Chapter 22: The Respiratory System

What are the four predominate components of inspired air?

-Carbon dioxide -Nitrogen -Oxygen -Water vapor

What factors would decrease the affinity of hemoglobin for oxygen?

-Decreased PO2 of surrounding tissue -Decreased blood pH

What two factors contribute most to airflow resistance?

-Diameter of the bronchioles -Lung compliance

What two muscles (or muscle groups) are primarily responsible for resting (non forced) inspiration?

-Diaphragm -Intercostals

Detect pH of the CSF

Central chemoreceptors

What factor is typically responsible for setting the respiratory rate in healthy individuals?

Cerebrospinal fluid pH

Detect: smoke, dust, pollen, chemical fumes, cold air, excess mucus

Irritant receptors

What describes the respiratory cycle?

Once complete inspiration and expiration

What calculated volume typically has the greatest value?

Total lung capacity

T/F: Evidence suggests that ventilation increases more quickly in response to high levels of CO2 than it does to low levels of O2 in the blood

True

What are examples of obstructive lung disorders?

-Asthma -Chronic bronchitis -Emphysema

Identify the forms in which carbon dioxide is transported in the blood

-Bicarbonate ion -Carbaminohemoglobin -Dissolved gas

What occurs during the "chloride shift" in red blood cells?

-Bicarbonate ions are transported out of the RBC -Chloride ions are transported into the RBC

What two factors facilitate systemic unloading of oxygen from hemoglobin in the peripheral tissues?

-Binding of protons to hemoglobin -Lower PO2 in tissue fluid

The peripheral chemoreceptors detect changes in what?

-Blood oxygen saturation -Blood carbon dioxide saturation -Blood pH

What factors would decrease the affinity of hemoglobin for oxygen?

-Increased bisphosphoglycerate production by RBC -Increased temperature

Which two factors facilitate systemic unloading of oxygen from hemoglobin in the peripheral tissues?

-Lower PO2 in tissue fluid -Binding of protons to hemoglobin

What locations contain the brainstem respiratory centers?

-Pons -Medulla oblongata

The functional residual capacity is obtained by adding together which respiratory volumes

-Residual volume -Expiratory reserve volume

What hormones promote oxygen delivery to tissues by stimulating bisphosphoglycerate (BPG) synthesis?

-Thyroxine -Growth hormone -Epinephrine -Testosterone

Hemoglobin is composed of how many subunits?

4

What is the normal systemic arterial blood gas value for PCO2?

40 mm Hg

What is the normal systemic arterial blood gas value for PO2?

95 mm Hg

A general term for a drop in the pH of blood below 7.35

Acidosis

Originates in the mucous glands of the lamina propria

Adenocarcinoma

A shift in the pH of blood above 7.45

Alkalosis

What term refers to the exchange of gases across the respiratory membrane

Alveolar gas exchange

Contains on the conducting zones that are incapable of gas exchange

Anatomical dead space

Inability of the blood to carry adequate oxygen due to anemia

Anemic hypoxia

What is the term for the collapse of a lobe or lung due to equalizing the intrapleural and atmospheric pressure?

Atelectasis

Why does air flow into the lungs during inspiration?

Atmospheric pressure is greater than intrapulmonary pressure, and air flows toward the lower pressure area

Most of the carbon dioxide you exhales comes from what?

Bicarbonate ions transported into the RBCs and used to generate free CO2

What would increase the efficiency of alveolar gas exchange?

Breathing air that contains 25% oxygen (Atmospheric air is 20.9% oxygen. Increasing the oxygen content at a given pressure would increase the partial pressure of oxygen in the air, which in turn would increase the amount of oxygen that diffuses into the blood).

Chronic ____ is characterized by a reduction in the number of cilia lining the airway and increased mucus production

Bronchitis

Why is carbon monoxide (CO) a serious health threat?

CO competes with oxygen for the same binding sites

Oxygen is unloaded in the body tissues because the affinity of hemoglobin for oxygen is lower in the systemic capillaries (compared to its affinity in the alveolar capillaries). What factor contributes to this?

CO2 produced in the peripheral tissues leads to increased H+ concentration

Compound of hemoglobin and carbon dioxide

Carbaminohemoglobin

The enzyme found in erythrocytes that catalyzes the formation of carbonic acid, which then dissociates into bicarbonate and hydrogen ions is what?

Carbonic anhydrase

What is true about carbon dioxide loading?

Carbonic anhydrase catalyzes the conversion of CO2 and H2) into bicarbonate and hydrogen ions

Hemoglobin with carbon monoxide bound to it

Carboxyhemoglobin

A bluish color of the skin and mucous membranes due to ischemia or hypoxemia is called

Cyanosis

____ law states that the total pressure of a gas mixture is equal to the sum of the individual partial pressures of gases?

Dalton's

Hemoglobin with no oxygen bound to it

Deoxyhemoglobin

The ____ respiratory group receives input from chemoreceptors and adjusts the respiratory rate accordingly.

Dorsal

Long term inhalation of cigarette smoke often leads to ____, a COPD that is characterized by a loss of alveolar surface area

Emphysema

What term refers to relaxed, quiet breathing?

Eupnea

When the diaphragm relaxes, air is forced from the lungs. This is known as what?

Exhalation

The ____ neurons inhibit the inspiratory neurons of the ventral respiratory group

Expiratory

The amount of air that may be exhaled over the tidal volume

Expiratory Reserve Volume (ERV)

T/F: All of the oxygen transported in the blood is usually unloaded at a systemic capillary

False

T/F: The residual volume may be exhaled with a forceful expiration

False

T/F: The respiratory control centers of the brainstem are involved in voluntary respiration.

False

T/F: The volume of anatomical dead space cannot be changed and does not vary with circumstances within a given individual

False

T/F: intrapleural pressure is always greater than atmospheric pressure

False

The amount of air that can be exhaled in a given time interval

Forced Expiratory Volume (FEV)

Deoxygenated blood can carry more carbon dioxide, whereas oxygenated blood has a lower carbon dioxide carrying capacity. This phenomenon is known as the ____ effect.

Haldane

____ law states that the amount of gas dissolved in water is determined by its solubility in the fluid and the partial pressure of the gas in the surrounding air

Henry's

Metabolic poison prevents tissues from using the oxygen delivered to them

Histotoxic hypoxia

What term describes a condition where there is an excess of CO2 in arterial blood (PCO2 greater than 43mm Hg)

Hypercapnia

What condition occurs when the CO2 in the blood falls below normal levels?

Hypocapnia

Inadequate pulmonary gas exchange

Hypoxemic hypoxia

What term refers to a deficiency of oxygen in a tissue?

Hypoxia

The intake of air during the respiratory cycle is called

Inhale

Contraction of the diaphragm leads to what?

Inspiration

The sum of the tidal and inspiratory reserve volumes is a measure of the ____ capacity.

Inspiratory

The ____ ____ volume represents the maximum amount of air that may be inhaled after the tidal volume

Inspiratory reserve

Which muscle (or muscle group) aids the diaphragm as a synergist during resting respiration?

Internal and external intercostals

As the thoracic cavity expands, the visceral pleura clings to the parietal pleura, and the surface of the lung is pulled outward. Why does this increase in lung volume cause inspiration?

Intrapulmonary pressure is temporarily lower than atmospheric pressure

Inadequate circulation of blood

Ischemic hypoxia

What best describes the action of carbonic anhydrase?

It converts carbon dioxide and water to carbonic acid which dissociates into bicarbonate and hydrogen ions

What happens during exhalation in terms of lung volume and intrapulmonary pressure?

Lung volumes decrease, intrapulmonary pressure increases

The Bohr effect occurs because CO2 lowers the pH of the blood, which facilitates the unloading of oxygen from hemoglobin. Given this, what is the physiological significance of the Bohr effect?

More oxygen is released to tissues that have higher metabolic rates

Active tissues are warmer than less active ones. Based on this information, how will oxygen be distributed?

More oxygen will be delivered to more active tissues

Hemoglobin with one or more oxygen molecules bound to it

Oxyhemoglobin

Chemoreceptors in the carotid and aortic bodies are called ____ chemoreceptors

Peripheral

Detect: oxygen level, carbon dioxide level, and pH of the blood

Peripheral chemoreceptors

What includes all of the regions of the airway incapable of gas exchange, including both conducting zones and respiratory zones that have been damaged by disease?

Physiological dead space

What is often increased in individuals with pulmonary disease?

Physiological dead space

A ___ is a clinical condition characterized by the presence of air in the pleural cavity

Pneumothorax

The ____ respiratory group adjusts the respiratory rate based on stimuli from the limbic system or cerebral cortex

Pontine

Where does voluntary control of respiration originate?

Primary motor cortex

What term describes the ease with which lung tissue expands during breathing?

Pulmonary compliance

An inactive person, unconscious of their respiratory rate, is performing which type of breathing?

Quiet

What process is facilitated by the elastic components of the lungs and bronchial tree?

Quiet exhalation

The amount of air remaining in the lungs after a forced expiration

Residual Volume (RV)

Emphysema is a respiratory disorder that results in the loss of alveoli. Based on this, what would be affected by emphysema?

Respiratory membrane surface area

Originates in the main bronchi but invades the mediastinum and metastasizes quickly

Small-cell carcinoma

Originates in the basal cells of the bronchial epithelium

Squamous cell carcinoma

Detect: inflation of the lungs

Stretch receptors

The lungs of premature infants often develop respiratory distress syndrome. Why do these infants experience alveolar sac collapse?

Surfactant is not produced yet in adequate quantities

Which term refers to the exchange of gases (O2 and CO2) that occurs in the capillary networks between the blood and the body's cells?

Systemic gas exchange

Why do the lungs expand along with the thoracic cage during inspiration?

The cohesion of water causes the visceral pleura to cling to the parietal pleura

What does oxygen bind to in the hemoglobin molecule?

The heme group

What statement best defines Boyle's law?

The pressure of a given quantity of gas is inversely proportional to its volume at a constant temperature

What best defines partial pressure?

The pressure that each gas in a mixture would exert alone

What best summarizes the Haldane effect?

The rate of CO2 loading into the blood is increased in metabolically active tissues

Oxygen loading in the lungs decreases hemoglobin's affinity for H+. How does this promote alveolar gas exchange?

The released H+ combines with HCO3- to form free CO2, which can diffuse out of the blood

Ambient (outside) air is 22C is inhaled. The gases are warmed to body temperature (37.5C) by the time they reach the alveoli of the lungs. According to Charles's Law, what will happen to the volume of the inhaled air?

The volume will increase

How do the elastic components of the lungs and bronchial tree help conserve energy?

They facilitate recoil during exhalation

The amount of air inhaled and exhaled during quiet breathing

Tidal Volume (TV)

T/F: decreasing the volume of air in the lungs will decrease intrapulmonary pressure relative to atmospheric pressure

True

T/F: prolonged exposure to oxygen at 2.5 ATM can be toxic.

True

T/F: the anatomical dead space is subtracted from tidal volume when calculating the alveolar ventilation rate.

True

Pulmonary compliance is reduced in what type of people?

Tuberculosis patients

The ___ maneuver entails increasing abdominal pressure by holding a deep breath while contracting the abdominal muscles. The depressed diaphragm increases abdominal pressure and helps push out organ contents during childbirth, urination and defecation.

Valsalva

The ____ respiratory group sets the basal respiratory rate which may then be adjusted by commands from the pontine and/or dorsal respiratory groups

Ventral

The primary generator of the automatic, involuntary respiratory rhythm

Ventral respiratory group

The sum of the expiratory reserve volume, tidal volume and inspiratory reserve volume is

Vital capacity

The majority of carbon dioxide is transported through the blood in the form of what?

bicarbonate