PHYSIO CH 16

Review the structures and functions of the conducting zone and respiratory zones of the lungs.

Conducting zone consists of nose, mouth, pharynx, larynx, trachea, primary bronchii, terminal bronchioles

Respiratory zone consists of respiratory bronchioles, alveoli, and terminal alveoli

Describe the structures involved in gas exchange in the lungs and explain how gas exchange occurs.

Diffusion through lung tissue between oxygen and blood in the lungs through pulmonary alveoli

Review the locations and significance of the pleural membranes.

Parietal pleura- lines inside of thoracic wall

Visceral pleura- covers surface of lungs

Explain how quiet inspiration and quiet expiration are accomplished

Quiet inspiration- diaphragm muscle contraction, increase thoracic volume vertically, external intercostals raise when contracted and increase thoracic volume,

Quiet expiration- passive process, muscles relax

Explain how forced inspiration and forced expiration are accomplished.

Forced inspiration- Diaphragm, external intercostal muscles, (scalenes, pectoralis minor)

Forced expiration- internal intercostals contract and depress, abdominal muscles contract

Describe the lung volumes and capacities and explain how pulmonary function tests relate to pulmonary diseases especially asthma, COPD, pulmonary fibrosis (as we did in lab).

Tidal Volume-

Inspiratory Reserve Volume-

Expiratory Reserve Volume-

Residiual Volume-

Total Lung Capacity-

Vital Capacity-

FEV1- forced expiratory volume in 1 second

Explain how partial pressures are calculated, and their significance in measurements of arterial gases.

Describe the factors that influence the partial pressure of blood gasses and the total content of oxygen in the blood.

Oxygen levels, atmospheric pressure

Describe the significance of ventilation/perfusion in the lungs.

Gas exchange, getting O2 in and CO2 out

Explain how ventilation is regulated by the CNS.

-Skeletal muscle contractions controlled by motor meurons (contracting diaphragm)

-Cerebrum sends APs to motor neurons to voluntary inspire

-Medulla has respiratory centers with pacemaker like cells and send APs to motor neurons that control diaphragm/external intercostals

-Chemoreceptos send info about blood or CSF to medullary respiratory centers to adjust ventilation

Explain how blood gasses and pH influence ventilation.

Peripheral chemoreceptors- sens PO2 and and ph of arterial blood, send info to medullary respiratory center to adjust ventilation

Central chemoreceptors- sense pH of CSF, send pH info to medullary respiratory center to adjust ventilation

Describe the effects of voluntary hyper and hypo ventilation on arterial PO2, pH.

Hyperventilation- increase PO2, PCO2 decrease, pH increase

Hypoventilation- decrease PO2, PCO2 increase, pH decrease

Explain the relationship between ventilation and arterial PCO2.

If ventilation increases, PCO2 decreases

If ventilation decreases, PCO2 increases

Explain the effect of increased PCO2 on: (1) chemoreceptors in the medulla, and (2) chemoreceptors in the carotid and aortic bodies

Central chemoreceptos in medulla- high PCO2= low pH, detect and adjust ventilation (increase breathing)

Peripheral chemoreceptors in carotid- high PCO2=low pH and low PO2

Explain the role of arterial PO2 in the regulation of breathing.

Describe the changes in percent oxyhemoglobin as a function of arterial PO2 and explain how this relates to O2 transport

Explain how various conditions influence the oxyhemoglobin dissociation curve and O2 transport.

Use a graph to illustrate the effects of PO2 on O2 loading and unloading.

Draw an oxyhemoglobin dissociation curve and label the PO2 values for arterial and venous blood at rest.

Explain how temp and pH affect O2 unloading.

Explain how CO2 is transported in the blood, and state the percentages of CO2 carried by each way.

Explain the relationship between blood PCO2 and blood pH. State the chemical equation that describes this relationship. Explain how blood CO2 influences blood pH.

Describe the acid-base balance of the blood. How is it influenced by the respiratory system and the renal system

Define: acidosis, alkalosis.

Acidosis- pH below 7.35

Alkalosis- pH above 7.45

Describe the effects of hyperventilation and hypoventilation on the pH of the blood. Explain the mechanisms involved.

Explain why a person with ketoacidosis hyperventilates.

Explain the effects of high altitude on respiration. How does the body compensate for low PO2 at high altitude?

Describe the structure of the respiratory membrane (include the tissues

present).

16.1

The actual sites of gas exchange within the lungs are _____.

A) bronchioles

B) alveolar ducts

C) pleural spaces

D) alveoli

E) terminal sacs.

16.1

D) alveoli

Ventilation is also known as _____.

A) breathing

B) inspiration

C) expiration

D) air conduction

E) blowing.

16.1

A) breathing

Pulmonary ventilation refers to the ______.

A) movement of air into and out of the lungs,

B) movement of dissolved gases from the alveoli to the blood

C) movement of dissolved gases from the blood to the interstitial space

D) movement of dissolved gases from the interstitial space to the cells

E) utilization of oxygen.

16.1

A) movement of air into and out of the lungs

Which of the following features of the alveoli allows for the ease of diffusion of gasses?

A) They are made of a single layer of simple squamous epithelium

B) Type II alveolar cells secrete surfactant

C) Elastin fibers allow the alveoli to stretch thin enough for diffusion to occur

D) They are made of a single layer of simple squamous epithelium and elastin fibers allow the alveoli to stretch thin enough for diffusion to

occur.

16.1

D) They are made of a single layer of simple squamous epithelium and elastin fibers allow the alveoli to stretch thin enough for diffusion to occur.

The distance between the alveolar airspace and capillary endothelium is ________, allowing gases to diffuse ________ between them.

A) short, rapidly

B) long, rapidly,

C) short, slowly

D) long, slowly

E) None of the answers are correct—distance does not affect diffusion rate.

16.1

A) short, rapidly

Explain what lung compliance is. Why is compliance important?

16.2 Ability of the lungs to stretch- required for inspiration

Explain what lung elasticity is. Why is elasticity important?

16.2 ability of lungs to return to original volume after stretching - required for expiration

The term used to describe the ease with which the lungs stretch in response to an increase in alveolar pressure is:

A) accommodation

B) pleurisy

C) pliability

D) compliance

E) elasticity.

16.2

D) compliance

Select the lung disease that best matches this description: "destruction of alveoli".

A) fibrotic lung disease (pulmonary fibrosis)

B) emphysema

C) asthma

D) pulmonary edema

E) none of these.

16.2

B) emphysema

Select the lung disease that best matches this description: "thickened alveolar membrane and decreased lung compliance".

A) fibrotic lung disease (pulmonary fibrosis)

B) emphysema

C) asthma

D) pulmonary edema

E) none of these.

16.2

A) fibrotic lung disease (pulmonary fibrosis)

Select the lung disease that best matches this description: "decreased surface area for gas exchange".

A) fibrotic lung disease (pulmonary fibrosis)

B) emphysema

C) asthma

D) pulmonary edema

E) none of these.

16.2

B) emphysema

Select the lung disease that best matches this description: "Increased airway resistance".

A) fibrotic lung disease (pulmonary fibrosis)

B) emphysema

C) asthma,

D) pulmonary edema

E) none of these.

16.2

C) asthma

________ is characterized by a decreased surface area for gas exchange in the lungs.

A) emphysema

B) asthma

C) pulmonary fibrosis.

16.2

A) emphysema

Are any motor commands required for quiet inspiration? Explain.

16.3

Yes, contraction of diaphragm and external intercostal muscles

Are any motor commands required for expiration? Explain.

16.3

No, relaxation of muscles

In some diseases (hint: emphysema) lung elasticity is lost. Explain what effect this has on ventilation.

16.3

Lungs cannot cannot push air out

List some reasons as to why alveolar PO2 might be lower than normal. Give examples of each.

16.3

Reduced oxygen supply

Decreased respiratory rate or tidal volume

Low atmospheric pressure

When the diaphragm and external intercostal muscles contract _____

A) the volume of the thorax increases

B) the volume of the thorax decreases

C) the volume of the lungs decreases

D) the lungs collapse

E) expiration occurs.

16.3

A) the volume of the thorax increases

In quiet breathing _______

A) inspiration and expiration involve muscular contractions

B) inspiration is passive and expiration involves muscular contractions,

C) inspiration involves muscular contractions and expiration is passive

D) inspiration and expiration are both passive processes

E) None of the answers are correct.

16.3

C) inspiration involves muscular contractions and expiration is passive

Forced expiration is accomplished by contraction of _____.

A) abdominal muscles only

B) diaphragm only

C) internal intercostals only

D) external intercostals only

E) abdominal muscles and internal intercostals.

16.3

E) abdominal muscles and internal intercostals.

It normally requires no muscular contraction to expire air from the lungs. A) True

B) False.

16.3

A) True

During ventilation, the amount of air that is expired in a breath is a _____.

A) tidal volume

B) inspiratory reserve volume

C) expiratory reserve volume

D) minimal volume

E) vital capacity.

16.3

A) tidal volume

Even after exhaling as forcefully as possible, a person still has about a liter of air within the respiratory system.

A) True

B) False.

16.3

A) True

During normal expiration ______.

A) elastic recoil of stretched muscles helps return the thorax to its resting volume

B) the internal intercostal muscles are required

C) the abdominal muscles become involved

D) elastic recoil of stretched muscles helps return the thorax to its resting volume and the internal intercostal muscles are required

E) elastic recoil of stretched muscles helps return the thorax to its resting

volume, the internal intercostal muscles are required, and the abdominal muscles become involved

16.3

A) elastic recoil of stretched muscles helps return the thorax to its resting volume

List the 4 main gases found in atmospheric air. Which are the 2 that make up most of our atmosphere? What percent of the air do these 2 contribute?

16.4

O2, CO2, N2, H2O

O2- 20.95%

N2- 78%

What is the partial pressure of oxygen in the alveoli?

16.4

105mmHg

What is the partial pressure of oxygen in the venous blood?

16.4

40mmHg

What is the partial pressure of CO2 in the alveoli?

16.4

40mmHg

What is the partial pressure of CO2 in venous blood?

16.4

40mmHg

Describe how O2 moves from the alveolar air and into the blood at the alveoli. Describe how CO2 moves out of the blood and into the alveolar air. What determines the rate of diffusion?

16.4

Oxygen moves from lungs to blood from high partial pressure to low partial pressure

Partial pressure differences, large surface area, think respiratory membrane

Which gas (O2 or CO2) is easiest to exchange? Explain why.

16.4

CO2 dissolves into water/blood

Diffuses faster

The partial pressure of CO2 in the pulmonary trunk would be about

________________ (include units). The partial pressure of O2 in the pulmonary trunk would be about ________________ (include units). We may not have explicitly stated these values in class, but you can determine what they must be.

16.4

45mmHg, 40mmHg

The partial pressure of CO2 in the aorta is ________________ (include units). The

partial pressure of O2 in the aorta is ________________ (include units). We may not have explicitly stated these values in class, but you can determine what they must be.

16.4

40mmHg, 105mmHg

What flow rate of blood through the pulmonary circuit is ________ (include units). We may not have explicitly stated this value in class, but you can determine what it must be based on your knowledge of blood flow in the cardiovascular system.

16.4

5L/min

Of the factors that influence diffusion of respiratory gases, the most variable and, therefore, important factor to consider is the _______.

A) partial pressure gradient

B) diffusion distance

C) membrane surface area

D) membrane thickness

E) electrical charge.

16.4

A) partial pressure gradient

The process by which dissolved gases are exchanged between the blood and interstitial fluid is _____________________.

A) pulmonary ventilation

B) external respiration

C) diffusion

D) cellular respiration

E) internal respiration.

16.4

E) internal respiration.

The process by which dissolved gases are exchanged between the blood and the alveolar air is _____________________.

A) pulmonary ventilation

B) external respiration

C) diffusion

D) cellular respiration

E) internal respiration.

16.4

B) external respiration

The partial pressure of oxygen in arterial blood is approximately ________ mm Hg.

A) 40

B) 45

C) 50

D) 70

E) 100

16.4

E) 100

The partial pressure of oxygen in venous blood is approximately ________ mm Hg.

A) 40

B) 45

C) 50

D) 70

E) 100

16.4

A) 40

The partial pressure of CO2 in arterial blood is approximately ________ mm Hg.

A) 40

B) 45

C) 50

D) 70

E) 100

16.4

A) 40

The partial pressure of CO2 in venous blood is approximately ________ mm Hg.

A) 40

B) 45

C) 50

D) 70

E) 100

16.4

B) 45

Generally, PO2 in arterial blood is ________ than PO2 in venous blood.

A) higher

B) lower

C) about the same as.

16.4

A) higher

Generally, PCO2 in arterial blood is ________ than PCO2 in venous blood.

A) higher,

B) lower

C) about the same as.

16.4

B) lower

Oxygen is the main (most numerous) molecule in atmospheric air.

A) True

B) False.

16.4

B) False.

The percent of the atmosphere that is CO2 is about:

A) 0.04%

B) 5%

C) 10%

D) 21%

E) 45%.

16.4

A) 0.04%

PCO2 tends to be ________ in tissues than in systemic capillaries.

A) higher

B) lower

C) about the same as.

16.4

A) higher

Write out the complete chemical equation that describes what happens to CO2 when it reacts with water. Name any enzyme involved.

16.5

CO2 + H20 -> H2CO3 -> H+ + HCO3-

Carbonic anhydrase

Explain how the concentration of hydrogen is related to the arterial PCO2. (hint: this will require the use of a chemical equation)

16.5

Hydrogen determines blood pH

Increased PCO2= more carbonic acid= more H+, reduces pH

Decreased PCO2= less carbonic acid= less H+=increase H+

The region (part) of the brain that contains the groups of neurons that set a basic pattern of ventilation is the _____________.

16.5

Medulla oblongata

Of the chemoreceptors that deliver sensory information to respiratory centers, the most important are the ____________________. These are located in the __________________ (be specific). These neurons directly monitor the

concentration of hydrogen in the __________________. This concentration of

hydrogen is strongly affected by the partial pressure of ___________ in the

__________________ (which vessels?).

16.5

Central chemoreceptors, medulla oblongata, CSF, PCO2 in aterial blood

Use arrows (up or down) to complete the following:

a. Increases in arterial PCO2 will ________ the hydrogen ion concentration of

the cerebrospinal fluid. This will __________ the pH of the cerebrospinal

fluid. The compensatory response will be a/an ________ in ventilation.

16.5

Increase, decrease pH, increase

Decreases in arterial PCO2 will ________ the hydrogen ion concentration of

the cerebrospinal fluid. This will __________ the pH of the cerebrospinal

fluid. The compensatory response will be a/an ________ in ventilation.

16.5

Decrease, increase pH, decrease

The peripheral chemoreceptors that influence respiration are the ______________ and _________________.

16.5

carotid bodies, aortic bodies

The peripheral chemoreceptors sense/detect what qualities of the arterial

blood? There are 2 that are directly detected (the third is only indirectly

detected). Of these which is most important?

16.5

Chemical changes in blood or CSF to adjust ventilation

Decrease in PCO2

Specialized cells in the ______ and _____ bodies are stimulated by a decrease in PO2 and/or change in arterial blood pH.

16.5

Carotid and aortic

List the sources of hydrogen ions in the arterial blood. For each, give an example of a situation when H+ concentration would increase due to that source.

16.5

Hypoventilation- increased CO2-> increase H+

Excessive exercise- LAP

The carotid bodies are most sensitive to ___________________ in arterial blood. They send action potentials to the brain only when levels of ____________ (a gas) reach about ___________________ (include units). The partial pressure of that gas in arterial blood is normally about __________________ (include units).

16.5

Decrease, oxygen, below 40mmHg, 100mHg

Generally, how important are the peripheral chemoreceptors compared to the central chemoreceptors in helping to determine ventilation rate?

16.5

Important for moment to moment breathing

Which of the following has the strongest stimulatory effect on pulmonary ventilation?

A) high PCO2 of the arterial blood

B) low PO2 of the arterial blood

C) low PO2 of the alveolar air

D) low arterial blood pressure

E) all of these have an equal influence on ventilation.

16.5

A) high PCO2 of the arterial blood

________ is the enzyme that converts CO2 into carbonic acid (which may then dissociate into bicarbonate ions).

A) carboxylic acidase

B) bicarbonase

C) carbonara

D) carbonic anhydrase

E) carbonic acidase.

16.5

D) carbonic anhydrase

The respiratory centers of the CNS that contain a sort of pacemaker that sets the rhythm of quiet ventilation, are located in the:

A) spinal cord

B) hypothalamus

C) medulla oblongata

D) diaphragm

E) cerebrum.

16.5

C) medulla oblongata

The central chemoreceptors increase their firing rate when they detect an increase in the concentration of ____________ in the CSF, resulting in _____________ ventilation.

A) H+; increased

B) H+; decreased

C) carbon dioxide; increased

D) carbon dioxide; decreased.

16.5

A) H+; increased

The central chemoreceptors decrease their firing rate when they detect a decrease in the concentration of ____________ in the CSF, resulting in _____________ ventilation.

A) H+; increased

B) H+; decreased

C) carbon dioxide; increased

D) carbon dioxide; decreased

E) oxygen ; normal ventilation

16.5

B) H+; decreased

Predict the effect of hyperventilation on blood PCO2.

A) increase

B) decrease

C) no effect.

16.5

B) decrease

Which of the following variables influences pulmonary ventilation rate the most?

A) the PCO2 of the arterial blood

B) the PO2 of the arterial blood

C) the PO2 of the alveolar air

D) the arterial blood pressure

E) all of these have an equal influence on ventilation.

16.5

A) the PCO2 of the arterial blood

Which of the following is the most important chemical regulator of respiration?

A) oxygen

B) carbon dioxide

C) bicarbonate ion

D) sodium ion

E) hemoglobin.

16.5

B) carbon dioxide

An increase in the level of carbon dioxide in the blood will _____.

A) decrease the rate of breathing

B) increase the rate of breathing

C) decrease pulmonary ventilation

D) decrease the alveolar ventilation rate

E) increase the pH of arterial blood.

16.5

B) increase the rate of breathing

If the neural connections between the pons and medulla are severed, breathing will stop.

A) True

B) False

16.5

B) False

Blocking action potentials from the chemoreceptors in the carotid and aortic bodies to the CNS might interfere with the brain's ability to regulate breathing in response to all EXCEPT which of the following?

A) changes in PCO2

B) changes in PO2

C) changes in pH due to carbon dioxide levels

D) changes in blood pressure

E) All of the answers are correct

16.5

D) changes in blood pressure

The protein that carries O2 in the blood is _______________. How many O2 molecules does one of these proteins carry?

16.6

Hemoglobin, 1 hemoglobin-4 O2 molecules

Describe how O2 moves into or out of an RBC. Describe how O2 moves out of an RBC into the alveolar air (mechanism). What determines the rate that O2 moves out of/in to the cell?

16.6

O2 bond to hemoglobin and pass through partial pressure gradient. Alveolar air has 105mmHg push out to capillaries where pressure is 40mmHg (high to low), O2 pushed out and bind to hemoglobin

What are the ways that O2 is carried in the blood? For each list the percent of oxygen carried in this way. Hint there are two.

16.6

99% O2 bound to hemoglobin, 1% dissolved