Pulm Content; Final Exam Flashcards

Question

Strong Bases vs Weak Bases: What are the differences? Examples of Each?

Answer 1

**Strong Bases** - dissociates fully & easily in solution to form OH- ions - accepts H+ well - forms weak conjugate acids - Ex: NaOH -main component in drain cleaner **Weak Bases** - partially dissociates in solution - does not accept H+ as well - forms strong conjugate acids - Ex: Flouride in toothpaste & **HCO3-**

Answer 2

**Strong Acids** - dissociate very easily in solution and are prone to donating H+ - generate weak conjugate bases - Ex: HCL ⇌ H+ + Cl- - Cl- is a weak conjugate base because it does like to accept protons after dissociation **Weak Acids** - do not dissociate as easily in solution - generate strong conjugate bases - Ex: H2CO3⇌ H+ + HCO3- - HCO3- is a strong conjugate base because it will accept protons

Answer 3

**Protein Structure Depends on pH** - Proteins rely on ionic interactions to maintain their 3D shape (tertiary/quaternary structure). - Changes in pH can alter the charge on amino acid side chains (especially histidine, lysine, arginine, glutamate, and aspartate). - This can disrupt folding, causing denaturation or loss of function. **Acidosis or Alkalosis Can Impair Protein Function** - Acidosis → more H⁺ binds to proteins → altered charge and conformation → impaired function (decreased Hb affinity for O2 in the presence of too many H+ ions) - Alkalosis→ fewer H⁺ ions → abnormal ionization → impaired protein binding (decreased Ca²⁺ binding to albumin in alkalosis).

Answer 4

- Every enzyme has an optimal pH - Deviations from this range reduce catalytic efficiency or inactivate the enzyme entirely. - Changes in pH can alter the charge and shape of the active site **Na+/K+ATPase Pump:** - Extra H+ ions reduce effectiveness and efficiency of the pump - K+ is no longer pumped into the cell --> hyperkalemia **ATPase Enzyme** - Produces ATP - Located in mitochondria - Extra H+ reduces effectiveness of pump ---> decreasing ATP production --> further increasing hyperkalemia

Answer 5

- Usually a HCl salt to promote absorption or distribution of the drug - Sodium pentobarbitol: very painful if infused too fast

Answer 6

- pH is a logarithmic scale - a pH difference in 1 will give us a 10x change: pH of 8: [H+] =10 nmol/L pH of 7: [H+] = 100 nmol/L pH of 6: [H+] = 1000 nmol/L **How do we calculate pH?** pH= -log[H+] **How do we calculate [H+]?** 1 x 10^-pH [H+] concentration is measured in moles/L .**000**000000 = milimole .000**000**000 = micromole .000000**000** = nanomole

Answer 7

**Gastric pH: 1** - Acidity facilitates degradation of food products - Intestinal obstruction or vomitting stomach contents will cause a significant loss of acid --> can cause alkalosis **Pancreatic pH: 8** - Most alkaline pH in the body - Neutralize the acid found in the stomach before it moves into the intestines - High volume of pancreatic secretions/enzymes needed to neutralize the significant acid load - Very high intestinal motility will cause acidosis because HCO3- produced by pancreas is lost

Answer 8

- HCO3- (extracellular) - Hb (and other proteins) - Phosphate (intracellular) -ATP storage, ATP is released when pulled from adenosine, phosphorylates & dephosphorylates things Reduce the overall concentration of H+ Can donate protons if they have to Can acquire protons Both are dependent on the composition of the buffer and it's pKa The functionality of these buffers largely rely on Hb concentration

Answer 9

**Small changes in pH = drastic changes in [H+]**

Answer 10

The lungs are able to rid the body of CO2 quickly, acting as a buffer The lungs removing CO2 from the body allow the physiologic buffers in our blood to function optimally

Answer 11

- This graph shows us how well we are able to buffer protons with varying levels of Hb - The steepness of the buffering line slope correlates to blood buffering capacity **High Hb Levels:** - Higher amount of Hb inside the RBC - Increased buffering capacity - Steep buffering line on graph **Low Hb Levels:** - Lower amount of Hb inside the RBC - decreased buffering capacity - Flatter buffering line on graph

Answer 12

This graph shows us how different systems behave under normal & abnormal conditions - Isobars are lines of constant PCO₂ - Based on the Henderson–Hasselbalch equation: - pH=6.1+log [(HCO3-) / (0.03 × PCO2)] **Main Patterns Seen** - pH and bicarbonate move in the same direction in metabolic disorders. - pH and PCO₂ move in opposite directions in respiratory disorders

Answer 13

CO₂: Increased (hypercapnia). HCO₃⁻: Slightly elevated as a byproduct of CO2 levels. pH: Decreased (acidosis). **CO2** + H2O ↔ H2CO3 ↔ **H+ + HCO3−** More CO₂ drives the reaction to the right → more H⁺ → slightly elevated HCO₃⁻ → lower pH (acidosis). In uncompensated respiratory acidosis, HCO₃⁻ may be slightly elevated due to CO₂-driven H₂CO₃ dissociation, but this small rise is not considered true compensation

Answer 14

CO₂: Decreased (hypocapnia). HCO₃⁻: Slightly decreased as a byproduct of having less CO2 pH: Increased (alkalosis). **CO2** + H2O ↔ H2CO3 ↔ **H+ + HCO3−** Mechanism: Less CO₂ shifts the reaction to the left → fewer H⁺ ions → slightly less HCO₃⁻ → higher pH (alkalosis).

Answer 15

Nomogram- Acute: Uncompensated Chronic: Compensation

Answer 16

Anything that can decrease VE or decrease chest wall compliance - Kyphoscoliosis is abnormal curvature in the sagital and coronal plane. Surgical correction actually decreases chest wall compliance - Barbituates, such as pentobarbitol, cause significant respiratory depression

Answer 17

C3, C4, C5 This becomes a problem with regional blocks in the shoulder/interscalene area if you block the phrenic nerve

Answer 18

-log [H+] = -logK + log (A-/HA) or pH = pK + log(A-/HA)

Answer 19

HB ⇌ B- + H+ When a base dissociates, it breaks down into the base (B-) and conjugate acid (H+)

Answer 20

Buffer + H+ ⇌ HBuffer - In solution, buffers are ionized in order to better combine with a H+ - If the environment becomes more acidic, the buffer soaks up some of those hydrogen ions to form HBuffer. - If the environment becomes less acidic, the reaction can go backward: HBuffer can release H⁺ back into the solution **Deoxy Hb buffering the blood** Hb− +H + ↔ HHb **Bicarb buffering the blood** HCO3− +H + ↔ H2CO3

Answer 21

Ammonia-based buffer- buffers the urine so it is not acidic

Answer 22

- pK is the pH at which a buffer is equal parts ionized and unionized - A buffer is best at buffering when the pH is at it's pK value pK of HCO3-? 6.1; meaning HCO3- is most effective at a pH of 6.1

Answer 23

- The different buffer systems in the body respond to changes in H⁺ concentration at the same time and in the same way — so the pH stays coordinated across all the buffers - If the H⁺ concentration in the blood changes, it affects every buffer instantly. - Buffers don’t act in isolation — they’re all reacting to the same "pool" of H⁺ ions. ✅ So a shift in H⁺ → all buffers shift their reactions together → one consistent blood pH.

Answer 24

- Albumin is a protein in the *plasma* - This protein is more important for oncotic pressure, and keeping the plasma within in the cardiovascular system - Hb is in high concentrations *inside* the RBC, allowing for Hb to be a more potent H+ buffer - The Hb that is dissolved in plasma is hematocrit, and that is not nearly as effective as Hb inside the RBC

Answer 25

As Hb increases --> Buffering capacity increases --> Causing the PCO2 Isobars become compressed or move closer towards "normal." This allows for a greater variability in the HCO3- response to changes in pH: - Larger availability of HCO3- to buffer an increase in H+ - Faster response to decrease HCO3- in the presence of alkalosis

Answer 26

As Hb decreases ---> decreased buffer capacity --> isobars are stretched further from the point of "normal." Less variability in HCO3- response, meaning we will not see as much of a change in HCO3- levels in response to a change in pH.

Answer 27

How strongly a system is able to respond to change - High gain: Large correction - Low Gain: Small correction

Answer 28

- **Reabsorbs HCO₃⁻ to preserve base** - The kidneys reabsorb almost all filtered bicarbonate in the proximal tubule. - **Secretes H⁺ to eliminate acid.** - The kidneys actively secrete hydrogen ions into the urine, mainly in the proximal tubule, distal tubule, and collecting duct. - **Generates new HCO₃⁻ during acidosis.** - **Acidifies urine to safely excrete H⁺** - H+ ions are buffered in the urine by phosphate and ammonia, allowing the urine to become very acidic while protecting kidney tissues

Answer 29

* In metabolic acidosis, lungs increase ventilation → blow off CO₂ → partially compensate almost immediately * In metabolic alkalosis, lungs decrease ventilation → retain CO₂ → partially compensate almost immediately Because the respiratory system compensates so quickly, acute and chronic metabolic disorders don't look dramatically different in terms of the basic acid-base measurements like pH, CO₂, and HCO₃⁻. (At least not nearly as different as respiratory problems do.)

Answer 30

Congenital Hyperventilation Syndromes Inflammation in brain Brainstem Tumor Salicylates: ASA Toxicity Progesterone: "Breathing for two" Acute asthma- basically anxiety induced alkalosis

Answer 31

Losing HCO3- Producing too many H+ Inability to excrete H+ Consuming acids in diet or drugs - Methanol: byproduct of fermentation. In moonshine. Can make you go blind - Ethanol: methanol & ethanol stimulates the pancreas - Ethylene Glycol: Component of antifreeze. Smells sweet, make sure pets and kids are not around a leak -Blue if european car. Green if japanese or american - Ammonium chloride: Component of fertilizer

Answer 32

- 30 ATP - 2 ATP in anaerobic metabolism

Answer 33

Loss of H+ ions Ingestion of excess HCO3- Gastric Fistula: Causes loss of stomach acid Overproduction of steroids- aldosterone or cortisol

Answer 34

- Uncompensated respiratory acidosis - Uncompensated respiratory alkalosis - Uncompensated metabolic acidosis - Uncompensated metabolic alkalosis - Both are uncommon. Respiratory system usually compensates quickly - Partially compensated respiratory acidosis - Partially compensated respiratory alkalosis - Partially compensated metabolic acidosis - Partially compensated metabolic alkalosis - Ventilation can only be reduced so much to compensate for alkalosis without compromising oxygenation

Answer 35

* (Cations+) = (Anions-) * Blood needs to be electrically neutral. Cations should equal Anions * Normal value should 12 mEq/L , +/- 4 mEq/L * The normal anion defecit is due to the unmeasured proteins that are negatively charged

Answer 36

**Cations/Unmeasured Cations** Na: 142 mEq/L K: 4 mEq/L Ca: 1.3 mEq/L Mg: 0.8mEq/L **Anions/Unmeasured Anions** Cl: 106 mEq/L HCO3: 24 mEq/L HPO4, H2PO4: 2 mEq/L SO4 2-: 0.5mEq/L

Answer 37

[Na+] + [unmeasured cations] = [Cl-] + [HCO3-] + [unmeasured anions] or [Na+] - ([Cl-] + [HCO3-]) = [unmeasured anions] - [unmeasured cations]

Answer 38

**Loss of HCO3:** - Diarrhea - Pancreatic fluid loss **Cl retention:** - Renal tubular acidosis - Anion gap is normal because the kidney can maintain the charge balance by increasing/decreasing HCO3- or Cl- as necessary - Children cannot maintain this balance as well as adults

Answer 39

Overproduction of non-volatile acids **Presence of unmeasured metabolic anions:** * DKA from DM, ETOH, starvation * Lactic acidosis from hypoxemia, anemia, CO, hypovolemia, ARDS, shock, strenous exercise * Renal insufficiency **Presence of ingested drugs or toxic substances:** * Methanol * Ethanol * Salicylates * Ethylene glycol * Ammonium chloride MUDPILEES: Methanol, Uremia, DKA, Propylene glycol, Iron/Isoniazide, Lactic acidosis, Ethylene Glycol/ETOH, Salicylates

Answer 40

- About 2 liters of air - As the cough becomes more muffled, the less air that's moved

Answer 41

**Sensors** - Looking at levels of PO2, pH, PCO2 - Peripheral chemoreceptors; carotid body - Secondary peripheral chemoreceptors; aortic body - Central chemoreceptors in brain stem are mostly responsive to fluctuations in H+ - Respond fastest to H+ changes as a function of changes in PCO2 - Non-volatile acids do not cross the BBB, central chemoreceptors will have a delayed response to a buildup of these **Controller** - Pons/Medulla react to information from sensors, monitor for disturbances, and react to maintain a normal pH - If we have a plan to exercise in a healthy system, our ventilation increases as needed almost instantly **Control System** - Alveolar ventilation: - Changes in metabolism cause an increase or decrease in VE, first by adjusting Vt, secondly by adjusting RR **Regulated Variables** - pH: illicit the strongest response from chemoreceptors - PaCO2: Second to [H+] - PO2: Chemoreceptors do not usually respond to a decrease in PO2 until it is ~70mmHg

Answer 42

Central respiratory sends stronger inspiratory signals → recruitment of A⍺ skeletal muscle motor neurons (very large, myelinated nerve fibers) → increased motor unit size → frequency of motor neuron firing increases → more force generated

Answer 43

Governed by the duration of the respiratory cycle and time in between each of the events

Answer 44

A⍺ motor neurons are the hardest to block because of their size Pain neurons are easier to block because they are smalled Rule of thumb: if motor function is blocked, pain is likely blocked as well

Answer 45

**Higher Order Control Centers** - Frontal Lobe - Motor Cortex - Allows for voluntary control of breathing **Cycle of inspiration and expiration** - Automatic control of breathing in the central respiratory center **Reflexes** - Response from sensors - Baroreceptors are also included **Lung Sensors** - Irritant sensors; cough - Stretch (volume) sensors: Inhibits inspiration at a certain volume **Airway Sensors** - Irritant sensors; cough - Trachea **Other sensors that affect breathing** - Pain sensors **Main muscles of breathing** - Diaphragm - External intercostal - Internal intercostal - Accessory: sternocleidomastoid, scalene, abdominal, pec minor - Coordination of these muscles is organized by the brainstem; duration of inspiration and expiration are affected

Answer 46

Pons: - Pontine respiratory group (bottom of pons, top border of medulla) Medulla: - Dorsal respiratory group (posterior) - Ventral respiratory group (anterior) All considered nuclei because they are bundles of nerves/cell bodies within the CNS

Answer 47

**1. PRG** **2. DRG** **3. VRG** **4. Decussation of the pyramids:** cross-over point at the distal border of medulla or most superior border of the spinal cord **5. Phrenic nerve** **6. Nucleus tractus soltarius** **7. Nucleus ambiguus** **8. Botzinger/Prebotzinger Complex:**

Answer 48

The process where inspiratory and expiratory neurons in the brainstem alternate activity by inhibiting each other, creating a smooth breathing rhythm without overlap between inhalation and exhalation

Answer 49

Central chemoreceptors in the medulla detect increased CO₂ (via H⁺) in cerebrospinal fluid and stimulate the DRG to increase respiratory rate and depth.

Answer 50

Peripheral chemoreceptors in the carotid and aortic bodies detect low PaO₂, high PaCO₂, and low pH. They send signals via CN IX and X to the DRG to increase ventilation.

Answer 51

Central chemoreceptors are more sensitive to PaCO₂ (H+ primarily) changes and are the primary drivers of respiratory rate under normal conditions.

Answer 52

- It receives sensory input ([H+, PaCO2, PO2]) from the vagus (X) and glossopharyngeal nerves (IX) - Receives input indirectly from baroreceptors via NTS - **Sends inspiratory signals via phrenic nerve to the diaphragm and external intercostals** - Sends forced/labored expiratory signals to abdominal and internal intercostal muscles - Located within the NTS

Answer 53

- It regulates motor output in the pharyngeal constrictor muscles to maintain an open upper airway - Located within the VRG is the Botzinger & Prebotzinger Complex

Answer 54

**Phase-Switching** - The PRG helps smooth transitions between inspiratory and expiratory phases - It adjusts the duration of inspiration by inhibiting or stimulating the DRG/VRG, ensuring adaptive breathing patterns during different physiological conditions Primary function is limiting inspiratory time

Answer 55

1. Decussation of the pyramids 2. Trigeminal nerve (V) 3. Glossopharyngeal nerve (IX) 4. Vagus Nerve (X) 5. Hypoglossal nerve (XII) 6. Accessory nerve (XI)

Answer 56

It provides sensory input from the face and nasal mucosa, helping trigger reflexes like sneezing and altered breathing in response to nasal irritation.

Answer 57

It carries afferent signals from carotid body chemoreceptors, relaying information about PaO₂, PaCO₂, and pH to the DRG to adjust ventilation.

Answer 58

It transmits sensory input from pulmonary stretch receptors, aortic bodies, and lung irritant receptors, and mediates the Hering-Breuer reflex to prevent overinflation.

Answer 59

Reticular Formation: A broad term that describes a swath of tissue in the brainstem Portion of the reticular formation that is considered the "Medullary Area" or "Medullary Respiratory Center" Contains inspiratory and expiratory neurons

Answer 60

- Located within the reticular formation - DRG is located within the NTS - Primary function is to generate inspiratory signals, but also inhibits expiratory signals when the NTS is active - Receives input from baroreceptors - Sends inspiratory signals via phrenic nerve - Crosses over at pyramidal decussation

Answer 61

- Glossopharyngeal nerve (CN IX) from the carotid sinus - vagus nerve (CN X) from the aortic arch.

Answer 62

Nucleus tractus solitarius (NTS) in the medulla.

Answer 63

In the rostral portion of the ventral respiratory group (VRG) in the ventrolateral medulla.

Answer 64

Expiratory neurons.

Answer 65

→ Inhibits inspiratory neurons to help terminate inspiration and allow the transition to expiration **Sends inhibitory signals to:** - Dorsal respiratory group (DRG) - Pre-Bötzinger complex (the rhythm generator) This action "turns off" inspiratory neurons, promoting passive expiration and setting the rhythm for breath-to-breath cycling. - Controls **respiratory rhythmogenesis**

Answer 66

The pneumotaxic center tells the DRG to limit inspiratory time based on sensory feedback Lesions to this region cause prolonged inspirations (apneustic breathing) and short expirations (terribly awful)

Answer 67

**Stretch/irritant receptors → CN X → PRG → DRG/VRG → Phrenic motor output** - PRG interprets information --> sends signals to the DRG: - When to stop inspiration - How long inspiration should last - Adjusting rhythm to match sensory context **Reflex: Hering-Breuer Inflation Reflex** - Inhibits inspiration when lungs are overly inflated. - The PRG uses this input to terminate inspiration sooner, helping regulate tidal volume and prevent overinflation.

Answer 68

**Stretch/irritant receptors → CN X → PRG → DRG/VRG → Phrenic motor output** Trigger protective reflexes such as: - Coughing - Bronchoconstriction - Rapid shallow breathing The PRG adjusts the breathing pattern (e.g., shortening inspiration, increasing rate) to minimize further exposure.

Answer 69

**CO2** - Increase in peripheral CO2 leads to and increase in CO2 in the brain; - Can easily diffuse across the BBB and central chemoreceptors respond almost instantaneously **Non-Volatile Acids** - Non-volatile acids have a harder time crossing the BBB due to their charged nature - Sometimes need a carrier protein - Delay in brainstem response to non-volatile acids

Answer 70

**Conditions in CSF** - Clear - Minimal protein - pH: 7.31-7.32 - Contains it's own buffering system - Produces HCO3- (HCO3- cannoted cross BBB) - Glial cells act as a buffer - PCO2: 50mmHg - Higher than PaCO2 due to neurons producing CO2 as a byproduct of metabolism - CO2 (all gasses) must move down a pressure gradient --> needs to be higher in the brain to reach the lungs

Answer 71

↑ CO2 → vasodilation → ↑CBF ↓ CO2 → vasoconstriction → ↓ CBF

Answer 72

- Apneustic center in the PRG - Responsible for apneustic breathing - Can limit activity of pneumotaxic center

Answer 73

**Aortic bodies** - Group of 3-5 aortic bodies located on the aortic arch - Monitors gas concentration of blood coming from the LV - Transmit info to medullary brainstem via vagus **Carotid Bodies** - Carotid body on each side of the neck located between the internal and external carotid arteries - Monitors gas concentration going to the brain - Transmit info to medullary brainstem via glossopharyngeal

Answer 74

**Respiratory** ↑CO2 or ↓pH: - Vt is increased first - RR increased second if needed **Cardiac** ↑CO2 or ↓pH: - CO is increased - BP is increased - Allows for more blood to be pumped through the lungs --> increased surface area in the lungs for gas exchange --> blow off more CO2

Answer 75

- Albumin/ proteins are negatively charged and attract H+ - If too much H+ is removed from the body, Ca++ takes it's place - Leads to decreased serum ionized Ca++ → heart cannot properly contract

Pulm Content; Final Exam Flashcards

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