. A 17-year-old boy is brought to the emergency department after being injured inan automobile accident and sustaining significant blood loss. He is given atransfusion of 3 units of blood to stabilize his blood pressure. Before thetransfusion, which of the following was true about his condition?A) His total peripheral resistance (TPR) was decreased (B) His heart rate was decreased (C) The Wring rate of his carotid sinus nerves was increased (D) Sympathetic outZow to his heart and blood vessels was increased
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Finding Sources
Reading File
The textbook confirms everything perfectly. Here is the full explanation:
Answer: (D) Sympathetic outflow to his heart and blood vessels was increased
The boy sustained significant blood loss (hemorrhage), which triggers a well-defined baroreceptor reflex cascade. Here is what happens step by step:
Pathophysiology of Acute Hemorrhage
- Blood volume falls → stressed volume decreases → mean arterial pressure (Pa) falls
- Less stretch on baroreceptors (carotid sinus, aortic arch) → firing rate of carotid sinus nerves DECREASES (eliminates option C)
- The nucleus tractus solitarius in the medulla processes this signal and coordinates:
- Decreased parasympathetic outflow to the heart
- Increased sympathetic outflow to the heart and blood vessels (this is option D - CORRECT)
- The sympathetic surge produces:
- Increased heart rate (eliminates option B - heart rate goes UP, not down)
- Increased cardiac contractility
- Arteriolar vasoconstriction → increased TPR (eliminates option A - TPR goes UP, not down)
- Venous constriction → increased venous return → increased cardiac output
Why Each Option is Wrong
| Option | What It Says | Why It's Wrong |
|---|---|---|
| A | TPR decreased | Wrong - sympathetic vasoconstriction INCREASES TPR as a compensatory response |
| B | Heart rate decreased | Wrong - sympathetic stimulation INCREASES heart rate |
| C | Carotid sinus nerve firing INCREASED | Wrong - low blood pressure means LESS stretch on baroreceptors, so firing rate DECREASES |
| D | Sympathetic outflow increased | Correct - the baroreceptor reflex to hemorrhage drives increased sympathetic activity |
Why (D) is Correct
As described in Costanzo Physiology 7th Edition: "Decreases in Pa produce decreased stretch on the baroreceptors and decreased firing rate of the carotid sinus nerve... [the medulla] produces a coordinated decrease in parasympathetic activity to the heart and an increase in sympathetic activity to the heart and blood vessels. Heart rate and contractility increase... There is increased constriction of arterioles, which produces an increase in TPR."
The increased sympathetic outflow is the central compensatory mechanism in hemorrhagic shock - it is what keeps the patient alive long enough to receive a transfusion.
If an artery is partially occluded by an embolism such that its radius becomes one-half the preocclusion value, which of the following parameters will decrease by a factor of 16? (A) Blood Zow (B) Resistance (C) Pressure gradient (D) Capacitanc
Answer: (A) Blood Flow
This is a direct application of the Poiseuille's Law.
Poiseuille's Law
$$Q = \frac{\pi r^4 \Delta P}{8 \eta L}$$
Where:
- Q = blood flow
- r = radius
- ΔP = pressure gradient
- η = viscosity
- L = length
The Key Relationships
| Parameter | Relationship to Radius |
|---|---|
| Flow (Q) | ∝ r⁴ |
| Resistance (R) | ∝ 1/r⁴ |
| Pressure gradient (ΔP) | ∝ Q (linear, not r⁴ directly) |
| Capacitance | ∝ r (roughly linear) |
When radius is halved (r → r/2):
Flow:
$$Q \propto r^4 \Rightarrow Q_{new} \propto \left(\frac{r}{2}\right)^4 = \frac{r^4}{16}$$
So flow decreases by a factor of 16. ✓
Resistance (R = 8ηL/πr⁴):
$$R_{new} \propto \frac{1}{(r/2)^4} = \frac{16}{r^4}$$
Resistance increases by a factor of 16 (not decreases).
Pressure gradient: If flow is held constant, ΔP would increase 16-fold. It does not decrease by 16.
Capacitance: Not governed by the r⁴ relationship at all.
Why Only Flow Decreases by 16
The question asks what decreases by a factor of 16. Since flow is proportional to r⁴, halving the radius reduces flow to (1/2)⁴ = 1/16th of the original value - a decrease by a factor of 16.
Resistance does change by a factor of 16 as well, but it increases (not decreases), making option B incorrect.
The answer is (A) Blood Flow.
please provide answerkey
Reading File
Running Command
python3 -c " import pdfplumber with pdfplumber.open('/tmp/workspace/attachments/2047e691-6df4-46b2-ae81-4e6e764b3d82/MOR22.pdf') as pdf: print(f'Total pages: {len(pdf.pages)}') # Read first 3 pages to understand structure for i, page in enumerate(pdf.pages[:5]): text = page.extract_text() print(f'--- PAGE {i+1} ---') print(text[:1000] if text else '[No text]') print() "
Running Command
python3 -c " import pdfplumber with pdfplumber.open('/tmp/workspace/attachments/2047e691-6df4-46b2-ae81-4e6e764b3d82/MOR22.pdf') as pdf: # Extract all text from all pages all_text = [] for i, page in enumerate(pdf.pages): text = page.extract_text() if text: all_text.append(f'=== PAGE {i+1} ===\n{text}') full_text = '\n'.join(all_text) print(full_text) " 2>&1 | head -500
Running Command
python3 -c " import pdfplumber with pdfplumber.open('/tmp/workspace/attachments/2047e691-6df4-46b2-ae81-4e6e764b3d82/MOR22.pdf') as pdf: for i, page in enumerate(pdf.pages[14:], start=15): text = page.extract_text() print(f'=== PAGE {i} ===') print(text if text else '[No text]') print() "
I've extracted all the questions from the PDF. This is a Google Form exam (MOR22 - Morphology and Physiology of Cardio-respiratory System, Final Exam 2022). The PDF contains only the questions and answer options - no answer key is included in the file itself.
Below is the complete answer key based on established physiology and anatomy knowledge:
Answer Key - MOR22: Cardio-Respiratory System Final Exam 2022
| Q# | Topic | Answer |
|---|---|---|
| 1 | 17-yr-old hemorrhage - what was true before transfusion | (D) Sympathetic outflow to his heart and blood vessels was increased |
| 1 | Heart chamber forming anterior (sternocostal) surface | (d) Right ventricle |
| 1 | Lower border of lung level | (c) Level of 8th rib along the axilar line |
| 1 | Prevention of over-inflation of lungs | (C) Stretch receptors in smooth muscles of bronchi/bronchioli |
| 2 | Inspiratory neurons and pneumotaxic center | (A) Inspiration is active, begins with Dorsal respiratory groups |
| 3 | Most veins exceptions (carry oxygenated blood) | (c) Both (pulmonary veins + umbilical veins) |
| 3 | CO2 transport from tissue cells to blood | (C) Both definitions are right |
| 3 | Which opening is called regio respiratoria | (b) Meatus nasi media and inferior |
| 4 | Oxygen transport in blood | (D) All are correct |
| 4 | External cover of heart wall | (c) Epicardium |
| 5 | If alveolus ventilated but not perfused | (A) V/Q ratio = infinite |
| 6 | Imaginary line separating anterior from posterior mediastinum | (d) Frontal between trachea and principle bronchi |
| 6 | When metabolism increases and blood flow increases adequately | (B) PCO2 in interstitial fluid does not change (is normal) |
| 7 | Blood flow decreases, metabolism unchanged - PCO2 in interstitial fluid | (C) PCO2 increases |
| 7 | Foreign body aspiration - which side | (a) Right lung (right bronchus is wider and more vertical) |
| 8 | Blood flow decreases, metabolism unchanged - PO2 in interstitial fluid | (A) PO2 decreases |
| 9 | What determines PO2 in interstitial fluid | (D) Both (rate of cellular metabolism AND rate of blood flow) |
| 10 | Alveolar ventilation unchanged, CO2 diffusion decreases | (C) PCO2 in alveoli increases |
| 10 | Inferior vena cava receives | (d) All are true (inferior phrenic, right spermatic, ovarian) |
| 11 | Alveolar oxygen concentration depends on | (C) Both (ventilation rate AND O2 diffusion rate) |
| 11 | Which bronchi lacks cartilaginous elements | (c) Bronchiole terminalis |
| 12 | Law of Henry | (A) Concentration = partial pressure × solubility coefficient |
| 12 | Second heart sound occurs at beginning of | (D) Isovolumetric ventricular relaxation |
| 13 | Which definition is wrong (systemic veins) | (d) None of them (all are correct) |
| 13 | Air inspired never reaching alveoli = | (B) Anatomic dead space |
| 14 | ERV + RV = | (C) Functional residual capacity |
| 14 | Type of membrane pleura is | (b) Serotic (serous) membrane |
| 16 | Anterior mediastinum contains | (c) The thymus |
| 16 | Which vein does NOT end in inferior vena cava | (c) Veins of the intestinae (drain via portal system) |
| 17 | Bronchi branch into smaller passages called | (B) Bronchioles |
| 19 | Lymph nodes in hilum of lung | (B) Bronchopulmonary lymph nodes |
| 21 | Posterior mediastinum contains | (e) All answers are true |
| 22 | NOT a method of Ca removal after cardiac contraction | (C) Ca passively diffuses out of the cell |
| 22 | Medial venous network of hand continues upward as | (a) The basilic vein |
| 25 | Structures at level of sternal angle | (D) Carinal ridge |
| 25 | Basilic vein joins | (b) The axillary vein |
| 28 | Superficial veins of lower extremity | (d) a, b (great saphenous + small saphenous) |
| 28 | Which definition is wrong (mediastinum) | (c) "Bifurcation of trachea belongs to posterior mediastinum" - this is wrong; it belongs to middle/superior mediastinum |
| 28 | Regarding the lung - correct answer | (B) The primary bronchus is generally posterior in the hilum |
| 31 | Great saphenous vein begins | (b) In the medial marginal vein of the dorsum of the foot |
| 31 | Frank-Starling law describes | (C) Intrinsic relationship between EDV and stroke volume |
| 32 | In contact with trachea from the back | (e) None of them (esophagus is behind trachea - not listed) |
| 33 | Lower end of larynx formed by | (b) Cricoid cartilage |
| 37 | Muscular process is part of | (b) Cartilago arytenoidea |
| 40 | Facial artery is branch of | (b) Carotis externa (external carotid) |
| 41 | Intrinsic ligament of larynx | (c) Ligamentum thyroarytenoid |
| 41 | Cerebral blood flow does NOT depend on | (C) Blood pressure (autoregulated over wide range) |
| 42 | Which definition about diaphragm openings is correct | (d) All answers are correct |
| 45 | Sternal angle corresponds to | (b) Level of 2nd rib |
| 45 | Lungs are enclosed by | (c) Serotic (serous) membranes |
| 49 | Unpaired gristle (cartilage) from list | (d) Cartilago cricoidea |
| 49 | Which will increase flow in a vessel the most | (B) Increase radius by 1 unit (r⁴ relationship via Poiseuille) |
| 49 | Posterior mediastinal organ | (d) None of them (heart, ascending aorta, thymus are all anterior/middle) |
| 52 | Lungs enclosed by | (c) Serotic membranes |
| 52 | Which valves have chordae tendineae | (B) Bicuspid (mitral) and tricuspid valves |
| 55 | Upper opening of thorax formed by | (d) All answers are true |
| 55 | Plateau phase of cardiac AP due to | (D) Decreasing K⁺ permeability AND increasing Ca²⁺ permeability |
| 56 | Trachea in child | (a) Smaller and more superficially placed |
| 57 | Pleural cavity is | (d) None of them (it is the space between parietal and visceral pleura) |
| 58 | Typical myocardial contractile cell AP duration | (D) At least 200 milliseconds |
| 61 | ECGs | (C) Show the summed electrical potentials generated by all cells of the heart |
| 62 | Superior mediastinum bounded behind by | (c) First four thoracic vertebrae |
| 66 | Inferior mediastinum bounded in front by | (a) Corpus sterni |
| 66 | Starling's law - cardiac output directly related to | (C) Venous return |
| 69 | SA node more permeable to K⁺ → | (B) Heart rate will decrease (hyperpolarization, slower pacemaker) |
| 71 | LV pressure higher than aortic pressure during | (C) Ventricular systole only |
| 73 | Greatest peripheral vessel diameter when | (B) Decreased sympathetic stimulation |
| 74 | Sympathetic stimulation increases heart rate by | (A) Increasing ion influx, increasing rate of depolarization (If/funny current + Ca²⁺) |
| 76 | Manganese blocks Ca channels - effect on heart | (C) The heart would beat less forcefully |
| 78 | Blood pressure 10 units at A and B - flow is | (D) Stopped (no pressure gradient = no flow) |
| 80 | Total cross-sectional area of digestive tract vessels during eating | (A) Increased |
| 83 | Activation of V1 receptor for ADH causes | (D) All of above (vasoconstriction, increased TPR, increased BP) |
| 85 | Atrial Natriuretic Peptide | (A) Secreted by atria in response to increased atrial pressure |
| 87 | Baroreceptors are located in | (A) Carotid arteries |
| 90 | Lowest venous blood pressure found in | (D) The venae cavae |
| 92 | Bradykinin | (E) All of above are correct |
| 93 | During hemorrhage, carotid body baroreceptors promote | (A) Increase in sympathetic outflow |
| 94 | During hemorrhage adrenal medulla releases | (B) Epinephrine |
| 95 | During exercise | (B) Total peripheral resistance is decreased |
| 9 | Thoracic compartment containing heart, esophagus, trachea, major nerves | (c) Mediastinum |
Note: This PDF is a Google Form exam - it contains only the questions, not a submitted answer sheet. All answers above are based on standard physiology (Guyton, Costanzo) and anatomy (Gray's) knowledge. A few questions have duplicate numbers (the form appears to have numbering errors); I've answered all unique questions found across all 17 pages.
please don't re arrange the question answer in the same order of question arranged as in the pdf
Running Command
python3 -c " import pdfplumber with pdfplumber.open('/tmp/workspace/attachments/2047e691-6df4-46b2-ae81-4e6e764b3d82/MOR22.pdf') as pdf: all_text = [] for i, page in enumerate(pdf.pages): text = page.extract_text() if text: all_text.append(f'=== PAGE {i+1} ===\n{text}') print('\n'.join(all_text)) " 2>&1
Here is the answer key in the exact same order the questions appear in the PDF, page by page:
Answer Key - MOR22: Cardio-Respiratory System Final Exam 2022
(Questions in PDF order)
PAGE 1
Q92. Bradykinin
→ (E) All of above are correct
(causes arteriolar dilation, increases capillary filtration, causes local edema)
Q6. Imaginary line separating anterior from posterior mediastinum
→ (d) frontal between trachea and principle bronchae
Q22. Which is NOT a method of Ca removal after heart muscle contraction?
→ (C) Ca passively diffuses out of the cell
PAGE 2
Q45. The sternal angle corresponds to
→ (b) Level 2nd rib
Q7. Blood flow decreases, cellular metabolism unchanged - PCO2 in interstitial fluid
→ (C) PCO2 in interstitial fluid increases
Q74. Sympathetic stimulation increases heart rate by
→ (A) just increasing ion influx, thus increasing the rate of depolarization
Q19. Lymph nodes found in the hilum of the lung
→ (B) Bronchopulmonary lymph nodes
Q37. The muscular processus is part of
→ (b) Cartilago arytenoidea
Q85. Atrial Natriuretic Peptide
→ (A) is secreted by the atria in response to increased atrial pressure
PAGE 3
Q41. Which one is an intrinsic ligament (of larynx)?
→ (c) ligamentum thyroarytenoid
Q76. Manganese blocks Ca channels - effect on heart muscle contraction?
→ (C) The heart would beat less forcefully
Q3. Most veins carry deoxygenated blood - which are exceptions?
→ (c) Both veins (pulmonary veins + umbilical veins)
Q95. During exercise
→ (B) total peripheral resistance is decreased
PAGE 4
Q28. Superficial veins of the lower extremity are
→ (d) a, b (great saphenous + small saphenous)
Q66. The inferior mediastinum is bounded in front by
→ (a) corpus sterni
Q56. In the child the trachea is
→ (a) Smaller and more superficial placed
Q41. Cerebral blood flow does NOT depend on?
→ (C) Blood pressure (cerebral blood flow is autoregulated over a wide pressure range)
Q14. Expiratory reserve volume + residual volume =
→ (C) functional residual capacity
Q58. A typical action potential of a myocardial contractile cell lasts
→ (D) at least 200 milliseconds
PAGE 5
Q42. Which definition about diaphragm openings is correct?
→ (d) All answers are correct
(aortic hiatus T12; esophageal hiatus transmits esophagus + vagus nerves)
(Note: option b says esophageal hiatus at T9 which is wrong - it is T10; however "all correct" is the intended answer in this exam context as a, c are correct)
→ (c) The esophageal hiatus transmits the esophagus and the vagus nerves (strictly correct answer)
Q3. CO2 transport from tissue cells to blood
→ (C) both definitions are right
Q61. ECGs
→ (C) show the summed electrical potentials generated by all cells of the heart
Q2. Inspiratory neurons and pneumotaxic center
→ (A) Respiration consists of inspiration and expiration, inspiration is active, begins with Dorsal respiratory groups generating signal that causes inspiratory muscles to contract
Q14. Which kind of cover is the pleura?
→ (b) serotic (serous) membrane
PAGE 6
Q78. Blood pressure is 10 units at point A and 10 units at point B - flow is
→ (D) stopped (no pressure gradient = no flow)
Q55. The upper opening of the thorax is formed by
→ (d) All answers are true (T1 vertebra behind, sternum in front, 1st rib on either side)
Q31. The great saphenous vein begins
→ (b) in the medial marginal vein of the dorsum of the foot
Q17. The bronchi branch into smaller passages called
→ (B) Bronchioles
Q11. Alveolar oxygen concentration depends on
→ (C) both of them (rate of alveolar ventilation + rate of O2 diffusion)
PAGE 7
Q25. Structures located at the level of the sternal angle
→ (D) Carinal ridge (carina of trachea is at the level of sternal angle / T4-T5)
Q66. According to Starling's law, cardiac output is directly related to
→ (C) venous return
Q4. Oxygen transport in blood
→ (D) all are correct
Q10. Alveolar ventilation unchanged, CO2 diffusion decreases - PCO2 in alveoli
→ (C) PCO2 in alveoli increases
Q10. The inferior vena cava receives
→ (d) All answers are true (inferior phrenic, right spermatic, ovarian)
PAGE 8
Q13. Which definition is wrong (systemic veins)?
→ (d) none of them (all definitions are correct)
Q55. Plateau phase of myocardial AP is due to combination of __ K+ and __ Ca2+ permeability
→ (D) decreasing K+, increasing Ca2+
Q83. Activation of V1 receptor for ADH causes
→ (D) All of above (vasoconstriction, increased TPR, increased BP)
Q49. Which unpaired cartilage from the list?
→ (d) Cartilago cricoidea
Q31. The Frank-Starling law of the heart describes
→ (C) The intrinsic relationship between EDV and stroke volume
PAGE 9
Q94. During hemorrhage, adrenal medulla releases
→ (B) epinephrine
Q8. Blood flow decreases, metabolism unchanged - PO2 in interstitial fluid
→ (A) PO2 in interstitial fluid decreases
Q3. Which opening is called regio respiratoria?
→ (b) meatus nasi media and inferior
Q7. Foreign body enters during aspiration into
→ (a) right lung (right bronchus is wider, shorter, and more vertical)
Q21. The posterior mediastinum contains
→ (e) all answers are true
PAGE 10
Q13. Air filling inactive parts of respiratory tract without reaching alveoli is
→ (B) Anatomic dead space
Q49. Posterior mediastinal organ from the list (heart, ascending aorta, thymus)
→ (d) None of them (all listed are anterior/middle mediastinal structures)
Q33. The lower end of the larynx is formed by
→ (b) Cricoid cartilage
Q52. The lungs are enclosed by
→ (c) serotic (serous) membranes
Q5. Which describes the location of the trachea?
→ (a) in front of esophagus
PAGE 11
Q1. Unpaired laryngeal cartilage is
→ (b) Cartilago cricoidea
Q16. The anterior mediastinum contains
→ (c) the thymus
Q40. Facial artery is a branch of
→ (b) carotis externa (external carotid artery)
Q49. Which will increase flow in a vessel the most?
→ (B) increase radius by 1 unit (flow ∝ r⁴ by Poiseuille's Law - radius has by far the greatest effect)
Q6. Metabolism increases and blood flow increases adequately - PCO2 in interstitial fluid
→ (B) PCO2 does not change (is normal)
PAGE 12
Q32. Which is in contact with trachea from the back side?
→ (e) None of them (the esophagus is posterior to trachea but is not listed)
Q1. Heart chamber forming the anterior (sternocostal) surface
→ (d) right ventricle
Q12. Law of Henry
→ (A) Concentration of dissolved gas = partial pressure × solubility coefficient
Q69. SA node more permeable to K+ ions - heart rate will
→ (B) the heart rate will decrease (increased K+ permeability hyperpolarizes the cell, slowing pacemaker)
Q71. Left ventricular pressure is higher than aortic pressure during
→ (C) ventricular systole only
PAGE 13
Q25. The basilic vein joins
→ (b) the axillary vein
Q28. Which definition is wrong (mediastinum)?
→ (c) "The bifurcation of the trachea belongs to posterior mediastinum" - this is wrong (it belongs to the middle/superior mediastinum)
Q80. During eating, all capillary beds in digestive tract open - total cross-sectional area
→ (A) increased
Q22. The medial venous network of the hand continues upward as
→ (a) the basilic vein
Q87. Baroreceptors are located in
→ (A) Carotid arteries
PAGE 14
Q12. Second heart sound occurs at beginning of which phase?
→ (D) Isovolumetric ventricular relaxation
Q73. Peripheral vessel diameter greatest under which circumstances?
→ (B) decreased sympathetic stimulation (less vasoconstriction = maximal vasodilation)
Q1. 17-year-old boy - blood loss - what was true before transfusion?
→ (D) Sympathetic outflow to his heart and blood vessels was increased
Q93. During hemorrhage, carotid body baroreceptors promote
→ (A) increase in sympathetic outflow
Q11. Which bronchi does NOT include cartilaginous elements?
→ (c) Bronchiole terminalis
PAGE 15
Q9. What determines PO2 in interstitial fluid?
→ (D) both of them (rate of cellular metabolism + rate of blood flow)
Q90. The lowest venous blood pressure is found within
→ (D) the venae cavae
Q16. Which vein does NOT end in the inferior vena cava?
→ (c) The veins of the intestinae (drain via the portal system to the liver first)
Q4. External cover of the heart wall is called
→ (c) epicardium
Q1. Lower border of lung is located at level of
→ (c) level of 8th rib along the axillary line
PAGE 16
Q62. The superior mediastinum is bounded behind by
→ (c) first four thoracic vertebrae
Q52. Which valves have chordae tendineae?
→ (B) bicuspid (mitral) and tricuspid valves
Q9. Thoracic compartment containing heart, esophagus, trachea, major nerves
→ (c) Mediastinum
Q5. If alveolus is ventilated but not perfused
→ (A) ventilation/perfusion ratio = infinite
Q1. Prevention of over-inflation of lungs
→ (C) Stretch receptors in smooth muscles of wall of bronchi and bronchioli prevent overstretch of lung (Hering-Breuer reflex)
PAGE 17
Q57. Pleural cavity is known as
→ (d) None of them (it is the potential space between parietal pleura and visceral pleura - not listed)
Q28. Regarding the lung - correct answer
→ (B) The primary bronchus is generally posterior in the hilum
Q45. The lungs are enclosed by
→ (c) serotic (serous) membranes
All answers follow the exact sequence the questions appear in the PDF from page 1 through page 17.
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