Respiratory System Part 2 Flashcards
learn the respiratory system
1
Q
What are the two phases of pulmonary ventilation?
A
Inspiration and Expiration
2
Q
Inspiration
A
air flows into lungs
3
Q
Expiration
A
air exits the lungs
4
Q
The direction of air flow is determined by the________
A
relationship of atmospheric pressure and pressure inside the respiratory alveoli
5
Q
Flow is always from ________ to _________ pressure
A
higher to lower
6
Q
Pressure differential
A
the difference in pressure between two spaces that are occupied by gas independent of whether or not the gas can move between the spaces
7
Q
Pressure gradient between atmosphere and alveoli
A
atm= 760 mmHg
alv press= 758 mmHG
Pressure differential= 2 mmHG
pressure flows from atmosphere into alveoli
8
Q
pressure gradient between alveolar and pleural spaces
A
pressure differential= 4mmHg
No pathway between alveoli and pleural space, so no movement
9
Q
slide 47- respiratory pressures
A
10
Q
Respiratory Pressures are described __________ to atmospheric pressure
A
relative
11
Q
Intrapulmonary pressure (Palv)
A
- pressure in alveoli
- fluctuates with breathing
- always eventually equalizes with atmospheric pressure
12
Q
Intrapleural pressure (Pip)
A
- pressure in pleural cavity
- fluctuates with breathing
- always a negative pressure, (less that Patm and Palv)
13
Q
Transpulmonary Pressure
A
- pressure that keeps lung spaces open (keeps lungs from collapsing)
- the greater the transpulmonary pressure, the larger the lungs will be
13
Q
Lungs will collapse if:
A
- Pip= Palv
or
Pip= Patm - Negative Pip must be maintained to keep lungs inflated
14
Q
Pneumothorax
A
- Air enters the plueral cavity and collapses the lung
- can occur from wound in parietal pleura or the rupture of visceral pleura
- treated by removing air with chest tubes
- when pleurae heal, lung re-inflates
15
Q
Pulmonary Ventilation
A
- Consists of inspiration and expiration
- mechanical process that depends on volume changes in thoracic cavity
16
Q
The determinants of gas pressure
A
amount of gas particles, temperature, volume of space
17
Q
amount of gas particles
A
if the number of gas particles in a given volume increases, pressure increases
18
Q
temperature
A
if temperature increases, pressure increases
19
Q
volume of space
A
if volume increases while all other factors remain the same, pressure decreases
20
Q
Boyle’s Law
A
the pressure of a fixed number of gas molecules is inversely proportional to the volume of the container
21
Q
Resting breathing slide 57
A
22
Q
Active process involving_________ ______
A
inspiratory muscles
23
Q
Action of the diaphragm
A
when dome-shaped diaphragm contracts it move inferiorly and flattens out
24
Action of external intercostal muscles
when external intercostals contract, rib cage is lifted up and out
25
During Inspiration the volume...
- changes result in a drop in pressure in the pleural space (Pip) causing the lungs to expand
- now Palv< Patm
- air flows into lungs, down its pressure gradient, until Palv= P atm
25
Deep Inspirations
forced inspirations can occur during vigorous exercise
- accessory muscles are activated (scalenes, sternocleidomastoid, and pectoralis minor)
26
Quiet expiration is normally a ______ process
passive
26
In expiration>>>
- inspiratory muscles relax, thoracic cavity volume decreases and lungs recoil (elastic properties )
- Palv> Patm so air flows out of lungs down its pressure gradient until the pressure of the alveoli equals atmospheric pressure
26
forced expiration
an active process that uses abdominal muscles as well as internal intercostal muscles
26
Physical factors influencing Pulmonary Ventilation
airway resistance
alveolar surface tension
lung compliance
27
determinants of air flow slide 65
28
friction
major, nonelastic source of resistance to gas flow; occurs in airways
29
Asthma Attack
As airway resistance rises, breathing movements become more strenuous
- severe constriction or obstruction of bronchioles (can prevent life-sustaining ventilation)
- epinephrine relaxes smooth muscle resulting in dilation of bronchioles which reduce air resistance
30
Surface tension
the attraction of liquid molecules to one another at a gas-liquid interface
31
Surfactant
lipid and protein complex that helps reduce surface tension of alveolar fluid
32
What type of cells produce surfactants?
type 2 alveolar cells
33
Infant respiratory distress syndrome
insufficient quantity of surfactant in premature infants that results in the collapse of alveoli after each breath
34
Treatment of Infant respiratory distress syndrome
spraying natural or synthetic surfactant into newborn's air passages
35
Lung Compliance
A measure of the change in lung volume that occurs with a given change in transpulmonary pressure (how much stretch the lung has)
36
Lung compliance is normally high because of...
distensibility of lung tissue and surfactants
37
Higher lung compliance means
it is easier to expand the lungs
38
Compliance can be diminished by:
- nonelastic scar tissue replacing lung tissue (fibrosis)
- reduced production of surfactants
- decreased flexibility of thoracic cage
39
Coughing and sneezing
respiratory system trying to clear irritants from the airways
40
yawn
results from deepest possible breath
41
hiccup
spasm of the diaphragm that causes rapid burst of air through the vocal cords
42
laughing/crying
when emotional states drive the ventilatory pattern
43
Valsalva maneuver
attempt to exhale against a closed airway
44
Ventilatory Volumes can be used to ...
assess respiratory status
45
Respiratory volumes can be combined to calculate ________ _______ which can give information on a person's respiratory status
ventilatory capcities
46
Ventilatory volumes and capacities are usually abnormal in people with __________ ____________
pulmonary disorders
47
spirometer
original, cumbersome clinical tool used to measure patient's ventilatory volumes
48
Tidal volume (TV)
amount of air moved into and out of the lung with each breath
49
inspiratory reserve volume (IRV)
amount of air that can be inspired forcibly beyond the tidal volume (2100-3200 ml)
50
Expiratory reserve volume (ERV)
amount of air that can be forcible expelled from the lungs (1000-1200 ml)
51
Residual volume (RV)
amount of air that always remains in the lungs (needed to keep alveoli open)
52
Inspiratory capacity (IC)
sum of TV + IRV
53
Functoinal residual capacity (FRC)
sum of RV + ERV
54
Vital capacity (VC)
sum of TV + IRV + ERV
55
total lung capacity
sum of all lung volumes ( TV + IRV + ERV + RV)
56
Anatomical dead space
doesn't contribute to gas exchange (consists of air that remains in passageways)
57
Minute Ventilation rate ( MVR)
total amount of gas that flows into or out of respiratory tract in 1 minute
58
Alveolar Ventilation rate (AVR)
flow of gases into and out of alveoli during at a particular time (better indicator of effective ventilation)
59
Alveolar Ventilation takes into account what 3 factors?
TV, dead space, and rate of breathing
60
How is alveolar Ventilation calculated?
frequence (breaths/min)* (TV - dead space)
61
What is alveolar Ventilation affected by?
Only the tidal volume and frequence
62
Significant increases in Alveolar Ventilation are brought about by increasing _____ ______ rather than frequence
tidal volume
63
What kind of breathing can actually decrease Alveolar Ventilation?
rapid, shallow breathing
64
Restrictive pulmonary diseases
reduced TC due to disease (tuberculosis, pneumonia) or exposure to environmental agents (pulmonary fibrosis)
65
What happens to the lungs with restrictive disease?
- lungs become stiff
- more pressure is required to give the same increase in volume
- VC and TLC decline because lung expansion is compromised
66
Obstructive pulmonary disease
increased airway resistance (asthma, emphysema, COPD, bronchitis)
67
What happens with the lungs due to an obstructive pulmonary disease?
- greater pressure is needed to overcome the resistance to flow and the volume of each breath gets smaller
- TLC, RV may increase because of hyperinflation of lungs
68
Dalton's law of partial pressures
total pressure exerted by mixture of gases is equal to sum of pressures exerted by each gas
69
Partial Pressure
- pressure exerted by each gas in mixture
- directly proportional to its percentage in mixture
69
At high altitudes, partial pressure _________, but at lower altitudes, partial pressures _____________ significantly
declines, increases
69
partial pressure equation
partial pressure= total pressure x fraction of Gas
69
Amount of gas that will dissolve depends on its ________
solubility
69
For gas mixtures in contact with liquids:
- each gas will dissolve in the liquid in proportional to its partial pressure
- at equilibrium, partial pressures in the two phases will be equal
70
external respiration
occurs between air in the alveoli and blood in the capillaries
71
how to find amount of gas dissolved in a liquid?
(partial pressure)(solubility coefficient)
72
larger partial pressure changes result from a ......
greater change in gas volumes
73
If a gas has a higher solubility coefficient...
a greater volume will transfer into or out of the liquid
74
Higher solubility coefficients are associated with....
a higher rate of diffusion
75
gas exchange is influenced by:
- partial pressure gradients
- gas solubilities
- thickness of respiratory membrane
- surface area of respiratory membrane
76
Why do alveoli contain less O2 and more CO2 than atmospheric air?
newly inspired air mixes with air that was left in passageways between breaths
77
Gas exchange in the lungs (external respiration)
O2 moves from air to blood
CO2moves from blood to air
78
Gas exchange in the tissues (internal respiration)
O2 moves from blood to tissue
CO2 moves from tissue to blood
79
A steep partial pressure gradient for O2 exists between ______ and _______
lungs and blood
80
in gas exchange, the partial pressure gradient for CO2 is _____ steep, but CO2...
less, still diffuses to equilibrium
81
Study the diagram on slide 15 of last lecture
82
At the body tissues the ______ _______ and ______ ________ are reversed compared to the lung
partial pressures, diffusion gradients
83
Tissue PO2 is always lower than in _______ blood Po2
arterial
84
Tissue PCO2 is always higher than ________ blood PCO2
arterial
85
How is molecular oxygen carried in the blood?
1.5% dissolved in plasma
98.5% is loosely bound to each Fe atom of hemoglobin in RBC's
86
Oxyhemoglobin
hemoglobin- O2 combination
87
Deoxyhemoglobin
hemoglobin that has released O2
88
Each Hb molecule is composed of __________ ____________ ________ each with an iron-containing heme group
four polypeptide chains
89
Hemoglobin
- transports more that 98% of blood's oxygen
90
study the dissociation curves
91
Hypoxia
inadequate O2 deliver to tissues
92
Anemic hypoxia
too few RBCs or abnormal or too little Hb
93
Ischemic hypoxia
impaired or blocked circulation
94
Carbon monoxide poisoning
Hb has 200x greater affinity for carbon monoxide than oxygen
95
How is carbon dioxide transported in the blood?
- 10% is dissolved in plasma as PCO2
- 20% is bound to globin part of hemoglobin
- 70% is transported as bicarbonate ions in plasma
96
carbonic acid-bicarbonate buffer system
helps the blood resist changes in pH
97
Acidosis
pH< 7.35
98
Alkalosis
pH> 7.45
99
How do changes in respiratory rate and depth affect blood pH?
decreased ventilation= increase in CO2 resulting in pH drop
increased ventilation= decrease in CO2, makes pH rise
100
Breathing is initiated by brain centers in the_____ ____
medulla oblongata
101
Respiratory rhythms are regulated by
higher brain centers, chemoreceptors, and other reflexes
102
sensors (control of ventilation)
chemoreceptors that detect chemicals in blood
103
Integrators
respiratory center in the brainstem (neurons in medulla oblongata and pons)
104
Effectors
diaphragm and intercostal muscles that control breathing
105
What is in the medulla oblongata?
consists of inspiratory neurons that drive inspiration and expiratory neurons
106
pons
adjusts length of inspiratory stimulation (activities of medullary rhythmicity center)
107
The inspiratory neurons excite inspiratory muscles via ____________ and ____________ nerves
phrenic and intercostal
108
study slide 34 and beyond
109
