Respiratory phys I & II Flashcards
(63 cards)
1
Q
Respiratory functions / regulated processes
A
- External respiration
- pulmonary ventilation /breathing
- gas exchange in pulmonary capillaries of the lungs - Transport of gases by blood
- Internal respiration
- systemic tissue gas exchange
- cellular respiration - Overall regulation of respiration
2
Q
Pulmonary ventilation/breathing
A
- Inhalation / inspiration
- moves air into the lungs - Expiration / exhalation
- moves air out of the lungs
*air flows form high pressure to low pressure
3
Q
Pic
A
Pic
4
Q
Mechanisms of pulmonary ventilation
A
- pressure gradients are established by changes in the size of the thoracic cavity
- produced buy contraction and relaxation of respiratory mm
- boyle’s Law is important for understanding the pressure changes that occur in the lungs and the oral during the breathing cycle
5
Q
Boyle’s law
A
The pressure of a gas in a closed container is inversely proportional to the volume of the container
6
Q
Inspiration
A
Expansion of the thorax - decreased alveolar pressure - air flows in to lungs
- expansion of the thorax results in decreased alveolar pressure
- air moves into the lungs when alveolar pressure drops below atmospheric pressure
- atmospheric = 760 mmHg
- alveolar = 758 mmHg
7
Q
Inspiration
A
- contraction of the diaphragm
- quiet respiration: diaphragm descends about 1 cm producing pressure difference of 1-3 mmHg
- strenuous breathing: diaphragm can descend up to 10 cm producing a pressure difference of 100 mmHg
8
Q
Pic
A
Pic
9
Q
Pic
A
Pic
10
Q
Quiet expiration
A
- a passive process that begins when inspriatory mm are relaxed, decreasing the size of the the thorax
- no active mm involvement
11
Q
Expiration
A
- decreasing thoracic volume increases alveolar pressure above atmoshpheric pressure and air moves out of lungs
- air moves out of the lungs when alveolar pressure exceeds atmospheric pressure
- atmospheric = 760mmHg
- alveolar = 761mmHg
12
Q
Elastic recoil
A
Tendency of pulmonary tissuese to return to a smaller size after having been stretched during inspiration
13
Q
Pic
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Pic
14
Q
Compliance
A
How much effort is required to stretch the lungs and chest wall
- high = lungs and chest wall expand easily
- low = lungs and chest wall resist expansion
- factors include elasticity and surface tension
15
Q
Airway resistance
A
- Normal inspiration
- bronchioles enlarge because their walls are pulled outward in all directions
- decreased resistance - Normal exhalation
- bronchioles return to resting diameter with elastic recoil of lungs
- increased resistance
16
Q
Inspiration mm
A
- Diaphragm
- External intercostals
- Muscles that aid in forced inspiration:
- scalenes - SCM - trapezius - pec min - pec major
17
Q
Forced exhalation mm
A
- Internal intercostals
- rectus abdominis - external oblique - internal oblique - transverse abdominis
18
Q
Pulmonary volumes
A
The amounts of air moved in and out of the lungs and remaining in them are important to the normal exchange of O2 and CO2
19
Q
Spirometer
A
Instrument used to measure volume of air exchanged in breathing
20
Q
Tidal volume
A
Amount of air inhaled and exhaled in normal breathing
21
Q
Inspriatory reserve volume
A
When you take a deep breath, more than 500mL of air is inhaled
- this additional air is the inspriatory resever volume
22
Q
Expiratory reserve volume
A
Amoun of air that can be exhaled after normal exhalation (approx. 1200 mL in men and 700mL in women)
23
Q
Residual volume
A
Amount of air that cannot be forcible exhaled
24
Q
Chart
A
Chart
25
Pulmonary capacities
Measuring lung capacities helps monitor the response of treatment and progression of respiratory disease
- lung capacity dependent on the lungs ability to get air in = inspiration
- things that affect lung volumes:
1. Chest wall deformities (scoliosis, kyphosis)
2. Neuromuscular disorders (Lou Gehrig’s, quadriplegia)
3. Pleural disease (fluid in pleural space)
26
Vital capacity
Represents the largest volume of air an individual can move in and out of the lungs
VC = TV + IRV + ERV
27
Inspiration capacity
Maximal amount of air an individual can insprire after a normal expiration
IC = TV + IRV
28
Functional residual capacity
The amount of air in lungs at the end of normal expiration (no contraction of expiratory mm)
FRC = ERV + RV
29
Total lung capacity
Total volume of air a lung can hold
TLC = VC + RV
30
Chart
Chart
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Forced expiratory volume
FEV1
| Volume of air blown out in the 1st second of forced expiration
32
Forced vital capacity
FVC
| Vital capacity measured during a forced expiration
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Chart
Chart
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Obstructive lung disease
Diseases that affect the airways themselves, causing an airflow limitation or an airflow obstruction
- bronchitis
- emphysema
- COPD
- asthma
35
Chart
Chart
36
Alveolar ventilation
- the volume of inspired air that reaches the alveoli
- only this volume of air takes part in the exchange of gases between air and blood = gas exchange only occurs in the alveoli
- alveoli must be properly ventilated for adequate gas exchange
37
Alveolar dysventilation
- anatomical dead space: air in passageways that do not participate in gas exchange (trachea, bronchi)
- physiological dead space: anatomical dead space plus the volume of any non functioning alveoli (pulmonary disease)
38
Treatments to increase alveolar ventilation
- diaphragmatic breathing
- mobilization = exercise
- aiding clearance of secretions (CPT, postural drainage)
- positive pressure assistance: prevent collapse of alveoli during ventilation (mainly during expiration)
39
Pulmonary gas exchange (external respiration)
Partial pressure of gas
- pressure exerted by one gas in a relative mixture of gases or in a liquid
- nitrogen (PN2) 78%
- oxygen (PO2) 21%
- carbon dioxide (PCO2) 0.03%
- other gases (P) 0.97%
- total atmospheric pressure = 100%
- partial pressure of a gas is directly related to the relative concentration of the gas in the mixture
- gases will diffuse down their concentration gradient from an area of high concentration to low concentration
40
Pic
Pic
41
Four main factors
Determine the amount of oxygen that diffuses into blood
1. The oxygen pressure gradient between alveolar air and incoming pulmonary blood
2. The total functional surface area of the respiratory membrane
3. The respirarte minute volume (respiratory rate per minute X volume of air inspired per respiration)
4. Alveolar ventilation
42
Oxygen pressure gradient
The oxygen pressure gradient between alveolar air and incoming pulmonary blood
- anything that lowers alveolar PO2 will decrease the pressure gradient
- PO2 sea level = 159 mmHg
- PO2 7000ft = 124 mmHg
- PO2 10,000ft = 110mmHg
43
Total functional surface area of respiratory membrane
Anything that decreases the number alveoli available for gas exchange will decrease functional surface area.
- emphysema (alveoli collapse); lung cancer; lobectomies
44
Respiratory minute volume
Total volume of air inhaled and exhaled each minute
- RR/min X TV = MV
- anything that decreases respiratory rate or volume inspired per minute will decrease minute volume
- drugs that depress respiratory rate (morphine, sedatives, narcotics)
45
Alveolar ventilation
Decreased exchange of gases related to obstruction
- preventing inspired air form getting to the alveoli
- foreign body, secretions, disease
46
Structural factors that facilitate O2 diffusion from alveolar air to blood
- walls of the alveoli and capillaries form only a very thin barrier for gases to cross
- alveolar and capillary surfaces are large
- blood is distributed through the capillaries in a thin layer so each red blood cell comes in close contact to alveolar air
47
Summary
- the exchange takes place between alveolar air and blood flowing through lung capillaries
- gases move in both directions through the respiratory membrane
- this two way exchange of gases between alveolar air and pulmonary blood converts deoxygenated blood to oxygenated blood
48
How blood transports gases
- O2 and CO2 are transported as solutes and as parts of molecules of certain chemical compounds
- immediately upon entering the blood, both O2 and CO2 dissolve in the plasma
- most of the O2 and CO2 molecules form a chemical union with some other molecule: such as hemoglobin
49
Hemoglobin
- a reddish protein pigment found only inside red blood cells
- made up of four polypeptide chains each with an iron-containing heme group
- an iron atom is the binding agent for oxygen on the hemoglobin molecule
- as hemoglobin has 4 binding heme groups, it can transport up to 4 atoms of oxygen
- CO2 binds to amino acid chains on hemoglobin
50
O2 transport
- oxygenated blood contains about 0.3mL of dissolved oxygen / 100mL of blood
- hemoglobin increases the oxygen-carrying capacity of blood
- the exact amount of O2 in the blood depends mainly on the amount of hemoglobin present
- blood that contains more hemoglobin can transport more oxygen
- to combine with hemoglobin, oxygen must diffuse from plasma into the red blood cells where hemoglobin molecules are located
51
O2 traveling forms
1. As dissolved O2 in plasma (0.3/100mL)
| 2. As O2 associated with hemoglobin (oxyhemoglobin)
52
O2 - Hb dissociation curve
- an illustration of the rate at which hemoglobin combines with oxygen in lung capillaries
- increasing blood PO2 accelerates hemoglobin association with oxygen (concentration gradient)
- oxyhemoglobin carries the majority of the total oxygen transported by blood
53
Pic
Pic
54
Pulse oximetry
- small, hand-held device that measure the color of blood in a superficial capillary bed (flails, earlobe)
- the device gives an indirect reading of the oxygen saturation of the blood
55
Transport of CO2
- carried in the blood similarly to oxygen
- a small amount of CO2 is dissolved in plasma
- about 20% of CO2 combines with NH2 (amine) groups of hemoglobin = carbamino compounds)
- CO2 association with hemoglobin is accelerated by an increase in blood PCO2
- down concentration gradient
- most CO2 (about 60%) is carried in plasma as bicarbonate ions
- an increase in carbon dioxide in the blood causes an increase in the acidity, or a drop in pH in the blood
56
Pic
Pic
57
Systemic gas exchange
- exchange of gases in tissues takes place between blood flowing through tissue capillaries and tissue cells
- this occurs because of pressure gradients for both oxygen and carbon dioxide
- oxygen diffuses out of arterial blood into cells and carbon dioxide diffuses from cells into venous blood
58
Pic
Pic
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Regulation of pulmonary function
- mechanisms operate to maintain relative constancy of the blood PO2 and PCO2
- homeostasis of blood gases is maintained primarily by means of changes in ventilation: rate and depth of breathing
- the main integrators are located within the brainstem, carotid bodies, and the aorta
60
Respiratory center
Several mechanisms help match breathing effort to metabolic demand
- respiratory center is divided into 2 parts
1. Medullary respiratory center
2. Pontine respiratory group
61
Factors that influence breathing
Basic breathing rhythm can be altered by different inputs to the medulla and pons
- input form the pons helps to regulate breathing rhythm (inspiration and expiration)
- input form the cerebral cortex can override subconscious control of breathing - intentional deep breath, etc
- input form chemoreceptors within the medulla are sensitive to PCO2 and pH
- feedback info to the medulla is also brough in from other control centers
- peripheral chemoreceptors in the carotid bodies and aorta
- sensitive to changes in PCO2 and pH
1. Increase in PCO2 = faster breathing
2. Decrease in PCO2 = slower breathing
62
Drive to breathe
1. CO2 levels whether low or high
2. More chemoreceptors in the body for CO2
3. Concentration gradients are typically held in a narrow range
4. More mechanisms to transport CO2
63
Ventilation and perfusion
- alveolar ventilation: air flow to the alveoli
- alveolar perfusion: blood flow to the alveoli
- matching ventilation and perfusion is important for efficient gas exchange in the lungs
