Respiratory System I Flashcards
There are 4 primary functions of the respiratory system:
1. Exchange of gases between the _____ and the ____
2. ______ regulation of body pH
3. Protection from inhaled ______ and _____ ______
4. ______
- atmosphere, blood
- Homeostatic
- pathogens, irritating substances
- Vocalization
Air exchange occurs by ____ ____ and follows many of the principles that govern the CV system
bulk flow
Air exchange occurs by bulk flow and follows principles:
i. Flow occurs from region of ____pressure to ___ pressure
ii. ______ ____ creates the pressure gradients
iii. Resistance is primarily influenced by _____ of tubes through which air is flowing
i. high, low
ii. Muscular pump
iii. diameter
What is external respiration?
The movement of gases between the environment and the cells within the body.
External respiration requires coordination between the ______ and ______ systems
respiratory, cardiovascular
External respiration is a 4 step process: ?
- Exchange I: atmosphere to lung (ventilation)
- Exchange II: lung to blood
- Transport of gases in the blood
- Exchange III: blood to cells
What are the 3 main structures involved in ventilation and gas exchange?
- Conducting system or airways
- Alveoli
- The bones and muscles of the thorax (chest cavity)
What are the 4 structures considered as the Upper respiratory system?
Nasal cavity
Mouth
Pharynx
Larynx
What are the 2 structures considered as the Lower respiratory system?
Trachea and lungs
The lungs are composed of light spongy tissue whose volume is occupied mostly by ____-filled spaces
air
The _____ lung is slightly larger than ____ due to the _____ ____
right, left, cardiac notch
The ____ lung is divided into 3 lobes, and the ____ lung is divided into 2 lobes
right, left
What are the 3 lobes of the right lung?
Superior, middle, inferior
What are the 2 lobes of the left lung?
Superior, inferior
Each lung is surrounded by a double-walled _____ ___
pleural sac
One layer of the pleural sac is connected to the outside surface of the lungs which is called the _____ ____ and the other to the inside surface of the thoracic cavity _____ ____
visceral pleura, parietal pleura
Pleural fluid in the pleural cavity acts like water between two glass panes, where it is very easy to slide against one another, but very difficult to ?
pull apart
What are the 2 main functions of the pleural sac?
- Created a moist slippery surface
- Holds lungs tight to the thoracic wall
______ connect lungs to the external environment
Airways
Air enters the _____ through the nasal cavity and/or mouth, from there air flows through the _____ (vocal cords) to the _____ (wind pipe)
pharynx, larynx, trachea
The trachea is a semi-flexible tube held open with ?
15-20 cartilage rings
Arrange these in order of “branching of the airways:”
smaller bronchi, bronchioles, trachea, alveoli, primary bronchi
Trachea, primary bronchi, smaller bronchi, bronchioles, alveoli
What 3 components of the airway is considered the “conducting system”?
Trachea, primary bronchi, smaller bronchi
What 2 components of the airway is considered the “exchange surface”?
Bronchioles, alveoli
A major difference between bronchi and bronchioles is that bronchi have _____ (either rings or plates the further down you go) but bronchioles have _____ _____ that selectively controls
cartilage, smooth muscle
The upper _____ and _____ play an important role in conditioning air before it reaches the alveoli
airways, bronchi
What are the 3 important roles of conditioning air before it reaches the alveoli?
Warming air to body temperature
Adding water vapor
Filtering out foreign material
These three processes in conditioning air before reaching the alveoli are more efficient with _____ ______
nose breathing
The nasal cavity has a large surface area, has rich blood supply and nasal hair, the ____ of nasal airway tends to cause particles to embed in ____ in the back of the _____ and slide down to the esophagus
shape, mucus, pharynx
Air is filtered in the _____ and ____
trachea, bronchi
Epithelial cells lining the airways and submucosal glands secrete ____ and ____
saline, mucus
______ move the mucus layer toward the pharynx, removing trapped pathogens and particulate matter
Cilia
Saline is produced by the epithelial cells and overtop of the saline is a layer of mucus produced by ____ _____, the mucus contains _________
goblet cells, immunoglobulins
The epithelial cells contain cilia which push the mucus towards the pharynx, this phenomenon is called the ?
mucocilliary escalator
______ is necessary for mucocillary escalator function
Saline
Without the saline layer, cilia would become ? and ?
embedded in thick mucus, unable to move
Arrange these statements in order of “one model of saline secretion by airway epithelial cells:”
1. Apical anion channels, including CTFR, allow Cl- to enter the lumen
2. NaCl movement from ECF to lumen creates a concentration gradient so water follows into the lumen
3. Na+ goes from ECF to lumen by the paracellular pathway, drawn by the electrochemical gradient
4. NKCC brings Cl- into epithelial cells from ECF
4, 1, 3, 2
Cystic Fibrosis is caused by reduced production of ____. The mucus cannot be cleared properly allowing bacteria to colonize in the airways leading to reoccurring ____ _____. It also affects the _____
saline, lung infections, pancreas
_____ are the site of gas exchange
Alveoli
Alveoli are clustered at the ends of _______
bronchioles
Alveoli are heavily _______ (80-90% alveoli covered) and huge _____ ___ optimal for gas exchange
vascularized, surface area
Type __ alveolar cells: majority (95%) of the cells, very thin, act as the exchange epithelium
I
Type __ alveolar cells: other ~5% of the cells, thicker, specialized and produce a detergent like substance called surfactant
II
? : just in case there are any pathogens left that have avoided filtration already, can neutralize them and prevent damage or destruction done by them
Resident alveolar macrophages
_______ reduces surface tension and prevents the alveoli from collapsing
Surfactant
The pulmonary circulation has ____ flow but ___ pressure
high, low
The pulmonary circulation contains about 0.5 L or ___% of the total blood volume (75ml in capillaries)
10
Low pressure due to low ______ (shorter length circuit, more distensible and larger total cross sectional area of arterioles)
resistance
Low pressure means minimal _____ of fluid out of capillaries but there are lymphatics to remove any fluid that does get filtered and keep the diffusion distance to a minimum
filtration
Respiratory air flow is similar in many aspects to blood flow in the cardiovascular system, mainly the pressure gradients created to cause ____
flow
Normal sea level atmospheric pressure is considered to be ____ mmHg but is usually set to 0 cm H2O or mmHg by respiratory physiologists
760
What is Daltons law?
The total pressure exerted by a mixture of gases is the sum of the pressure exerted by each gas.
Daltons law is also dependent on the ______ of the air
humidity
The pressure exerted by one gas is known as its _____ _____ (interested in PO2 and PCO2 specifically)
partial pressure
What is the formula for Partial Pressure of a Gas?
Patm × % of gas in atmosphere
What is the formula for Partial Pressure of a Gas that takes humidity into account?
Pgas in humid air = (Patm - Ph2o) × % of gas
We are concerned with atmosphere pressure because it is the difference between ______ ______ and the ? that drive airflow
atmospheric pressure, pressure in the lungs
We are also concerned with partial pressures, which is exerted by a single gas, usually oxygen or carbon dioxide specifically, which drives ______
diffusion
To get a true partial pressure, _______ always needs to be considered as true dry air is rare on earth
humidity
Gases move ______ pressure gradients
down
Air moves by ____ flow
bulk
What is the symbol for Alveolar pressure?
Palv
What is the formula for flow?
F = (Palv - Patm) / R
In inspiration, Palv ? Patm?
<
In expiration, Palv ? Patm?
>
What is the formula describing Boyle’s Law?
P1V1 = P2V2
______ law helps explain how a change in lung volume results in a change in lung pressure driving the bulk flow of air
Boyle’s
During ventilation, air flows because of _____ _____
pressure gradients
During inspiration we make the volume of our alveoli _____ resulting in a _____ in pressure below atmospheric pressure resulting in air flow from the atmosphere ____ our alveoli
larger, drop, into
_______ is the bulk flow exchange of air between the atmosphere and the alveoli
Ventilation
A single respiratory cycle consists of a single ______ followed by an ______
inspiration, expiration
What instrument could we use to measure changes in lung volume?
Spirometer
The amount of air enter and exiting the lungs during quiet respiration (resting respiration) is the _____ _____
tidal volume (TV)
The total ventilation during rest represents the product of _____ _____ and ?
tidal volume, frequency of breaths
Total pulmonary ventilation = ?
TV x frequency of breaths
? : ~3000ml, the additional air that could still be inspired after quiet inspiration
Inspiratory reserve volume (IRV)
? : ~1100ml, at the end of quiet expiration, the volume of air that still remains within the lungs that can be expired
Expiratory reserve volume (ERV)
? : ~1200ml, and cannot be measured with spirometer. Even with maximal expiratory effort air always remains in the lungs
Residual Volume
What are the four primary lung volumes that do not overlap?
- Tidal volume
- Inspiratory reserve volume
- expiratory reserve volume
- residual volume
What are the 2 most important functions of Residual Volume?
- Prevents airway collapse, after a collapse it takes an unusually large pressure to re-inflate it.
- It allows continuous exchange of gases.
The capacities of the lung are made up of different combinations of the four primary volumes: ?
- Total lung capacity
- Functional residual capacity
- Inspiratory capacity
- Vital capacity
What is Total lung capacity?
The sum of all 4 volumes
What is functional residual capacity?
The capacity of air remaining in the lungs after quiet expiration, the sum of ERV and RV
What is inspiratory capacity?
The sum of IRV and TV representing the maximal amount of air that one can inspire
What is Vital capacity?
The sum of IRV, TV, and ERV representing the maximal achievable tidal volume
What is the Pulmonary Function Test?
Involves testing an individuals forced vital capacity (FVC) and comparing it to their Forced expired volume in one second (FEV1)
Low initial FVC is indicative of ?
restrictive pulmonary disease (decrease in lung compliance)
FEV1 is normally ~80% of vital capacity, so < 80% is indicative of ?
obstructive pulmonary disease (increased resistance)
What is another word for atmospheric?
Barometric
Inspiration occurs when alveolar pressure ______.
decreases
How do we change alveolar pressure?
We use our inspiratory muscles (skeletal) to increase the volume of alveoli, resulting in a decrease in pressure
60-75% of inspiratory volume change due to ____
diaphragm
At rest, the diaphragm is _____; while during inspiration the thoracic volume _____
relaxed, increases
Main muscle of resting respiration/quiet respiration is the _____, it is a sheet of skeletal muscle. When contracted it ____ and pulls the lungs _____-
diaphragm, flattens, downward
The last 25-40% of inspiratory volume change due to ___ ____
rib cage
What are the 2 main muscles associated with the rib cage and are important for inspiration?
External intercostals
Scalenes
The external intercostals of the upper ribs and the scalenes cause a ?
“pump handle” motion
The external intercostals in the lower ribs cause a ?
“bucket handle” motion
The ? are important for creating an increase in thoracic volume while the ? extend from neck to upper ribs, lifting the upper ribs up
external intercostals, Scalenes
Expiration occurs when alveolar pressure _____
increases
Quiet expiration is _____ (relaxation of the inspiratory muscles)
passive
During expiration, the diaphragm ____, and thoracic volume ______
relaxes, decreases
During _____, the external intercostals and scalene muscles relax as well
expiration
As alveolar volume decreases, the pressure inside increases above ______ ______
atmospheric pressure
During expiration, the thoracic volume decreases which causes a ______ in alveolar volume and an _____ in pressure that drives the air flow ___
decrease, increase, out
At the end of inspiration and expiration, when you’re not breathing that’s when the atmospheric pressure and the alveolar pressure are _____
equal
Additional accessory or secondary muscles become activated during forced inspiration, which include: ?
- Sternocleidomastoids
- Neck and back muscles
- Upper respiratory tract muscles
What is the the role of the Sternocleidomastoids?
Lift the sternum outward, contributing the water pump handle effect
What is the the role of the Neck and back muscles?
Elevate pectoral girdle increasing thoracic volume
What is the the role of the Upper respiratory tract muscles?
Decrease airway resistance
To tap into the respiratory reserves, you need the ?
accessory/secondary muscles
What are the 3 accessory muscles of forced expiration?
- Abdominal muscles
- Internal intercostals and triangularis sterni
- Neck and back muscles
What is the the role of the triangularis sterni?
Depresses the sternum, further decreases thoracic volume
What is the the role of the Internal intercostals?
Cause downward contraction of the ribs, further decreases thoracic volume
Is the lung directly attached to the diaphragm or thoracic wall?
No
For simplicity sake intrapleural pressure is ?
~-3 mmHg
Thoracic wall and lungs have a _____ ____, and the ____ holds both in place, which gives it a negative pressure
natural recoil, pleura
The pressure that exists in the intrapleural cavity is or is not uniform around the entire lungs?
is not
The pressure that exists in the intrapleural cavity is more ____ at the base of the lung, this is due to ?
positive, gravity in a standing position
Inspiratory muscles pull the _____ layer of pleura away from _____ layer, ______ the volume of the intrapleural cavity and thus ______ the intrapleural pressure. This creates a more _____ pressure pulling lungs outward
parietal, visceral, increasing, decreasing, negative
The lungs do or do not expand at the same degree that the diaphragm and the thoracic cavity
do not
Order these statements in accordance to Inspiration:
1. Lungs expand
2. Palv becomes subatmospheric
3. Thorax expands
4. Air flows into alveoli
5. Diaphragm and inspiratory intercostals contract
6. Pip becomes more subatmospheric
5, 3, 6, 1, 2, 4
Order these statements in accordance to Expiration:
1. Air in alveoli becomes compressed
2. Chest wall recoils inwards
3. Diaphragm and inspiratory intercostals stop contracting
4. Air flows out of lungs
5. Pip moves back towards pre-inspiration value
6. Palv becomes greater than Patm
7. Lungs reoil toward pre-inspiration size
3, 2, 5, 7, 1, 6, 4
An interruption in intrapleural pressure results in ________
pneumothorax (collapsed lung)
_____ pneumothorax is air in the pleural space resulting from trauma and causing partial or complete lung collapse.
Traumatic
______ pneumothorax can be caused by an underlying disease, breakdown of the visceral layer where is ruptures then air can leak from your lungs into the intrapleural cavity, which eventually causes collapse
Spontaneous
Pneumothorax only occurs on the ? and why?
affected side, as the pleural layer is separate for each lung
The degree of lung expansion at any time is proportional to the ?
change in pressure
How much any given change in P expands the lungs depends on the ?
compliance of the lungs
The reciprocal of compliance, lung elastance (elastic recoil) is the ?
ability to resist being deformed
What is a mathematical formula representing compliance?
ΔV / ΔP
________ pressure: the pressure across the wall of the lung itself, the difference between intrapleural pressure and alveolar pressure
Transpulmonary
Compliance is _______: more stretchable, smaller change to increase it faster, inspire very easily, but its hard to expire
increased
Compliance is _______: less stretchable, bigger change to increase it, a lot of effort to inhale air, very stiff, but expiration is easier
decreased
What is pulmonary fibrosis?
Formation or development of excess fibrous connective tissue in the lungs
Is pulmonary fibrosis an example of increased or decreased compliance?
decreased
Is emphysema an example of increased or decreased compliance?
Increased
_______ : proteolytic enzymes secreted by leukocytes attack alveolar tissue. The alveoli merge: loss of capillaries and reduction of surface area. There is a loss of lung recoil, and weakens alveoli walls creating airway resistance
Emphysema
What is the main cause of an emphysema?
Cigarette smoking
The main determinant of compliance isn’t the _____ themselves or the _____ tissue its ____, it’s the ? of the alveoli is the main determinant of the elastic recoil
alveoli, connective, water, fluid that lines the inner walls
An equally important determinant of compliance and a major determinant of the lungs elastic recoil is ______ ____ at the air water interface of the airways.
surface tension
True or False: all alveoli are the same size?
False
What is Laplace’s equation and what are the variable represented?
P = 2T/r
T = surface tension (at pure air water interface ~70dynes/cm)
r = bubble radius
According to Laplace’s law, ______ as much pressure is needed to keep the small bubble inflated
twice
In our alveoli, we do not have a pure air-water interface, we have ______ that helps to reduce the surface tension, and help that all alveoli inflate equally
surfactant
Surfactant is a detergent-like molecule secreted by ?
Type II alveolar cells
Surfactant is ~90% ______ and ~10% _____
phospholipids, protein
Is surfactant hydrophobic, hydrophilic, or amphipathic?
amphipathic
Surfactant reduces surface tension by decreasing ____ of water molecules at air-water interface
density
If we have 2 bubbles shown to have the same surface tension, according to Laplace’s law, the pressure is greater in the larger/smaller bubble
smaller
In the lungs, _____ alveoli have more surfactant, which equalizes the pressure between large and small alveoli
smaller
What is Infant Respiratory Distress Syndrome?
In premature infants: developmental insufficiency of surfactant production and immaturity of the lungs
Prevalence of Infant Respiratory Distress Syndrome decreases with ______ age:
__% 26-28 weeks
__% 30-31 Weeks
gestational, 50, 25
What is the prevention of Infant Respiratory Distress Syndrome?
Glucocorticoid injection
What are the 3 treatment options for Infant Respiratory Distress Syndrome?
- Artificial surfactant
- Continuous Positive Airway Pressure (CPAP)
- Intubate
In a healthy individual ~90% of airway resistance occurs in _____ and _____ and is _____
trachea, bronchi, constant
What is Poiseuille’s Equation?
R = (8nl)/(πr^4)
Length of the airway system is affected by?
Nothing, it is considered constant so is not considered a factor
Viscosity of the air is affected by?
Nothing, it is usually constant and not considered a factor; humidity and altitude may alter slightly
Diameter of the upper airway system is affected by? and is mediated by?
Physical obstruction
Mucus and other factors
____ levels of CO2: bronchioles relax, increases the diameter, increases flow
High
____ levels of CO2: bronchioles contract, decreases the diameter
Low
Slight changes in bronchoconstriction/dilation are commonly due to ?
paracrine control, CO2 being the major one
________ : parasympathetic nerves innervate bronchiole smooth muscle and activate PLC-IP3 pathway via M3 muscarinic receptor
Bronchoconstriction
_________: circulating epinephrine binding B2 adrenergic receptors (dilation)
Bronchodilation
_______: characterized by chronic inflammation of the airways, and intermittent sensitivity of the smooth muscle
asthma
What is the treatment for asthma with more infrequent attacks?
β2-adrenergic agonist, opposes bronchoconstriction
What is the treatment for asthma with more frequent attacks?
Weekly inhaled corticosteroid
In respiratory system effectiveness of ventilation is determined by ?
total pulmonary ventilation
What is total pulmonary ventilation?
The volume of air moved into and out of the lungs each minute (minute ventilation)
What is the normal ventilation rate?
12-20 breaths/min, tidal volume = 500ml
How do calculate total pulmonary ventilation?
Ventilation rate × tidal volume
Is Total pulmonary ventilation a good indicator of how much fresh air reaches the alveoli?
No, because air always remains within the conducting air space and does not take part in gas exchange
What is Alveolar Ventilation?
Ventilation rate × (tidal volume - dead space)
Anatomic dead space is constant at roughly ?
~150ml
What is the normal total pulmonary ventilation value?
6 L/min
What is the normal Total alveolar ventilation value?
4.2 L/min
What is the normal Maximum voluntary ventilation value?
125-170 L/min
