Physiology Flashcards
(108 cards)
1
Q
Pleural Pressure at rest
A
-5
2
Q
pleural pressure during inspiration
A
-8
3
Q
Why does the pleural pressure decrease?
A
The diaphragm contracts (downward) increasing the volume of the thoracic cavity, lowering the pressure
4
Q
What does the parietal fluid do?
A
Keeps the visceral & parietal pleuras together so that the visceral also expands with the cavity pleura
5
Q
If there wasn’t any parietal fluid what would happen?
A
The visceral pleura would stick to the lungs, inhibiting the lungs from expanding, so the alveoli pressure would stay the same, and not allow air in.
6
Q
What is the equation for transpulmonary pressure
A
Ptp= PA- PpL
7
Q
What would happen if Ptp=0?
A
Lungs collapse. The pressure is what keeps the lungs open/not collapsing
8
Q
At mid-inspiration what is the volume?
PA?
PPL?
Air Flow?
A
Volume: like .25 Liters
PA: -1
PPL: -6.5
Air Flow: -1
9
Q
End Inspiration. What is the Volume in liters? PA? PPL? Air Flow?
A
Volume: .5
PA: 0
PPL: -8
Air flow: 0
10
Q
Why does hte PA go to 0 while the PPL gets more negative?
A
Air flows into the alveoli, increasing the pressure back to 0, whereas nothing flows into the intrapleural space.
11
Q
Mid expiration Volume? PA? PPL? Air flow?
A
V: .25 ish
PA: +1
PPL: -6.5
Air flow: +1
12
Q
End of Expiration: Volume: PA: PPL: Air flow
A
Volume: 0
PA: 0
PPL: -5
Air flow: 0
13
Q
What is the equation for minute ventilation (VE)
A
VE= Vt x f
Minute Ventilation = Tidal Volume X frequency
14
Q
What is the “normal” minute ventilation in L/min
A
7L/min
Normal breath frequency (RR) = 14 b/min; multiplied by normal tidal volume 500 mL/breath
15
Q
I can’t add pictures, but know the Volumes and Capacities on a squiggly air line graph
A
Inspiratory Reserve Volume IRV Tidal Volume TV Expiratory Reserve Volume ERV Residual Volume RV
Capacities:
Inspiratory Capacity (IC): IRV & TV
Functional Residual Capacity FRC: ERV & RV
Vital Capacity VC: IRV & TV & ERV
Total Lung Capactity TLC: All dem.
16
Q
What are the respiratory capacities influenced by?
A
Size, gender, age, pregnancy/disease
“Pregnancy is a disease caused by a parasite” as my phys professor used to say
17
Q
During prenganantcy what happens to the capacities?
A
Goal is to preserve vital capacity. TLC decreases, so to counteract that, IRV, TV increases & RV, ERV, and FRC decrease
18
Q
What is FEV1 and what is normal?
Whats the ratio?
A
Forced Expiratory volume in 1 second.
80% is normal . 4.0
FEV1/FVC. Normal 4.0/5.0
19
Q
In Obstructive respiratory disorder, what happens to the FEV1
A
the FEV1 decreases. The FVC may decrease as well, but not that much.
It’ll go down to like 42%. Normal is 80%. They can’t EXPEL air as quickly or as much.
(Great picture on slide 20 of Lung Volumes to illustrate this)
20
Q
In restrictive respiratory disorder what happens to the FEV1
A
FEV1 and FVC go down, but at the same rate, so the percentage is actually higher.
Whereas Normal FEV% is 80, in Restrictive it’s like 90%.
Which means although they can’t expel the QUANTITY of air, they can do it faster. (remember restrictive is an inhalation disorder)
(Great picture on slide 20 of Lung Volumes to illustrate this)
21
Q
What happens to the respiratory capacities/volumes in obstructive diseases?
A
RV increases and IRV decreases.
[Obstructive is an exhalation problem, so if you can’t exhale much, then you have a bunch of air left over in your lungs (high RV) so you can inhale as much air either]
22
Q
What is anatomic dead space and how do you calculate it?
A
Air that doesn’t get to the respiratory alveoli but gets in lung.
anatomical dead space in mL = weight of person in lb
23
Q
What is physiological dead space and how do you calculate it?
A
PDS = Vt x (PaCO2-PeCO2)/ PaCO2
the arterial pressure of CO2 subtracts the Pressure of CO2 that is exhaled, divided by the arterial pressure of CO2, multiplied by the tidal volume.
Typically it’s 0
24
Q
Minute alveolar ventilation equation
A
Valv =Vt - Vds
VdotALV (Minute alveoar ventilation) = Valv x f
assume tidal volume is 500mL unless told otherwise.
so subtract the pt’s weight by 500 to get Valv
Multiple Valv by the frequency to get the minute
25
What are extra-alveolar blood vessels? What effect do they have on the circulatory system
Ones that are supplying the actual alveoli tissue (which is simple cuboidal).
The deoxygenated blood from these goes into circulation right away, so the blood out of the lung is technically not as oxygenated as it could have been. Called: Venous admixture
26
Vascular resistance is higher in pulmonary or systemic vessels? What can cause these differences?
systemic.
Really depends on (Input pressure - output pressure)/Blood flow
When talking about input/output, talking about LUNGS. In and out of LUNGS.
Capilllary density - more caps in pulmonary.
Sympathetic tone - No idea what this is or does.
Smooth muscle - can vasodilate and constrict, so can change pressure
27
What is the normal Blood pressure in the lungs?
Systemic?
What is the normal cardiac output
Lungs: 25/15
Systemic: 120/80
Cardiac Output: 5L/min
(Do not confuse L/min of air into the lungs *7* with the cardiac output *5*)
28
Vascular Resistnace can chance in a healthy individual in certain states. When excercising, what happens to the VR? How?
Decreases due to recruitment of capillaries and vasodilation of them.
29
There are 3 zones in the lungs. What are the Pressures of arteries, alveoli, and veins in each? And which of these pressures is constant?
Zone 1: PA> Pa> Pv
Zone 2: Pa>PA>Pv
Zone 3: Pa>Pv>PA
The Pa and Pv change, but PA is constant.
Easy way to remember: Pressure in arteries will ALWAYS be higher than veins, so just memorize that the PAlveolar pressure is decreasing with each zone. (except PA stays the same throughout, the others are just increasing, but do that way if it helps to remember)
30
```
What do the following molecules/drugs do?
Thromboxane
Nitric Oxide
Angiotension II
Endothelin 1
Bradykinin
```
Thromboxane (drug): Vasoconstrictor.
Nitric oxide (natural molecule): Vasodilates. Secreted by endothelium
Angiotensin II (natural): angiotensin I -- by ACE --> Angiotensin II. Vasoconstricts. (if you take ACE inhibitors it'll increase vasodilation and thereby lower BP)
```
Endothelin 1 (natural):
Vasoconstrictor. (ET-1 Inhibitors treat pulmonary hypertension)
```
Bradykinin: Vasodilator, decreases BP. When pt take ACE inhibitors, they develop cough due to inactivation of bradykinin for some reason.
31
What is hypoxic pulmonary vasoconstriction?
hypoxic: little O2.
If the PAO2 is low in the lungs, the blood vessels vasoconstrict, I think this is shunting of blood.
This happens in the fetus a lot, and causes smooth muscle contractions?
[I have no idea]
32
What are Starling forces? Describe the 2 forces and how they affect fluid.
Hydrostatic pressure & oncotic pressure that "keep the alveoli dry"
Hydrostatic = Pushing;
Oncontic = Pulling
Hydrostatic pushes fluid out of capillaries and alveoli into tissue
Oncontic pulls fluid out of alveoli and capillaries into tissue.
Happens due to negative tissue pressure
33
What does Alveolar Gas Exchange depend on?
Perfusion: blood to lungs
Ventilation: Gas to lungs
34
What is the normal perfusion rates?
Ventilation?
When exercising what happens to ventilation?
Perfusion: 5L blood/min
Ventilation: 4L/min
Not to be confused with the amount of air that enters the lungs which is 7. only 4L actually make it to gas exchange.
Ventilation increases during exercise
35
What is the relationship between airflow, pressure, and resistance?
What is the MAIN determinate of air flow:
Know that Q = Air flow
Q= (P1-P2)/R
If pressure increases, air flow decreases.
If Resistance increases, air flow decreases.
Main determinate; Radius of bronchiole
36
```
Need to know #s:
What's the concentration % in the air?
O2
N2?
CO2?
What about pressures in the Alveoli?
O2:
CO2:
Pressure in arteries?
O2:
CO2:
Venous Pressure?
O2:
CO2:
```
Understand how this affects the movement of gas. (High to low0
O2: 21%
N: 78%
CO2: 1%
PA:
O2: 100
CO2: 40
Pa
O2: 95
PCO2: 40
Pv:
O2: 40
PCO2: 46
37
What cells are in alevoli?
Macrophages
| Pneumocytes I & II
38
What 7 structures must O2 go through to get from the Alveoli to the RBC?
What effect does collagen have on diffusion?
1. Layer of surfactant
2. Alveolar epithelial cells
3. Alveoli epithelial basement membrane
4. Interstitial space
5. Capillary basement membrane
6. Cap Endothelial cells
7. Cap lumen
Collagen in interstitial space decreases diffusion of gas
39
What allows higher transfer of gas? Which gas diffuses more rapidly (CO2 vs O2) & why?
Remember that gas exchange = J (I think)
Surface area, Thin walls, Diffusion constant.
The diffusion constant (GMW) is higher in CO2, so it diffuses 20x more rapidly.
[The diffusion is independent of each other]
40
What is the method of emphysema?
Emphysema alveoli are bigger, but damaged with holes.
41
How much time is needed for O2 to diffuse? When resting, how much time is available?
When exercising how much time is available?
.25 needed.
.75 resting available
.25 exercising available
42
Carbon Monoxide's role in blood. What can carbon monoxide be clinically used for?
(Don't know how much we need to know here, sorry)
Doesn't diffuse much, but if it does, binds more readily to RBCs and keeps O2 from binding. You can use it to measure oxygen diffusion capacity
43
2 alveoli sit next to each other. Alveoli A is bigger than Alveoli B. What does this mean for air flow and pressure in these 2 alveoli?
Air will flow from high pressure to low pressure. Since the volume of A is larger, it will have a smaller pressure. Air will flow out of B into A. B is now at risk for collapsing.
44
Surfactant is utilized more so in what size of alveoli?
What produces surfactant?
What does it do?
What is the half life of surfactant and what degrades it?
Smaller Alveoli bc low volume = high pressure.
Keeps alveoli open
Type II Pneumocytes
5-10 hrs, macrophages degrade it.
45
Total volume of O2 in arteries?
Veins?
Volume dissolved without Hb?
Total volume of CO2 in blood?
Volume CO2 dissolved?
Total volume of O2 in artery: 20mL O2/100mL blood
Total volume in vein: 15 mL
Volume dissolved: .3 mL O2/ 100mL blood
CO2 volume: 50 mL CO2/100mL
CO2 dissolved: 3 mL
46
What determines oxygen carrying capacity?
HB concentration. NOT O2 saturation.
You can have perfect O2 saturation, but not enough HB,
47
What is the mechanism of Respiratory acidosis?
When CO2 enters the lungs:
CO2 + H2O H2CO3 (acid) HCO3- + H+
The Overaccumulation of H+ & H2CO3 results in acidic .
48
In regards to the O2 dissociation curve:
What is it's shape? What does this mean?
What can cause a right shift?
Left shift?
Sigmoid = cooperative affinity
Right shift: low affinity for O2. Tissues need the Oxygen more, so oxygen leaves RBCs more readily; exercise. (High temp, high CO2, low pH)
Left shift: high affinity for O2. (High pH, low temp, low CO2)
49
The difference in Artery vs. Venous O2 can be used for what? What tissues have high Oxygen Consumption? Low?
Find oxygen consumption.
High: skeletal muscle and kidney
Low: White adipose
50
Equation for Respiratory Quotient
What is normal?
What can affect this?
RQ = Volume of CO2 produced/Volume of O2 consumed
Normal: 0.8 mL
Carb vs fat diet:
Carb burn 1:1
burns 1 CO2 for every 1 CO2 consumed
Fat:
burns 7 CO2 for every 10 Co2 Consumed
51
Pulmonary function tests
Indications:
Contraindications:
Most important measures?
Indications:
- Sx of lung disease (dyspnea, cyanosis, wheezing, hypoxemia, hypercapnia)
- Therapy efficiency
- Screening for pulmonary disease (Smokers, occupation hazards)
Contraidndicaton: Congestive heart failure - messes with numbers
Most important: FEV1, FVC, and their ratio: FEV1/FVC
52
You screen a patient and see a normal total lung capacity, but a decreased FEV1/FVC ratio. What respiratory ailment?
Obstructive disease
53
You screen a patient with decreased Total lung capacity, but a normal FEV/FVC ratio. Respiratory ailment?
Restrictive pattern
54
What are the Obstructive diseases?
COPD (Chronic bronchitis and emphysema)
| Asthma.
55
If tht pt's FEV1/FVC ratio i slow, and the vital capacity is low, what ailment?
Mixed disease
56
If the only abnormality is a decreased ERV, what is the diagnosis
Obese.
57
Decreased FRC probably means what?
| Increased FRC probably means what?
Decreased: Fat
Increased: COPD.
58
What is the mechanism of pulmonary fibrosis
Elastic recoil is increased, so the FRC functional reserve capacity is decreased
59
```
Normal Arterial Blood gases
PaO2
PaCO2
Arterial pH
HCO3
```
PaO2: 80-100 mmHg (alveolar= 100/105)\
PaCO2: 35-45 mmHg (Use 40)
pHa: 7.35- 7.45 (Use 7.40)
HCO3: 22-26 mEq/L (use 24)
60
What is the blood pH of a pt with acidosis?
| Alkalosis?
Acidosis: pH < 7.35
Alkalosis: pH > 7.45
61
How do you change the pH?
What happens in kidneys?
GI?
"Metabolic disturbances"
Change CO2, change bicarbonate.
Increase in bicarbonate = increase in pH = Alkalosis
Kidneys: Move HCO2 into urine or reabsorb. Concentrates the H+. Main pH dude.
GI: Makes HCO3. Vomiting or diarrhea = decreased bicarbonate
[people with GI problems may takeAntacids (anti-acids)] = alkalosis
Surprise acids: diabetics make ketoacids = acidosis
Exercise: SLIGHT Decrease in pH
62
Increased CO2 leads to what?
| Decreased CO2?
Inceased: Acidosis
Decreased: Alkalosis
63
What are the steps for interpreting blood gasses?
Step 1: look at pH. Acidic or Alkalitic
Step 2: Is CO2 or HCO3- levels normal?
Step 3:
64
A Pt's blood pH is abnormal. You want to find out if it's a respiratory problem or a metabolic problem. How would you know?
If the Carbon dioxide levels are whack --> Respiratory (lung)
If the Bicarbonate levels are whack --> metabolic (Kidney)
65
A Pt's blood pH is over 7.45. What does this mean?
| The CO2 levels are below 35. What does this mean?
Alkalosis.
| CO2: Respiratory Alkalosis.
66
A pt's blood is under 7.35. What does this mean?
| The CO2 levels are over 45. What does this mean?
Acidosis
Respiratory Acidosis.
67
Pt's blood is over 7.45. What does this mean?
The bicarbonate level is over 26. what does this mean?
Okay, now the bicarbonate level is under 22, and the pH is under 7.35. What's up now?
Alkalosis
Metabolic Alkalosis
Metabolic Acidosis
68
What are the 2 rules to compensation in systems?
1. Compensation will never get you back to normal.
| 2. Compensation is made by the opposite system. (respiratory for metabolic. vv)
69
What is the kidney's compensation role if the blood is acidic?
Alkolitic?
H+ will be excreted in the urine.
HCO3 will be pushed into blood
opposite. HCO3 to urine, H+ to blood.
70
How does the body know the CO2 & O2, pH in the systemic blood?
Chemo receptors send signals to medullary centers to change diaphragm, which changes breathing depending on the CO2 O2 content
71
If the system is in metabolic acidosis, what is the lung's reaction?
Metabolic alkalosis?
hyperventilation
Hypoventilation
72
How to tell if it's chronic or acute?
1. There is no such thing as acute/chronic metabolic acidosis/alkalosis. It is JUST metabolic acidosis/alkalosis.
So to figure out RESPIRATORY chronic or acute:
2. Acute is 10 CO2 = 1 HCO3 above normal.
Ex: For acute, Normal PCO2 = 40, and the pt's level is PCO2 is 50, then the compensated value of HCO3, which is normally 25, would be 26.
3. Chronic: 10 CO2 = 3-4 HCO3 above normal.
Ex: Normal is 40, and the Pt's value is PCO2 is 50. So the HCO3, which is normally 25, would be 28-29.
4. Or you can use the formula
73
What is the anion gap equation and normal numbers?
Anion gap = [Na+] - (Cl- & HCO3-)
| Positive minus the negative. Normal range: 6-12
74
How do you know if the body is compensating for the other system?
1. Look at pH to determine if person is acid or alkaline
2. Look at the PCO2 for resp or HCO3 for metabolic
3. Whatever one matches the direction pH change is causing the disturbance
Example:
pH is 7.30 (acidic)
HCO3 is 24 (normal)
PCO2 is 50 mmHg (high so acidic)
Person has respiratory acidosis
Look at other system to determine compensation
- If the other system shows a change that would shift the pH in the opposite direction of the persons (e.g. HCO3 is elevated) that person is compensated
If the other system has a normal value=uncompensated
(copied and pasted from your LOs Eric. Thanks, man)
75
What is normal Osmolarity?
| What is the equation?
290 mOsmoles/L
Osmolarity = (2* Serum Na+) + (BUN/2.8) + (glucose /18)
TBH - no idea what we need to know here. LMK if anyone has a suggestion for this card.
76
Why is dissolved oxygen inadequate for blood supply? [How much oxygen is dissolved in one minute? How much oxygen do we need?]
Dissolved 90 mL/Minute
| Need: 3,000mL O2/minute
77
What are the normal saturation levels for arteries? Veins?
| What is the PO2 at these numbers?
Arteries: 95% saturation - Pa: 100 mmHg
Venous: 75% saturation - Pv: 40 mmHg
78
For the O2 dissociation curve, what is the Y axis?
X axis?
Y axis: % saturation & O2 concentration
X axis: Pressure of O2
79
What is the relationship between HB (hemoglobin) concentration and saturation?
What illness is this important to understand?
No relationship.
If HB concentration is low, the O2 dissociation curve will lower, but the saturation is not affected.
Check out picture for under Gas Transport
Anemia. Their HB concentration will be low, but their saturation will be fine.
80
Why is dissolving CO2 not adequate for removal of CO2? (What are #s?)
How else can we get rid of CO2 besides dissolving?
What is the Haldane shift?
We produce 200mL of CO2, and we can only dissolve 2.7 mL.
CO2 binds to amino groups on RBCs
Presence of O2 reduces affinity of amino groups for CO2 on RBCs
81
What is a flow-volume curve and how does it change during obstructive diseases?
Can't add pictures. But remember it's a big circle. The resting circle is small, and with obstructive disease the expiration line will sink further and further inferiorly until it encroaches on the resting circle.
82
What are some extra-parenchymal (lung alveoli) causes of restriction?
Obesity
Neuromuscular disease,
Chest deformation
Pleural effusion (fluid in lungs)
83
What central respiratory centers are located in the medulla?
Dorsal Respiratory gorup
| VEntral Respiratory group
84
What peripheral respiratory centers are located it the pons?
Pneumotaxic center
| apneustic center
85
What is the function of the dorsal respiratory group? How does it accomplish this?
Controls basic rhythm.
DRG receives sensory from vagus and glossopharyngeal nerves, it controls the rhythm by controlling the depth of inspiration via the phrenic nerve.
86
What is the function of ventral respiratory group? How does it accomplish this?
Controls rhythm in times of exercise, stress, and babies.
| Excites expiratory muscles (Intercostals and abdmonial muscles)
87
The ventral respiratory group can control expiratory and inspiratory. What regions are these associated with?
Caudal --> expire. upper airways
| Rsotral --> Inspire. Phrenic
88
What is the pre-botzinger region and where is it located
Frequency of respiratory (RR)
| Located in Ventral Respiratory group
89
What is the function of the apneustic center?
Inspiration only.
90
What is the function of the pneumotaxis center.
What happens if this is lesioned?
What is the opposite of this?
inhibits apneustic center so that the patient can stop inhaling.
Apneusis = Absence of expiration
Apnea = absence of inhalation
91
When do chemoreceptors fire?
Increased CO2 or H+ (acidosis) or decrease n O2
92
What are the Central chemoreceptors especially sensitive to? Where are they located? How are they different from Peripheral chemos?
H+ and CO2 (indirectly).
SO acidosis.
Need to increase breathing. (drive to breath_
ventral surface of the medulla.
Slower.
93
What are the Peripheral chemoreceptors especially sensitive to? Where are they located? How are they different from Central Chemos?
```
O2 first
CO2, H+ (Same same)
SO acidosis.
Need to increase breathing.
aortic arch and carotid body.
```
Faster.
94
What are the glomus cells especially sensitive to? Where are these located? What is their action?
Sense PO2
Peripheral chemoreceptors
Send ACh out.
95
What are the slow adapting mechanoreceptors especially sensitive to? Where are they located? What is it's reflex?
Stretch.
Location unknown
- "Hering Breuer expiratory reflex" - stops overinflation of lung
- Important in infants and exercising adults.
96
What are the rapid adapting mechanoreceptors especially sensitive to? Where are they located? What is it's reflex?
Stretch, foreign bodies, irritation
Located: Airways to larynx.
Reflex: Cough.
97
What are the J mechanoreceptors especially sensitive to? Where are they located? What is it's reflex?
Pulmonary edema
Located: Alveoli capillaries
Reflex: Cough, tachypnea.
98
You can bypass the medulla and tell yourself to stop breathing. What is this called? How does that work?
Cortical influences.
Uses skeletal muscle
99
In a pressure/volume graph, where is compliance decreased?
| In what dysfunction is the compliance decreased
(Measure of stretchability)
At the bottom of the graph and the top (Very very beginning & very end of inhalation)
Pulmonary fibrosis (Also: pneumonia, and edema)
100
In a pressure/volume graph, where is compliance increased?
| In what dysfunction is the compliance increase
In the middle of the graph- during resting breathing
| Emphysema and aging
101
Rib cage wants to expand or compress?
Lungs want to expand or compress?
When do they both get what they want?
Expand
Compress
Pneumothorax
102
What does interdependence of alveoli mean?
The alveoli has elastic recoil, but since they are attached to other alveoli with elastic recoil, they hold each other open
103
What "line" does the chest wall want to be at?
At what line does the lungs want to be at?
What line are they at together?
Resting Chest wall line
minimal volume.
FRC
104
When is work of breathing highest?
Low compliance.
Baby's first breath,
Getting wind knocked out of you.
105
On a volume/pressure diagram, what represents the work done to stretch lungs and chest wall?
Left side of middle line
106
On a volume/pressure diagram, what represents the work done to overcome airway resistance?
Between middle line and inhalation line
107
What is pressure at sea level?
| How do you calculate alveoli pressure?
760mmHg
Pressure x % in air
760x.21
Subtract water vapor (unless dry air) *47*
(760x.21)-47
108
What is the significance of 2,3 BPG?
Shifts O2 dissociation curve to the right. = higher O2 unloading
