Unit 4 Respiratory Flashcards by Paula Mokrzycka

Major functions of the respiratory system

Gas exchange
pH regulation
Pathogen protection
Vocalization
Route for water and heat loss
Activation of some plasma proteins

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Anatomy of: Conducting zone

nose, nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, terminal bronchioles

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Anatomy of: Respiratory exchange zone/ gas exchange tissue

(actual site of gas exchange)

respiratory bronchioles, alveolar sacs, alveoli

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Anatomy of: Pleural cavities

in the thoracic cavity (above diaphragm), there are (2) pleural cavities, each hold a lung, the pleura form a thin double-layered serosa (visceral and parietal). pleural cavity is in between them

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Visceral pleura

lines the exterior surface of lungs

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Parietal pleura

lines the thoracic wall, superior face of diaphragm, continues around the heart between lungs

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Intrapleural pressure

pressure in pleural cavity; rises and falls but is always about -4 than intrapulmonary pressure (756 mm Hg)

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Intrapulmonary pressure

pressure in the alveoli; rises and falls but eventually equalizes with atmospheric pressure =0 (760 mm Hg)

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Transmural/transpulmonary pressure

difference between intrapulmonary and intrapleural pressure +4

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How do intrapulmonary and intrapleural pressures counter lung elasticity?

elasticity tries to pull air in and compress the lungs; negative pressure tries to pull lungs out/ expand the lungs

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Explain the mechanics of rhythmic inspiration. Include muscles involved, volume changes, and pressure changes.

(AKA “normal” inspiration)

Active process b/c it involves contraction of diaphragm and external intercostals
This muscle contraction causes thoracic cavity to enlarge
Intrapleural pressure decreases from -4 to -6 mm Hg (Boyle’s Law)
This expands the lungs
Intra-alveolar pressure decreases from 0 to -1 mm Hg
This allows the atmospheric pressure to push air into the lungs
The intra-alveolar pressure then increases back to zero and air stops moving in

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Explain the mechanics of rhythmic expiration. Include muscles involved, volume changes, and pressure changes.

(AKA normal “quiet” expiration)

A passive process/ relaxation of diaphragm and external intercostal muscles
Causes thoracic cavity to compress
Intrapleural pressure increases from -6 to -4 mm Hg
Lungs compress
Intra-alveolar pressure increases from 0-+1 mm Hg
This forces the air in lungs to move outward
Intra-alveolar pressure decreases back to 0 and air stops from moving out

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Explain the mechanics of enhanced inspiration. Include muscles involved, volume changes, and pressure changes.

(AKA forced inspiration)
This is an amplification of the normal pattern
1. More muscle fibers in the diaphragm and external intercostals and may involve the accessory inspiratory muscles such as the scalene muscles and sternocleidomastoid.
2. This muscle contraction causes the thoracic cavity to enlarge
3. The intrapleural pressure then decreases from -4 to -8 mm Hg (Boyle’s Law)
4. This expands the lungs
5. The intra-alveolar pressure decreases from 0 – 2 mm Hg
6.This allows the atmospheric pressure to push air into the lungs
7. Intra-alveolar pressure then increases back to zero and air stops moving in

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Explain the mechanics of enhanced expiration. Include muscles involved, volume changes, and pressure changes.

(AKA forced expiration)
An amplification of the normal pattern except that this is an active process
1. It involves the contraction of the abdominal muscles and internal intercostal and the relaxation of the inspiratory muscles
2. This causes the thoracic cavity to compress
3. The intrapleural pressure increases from -8 to -2 mm Hg
4. This compresses the lungs
5. The intra-alveolar pressure increases from 0 to +2 mm Hg
6. This forces the air in the lungs to move outward
7. Intra-alveolar pressure then decreases back to zero and air stops moving out

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Describe how surfactant influences ventilation.

Surface active agent; decreases the

cohesiveness of water molecules (surface tension), easier to breath (without surfactant, our alveoli would collapse)

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Describe lung compliance and how it influences ventilation.

“How easy is it to expand the lung?”
A measure of the change in lung volume that occurs with a
given change in transpulmonary pressure.
More compliance= easier to breathe

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How does gas travel?

From an area of high pressure to low pressure

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Describe how airway resistance can influence ventilation.

Resistance is influenced by:

Bronchiolar diameter
Amount of mucus

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Airway resistance formula

F= Δ P/ R

gas flow = [change in pressure] / [resistance]

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What is the major nonelastic source of resistance to gas flow?*

Friction

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The amount of gas flowing into and out of the alveoli

is directly proportional to….*

… the difference in pressure, or pressure

gradient, between the external atmosphere and the alveoli.

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Small differences in pressure produce….*

… large changes in the volume of gas flow.

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What does “gas flow changes inversely

with resistance” mean?

gas flow decreases as resistance

increases.

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Define dyspnea.

Difficulty breathing or catching breath.

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Lung compliance is determined largely by which factors?

1. lung tissue | 2. alveolar surface tension

What are some physical factors that influence airway resistance?

- Asthma | - Inspiration/ Expiration influence diameter

In which ways does the nervous system influence airway resistance?

1. Sympathetic stimulation dilates bronchioles | 2. Parasympathetic stimulation constricts bronchioles

How do chemicals influence airway resistance?

Epinephrine- dilates bronchioles Histamine- constricts Anti-histamine- dilates

What are the factors responsible for generating the alternating inspiration and expiration pattern?

1. Dorsal respiratory group | 2. Rhythmic inspiratory neurons

Which factors regulate the rate and depth of ventilation?

1. Chemoreceptors (peripheral chemoreceptors in arteries; Central chemoreceptors in medulla oblongata) 2. CO2, (major control) 3. O2 4. H+

Define hypocapnia.

low CO2 levels, slow & shallow breathing, decreased ventilation, possible apnea.

Define hypercapnia.

high CO2 levels in

Define hyperventilation.

An increase in the rate and depth of breathing that exceeds the body's need to remove CO2. Hyperventilation may be involuntary, pt becomes hypocapniac and become alkaline

Define tetany.

Involuntary muscle spasms, caused by falling levels of calcium while rising levels of pH.

Factors that influence voluntary control

Cerebral cortex can override rhythmic breathing

Control of breathing during rest is aimed primarily at regulating...

the H+ concentration in the brain.

Define hypoventilation.

holding breath-> high CO2 levels-> high H+ (become acidic)

pH greater than 7

Alkaline/ basic

pH levels below 7

Acidic

High levels of CO2 make your pH...

Acidic

Low levels of CO2 make your pH...

Alkaline/ basic

Define Dalton's Law.

(of Partial Pressure) how gas behaves when mixed; states that partial pressure is directly proportional to the percentage of that gas in the mixture. (total of mixed pp is the sum of pressures exerted by each independent gas.

Define Henry's Law.

How gases move in and out of solutions; states that the amount of gas that will dissolve in a liquid is proportional to the partial pressure of that gas

Partial pressure

The pressure exerted by each gas.

What is the percent of oxygen in our atmosphere at sea level?

21%

What is the partial pressure of one atmosphere at sea level?

760 mm Hg

Increased temperature of a liquid ___________ the amount of dissolved gases

decreases

Higher partial pressures in the atmosphere or lungs ___________ the potential amount in the liquid or bloodstream.

increases

Which is more soluble in blood: oxygen or carbon dioxide?

CO2 is 20x more soluble than O2

What are the partial pressures of O2 and CO2 in the atmosphere/inspired air? (mm Hg)

``` PO2= 160 PCO2= 0.3 ```

What are the partial pressures of O2 and CO2 in alveolar pressures? (mm Hg)

``` PO2= 100 PCO2= 40 ```

What are the partial pressures of O2 and CO2 in pulmonary veins and systemic arteries? (mm Hg)

``` PO2= 100 PCO2= 40 ```

What are the partial pressures of O2 and CO2 in systemic veins and pulmonary arteries? (mm Hg)

``` PO2= 40 PCO2= 46 ```

What are the partial pressures of O2 and CO2 in expired air? (mm Hg)

``` PO2= 116 PCO2= 32 ```

How would we calculate the pp of oxygen in the atmosphere (at sea level)?

Use Dalton's law | [Atmosphere= 760 mm Hg] x [21% oxygen= 0.21]= 160 mm Hg

What factors influence the solubility of gases in liquid/blood?

(1) solubility of gas (2) temp of liquid (3) concentration gradient (per Henry's Law)

If the air has a pp of 100 mm Hg, what would be the pp of the liquid? *

100 mm Hg

Define external respiration.

The uptake of O2 and unloading of CO2 from hemoglobin in RBCs.

Explain Hemoglobin F.

Fetal hemoglobin has higher affinity then maternal hemoglobin because it can’t bind to BPG (influencing the O2- Hg curve).

What is the difference between atmospheric and alveolar gaseous makeup?

Atmospheric is mostly made up of O2 and N2. Alveolar is contain more CO2 and water vapor and much less O2.

Define Tidal volume (TV)*

air that moves into and out of the lungs with each breath (~500 mL)

Define Inspiratory reserve volume (IRV)*

air that can be inspired forcibly beyond the tidal volume (2100–3200 ml)

Define Expiratory reserve volume (ERV)

air that can be evacuated from the lungs after a tidal expiration (1000–1200 ml)

Define Residual volume (RV)*

air left in the lungs after strenuous expiration (1200 ml)

Define Dead Space*

volume of the conducting respiratory passages (150 ml)

Define Total Ventilation*

amount of gas flow into or out of the respiratory tract in one minute

Define Forced vital capacity (FVC)*

gas forcibly expelled after taking a deep breath

Define Forced expiratory volume (FEV)*

the amount of gas expelled during specific time intervals of the FVC

A steep partial pressure gradient exists between the ________ and ________, and O2 diffuses rapidly from the alveoli into the blood

pulmonary arteries; alveoli

CO2 moves in the opposite direction along ____________________ that is much less steep

a partial pressure gradient

The difference in the degree of the pp gradients of O2 and CO2 reflects the fact that....

CO2 is much more soluble than oxygen in blood.

The pp of O2 in the tissues is always ______ than the blood, so O2 diffuses ______ into the tissues; similar gradient exists in the opposite direction for CO2.

lower; readily

A shift downward to the right will ______ the afffinity of oxygen to hemoglobin thus making it easier to _______

decrease; unload oxygen from the Hg molecule.

Describe (Hb) hemoglobin

composed of 4 polypeptide chains bound to an iron-containing heme group, thus carrying a maximum of 4 O2 molecules.

Equation | which describes the loading and unloading of O2 in hemoglobin

O2 + Hb Hb - O2

The oxygen dissociation (saturation) curve has two important areas in its sigmod shaped curve, what are they?

1. Plateau (Hg maintains high O2 saturation while pO2 drops from 100 to 60 mm Hg. 2. Reserve (75% O2 reserve is available for exercising muscles)

A shift downward to the right will _______ in BPG (DPG), hydrogen ions, and temperature; __________ capillaries.

increase; | skeletal muscle capillaries during exercise.

A shift upward to the left will _____ the affinity of oxygen to hemoglobin thus making it easier to _______

increase; attach oxygen to Hg

A shift upward to the left will _______ in BPG (DPG), hydrogen ions, and temperature; __________ capillaries.

Decrease; pulmonary capillaries

CO2 shifts to the right in _______ capillaries and shifts the left in _______ capilarries

systemic; pulmonary

What are the 3 ways CO2 is transported?

1. Dissolved in CO2 (5%) 2. Carbamino Hemoglobin (8%) 3. Bicarbonate (87%)

Define BPG.

An organic chemical found in RBC that binds O2 to hemoglobin

Describe the shift in carbamino hemoglobin.

Dissolved CO2 + Hb-N-H2 Hb-NH-COO- + H+

Describe the shift in bicarbonate

Dissolved CO2 + H2O H2CO3 HCO3- + H+

Describe asthma.

Characterized by coughing, dyspnea, wheezing, and chest tightness, brought on by active inflammation of the airways.

Describe chronic bronchitis.

Excessive mucus production, as well as inflammation and fibrosis of the lower respiratory mucosa.

Describe emphysema.

Characterized by permanently enlarged alveoli and deterioration of alveolar walls.

Describe pneumothorax.

Presence of air in the pleural cavity.

Describe pneumonia.

Infectious inflammation of the lungs, in which fluid | accumulates in the alveoli. May be bacterial or viral.

Atelectasis

Collapsed lung

Dyspnea

difficult or labored breathing often | referred to as “air hunger,” gets progressively worse.

Unit 4 Respiratory Flashcards

(91 cards)