L16

Question 1

What are five mechanical descriptions of breathing?

Answer 1

1. Movement of air into and out of the lungs is caused by a pressure gradient
2. ATM pressure remains constant during breathing cycle
3. Alveolar pressure changes affect gradient
4. Boyles Law= pressure is inversely related to volume
5. Resistance to airflow is related to airway radius and mucus

Question 2

What is the formula for flow?

Answer 2

Patm-Palv/R

Question 3

At rest, diaphragm is _____
At inspiration, thoracic volume _____, diaphragm _____ and ________
At expiration, diaphragm ______, thoracic volume ______

Answer 3

Relaxed
increases, contracts, flattens
relaxes, decreases

Question 4

Describe characteristics of inspiration

Answer 4

• Pressure in lungs < ATM pressure
• occurs when alveolar pressure decreases
• involves contractions of skeletal muscles of rib cage and diaphragm

Question 5

Describe characteristics of expiration

Answer 5

• Pressure in lungs > ATM pressure
• occurs when alveolar pressure increases
• involves passive relaxation, elastic recoil returns rib cage and diaphragm to original relaxed position

Question 6

What is intrapleural pressure?

Answer 6

This is pressure inside the pleural sac, the surface tension of intrpleural sac/fluid prevents chest walls from pulling apart

Question 7

Subatompheric pressure keeps lungs inflated, what is the Normal intrapleural pressure of it? What happens during inspiration and expiration of the pressure?

Answer 7

3 mm Hg

Inspiration: pressure drops
Expiration: increases to normal pressure

Question 8

Explain what happens to the following during quiet breathing

Alveolar pressure
Intrapleural pressure
Volume of air moved

Answer 8

Alveolar pressure= decreases during inspiration, increases in expiration
Intrapleural pressure= decreases during inspiration, increases in expiration
Volume of air moved= increases during inspiration, decreases during expiration

Question 9

Explain what Pnemothroax is and what happens

Answer 9

If the sealed pleural cavity is opened to the atmosphere, air flows in. The bond holding the lungs to the chest wall is broken and lungs collapse. This creates Pnemothroax (air in thorax)

Question 10

What is compliance, what happens during high compliance, what happens during low compliance?

Answer 10

Compliance= this is the ability to stretch

High compliance mean stretches easily
Low compliance means it requires more force and restrictive to lung diseases. Fibrotic lung diseases is inadequate for surfactant production

Question 11

What does elastance mean?

Answer 11

This is the ability to return to resting volume when stretching forces is released (force exerted by elastic fibres)

Question 12

What is surface tension? What are surfactants?

Answer 12

Surface tension is the thin layer of fluid that lines alveoli, the surface tension arises due to attraction between water molecules

Surfactants are surface active agents that disrupt cohesive forces of water and are mixtures containing proteins and phospholipids. More [ ] in smaller alveoli. More surfactants you have, the less surface tension you have.

Question 13

what is the law of Laplace? What does the Law of Laplace state? Give examples with bubbles and surface tension.

Answer 13

• 2T/r
• if two bubbles had the same surface tension, the smaller bubble will have higher pressure
• in lungs, smaller alveoli have more surfactants which equalize pressure between large and small alveoli
• smaller radius means an increase in surfactants and more surfactants means a reduced surface tension

Question 14

What is the primary determinant of airway resistance?

Wider airways have _______ resistance

Answer 14

Airway diameter

Less resistance

Question 15

What is bronchocosntriction?

What is broncodialation

Answer 15

Bronchoconstriction:

• This is an increase in resistance.
• caused by parasympathetic and histamines

Bronchodialation:

• this is a decrease in resistance
• sympathetic, epinephrine (beta 2 receptors and Co2)

Question 16

What are the five factors that impact the airway?

Answer 16

1. Length of system (constant, not really a factor)
2. Viscosity of air (usually constant, but humidity and altitude may affect)
3. Diameter of airway
4. Upper airways (physical obstruction is and effector, mediated by mucus)
5. bronchioles (bronchodialation and constriction)

Question 17

What is total pulmonary ventilation?

Answer 17

• volume of air moved out of lungs per minute

- TPV= ventilation rate x tidal volume

Question 18

What is alveolar ventilation?

Answer 18

This is volume of air receiving alveoli per minute and its more accurate

Question 19

Name and describe the five types of ventilations

Answer 19

Eupnea- Normal quiet breathing
Hyperpnea- increased respiratory rate/volume increases in response to metabolism (usually exercise based)
Tachypnea- rapid breathing, increased respiratory rate with decreased depth
Dyspnea- difficulty breathing (air hunger) various pathologies
Apnea- cessation of breathing, voluntary breath holding

Question 20

What are the four steps in the ventilation cycle?

Answer 20

1. At the end of inspiration, dead space is filled with fresh air
2. Exhale 500ml of air (tidal volume)
3. At end of expiration, dead space is filled with stale air from alveoli
4. Inhale 500ml of fresh air (tidal volume)

Question 21

When O2 entered the alveoli, O2 also enters ______

Answer 21

The blood

Question 22

A total of ___% of fresh air goes into lungs

Answer 22

10

Question 23

Ventilation and alveolar blood flow are _____ (to ensure efficient gas exchange)

Answer 23

Matched

Question 24

As alveolar ventilation increases, what happens to alveolar Po2 and Pco2?

Answer 24

Alveolar Po2 increases and Pco2 decreases. Opposite occurs when alveolar Op2 decreases

Question 25

What is the difference between hyper and hypoventilation?

Answer 25

Hyperventilation: exceeding demands, therefore PP increases and CO2 decreases Hypoventilation: isn’t meeting demands, CO2 increases and PP decreases

Question 26

As the following components increase of decrease, what happens to bronchioles, pulmonary arteries and systemic arteries? Pco2 increases Pco2 decreases Po2 increases Po2 decreases

Answer 26

Pco2 increases= bronchioles dilate, pulmonary arteries constrict, systemic arteries dilate Pco2 decreases= bronchioles constrict, pulmonary arteries dilate, systemic arteries constrict Po2 increases= bronchioles constrict, pulmonary arteries dilate, systemic arteries constrict Po2 decreases= bronchioles dilate, pulmonary arteries constrict, and systemic arteries dilate

Question 27

What percentage of O2 in blood is dissolved? What is the percentage of the other half, where does it go?

Answer 27

<2% of the oxygen in blood is dissolved, the other 98% of oxygen is transported by hemoglobin

Question 28

Hemoglobin in its normal form is called _______ | While hemoglobin attached to oxygen is called _____

Answer 28

Hemoglobin | Oxyhemoglobin

Question 29

How is saturation of Hb measured?

Answer 29

How much Hb is bound to oxygen measures the total saturation of it.

Question 30

What happens at 100% saturation?

Answer 30

All four binding sites of the heme groups are bounds to oxygen

Question 31

The composition of arterial blood: Hb is ____ saturated | The composition of Venous blood: Hb is ____ saturated

Answer 31

98% | 75%

Question 32

Explain the oxygen transport in the blood. Use reaction shifts to explain answer. What does a rightward and leftward shift mean?

Answer 32

An increase in Po2 shifts the reaction right (Hb+o2–>Hbo2) | A decrease in Po2 shifts the reaction left (Hb+o2

Question 33

Basic summary of a right shift

Answer 33

- decrease affinity, more O2 released - decrease in pH - increase in both temperature and Pco2 - represented by an increase in metabolic activity

Question 34

Basic summary of a left shift

Answer 34

- increases affinity - less O2 released - increase in pH - decrease in temperature and Pco2 - this represents a decrease in metabolic activity

Question 35

What is the Bohr effect?

Answer 35

This is a shift in the hemoglobin saturation curve resulting from from a pH change. (Lower pH increases O2 unloading)

Question 36

Explain 2,3, bisphosphoglycerate (2,3BPG) and its relation to saturation curves

Answer 36

- this causes a shift to the right | - chronic hypoxia increases RBC production of 2,3BPG

Question 37

Explain the effects of CO2 on saturation curves

Answer 37

- hemoglobin has a greater affinity for CO than for O2, this prevents O2 from binding to hemoglobin - low oxygen increases 2,3 BPG—> right shift and overall increases oxygen - increasing CO2 means Hb desaturation and results in right shift - decreasing CO2 means Hb saturation and results in left shift

Question 38

With saturation curves, what happens to temperature and pH? What are the right and left shifts?

Answer 38

pH: Increase in pH—> results in left shift Decrease in pH—> results in right shift (by increasing H+ you get a right shift) Temperature: Increasing in temperature—> results in right shift (less saturated) Decreasing in temperature—> results in left shift (more saturated)

Question 39

The hemoglobin in fetuses are 2 ___ and in adults are 4 ____ The total O2 content of arterial blood depends on the ______ dissolved in the plasma and bound to hemoglobin

Answer 39

Gamma, beta Amount of O2

Question 40

What are the carbamino effect and haldane effect?

Answer 40

Carbamino effect: when Co2 is bound to hemoglobin, the conformation of hemoglobin changes and decreases affinity for O2 Haldane effect: CO2 contents of blood falls as Po2 rises and binding of O2 to hemoglobin decreasing affinity of hemoglobin for CO2

Question 41

Carbonic anhydrase creates a ____ shift which exchanges HCO3 for CL to maintain electrical neutrality

Answer 41

Chloric

Question 42

Name the 8 steps for CO2 transport

Answer 42

1. CO2 diffuses out of the cell into systemic capillaries 2. Only 7% of CO2 remains dissolved in plasma 3. 1/4th of CO2 binds to Hb, forming HbCO2 4. 70% of CO2 is converted to bicarbonate and H+, Hb buffers H+ 5. HCO3 entrees plasma in exchange for CL (choleric shift) 6. At lungs, dissolved CO2 diffuses out fo plasma 7. CO2 unbind from Hb and diffuses out of RBC 8. HCO3 is pulled back into RBC and converts to CO2