Chapter 17- Mechanisms of breathing Flashcards
What does cellular respiration refer to?
Cellular metabolism that uses oxygen and produces ATP and CO2
What is external respiration?
The exchange of gas between the external environment and the cells and tissues of the body
Which parts are included in the upper respiratory tract?
The mouth, nasal cavity, pharynx and larynx
Which parts are incluced in the lower respiratory tract?
The trachea, bronchi, bronchioles, and the alveoli
There are two types of cells in the alveoli. Name them and their function
type 1 alveolar cells aid in gas exchange. type 2 alveolar cells produce surfactant and helps with fluid balance by moving solutes (and thus water) to and from the airways
Blood flow through the lungs equals ————————-
cardiac output
What are the four primary functions of the respiratory system?
pH regulation, gas exchange, vocalization, protection of the internal environment from foreign substances
What are the four processes of external respiration?
- Air moves in and out of the lungs by pulmonary ventilation
- Diffusion between air and blood allows for exchange of gases
- The gases are transported through the blood
- Diffusion between blood and tissues allows for exchange of gases
What are the three major components of the respiratory system?
The airways, the alveoli in the lungs, and the bones and muscles that assist in ventilation
What are the steps involved in inspiration? What happens with the intrapleural, intra-alveolar and transpulmonary pressure?
The thoracic cavity expands, so the intrapleural pressure drops. Because of this, the transpulmonary pressure goes up, and the lungs expand. The alveolar volume goes up. The intra-alveolar pressure drops, and the pressure gradient created by this causes air to flow into the lungs. Air flow stops when Patm= Palv
What are the steps involved in expiration? What happens with the pressures?
The muscles of inspiration relax, causing the lung volume to decrease. This increases intra-alveolar pressure, creating a pressure gradient causing outflow of air.
What is the relationship between the lungs, the pleura, and the pleural fluid?
Each lung is surrounded by a pleural sac, which imitates an air-filled balloon( the lung) surrounded by a water-filled balloon.
Which structures does an oxygen molecule pass starting in the air and ending at the exchange epithelium of the lungs
The mouth and nasal cavity, pharnyx, larynx, trachea, primary bronchi, bronchioles, alveoli
As the molecule moves into the airways, the diameter of the airways gets progressively smaller and the total cross-sectional surface area of the airways ————————- (increase or decrease)?
It increases
The velocity of air flow is highest in the —————————– and lowest in the ——————-
upper respiratory tract (mouth/ nasal cavity)
lower respiratory tract (bronchioles / alveoli)
How is the air conditioned before it reaches the alveoli? Name all three and explain how it is done
Warming air to body temperature, which is done by the body’s heat and moistened water evaporating from the mucosal lining of the airways
Adding water vapor until the air reaches 100% humidity.
Filtering out foreign materials, which is aided by ciliated epithelium and mucus that keep the foreign invaders from going into the lungs but rather to the pharnyx and then the stomach.
Describe the structure of the alveoli and the alveolar walls
The alveoli are air-filled sections composed of a single layer of epithelium. The walls are thin, allowing for rapid gas exchange. They cannot contract due to a lack of muscles
What is the surrounding tissue of the alveoli like? What type of tissue is it?
Connective tissue between the alveoli cells contains elastin and collagen fibers that create elastic recoil when lung tissue gets stretched.
What is the assocation between alveoli and the circulatory system?
Blood vessels fill 80-90% of the space between alveoli, forming a continuous sheet of blood in close contact with the alveoli. This short distance allows for rapid transfer.
Name the three aspects that affect the bulk flow of air
Air flows from high pressure to low pressure areas
The pressure gradient is created by a muscular pump
Resistance to air flow is influenced by the diameter of the airway
What are the two functions of pleural fluid?
Creating a slippery surface to decrease friction when the lungs move in the thorax. It also helps stick the pleural membranes to the thoracic cage.
How is air cleaned before it enters the alveoli?
The air passes ciliated epithelium bathed in a watery saline layer. Particles are trapped in this solution. The mucus is then rhythmically beaten upwards to the pharynx, this process is known as the mucocillary escillator.
What cells secrete mucus containing immunoglobins?
Goblin cells
How is the saline fluid in the airways produced?
As Cl- moves into the lumen, it draws Na+ with it. Movement of these solutes creates osmotic gradient, which makes water follow after the solutes.
Name the structures of the pulmonary circulation blood passes to become oxygenated.
Right ventricle, pulmonary trunk, pulmonary arteries, pulmonary arterioles, pulmonary capillaries, pulmonary veins, left atrium
What is the blood pressure in the pulmonary circulation? How does this compare to systemic circulation?
Pulmonary is 25/8 mmHg. Systemic is 120/80 mmHg
Why is the pulmonary blood pressure much lower than the systemic blood pressure?
The pulmonary circulation has low resistance, because of a short length of vessels, and a large area of blood vessels
Dalton’s law
Total pressure of mixture of gases is the sum of the partial pressure of each gas in mixture
Boyle’s law
PV=PV. If the volume of gas is reduced, the pressure increases and vice versa
O2 moves from ……….. PO2 to ………. PO2 (low/High)
High, low
What is the tidal volume (Vt)? How much is it?
The volume of air that moves during a normal inspiration/expiration. about 500 mL
What is the inspiratory reserve volume (IRV)? How much is it?
The additional volume inspired above the tidal volume. About 3000 mL
What is the expiratory reserve volume (ERV)? How much is it?
The amount of air forcefully exhaled after normal expiration. About 1100 mL
What is the residual volume? How much is it?
The volume that always remains after maximal exhalation. About 1200 mL
What is the vital capacity and how can it be calculated?
It is the maximum amount of air that can be voluntarily moved in our out of the respiratory system. It is IRV+ERV+Vt
What is the total lung capacity and how is it calculated?
Vital capacity plus the residual volume, so ERV+IRV+Vt+RV
How do you calculate the inspiratory capacity and the functional residual capacity?
Inspiratory is Vt+ IRV. Functional residual is ERV+RV
What are the primary muscles used in quiet breathing?
Diaphragm, external intercostals, scalenes
What happens with alveolar pressure and intrapleural pressure during inspiration and expiration?
The alveolar pressure decreases during inhalation, and so does the intrapleural pressure. The intrapleural pressure keeps dropping until exhalation. Then both intrapleural and alveolar pressure increase during expiration
Air flows in response to a ………. gradient. Flow ……… as resistance increases.
Pressure, decreases
EXPIRATION
………. of the internal intercostals decreases thoracic volume. Abdominal muscles contract, ………… abdominal volume which ………… thoracic volume
Contraction, decreasing, decreases
What is pneumothorax?
Air in pleural cavity, breaking the fluid bond holding lungs to thoracic wall, resulting in a collapsed lung
What is elastance and compliance? Do you want those to be high or low?
Elastance is the ability to turn back to original form after the lung is stretched. Compliance is the ability of the lung to stretch. We want high compliance, low elastance
If elastin in the lungs is destroyed but there is high compliance, what happens?
There is decreased elastance, the lungs don’t recoil back to their normal position
What is the purpose of surfactant in the lungs?
It decreases surface tension of the alveolar fluid, decreasing resistance to stretch in the lungs
What does resistance to airflow depend on (3 factors)?
The systems length, the viscosity of the flowing substance and the radius of the tubes in the system
A ……………. in diameter of bronchioles increases airway resistance (Decrease/increase)
decrease
What happens in bronchoconstriction with the diameter, resistance and the airflow to the alveoli?
Diameter down
resistance up
airflow alveoli down
What happens in bronchodilation with the diameter, resistance, and airflow to alveoli?
diameter up
resistance down
airflow alveoli up
How to calculate total pulmonary ventilation?
ventilation rate * tidal volume
How to calculate alveolar ventilation?
ventilation rate * (tidal volume - dead space volume)
What is the anatomic dead space and how much is it?
The air that remains in the conducting airways to prevent collapse, not participating in gas exchange. About 150 mL
An ………. PCO2 of expired air causes bronchioles to dilate (increase/decrease)
increased
An …………. PCO2 of expired air causes bronchioles to constrict
decreased
What happens with PO2 and PCO2 in hyperventilation and in hypoventilation
Hyper; PO2 up, PCO2 down
Hypo; PO2 down, PCO2 up
What does a spirometer measure?
It measures the volume of air moved with each breath
What does a forced vital capacity test measure? What is the purpose of this test?
It measures the total volume of air exhaled and how fast the air leaves the airways. Purpose is to assess respiratory system function and static lung volumes
What is diminished in obstructive lung diseases,, because of what? What is diminished in restrictive lung diseases, because of what?
In obstructive the air flow is diminished because of increased airway resistance. In resistrictive the lung complaince is diminished, because of inadequate alveolar production of surfactant or scar tissue in the lungs
What is diminished in obstructive lung diseases,, because of what? What is diminished in restrictive lung diseases, because of what?
In obstructive the air flow is diminished because of increased airway resistance. In resistrictive the lung complaince is diminished, because of inadequate alveolar production of surfactant or scar tissue in the lungs
Name three bronchoconstrictors and the receptors they act on, and two bronchodilators and the receptors they act on
Constrictors; histamine, acetylcholine and leukotrienes, acting on muscarinic receptors.
Dilators; CO2 and epinephrine acting on Beta 2 receptors
Histamine is released from ………………….. cells
mast
