Ch. 21: The Respiratory System (Professor's Study Guide)

2 functions of the conducting zone in respiratory tract?

1. To bring air to the respiratory zone

2. To prepare the air for the respiratory zone by warming, humidifying, and filtering it

What is the function of the respiratory zone of the respiratory tract?

Gas exchange: oxygen leaves lungs and enters pulmonary capillaries while CO2 leaves the pulmonary capillaries and enters the lungs

What are the 4 processes of respiration?

1. Pulmonary ventilation

2. Pulmonary gas exchange (external respiration)

3. Gas transport in blood

4. Tissue gas exchange (internal respiration)

What is the purpose of the mucus in the respiratory tract?

Traps pathogens, pollen, debris, etc that are inhaled so those debris does not move deeper into the respiratory tract

What is the purpose of the nasal conchae in the nasal cavity?

The nasal conchae force airflow through the meatuses. This creates turbulence to help debris get stuck in the mucus that lines the nasal conchae and to allow the air to pick up moisture from the mucus membranes

What is the purpose of the pseudostratified ciliated columnar epithelium in the upper portions of the respiratory tract?

It contains goblet cells that produce mucus, and the cilia on top of the epithelial cells function to move mucus up and out of the respiratory tract

Why can upper respiratory tract infections lead to sinus infections?

The nasal cavity connects to the paranasal sinuses through small tubes. This allows pathogens to travel to the sinuses and can cause mucus to build up and get stuck in the sinuses for bacteria to grow in

Why can upper respiratory tract infections lead to ear infections?

The Eustachian/ Pharyngotympanic tube connects the nasopharynx to the middle ear. An increase in mucus can cause mucus to back up into this tube with pathogens

Why is ear infections more likely in children than adults when having respiratory tract infection?

The Eustachian/ Pharyngotympanic tubes is horizontal until around age 5 when the tube becomes more angled to allow better drainage

How does smoking cigarettes affect the mucus and cilia of the upper respiratory tract?

Smoking causes mucus production to increase and paralyzes cilia in the respiratory tract. With continued exposure will destroy the cilia

Why might the effects of smoking cigarettes be an issue?

The mucus will sit in the respiratory tract and can only be removed by coughing. With more mucus, there is a higher chance that bacteria will replicate in the mucus to cause a lung infection

What is the purpose of the epiglottis?

Prevent aspiration of food/ drink into the lungs

Why does the amount of cartilage decrease as you move down the respiratory tract?

Less protection is needed deeper in the lungs to hold the airway open, and smaller volumes of air are moved through smaller tubes deeper in the lungs

Why does the epithelium get thinner as you move down the respiratory tract?

To facilitate gas exchange

Why do the amounts of smooth muscle and elastin increase as you move down the respiratory tract?

To better control the airflow to the alveoli since the amount of cartilage holding the tubes open is decreasing

What are the 3 types of cells in the alveoli?

Type 1 cells, Type 2 cells, Alveolar macrophages or dust cells

What is the function of Type 1 cells?

Thin enough for diffusion of gases

What is the function of Type 2 cells or Septal cells?

Produce surfactant to reduce surface tension on alveoli so they don’t collapse during exhalation

What is the function of Alveolar macrophages or dust cells?

Phagocytize pathogens/ debris that were not filtered out in the conducting zone

What is the role of surfactant?

To decrease surface tension on alveoli so they don’t collapse during exhalation

How does surfactant work?

Surfactant disrupts hydrogen bonds from water molecules lining the inside of the alveoli. This reduces surface tension so that alveoli remain partially open during exhalation

Why is surfactant important?

The alveoli would collapse during exhalation without surfactant

What would happen without surfactant?

Alveoli would collapse during exhalation, and it would be more difficult to inflate the alveoli with each inhalation

Why is it a concern that premature babies do not produce surfactant?

They would not be able to breathe well on their own if they were not producing surfactant

What are some symptoms of TB?

Fever, blood-tinged sputum, persistent cough

What causes TB?

Bacterium = Mycobacterium tuberculosis

What do TB cells infect?

Infects alveolar macrophages and replicates inside of them

What are the 3 parts of the respiratory membrane?

Type 1 alveolar cells, Basal lamina, capillary endothelial cells

Why does the respiratory membrane need to be so thin?

To allow adequate diffusion of gases between alveoli and pulmonary capillaries

Where are the parietal pleura?

Fused to structures that surround the lungs like the rib cage and diaphragm

Where are the visceral pleura found?

Lines the outside of the lungs

What is the pleural cavity?

The space between the parietal and visceral pleurae

What does the pleural cavity contain?

Filled with pleural fluid

What is pleuritis or pleurisy?

Inflammation of the pleurae that causes the membrane to rub against each other when lungs expand

What is the symptoms of pleurisy?

Sharp chest pain when inhaling, possible chest pain when exhaling

What are the causes of pleurisy?

Pneumonia and other lung infections, heart failure, heart attack, pulmonary embolism

What is ventilation?

Moving air into and out of the lungs

What is respiration?

Gas exchange

What is inspiration?

Inhaling

What is expiration?

Exhaling

True or False: ventilation occurs based on pressure changes

TRUE

Does air move to an area of higher or lower air pressure?

Lower

How does volume affect air pressure?

Opposite relationship

What is the intrapulmonary pressure?

Air pressure in the alveoli

What is the intrapleural pressure?

Air pressure in the pleural cavity

How do we change the intrapulmonary pressure to cause inspiration?

External intercostals contract and move rib cage up and out to increase diameter of thoracic cavity

How do we change the intrapulmonary pressure to cause expiration?

External intercostals relax and allow rib cage to fall to decrease diameter of thoracic cavity

How does atmospheric and intrapulmonary pressure compare during inspiration?

The intrapulmonary pressure goes below atmospheric pressure to 758 mm HG

How does atmospheric and intrapulmonary pressure compare during expiration?

The intrapulmonary pressure goes above the atmospheric pressure to 762 mm HG

What is pleural effusion?

Excess fluid in the pleural cavity between the parietal and visceral pleural

What is a pneumothorax?

Air enters the pleural cavity usually due to damage to one or both pleural membranes

If intrapleural pressure is increased, why does inspiration not occur?

Since air moves to the area with lower pressure, an increase in intrapleural pressure above atmospheric pressure will make inspiration IMPOSSIBLE

What could end up happening to the lung if the intrapleural pressure increased?

The lung or part of lung can collapse

True or False: The diameter of the bronchioles does NOT determine the amount of air that can flow to the lungs

FALSE

What is bronchoconstriction?

Decrease size of airways

How does bronchoconstriction occur?

Smooth muscle in airways contracts, caused by inflammation or inhaled irritants

What happens to the airways during an asthma attack?

Bronchoconstriction, increased production of thicker mucus, inflammation

What is bronchodilation?

Increase size of airways

How does bronchodilation occur?

Smooth muscle in the airways relaxes, effect of sympathetic nervous system

What are some signs/symptoms of an asthma attack?

Wheezing, shortness of breath, coughing

What are some triggers that can cause an asthma attack?

Allergens, air pollution, exercise, aspirin

How do medications like albuterol and levalbuterol work to treat asthma?

Causes bronchodilation

How do inhaled corticosteroids work to treat asthma?

Decreases inflammation

How does Singulair/ Montelukast work to treat asthma?

Decreases inflammation by inhibiting leukotrienes

True or False: Pulmonary compliance affects lung function and can be altered by several diseases

TRUE

What is compliance?

Ability of lungs and thoracic cavity to stretch

Easier to move air into and out of the lungs

Increased compliance

More difficult to move air into and out of the lungs

Decreased compliance

What 3 factors determine pulmonary compliance?

Alveolar surface tension (surfactant), Ability of elastic tissue in lungs to stretch and recoil, ability of chest wall to move

How does a lower compliance affect the lungs (as with cystic fibrosis)?

More difficult to move air into and out of lungs

What causes lower compliance in cystic fibrosis?

Excess of thicker than normal mucus in the respiratory tract

What happens to the lungs with emphysema (COPD)?

Alveolar walls are damaged causing a loss of surface area for gas exchange. Air can also become trapped in the alveoli

How is expiration affected during emphysema?

Expiration becomes an active process, meaning accessory muscles must contract to remove air from the lungs which can lead to a barrel chested appearance

What is the usual cause of COPD?

Smoking cigarettes

Where is the respiratory pattern generator located?

Medulla oblongata

What is the function of the respiratory pattern generator?

To set the basic rhythm for breathing

Where is the dorsal and ventral respiratory groups located?

Medulla oblongata

What is the function of the ventral respiratory group?

Controls inhaling and exhaling because it innervates diaphragm, external intercostals and many accessory muscles of breathing

What is the function of the dorsal respiration group?

Integrate sensory information from the blood and lungs and pass the information on to other respiratory nuclei, have some involvement in inhalation

Where is the Apneustic Center located?

In the Pons of the brain stem

What is the function of the Apneustic center?

Gives constant stimulus to inhale

Where is the Pneumotaxic Center located?

In the Pons

What is the function of the Pneumotaxic Center?

Inhibits Apneustic center to allow exhalation and to limit amount of air that is inhaled in each breath

How does the pons work to cause inspiration and expiration?

Controls inhalation and exhalation signals

How does the medulla oblongata work to cause inspiration and expiration?

Sets breathing rhythm (RPG), send signals to muscles for breathing (VRG), and allows changing to breathing based on signals from lungs and blood (DRG)

What is Tidal Volume (TV)?

Amount of air that is inhaled or exhaled in a normal breath

What is Vital Capacity (VC)?

Total amount of air that can be forcefully inhaled and exhaled

What is total lung capacity (TLC)?

Maximum amount of air in the lungs

What is Residual Volume (RV)?

Amount of air left in lungs after a forceful exhalation

What is Functional Residual Capacity?

Amount of air left in lungs after normal exhalation

What is Inspiratory Reserve Volume (IRV)?

Maximum amount of air that can be forcefully inhaled after a normal exhalation

What is Inspiratory Capacity?

Total amount of air that can be inhaled

What is Expiratory Reserve Volume (ERV)?

Maximum amount of air that can be forcefully exhaled after a normal exhalation

What is Dalton’s Law of partial pressures?

Each gas in a mixture contributes a partial air pressure that is related to the amount of that gas present in the mixture

If the partial pressure of a gas in the blood is 40 mm Hg and the partial pressure of the same gas is 45 mm Hg in the cell, where will the gas move?

The gas would move from the cell to the blood

What happens to the diffusion of a gas as its partial pressure in an area increases?

Diffusion will occur more quickly as the difference in partial pressure increases

What happens to the solubility of a gas as its partial pressure increases?

Gas becomes more soluble in liquid as it partial pressure increases

Explain how increased partial pressure increases for hyperbaric chamber therapy?

The partial pressure of oxygen is increased so the more oxygen will dissolve and can be carried in the plasma

What tissues are exchanging gases during pulmonary gas exchange/ external respiration?

Pulmonary capillaries and alveoli

What is the partial pressure of oxygen in the alveolus?

104 mm Hg