Department of medical physiology 4th week Semester: winter … week.pdf · 2016. 10. 27. ·...

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) 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


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)



• 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)



• 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



• 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

https://s-media-cache-/

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


• 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.


• Expiration

– Quiet breathing• elastic forces

– Heavy breathing• Internal intercostals

• abdominal recti


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


• 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


• 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


Rest

• Intrapulmonary pressure decreases (760 mm Hg)

• Intrapleural pressure

(755 mmHg),

(-5 cm H2O)

Inspiration/Inhalation

• Intrapulmonary pressure decreases (757 mm Hg)


(753 mmHg),

(-7,5 cm H2O)

Expiration/Exhalation

• Intrapulmonary pressure increases (763 mm Hg)


(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


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


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


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)


IRV

ERV

VC

VT

1 L

1 L = 20 rectangles

50 ml = 1rectangle

6 cm = 1 min


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)


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)


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 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


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)


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. 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)


• 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“


• 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

Department of medical physiology 4th week Semester: winter … week.pdf · 2016. 10. 27. ·...

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