CH13 - Respiratory System Flashcards
(120 cards)
1
Q
What is internal respiration?
A
cellular respiration (breakdown of glucose, producing CO2, etc.)
2
Q
What is external respiration?
A
respiration that is anything outside of the cell
3
Q
What is pulmonary circulation?
A
blood delivered from heart to lungs
4
Q
What is systemic circulation?
A
blood delivered to tissues/everywhere else in the body (delivering O2 + picking up CO2 at tissues)
5
Q
Name the conducting airways.
A
trachea + bronchi + bronchioles
6
Q
Where does gas exchange happen (the respiratory surface/airway)?
A
alveoli
7
Q
What are the purpose of conducting airways?
A
trying to get air to the (gas) exchanging area/lungs
8
Q
As the # of airways increase, their diameter ____
A
decreases
9
Q
What type of epithelial cell allows for efficient gas exchange at the respiratory tissue?
A
squamous cells, flattened/squished thin cells that make it easy to exchange gases
10
Q
What cells produce mucus?
A
goblet cells, secrete mucus to the surface of the epithelium
11
Q
Is there mucus in the respiratory zone?
A
no, would interfere with gas exchange
12
Q
What is the purpose of mucus + cilia in the conducting airways?
A
-mucus: engulfs foreign matter
-cilia: helps move the mucus up and out of the airways
13
Q
Interaction between cilia and mucus is called?
A
mucociliary escalator
14
Q
Purpose of elastic fibers in conducting airways?
A
keep airways stretchy (less in the respiratory zone)
15
Q
Is smooth muscle voluntary or involuntary?
A
involuntary
16
Q
Purpose of cartilage in conducting airways?
A
-prevent collapse of airway tubes with larger diameter (soft tissue, move air through)
-less/no cartilage in bronchioles b/c smaller diameter
17
Q
What conducting airway is bilateral?
A
bronchus/bronchi
18
Q
Purpose of smooth muscle in conducting airways?
A
allow change in diameter of airway tubes (mostly bronchioles, less rigid/less cartilage)
19
Q
How does smooth muscle ultimately control how much air gets to the gas exchange surface?
A
-bronchoconstriction = narrower tube, less air in
-bronchodilation = wider tube, more air in
20
Q
The bigger the airway hole, the _______ the air moves.
A
faster
21
Q
What surrounds the alveoli all around on the outside?
A
capillaries - tiny blood vessels (more efficient exchange, want to exchange as much gas as we can)
22
Q
Why is there epithelium lining the blood vessels that surround the alveoli?
A
provides a flat skinny surface, to prevent ruining the alveolus
23
Q
How is gas exchanged at the alveoli?
A
-O2 from alveoli travels to the blood vessels
-CO2 from the blood travels to the lungs
24
Q
What are type I alveolar cells?
A
flattened squamous cells that allow for easy gas exchange
25
What do type II alveolar cells produce?
surfactants
26
Purpose of surfactants?
prevent/loosen the interaction b/n water molecules around the alveolus, thus preventing alveolus collapse
27
What is quiet/normal/passive breathing?
breathing that occurs without trying
28
What is active/forced breathing?
controlled breathing
29
How much of quiet inhalation is due to the diaphragm?
70%
30
Is the lung a muscle?
NO, series of epithelium tissue + elastic fibers — instead, surrounded by muscle so it can stretch
31
What is the main muscle that changes the shape+size of the thoracic cavity?
diaphragm
32
Explain what the muscles involved in quiet inhalation do.
-diaphragm: contracts, moves DOWNWARD, increasing chest cavity
-external intercostal muscles: above the diaphragm, lifts the ribcage so the ribs can separate/stretch a bit
33
Explain what the muscles involved in quiet exhalation do.
-diaphragm: RELAXES back to original position
-external intercostal muscles: relax
34
Explain the additional muscles involved in forced inhalation.
-accessory muscles (scalenes + sternocleidomastoid) --> contract, lift the ribcage and connect head+neck to the ribcage
35
What muscles are involved in forced exhalation?
internal intercostal + abdominal muscles
-internal intercostal muscles: contract, bring ribs back closer together
36
What are the lungs attached to and how?
the thoracic wall by a double membrane (pleural membranes)
37
The parietal pleura is attached to the _____?
thoracic wall
38
The visceral pleura is attached to the _____?
lung
39
What is in between the pleural membranes?
the pleural space which is filled with pleural fluid
40
The thoracic wall allows for the lungs to ______
stretch
41
What is the function of the pleural fluid?
-it reduces the friction between the pleural membranes moving against each other
-helps attach the lungs to the thoracic cavity/wall
42
What are the two pleural membranes called and what do they attach to?
-visceral —> attached to lung
-parietal —> attached to thoracic wall
43
What allows air to flow in the lungs?
change in pressure
44
If pleural pressure = 0, it is equal to...?
the atmospheric pressure —> not likely b/c the pleural membranes are in a closed system
45
If alveolar/pleural pressure is positive/negative, it is _____/_____ than atmospheric pressure.
greater/less
46
Why is pleural pressure mostly -5mmHg — specifically, why is it mostly/always negative?
-lungs stretch out and want to go inward
-thoracic wall wants to go outward
-pull away from each other, creating negative pressure
47
What is alveolar pressure and what values can it take on?
-pressure inside the alveoli/lung
-exposed to atmosphere, therefore can be +, -, or 0
48
What is equation for the Law of LaPlace?
P = 2T/r
49
What are the main ideas of the Law of LaPlace & alveolar stability?
-with surfactants, different sized alveoli have equal (collapsing) pressure
-with surfactants, the smaller radius alveoli has less surface tension b/c the surfactants are packed together tightly (more surfactant per area)
-without surfactants, the different sized alveoli have equal surface tension -- but only the smaller radius alveoli would collapse
50
What is pneumothorax?
-lung collapse
-breaks open/severs pleural space (breaking connection between chest wall and lung, pleural pressure = 0)
51
An example of traumatic pneumothorax.
-puncture wound in chest wall (maybe got into a car accident, broken rib punctures pleural space)
52
An example of spontaneous pneumothorax.
-just happens by chance
-could be from pulmonary disease
-can be minor (sealed back itself if not exposed to atmosphere)
53
What is Boyle's Law?
-P1V1=P2V2
-more volume = less pressure (and vice versa)
54
Gas goes from ____ to ____ pressure.
high to low pressure
55
How does pressure change happen in the lungs (3 steps)?
1) size+shape of thoracic cavity/lungs changes
2) pressure changes
THEN
3) air can flow
56
If P-alveolar = P-atmosphere, then...?
-nothing happens
-cannot breathe, no pressure gradient
57
What is compliance?
-ability of lungs to stretch outwards
-poor compliance = harder to breathe in
58
What is recoil?
-ability of lungs to go back to original position
-poor recoil = harder to breathe out
59
HIGH surface tension = ____ compliance.
-low compliance = less able to stretch/harder to inflate lungs
60
During inhalation, how is a pressure gradient created, so air can flow in the lungs?
-diaphragm contracts (goes downward), increasing volume
-thus pressure decreases — pressure negative in lungs
-lower pressure in lungs, higher in atmosphere = air flows IN
61
During exhalation, how is a pressure gradient created, so air can flow OUT of the lungs?
-diaphragm relaxes to original position, decreasing volume
-thus, pressure increases — alveolar pressure becomes positive
-higher pressure in lungs, lower pressure in atmosphere = air flows OUT
62
Describe the respiratory cycle for passive breathing (one full inhalation, one full exhalation).
A) before inspiration:
-P-A (P-A is alveolar pressure) equals zero (thus, PA = P-atmosphere)
-P-pl (P-pl is pleural pressure) is negative
-not exchanging air (NO pressure gradient)
B) inspiration onset:
-contraction happens: increasing volume, thus P-A goes down (P-A = -1)
-pressure gradient (P-A < P-atmosphere), air can flow IN
-P-pl stays negative
C) end-inspiration:
-volume increased (stopped breathing in, before expiration starts)
-P-A = 0
-P-pl at lowest point (lags behind, sealed space)
D) expiration onset:
-thoracic muscles relax: decreasing volume, thus P-A increases (P-A = +1)
-pressure gradient (P-A > P-atmosphere), air can flow OUT
-P-pl less negative
63
Pleural pressure is more negative during inhalation or exhalation?
inhalation
64
________ pressure, in part, determines how fast the air will flow.
alveolar
65
The ______ the pressure gradient, the faster the diffusion (the air flows).
bigger/steeper
66
The rate of change (ROC) of volume is...
how quickly air can flow in/out of lungs
67
If ACTIVE breathing... alveolar pressure would be ________ (more/less) negative during inhalation, and _______ (more/less) positive during exhalation, and the ROC would be ________ (faster/slower) b/c the pressure gradient would be even ________ (bigger/smaller)
more, more, faster, bigger
68
The amount of air that can move through a tube is influenced by __________ ____________
airway diameter
69
Flow is proportional to changes in __________
pressure
70
What is resistance and how is it related to airflow?
-resistance is from the sides of the airway tubes themselves -- mucus + cilia creates friction
-works AGAINST airflow, and is INVERSELY proportional to it (more resistance = less flow)
71
Which airways have the most resistance?
conducting airways b/c they have more structure (more simple = less resistance)
72
Which airways can change diameter?
-bronchioles (little/none cartilage, high in smooth muscle)
-bronchoconstriction
-bronchodilation
73
Exchange occurs ______ and where?
-twice
-1) between the lungs/alveolus and blood
-2) between the blood and the tissues/cell
(oxygenated blood: lungs --> blood --> tissues)
74
Gases largely diffuse due to the difference in their ______ _________
partial pressures
-PO2
-PCO2
-air = mixture of O2 + CO2
75
Gases go _____ their individual partial pressure gradients
down
-example: O2 flows down PO2 gradient
76
What things influence diffusion across a membrane?
-1) pressure/concentration gradients (high --> low)... the steeper the gradient, the faster the diffusion
-2) permeability
-3) surface area (large SA = faster diffusion -- alveoli have clusters to increase SA)
-4) membrane thickness (less thick/thin membrane = faster diffusion)
77
Partial Pressure = P-atm x _______
% of gas
78
P-atm ~
760 mmHg
79
Air is ___% O2, so PO2 = ______ mmHg.
-21% O2
-PO2 = 160 mmHg
80
Air is ALWAYS 21% O2, so why does oxygen content change with elevation?
-increase elevation = DECREASE P-atm
(oxygen is still 21% of air)
81
What are the values of the partial pressures in the lungs?
-PO2 = 100 mmHg
-PCO2 = 40 mmHg
82
What are the values of the partial pressures in the blood, after exchange (oxygenated)?
-PO2 = 100 mmHg
-PCO2 = 40 mmHg
83
What are the values of the partial pressures in the blood, before exchange (blood approaching lungs)?
-PO2 = 40 mmHg
-PCO2 = 46 mmHg
84
-What are the values of the partial pressures in the tissue/cell?
-Really active tissues use _____ (more/less) O2 and make _____ (more/less) CO2.
-PO2 < 40 mmHg
-PCO2 > 46 mmHg
-more, more
85
CO2 is _____ (more/less) soluble in blood compared to O2.
less
86
____% of O2 in blood is bound to Hb.
98%
87
____% of O2 is dissolved in plasma.
2%
88
What is plasma? Why don't we carry O2 in it?
-liquid portion of blood
-saturates with O2 very quickly, only 2% of O2 stays dissolved in plasma (thus, can't carry a lot of O2)
89
What is the equation that shows how O2 binds to Hb near the lungs? What is this called when O2 is bound directly to Hb?
-O2 + Hb --> Hb.O2
-Hb.O2 = oxyhemoglobin
90
How does O2 bind to Hb near the lungs?
-1) O2 into plasma, gets filled up (only 2% dissolved)
-2) O2 diffuses into RBC
-3) when RBC gets saturated, O2 binds to Hb specifically
91
Where does O2 dissociate from Hb and what is the equation?
-at the cell/tissues
-Hb.O2 --> Hb + O2
-cells use free O2 (can't use bound form), so O2 dissociates from Hb
92
O2 binding to Hb + dissociating from it is a _________ process, and depends on __________
reversible, PO2
93
What molecules can bind to Hb?
-O2
-CO2
-H+ ions
-CO
94
What molecule competes with O2 for the same Hb binding site? Why is it deadly?
-CO (carbon monoxide)
-binds better (more preference) and non-reversibly to the site --> O2 can't bind, therefore deadly
95
Does CO2 have the same Hb binding site as O2? How can [CO2] affect the ability to carry O2?
-no, different --> but when it binds changes conformation of Hb (thus, high [CO2] can affect ability to carry O2)
96
Hb is made up of _____ globular proteins, which each carry a ______ group.
four, heme
97
Each Hb heme group has an _______
iron
98
What part of Hb actually binds O2?
iron
99
Each iron carries ___ oxygen, so for one Hb molecule how many O2 can you bind?
-one
-can bind 4 O2 for one Hb (100% saturated -- rare, average for ALL Hb is 98%)
100
Explain how binding O2 to Hb changes conformation and affinity.
-bind first O2 to first heme group = changes conformation, so its easier to bind the 2nd O2
-2nd O2 binds = changes conformation, so its easier to bind the 3rd O2
-etc.
-cooperative binding of O2
101
PO2 = 100 mmHg where?
alveoli
102
PO2 = 40 mmHg where?
resting cell
103
As you move away from the lungs, percent O2 saturation of Hb (sO2) _____ (increases/decreases).
decreases, but not by a lot —> thus, can give away O2, but still have lots of storage
104
Explain how PO2 (x-axis) on the oxygen dissociation curve tells you where the tissue is.
-right of x-axis (higher #) = near the lungs/arterial blood
-40 mmHg = venous blood, O2 used up
-far left (20 mmHg) = active strenuous exercise, metabolizing faster, thus using O2 faster
105
Why is the oxygen dissociation curve steep?
-due to the cooperative binding of O2
-conformational change as each Hb site binds O2, its easier to bind the next O2 (steep increase in sO2)
-1st O2 hardest to bind, 3rd/4th easiest
106
Why does the oxygen dissociation curve of someone with anemia look the same as a normal one? Essentially, how do they have 100% saturation but poor O2 content?
-have less sites for O2 to bind to, but still can be saturated (bind all the O2 to these sites)
-more likely to have 100% saturation b/c they have less sites
107
What is anemia?
-some sort of shortage of O2 in the blood
-ex. low RBC/Hb
108
What type of curve is better to understand the oxygen content of someone with anemia?
oxygen concentration curve
109
What is a right-shift of the oxygen dissociation curve typically associated with? What is the "advantage" of this right-shift?
-increased metabolism
-advantage: at given PO2, have lower saturation --> more free O2 available for tissues
110
What can cause a right-shift in the oxygen dissociation curve?
1) increased PCO2 (ex. strenuous exercise, need more O2 + make more CO2 as byproduct)
-the higher the [CO2], the more easily Hb offloads O2
2) increased acidity (lower pH, high [CO2] can cause this)
3) increased body temp
4) increased [2,3-BPG](product of metabolism)
111
Do we want oxygen to stay stored in Hb? Why or why not?
-NO
-have to let O2 go so we can use it --> has to dissociate as free oxygen
112
A right-shifted oxygen dissociation curve is associated with ________ (higher/lower) affinity for O2.
lower
113
A left-shifted oxygen dissociation curve is associated with ______ (higher/lower) affinity for O2.
higher
114
What are the three ways to transport CO2?
1) 5-10% in plasma
2) 5-10% on Hb
3) 80-90% as bicarbonate ion
115
What does carbonic acid (H2CO3) get converted to in the body?
H+ and HCO3- (bicarbonate)
116
What enzyme catalyzes the conversion of CO2 into bicarbonate (and the reverse)? Give the equation.
-carbonic anhydrase
-CO2 + H2O —> (H2CO3) —> H+ + HCO3-
117
Explain how CO2 from the tissue/cells is transported through systemic circulation.
-1) Small amount of dissolved CO2 in plasma and RBC
-2) CO2 binds to Hb (reversible): CO2 + Hb --> HbCO2
-3) CO2 converted to bicarbonate by Carbonic Anhydrase: CO2 + H2O --> H2CO3 --> H+ + HCO3-
-4) H+ can bind to Hb: Hb + H+ --> HbH
-5) Transporter protein: excess HCO3- moved out, Cl- moved in --> chloride shift
118
How is HCO3- moved out of the cell during systemic circulation? What is this called? Explain why this happens.
-transporter protein moves HCO3- out the cell, while bringing Cl- inside the cell
-called the chloride shift
-why? to get rid of HCO3- as RBC becomes saturated with it (thus, can no longer convert CO2) + move Cl- inside cell to maintain electrical balance
119
Explain how CO2 is breathed out near the lungs through pulmonary circulation.
-exactly reverse process compared to systemic circulation
-1) CO2 (and H+) dissociate from Hb --> dissolved CO2
-2) Bicarbonate and H+ converted back to CO2 by carbonic anhydrase: HCO3- + H+ --> H2CO3 --> CO2 + H2O
-3) Transporter protein: HCO3- moved back in, Cl- moved OUT --> reverse chloride shift
-4) End up with dissolved CO2 (from RBC + plasma) to breathe out of lungs
120
Why is there a time-lag/delay between onset of inspiration and end of inspiration?
takes time to reach max volume (full of air)
