Mechanics of Breathing

Question 1

what is respiration?

Answer 1

the exchange of oxygen and co2 w the external environment.

Question 2

Respiration requires what both systems?

Answer 2

cardiovascular and respiratory systems

Question 3

the respiratory system consists of those structures that move air into and out of the body. What are the systems called?

Answer 3

upper airways, conducting zone, and respiratory zone

Question 4

what do the upper airways include?

Answer 4

nose, mouth, pharynx, and larynx

Question 5

what does the conducting zone include?

Answer 5

trachea, primary bronchi, and bronchi and bronchioles within the lungs

Question 6

what does the respiratory zone include?

Answer 6

respiratory bronchioles, alveolar ducts, and alveolar sacs (all within the lungs)

Question 7

how do the systems function?

Answer 7

the upper airways and conducting zone function to transport air to and from the respiratory zone

Question 8

in which system does gas exchange occur?

Answer 8

within the respiratory zone

Question 9

gas exchange occurs in tiny, thin-walled sacs called

Answer 9

alveoli

Question 10

how is the wall of an alveolus structured? what do they consist of?

Answer 10

very thin, consist of a single layer of flat cells called type I cells.

Question 11

what else also makes up the alveolar wall? besides type I cells.

Answer 11

type II cells are interspersed among the type I cells

Question 12

what do type II cells produce? what else do they do?

Answer 12

pulmonary surfactant; are also stem cells that produce new type I and II cells

Question 13

what does pulmonary surfactant do?

Answer 13

prevents collapse of the alveolar wall

Question 14

what are the outer surfaces of the alveoli covered by?

Answer 14

pulmonary capillaries

Question 15

what separates the capillary walls from the alveolar walls? what does it consist of?

Answer 15

thin interstitial space; ISF and loose connective tissue

Question 16

what makes up the respiratory membrane?

Answer 16

alveolar wall, interstitial space, and capillary wall

Question 17

what occurs across the respiratory membrane? what is the total distance bw the air and plasma?

Answer 17

gas exchange; (very thin) 0.2 micrometers

Question 18

what is the chest? what is located here?

Answer 18

a closed compartment separated from the neck and abdomen by bone, connective tissue, and muscle; the lungs

Question 19

each lung is surrounded by what?

Answer 19

a double-walled pleural sac

Question 20

what is the outer wall of the pleural sac called? what is it attached to?

Answer 20

parietal pleura; attached by connective tissue to the chest and diaphragm muscle

Question 21

what is the inner wall of the pleural sac called? what is it attached to?

Answer 21

visceral pleura; attached to outer surface of the lung

Question 22

what are the two pleura layers separated by? what is the hydrostatic pressure of this fluid called?

Answer 22

thin layer of intrapleural fluid; intrapleural pressure

Question 23

what pressure is important in the process of ventilation?

Answer 23

intrapleural pressure

Question 24

the exchange of air bw the atmosphere and the alveoli

Answer 24

ventilation

Question 25

what are the two phases of ventilation?

Answer 25

inspiration and expiration

Question 26

movement of air from the atmosphere to the alveoli

Answer 26

inspiration

Question 27

movement of air from the alveoli to the atmosphere

Answer 27

expiration

Question 28

what does ventilation depend on?

Answer 28

the contraction and relaxation of respiratory muscles

Question 29

ventilation occurs by what? and what is it?

Answer 29

bulk flow; movement down a pressure gradient higher to lower pressure

Question 30

because pressures in the chest are set relative to the atmospheric pressure, atmospheric pressure is set at???

Answer 30

0mmHg

Question 31

what does a negative value for alveolar pressure mean?

Answer 31

that the pressure is lower than atm pressure

Question 32

what does a positive value for alveolar pressure mean?

Answer 32

the alv pressure is higher than atm pressure

Question 33

occurs when alveolar pressure is negative

Answer 33

inspiration

Question 34

occurs when alveolar pressure is positive

Answer 34

expiration

Question 35

how is airflow calculated?

Answer 35

F= (Palv-Patm)/R

Question 36

created by changes in the dimensions of the chest wall and lungs

Answer 36

pressure differences

Question 37

how are alveolar pressure and lung vol related?

Answer 37

inversely related (lung vol increases alv press decreases)

Question 38

how are pressure changes created?

Answer 38

contraction and relaxation of respiratory muscles

Question 39

what is the most important respiratory muscle at rest? what does it look like at rest?

Answer 39

diaphragm; dome shape

Question 40

what happens to the diaphragm when it contracts? what does it do to chest vol and alv press?

Answer 40

flattens the muscle, compressing the abdomen, expands the rib cage up and out; increasing the vol of the chest cavity and lungs, decreasing alveolar pressure.

Question 41

what happens to the diaphragm when it relaxes? what does it do to chest vol and alv press?

Answer 41

allows the abdomen to expand, compresses the rib cage down and in; decreases the vol of chest cavity and lungs, increases alveolar pressure.

Question 42

what connects the lungs to the chest wall?

Answer 42

pleural sac

Question 43

what does the magnitude of vol change depend on?

Answer 43

transpulmonary pressure (Ptp) and lung compliance

Question 44

the pressure difference bw the alveolar pressure and the intrapleural pressure. what is the formula?

Answer 44

transpulmonary pressure; Ptp= Palv-Pip

Question 45

transpulmonary pressure is a what kind of pressure? what does that mean?

Answer 45

transmural press; is acts across a barrier (wall of lung and pleural sac)

Question 46

driving force for expansion or recoil of the lungs? what does an increase in this cause? decrease?

Answer 46

transpulmonary pressure; inc press causes lungs to expand; dec press causes lungs to recoil

Question 47

measure of the stretchability of the lungs. the higher the more stretch, the higher this value is.

Answer 47

compliance

Question 48

compliance affects how much ____________ will change with ______________________ changes. what is the formula?

Answer 48

volume; transpulmonary pressure; change in vol= C x change in Ptp

Question 49

for any given change in transpulmonary pressure, ___________ compliance will cause a _____________ change in vol

Answer 49

higher; greater

Question 50

which lungs will expand more, the lungs with higher or lower compliance?

Answer 50

higher

Question 51

what are the two determinants of lung compliance?

Answer 51

stretchability and surface tension

Question 52

what does stretchability depend on?

Answer 52

amount of elastic connective tissue present

Question 53

what is surface tension referring to?

Answer 53

the air-water interfaces within the alveoli; surface tension of water resists stretching, making it harder to stretch

Question 54

how does pulmonary surfactant produced by type II cells affect surface tension?

Answer 54

reduces surface tension, increases compliance, reducing energy needed to expand the lungs

Question 55

how is airflow affected by resistance?

Answer 55

increases in resistance decreases airflow, decreases in resistance increase airflow

Question 56

what is the formula for airflow?

Answer 56

F= change in P/R

Question 57

what is resistance influenced by? what is the formula for it?

Answer 57

length, radius, and viscosity. R=8Ln/pi r^4

Question 58

what is the most important resistance factor in the lungs? how does it produce change?

Answer 58

radius; small changes in radius produce large effects on resistance

Question 59

normally, resistance in the airways is low, but it can be affected by what?

Answer 59

chemical signaling

Question 60

where do chemical signals primarily act on?

Answer 60

smooth muscle in the bronchiole wall

Question 61

decreases radius and increases resistance

Answer 61

bronchoconstriction

Question 62

increases radius and decreases resistance

Answer 62

bronchodilation

Question 63

examples of bronchoconstrictors?

Answer 63

parasympathetic stimulation and paracrine histamine

Question 64

examples of bronchodilators?

Answer 64

increased sympathetic stimulation and carbon dioxide