Unit 2: Respiratory System (Lecture) Flashcards
Refers to the exchange of gases between the atmosphere and pulmonary circulation
External respiration
Refers to gas exchange between capillary oxygen and tissue cells
Internal respiration
Refers to oxidation of glucose to produce ATP
Cellular respiration
Key functions of the respiratory system
- Filtering, warming, and humidifying of air
- Ventilation + gas exchange
- Sound production
- Smell
- Hormone metabolism
Components of the upper airway
- Nasopharynx
- Oropharynx
- Laryngopharynx
- Larynx
What separates the upper and lower parts of the respiratory system?
The larynx
What is the largest conducting airway?
Trachea
What is the trachea lined with?
ciliated epithelium and mucus secreting goblet cells
What supports the trachea?
Rings made of hyaline cartilage
Nutritional flow
Lung tissue receives oxygenated blood from the bronchial arteries
Where do bronchial arteries branch from?
Aorta
Pulmonary flow
pulmonary arteries supply the lung capillaries
Each lung lobule receives a branch of the…
pulmonary artery
Where do the pulmonary venules drain into?
Pulmonary veins
The two lungs are separated by the…
mediastinum
Which lung contains the superior, middle, and inferior lobes?
right lung
Which lung contains the superior and inferior lobes only?
left lung
The trachea divides and forms the right and left…
primary bronchi
Each primary bronchi divides into…
the secondary or lobar bronchi
Secondary bronchi divide into…
tertiary or segmental bronchi
There is one segmental bronchus for each…
bronchopulmonary segment
Tertiary bronchi branch extensively giving rise to smaller…
bronchi
As bronchi subdivide and become smaller, they lose their cartilage and become…
bronchioles
What are slightly smaller branch extensions of bronchioles?
Terminal bronchioles
Portion of the lung that is supplied by a tertiary bronchus
Bronchopulmonary segment
How many bronchopulmonary segments are in the right lung?
10
How many bronchopulmonary segments are in the left lung?
8
Each segment is divided into many smaller…
lung lobules
Each terminal bronchiole supplies one…
lung lobule
Each lobule contains…
- A lymph vessel
- A pulmonary arteriole
- A pulmonary venule
- Respiratory bronchioles
- Alveolar ducts
- Aveolie
What is formed as terminal bronchioles sub-divide into microscopic branches and alveoli begin to form?
Respiratory bronchioles
Respiratory bronchioles open into…
alveolar ducts
Sac-like pouchings of the respiratory portion of the bronchial tree
Alveoli
How many alveoli are in a normal lung
300 million
What are alveolar walls comprised of?
Type I alveolar cells
Type II alveolar cells secrete…
a surfactant (detergent)
Ventilation
The altering flow of air into and out of the lungs
Minute/Pulmonary ventilation
tidal volume x respiratory rate
Alveolar ventilation
(tidal volume - dead space volume) x respiratory rate
The region in the respiratory tract where no gas exchange occurs
Anatomic dead space
The skeletal portion of the thorax is called the…
thoracic cage
The respiratory muscles, rib cage, pleural membranes, and lung elastic tissues
Respiratory pump
Pleural cavity
Between the pleural membranes
What expands the thorax driving movement of air into lungs?
Inspiratory muscles
Elevates the sternum
sternocleidomastoid
Raises top two ribs
scalenes
Expand the rib cage by moving ribs upward and out
External intercostals
The primary inspiratory muscle
Diaphragm
What reduces the diameter of the thorax to create the driving movement of air out of the lungs
Expiratory muscles
Muscles pull the ribs down and inward reducing the diameter of the rib cage
Internal intercostal
Depress the lower ribs, and move the diaphragm up into the thorax
Abdominal muscles
What are the inspiratory (respiratory pump) muscles?
- Sternocleidomastoid
- Scalenes
- External intercostals
- Diaphragm
What are the expiratory pump muscles?
- Internal intercostals
- Abdominal muscles
What depends on periodic pressure changes in the lungs?
Ventilation
Pressure in the lungs becomes lower than atmospheric pressure
Inspiration
Pressure in the lungs is higher than atmospheric pressure
Expiration
During inspiration, what happens to the pleural membranes?
The parietal pleura is pulled outward and the visceral pleura follows it
When does inspiration begin?
When the diaphragm contracts enlarging the thoracic cage
When the diaphragm contracts what happens?
The contraction enlarges the intrapleural space and lowers the pressure to open alveoli
During inspiration, alveolar pressure…
drops below atmospheric pressure
At the end of inspiration, the diaphragm relaxes and the elastic tissues in the lung…
recoil
Recoil results in…
air compression and raises alveolar pressure above atmospheric pressure
Transpulmonary pressure (Ptp)
Palv (alveolar pressure) - Ppl (pleural pressure)
Lung compliance definition
Measure of the ease with which lungs can be inflated
Lung compliance equation
∆volume (ml) / ∆pressure (cmH2O)
What decreases compliance of lungs?
Thickening or stiffening of lung tissue by diseases such as asbestosis
Disease that increases lung compliance and FRC
Emphysema
Functional residual capacity
The volume of air remaining in the lungs after expiration
What does fresh air mix with in the lungs?
The FRC
When the FRC is larger breathing is…
labored
When the FRC is smaller, there is…
large fluctuations in O2 and CO2
In a mixture of gases, each gas exerts a pressure that is…
proportional to its concentration
The partial pressure exerted by each gas will be a function of the…
total gas pressure or atmospheric pressure
Atmospheric pressure in San Diego
760 mmHg
Atmospheric pressure in Tucson
705 mmHg
Atmospheric pressure in Denver
615 mmHg
Percent of O2 in the atmosphere
21%
Percent of N2 in the atmosphere
79%
Percent of CO2 in the atmosphere
0.04%
Most direct and accurate way to measure whole body O2 uptake is called…
the Fick method
O2 consumption ml/min =
cardiac output x (aterial - mixed venous)
CO2 production (ml/min) =
cardiac output x (mixed venous - arterial)
Typical O2 consumption at rest
250 (ml/minute)
Typical CO2 Production at rest
200 (ml/minute)
Typical O2 consumption at max exertion
3500 (ml/min)
Typical CO2 consumption at max exertion
3800 (ml/min)
Respiratory quotient
Amount of CO2 produced divided by O2 consumed
RQ for pure fat
0.7
Binding and release of O2 from hemoglobin is critically dependent on…
PO2
Where is PO2 quantity increased compared to the PO2 in the pulmonary capillaries?
Aveoli
Tissue PO2 is low, resulting in…
release of O2 from hemoglobin
Transit time
rate of diffusion and rate of blood flow through the pulmonary capillaries
At rest, what is blood transit time?
0.8 seconds
In a healthy lung, how long does complete oxygen diffusion take?
0.25 seconds
What percent of oxygen is transported dissolved in plasma?
1.5%
What percent of oxygen is transported bound to hemoglobin?
98.5%
What three factors alter the oxy-hemoglobin dissociation curve?
- pH
- Temperature
- CO2
What shift does a reduction in blood pH create?
shift to the right
What shift does an increase in PCO2 create?
shift to the right
What shift does an increase in temperature create?
a shift to the right
A shift to the right the oxy-hemoglobin curve is called?
A bohr shift
During a bohr shift, what happens?
The hemoglobin molecule will release more oxygen at any given PO2
When fully saturated with oxygen, each gram of hemoglobin can bind to how much oxygen?
1.34 ml
A normal adult male has how many grams of hemoglobin per liter of blood?
160 grams
A normal adult female has how many grams of hemoglobin per liter of blood?
140-150 grams
How saturated is arterial blood?
Nearly 100%
Anemia
Low blood hemoglobin concentration
Hypoxia
Low blood O2 –> therefore a low hemoglobin saturation
CO2 is released from active tissue cells and diffused into…
plasma and then RBCs
How much CO2 is transported in plasma as biocarbonate ions?
70%
How much CO2 is transported bound to Hb as carbamino-hemoglobin
23%
How much CO2 is transported dissolved in plasma?
7%
Where does the formation of carbonic acid and carbaminohemoglobin occur?
RBCs
Exchange of O2 and Co2 in pulmonary capillaries
External respiration
Exchange of O2 and CO2 in systemic capillaries
Internal respiration