• Internal respiration• Diffusion of oxygen• Diffusion of carbon dioxide
• Regulation of pH• CO2
2. Functional morphology of respiratory system
• The Respiratory Tree– Upper respiratory tract is for all
intensive purposes a single large conductive tube
– The lower respiratory tract starts after the larynx and divides again and again…and again to eventually get to the smallest regions which form the exchange membranes• Trachea• Primary bronchi• Secondary bronchi• Tertiary bronchi• Bronchioles• Terminal bronchioles• Respiratory bronchioles with
start of alveoli outpouches• Alveolar ducts with
outpouchingsof alveoli
conductive portion
exchange portion
https://s-media-cache-ak0.pinimg.com/564x/32/29/0d/32290dd6f40bd6efe5bfdc7e5ac2bfda.jpg
Mechanics of Pulmonary Ventilation
• means the inflow and outflow of air betweenthe atmosphere and the lung alveoli
• Two phases• Inspiration (inhalation) – air in• Expiration (exhalation) – air out
• Mechanical forces cause the movement of air• Gases (from higher pressure to lower)• Inspiration: the atmospheric pressure is higher than
pressure in the thorax
Mechanics of Pulmonary Ventilation
• Inspiration– Quiet breathing
• Diaphragm
– Heavy breathing• External intercostals
muscles (raise the ribcage)
• sternocleidomastoidmuscles (lift upward on the sternum)
• anterior serrati (lift manyof the ribs)
• Scaleni (lift the first tworibs) Copyright: Hall, J. E., & Guyton, A. C. (2006). Guyton and Hall textbook of
medical physiology. Philadelphia, PA: Saunders Elsevier.
Mechanics of Pulmonary Ventilation
• Expiration
– Quiet breathing• elastic forces
– Heavy breathing• Internal intercostals
• abdominal recti
Copyright: Hall, J. E., & Guyton, A. C. (2006). Guyton and Hall textbook of medical physiology. Philadelphia, PA: Saunders Elsevier.
PressuresThat Cause the Movement
• Alveolar Pressure(intraalveolar) PA
– is the pressure of the air inside the lung alveoli
• Pleural Pressure
(intrapleural) Ppl
– is the pressure of the fluid in the thin space between the lung pleura and the chest wall pleura
• Atmospheric pressure
(barometric) PBhttps://www.google.sk/search?q=transrespiratory+pressure&biw=1745&bih=807&source=lnms&tbm=isch&sa=X&sqi=2&ved=0ahUKEwje4JPXzuTPAhXHxxQKHRTUAJQQ_AUIBigB#imgdii=xwe79mEaHxgD8M%3A%3Bxwe79mEaHxgD8M%3A%3BCna-Xahd0h7PaM%3A&imgrc=xwe79mEaHxgD8M%3A
PressuresThat Cause the Movement
• Transmural pressure is the difference in pressure between two sides
• Transpulmonary pressure– difference between the alveolar pressure
and the pleural pressure
(Tpl = PA – Ppl)
• Transthoracic pressure(transchestwall)– difference between the pleural pressure and
the barometric pressure
(TTp= Ppl – PB)
• Transrespiratory pressure– difference between the alveolar pressure
and the barometric pressure
(TRS= PA – PB)
• Transairway pressure– difference between the airway pressure and the
pleural pressure
(TTA= PAW – Ppl)
https://www.google.sk/search?q=transrespiratory+pressure&biw=1745&bih=807&source=lnms&tbm=isch&sa=X&sqi=2&ved=0ahUKEwje4JPXzuTPAhXHxxQKHRTUAJQQ_AUIBigB#imgdii=xwe79mEaHxgD8M%3A%3Bxwe79mEaHxgD8M%3A%3BCna-Xahd0h7PaM%3A&imgrc=xwe79mEaHxgD8M%3A
PressuresThat Cause the Movement
• Pleural pressure
– slightly negative pressure
• Alveolar pressure
– normal inspiration, (decreases to about –1 centimeter of water)
– normal expiration,
(rises to about +1centimeter of water)
• Transpulmonary pressure
– the recoil pressure
Copyright: Hall, J. E., & Guyton, A. C. (2006). Guyton and Hall textbook of medical physiology. Philadelphia, PA: Saunders Elsevier.
Rest
• Intrapulmonary pressure decreases (760 mm Hg)
• Intrapleural pressure
(755 mmHg),
(-5 cm H2O)
Inspiration/Inhalation
• Intrapulmonary pressure decreases (757 mm Hg)
• Intrapleural pressure
(753 mmHg),
(-7,5 cm H2O)
Expiration/Exhalation
• Intrapulmonary pressure increases (763 mm Hg)
• Intrapleural pressure
(events are reversed)
• Forced expiration is active
Copyright: 2008 Thomson Delmar Learning
Compliance of the lungs
• Compliance = distensibility
• Compliance of the Lungs
– elastic properties tend to collapse:• 1) elastic forces of the lung
tissue itself
• 2) elastic forces caused by surface tension of the fluid that lines the inside walls of thealveoli and other lung air spaces
CL=Δ𝑉
Tpl=𝑃
𝐴−𝑃𝑝𝑙
Copyright: Hall, J. E., & Guyton, A. C. (2006). Guyton and Hall textbook of medical physiology. Philadelphia, PA: Saunders Elsevier.
Compliance of the chest wall and respiratory system
• Compliance of the Chest Wall– elastic properties tends to spring
up
CCW=Δ𝑉
TTp=𝑃
𝑝𝑙−𝑃𝐵
• Compliance of the RespiratorySystem– negative intrapleural pressure
opposes the natural tendency of the lungs to collapse and the chestwall to spring out
CRS=Δ𝑉
TRS=𝑃
𝐴−𝑃𝐵
Surface Tension, Collapse of theAlveoli, and Surfactant
Surface Tension
1. Tendency of collaps
2. Unequal alveoli
3. Tendency of edema
P= 2𝑥𝑇
𝑟
Surface Tension, Collapse of theAlveoli, and Surfactant
Surfactant (type II alveolar epithelial cells)
1. Reduce surface tension2. Keep alveoli dry3. Stabilisation size of alveoli
4. Reduce collapsy (P= 2𝑥𝑇
𝑟)
5. Increase compliance6. Decrease work of breathing
Copyright: https://sk.pinterest.com/khdel/mcat/
Respiratory Volumes and capacities• Vt (tidal volume)
• the volume of air inspired or expired with each normal breath (500 ml)
• IRV (inspiratory reserve volume)• the volume of air that can
be inspired over and above the normal tidal volume(3000 ml)
• ERV (expiratory reserve volume)• the maximum extra volume
of air that can be expired byforceful expiration after the end of a normal tidalexpiration (1100 ml)
• RV (residual volume)• the volume of air remaining
in the lungs after the most forceful expiration (1200 ml) Copyright: Hall, J. E., & Guyton, A. C. (2006). Guyton and Hall textbook of
medical physiology. Philadelphia, PA: Saunders Elsevier.
Respiratory Volumes and capacities• IC (inspiratory capacity)
• the tidal volume plus the inspiratory reserve volume(3500 ml)
• FRC (functional residual capacity)• The expiratory reserve volume
plus the residual volume(2300 ml)
• VC (vital capacity)• the inspiratory reserve
volume plus the tidal volume plus the expiratory reservevolume (4600 ml)
• TLC (total lung capacity)• the vital capacity plus the
residual volume (5800 ml)
All pulmonary volumes and capacities are about 20 to 25 per cent less in women than in men Copyright: Hall, J. E., & Guyton, A. C. (2006). Guyton and Hall textbook of
medical physiology. Philadelphia, PA: Saunders Elsevier.
Helium Dilution Method
• Determination of Functional Residual Capacity, ResidualVolume, and Total Lung Capacity– known volume is filled with air mixed with helium at a known
concentration– the end of expiration (FRC)– the subject begins to breathe from the spirometer (mixing the
gases of the lungs = helium is diluted)– Calculation
• FRC=(𝐶𝑖
𝐻𝑒
𝐶𝑓𝐻𝑒
- 1)Vispir
– CiHe is initial concentration of helium in the spirometer, – CfHe is final concentration of helium in the spirometer, – Vispir is initial volume of the spirometer
Copyright: https://o.quizlet.com/FZpR6.tPCZgvmXKSnUiu2Q_m.png
IRV
ERV
VC
VT
1 L
1 L = 20 rectangles
50 ml = 1rectangle
6 cm = 1 min
Static ventilatory values
1. Vt = Tidal volume (500 ml)
2. IRV = Inspiratory Reserve Volume (3000 ml)
3. ERV = Expiratory Reserve Volume (1100 ml)
4. VC = Vital capacity (4600 ml) Vt+IRV+ERV
5. RV = Residual Volume (1200ml)
6. FRC = Functional Residual Capacity (2300ml)
RV+ERV
7. IC = Inspiratory Capacity (3500ml) Vt+IRV
8. TC = Total Capacity (5800mL) RV+IRV+Vt+ERV
Spirography – testing by VOLUTEST
Dynamic ventilatory values
1. RESPIRATORY RATE or FREQUENCY is 12
to16 per minute in normal conditions at rest
2. MINUTE VENTILATION is quality of air
ventilated in one minute (5 to 9 liter per
minute) (volume x respiratory freq. per min)
3. MAXIMAL FORCED VENTILATION is the
maximum ventilation in the unit of time
(VxRR per min)
4. BREATHING RESERVE is relation between
quiet second ventilation and maximal second
ventilation. The breath reserve is very good if
this relation is 1:10
5. FVC (Forced Vital Capacity) is the volume of
air that can forcibly be blown out after full
inspiration, measured in liters (4,7 L)
Spirography – testing by VOLUTEST
IRV
ERV
VC
VT
1 L
1 L = 20 rectangles
50 ml = 1rectangle
6 cm = 1 min
Spirography – testing by VOLUTEST
FET
FEV1
MET
MMEV
25%
75%
FVC
1200 mm = 1 min
100% FVC
1200 mm/min = 20 mm/sec (2cm)
60 mm = 1 min
MF
V (V
xR
R)
Dynamic ventilatory values
6. FVC proper values:
Male FVCp = [28 – (0.11 x age)] x height in cm
Female FVCp = [22 – (0.10 x age)] x height in cm
Pathological values < 70%
7. FEV1 (Forced expiratory volume in 1 second)
is the volume of air forcibly in one second after
maximal inspiration (for 20-29 year old men =
? L)
8. FEV1/FVC ratio (FEV1%) FEV1% is the ratio
of FEV1 to FVC. In healthy adults this should
be approximately 75–80%
9. FET (Forced Expiratory Time) measures the
length of the expiration in seconds (for 20-29
year old men = ? s)
Measured FVC x100
Proper FVC
FET
FEV1
MET
MMEV
25%
75%
FVC
1200 mm = 1 min
100% FVC
1200 mm/min = 20 mm/sec (2cm)
60 mm = 1 min
MF
V (V
xR
R)
Dynamic ventilatory values
8. FVC and FET Relation is the average speed
of the air flow during forced expiration (for
20-29 year old men = ? L.s-1)
9. MMEV maximal (mid-) expiratory volume of
one half of FVC between 25 to 75 %
10.MET (Mid-Expiratory Time) is the time which
is needed for expiration of one half of FVC
between 25 to 75 % (? s)
11.MMEF= maximal (mid-)expiratory flow and
measured in liters per second.
Spirography – testing by VOLUTEST
Spirography – testing by EUTEST
1. FVC (Forced Vital Capacity) is the volume of air that can forcibly be blown out after full inspiration, measured in liters
Proper values:
Male FVCp = [28 – (0.11 x age)] x height in cm
Female FVCp = [22 – (0.10 x age)] x height in cm
Measured FVC x 100Proper FVC
Pathological values < 70%1. FVC
1 2 3
Spirography – testing by EUTEST
2. FEV1 (Forced expiratory volume in 1 second) is the volume of air forcibly in one second after maximal inspiration(for 20-29 year old men = ? L)
3. FEV1/FVC ratio (FEV1%) FEV1% is the ratio of FEV1 to FVC. In healthy adults this should be approximately 75–80%
4. FET (Forced Expiratory Time) measures the length of the expiration in seconds (for 20-29 year old men = ? s)
5. FVC and FET Relation is the average speed of the air flow during forced expiration (for 20-29 year old men = ? L.s-1)
1. FVC
1 2 3
2. FEV1
4. FET (1.8 ± 0.2)
6. MMEV maximal (mid-) expiratory volume of one half of FVC between 25 to 75 %
7. MET (Mid-Expiratory Time) is the time which is needed for expiration of one half of FVC between 25 to 75 % (? s)
Spirography – testing by EUTEST
1. FVC
1 2 3
2. FEV1
4. FET (1.8 ± 0.2)
6. MMEV 25-75%
25%
75%
7. MET 25-75%
8. MMEF or MEF stands for maximal
(mid-)expiratory flow and is the peak of expiratory flow as taken from the flow-volume curve and measured in liters per second.
Obstructive vs Restrictive
• Interstitial – (stiff lung)
• Increased tissue
• Relatively normalFEV1:FVC ratio
Types:
• Acute –ARDS, Viral
• Chronic-pneumoconiosis,sarcoidosis, Int.fibrosis
• Obstructive (soft lung)
• Destruction of tissue
• Low FEV1:VC ratio
Types:
• Localised or Diffuse
• Reversible orprogressive
• COPD
• Asthma
3. Ventilation – mechanisms and determinating parameters
• Factors that affect ventilation :1. Surfactant effect
2. Airway diameter
Upper airways – physical obstruction (mucus and other factors)
Bronchioles:
• Bronchoconstriction
(PSY – muscarinic receptors), histamine, leukotrienes
• Bronchodilatation
(carbon dioxide, epinephrine – β2 receptors)
3. Minute volume respiration (ventilation rate times tidal volume) anatomical dead space
4. Changes in ventilation patterns
3. Ventilation – mechanisms and determinating parameters
3. Minute volume respiration (ventilation rate times tidal volume) anatomical dead space
Minute ventilation:
- the sum of alveolar ventilation and dead space ventilation
(MV = f x Vt)
Alveolar ventilation:
- the volume of air that is exchanged in the alveolar space for 1 minute
VA = (Vt-VD).f (3,5-6,3 l/min)
3. Ventilation – mechanisms and determinating parameters
• Minute ventilation
- it is volume of the inspirated and expirated air per 1minute during quite breathing
• Bradypnea and tachypnea
- change of the minute ventilation by the changed respiratoryrate (decrease and increase)
• Hypopnea and hyperpnea
change of the minute ventilation by the changed tidalvolume (decrease and increase)• Dyspnea- means mental anguish associated with inability to ventilateenough to satisfy the demand for air. Common synonym is „ air hunger“
3. Ventilation – mechanisms and determinating parameters
• Hypoventilation and hyperventilation
- decrease and increase of the ventilation
• Inspiratory and expiratory apnoe
- voluntary stop of the breathing afterinspiration and expiration
• Maximal minute ventilation
- for the determination of the efficiency of therespiratory system