Respiration Flashcards
What is the Intra-alveolar (Intrapulmonary) pressure?
It is the pressure of air inside the lung alveoli in relation to the atmospheric pressure.
During inspiration -1, end of inspiration 0
During expiration 1, end of expiration 0
What is the Intrathoracic (intrapleural) pressure?
Pressure of fluid film in thin space between the 2 layers of pleura.
It is always negative, except in valsalva maneuver
Inspiration -6
Expiration -3
What is the tidal volume?
Volume of air expired or inspired during rest (normal breath)
+(Pulmonary minute ventilation)(Respiratory minute volume)= Volume of air expired or inspired during rest per minute
What is Residual volume?
Volume of air remaining in lungs after maximum expiration.
Diagnoses obstructive lung diseases because it increases the RV
What is Vital capacity?
Maximum volume of air expired by maximum expiration after maximum inspiration and it detects the strength of respiratory muscles.
+(Maximum voluntary ventilation)= Maximum volume of air expired by maximum expiration after maximum inspiration per minute.
Total lung capacity=….+….
Vital capacity+Residual volume
What is Forced vital capacity?
Fraction of vital capacity expired in seconds
Give examples of Obstructive lung diseases and their FEV1/FVC?
ABC:
A: Asthma
B:Bronchiectasis, bronchial obliterans
C: COPD, emphysema
+laryngeal malignancy
⬇️FEV1/FVC<80
Give examples of Restrictive lung diseases and their FEV1/FVC?
أي حاجة تأثر على الalveoli
-Lung collapse
-Fibrosing alveolitis
-Pulmonary Edema
-Asbestosis
-ARDS
-Kyphoscoliosis
⬆️FEV1/FVC>_80
What is the surfactant and it’s function?
It is a surface active agent secreted by type 2 pneumocyte and decreases the surface tension so prevents collapse.
What is lung compliance?
Expansibility of lung.
⬇️Compliance in all disease except ⬆️ in emphysema and old age
What is the work of breathing?
Work done only during inspiration (expiration is normally a passive process)
Components:
-Elastic work 65%: work done to overcome the lung elasticity and surface tension
-Non-elastic work 35%: work done to overcome the airway and tissue resistance
All disease ⬆️ work of breathing, but tracheostomy ⬇️ work of breathing
What is the dead space?
Part of the respiratory tract where gas exchange doesn’t take place.
1-Anatomical: air present down to respiratory bronchioles=150ml
2-Alveolar: air present in non-functioning alveoli=0ml
3-Physiological: anatomical+alveolar DS=150ml
What increases the anatomical dead space and how is it measured?
Measured by: Fowler method
Increased by: ⬆️size of subject, ⬆️size of lung, sympathetic as bronchodilators as adrenaline
What increases the physiological dead space and how is it measured?
Measured by: Bohr method
Increased by: hypoventilation as emphysema, hypotension as PE
What is the physical form of oxygen?
Free oxygen dissolved in blood—determines the pressure of oxygen (PO2)
What is the chemical form of oxygen?
Oxygen combined with ferrous in hemoglobin forming oxyhemoglobin—determines oxygen saturation (SO2)
What is meant by shift to right, it’s significance and causes?
-Less O2 bind to Hb (Right, raised, release)
-(⬇️affinity of Hb to O2)=More O2 supply to tissues.
Causes:
⬆️PCO2
⬆️H+ (acidosis)
⬆️2,3 DPG as in anemia
⬆️Temperature
Exercise
Pregnant female
What is meant by shift to left, it’s significance and causes?
-More O2 bind to Hb (left, low, load)
-(⬆️affinity of Hb to O2)=Less O2 supply to tissues.
Causes:
⬇️PCO2
⬇️H+
⬇️Temperature
⬇️2,3 DPG
CO (carboxyhemoglobin)
HBF and Myoglobin
What are the forms of CO2?
-Physical form: Free CO2 dissolved in blood (10%)
-Chemical form:
1-Bicarbonate either NAHCO3 in plasma or KHCO3 in RBCs (60-70%)
2-Carboamino group (COO) either with plasma proteins in plasma or with hemoglobin in RBCs (20-30%)
What are the sites of attachment of CO2 and O2 to the hemoglobin?
O2 binds to the ferrous atom
CO2 binds to amino group of protein
What is the Bohr effect and haldane effect?
-Bohr effect: When CO2 binds to Hb it displaces the O2 and release it to the tissue (put oxygen)
-Haldane effect: When O2 binds to Hb it displaces the CO2 and release it in the lung (hello oxygen)
Where is the peripheral chemoreceptors located and how is it stimulated?
It is located in the aortic and carotid bodies and stimulated by ⬇️arterial PO2, ⬆️H+, ⬆️PCO2
Where is the central chemoreceptors located and how is it stimulated?
Located in the medulla oblongata and stimulated by ⬆️arterial PCO2
