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Flashcards in Quiz 2 Practice Problems Deck (131):
1

A researcher opens the chest of an anesthetized mouse and microinjects a small amount of a fluorescent dye into a single cardiac muscle cell at the base of the left ventricle. Over time, the dye spreads toward the left atrium. Which structure listed below is most likely responsible for facilitating this spread? A. Endomysium B. Intercalated discs C. Parasympathetic fibers D. Sarcoplasmic reticulum E. T tubules

B. Intercalated Discs

2

2. While hiking in Canyonlands National Park, a 24-year-old medical student experienced a puncture wound on her leg from a cactus needle. Several days later, she noticed that the wound was swollen and tender, indicating an infection. Because of a class she had taken, she knew that immune system cells are attracted from the blood to the connective tissue involved. What barrier did these cells most likely have to move past to exit the blood and enter the infected tissue? A. Collagen fibers of the tunica adventitia B. Elastic fibers of the tunica intima C. Smooth muscle of the tunica media D. Tight junctions between endothelial cells

D - tight Junctions

3

3. Endothelial cells of a capillary bed can regulate the amount of blood flowing into the bed by releasing signaling molecules that affect which nearby structure? A. End arteries B. Lymphatics C. Metarterioles D. Pericytic venules E. Vasa vasorum

C- Smooth muscle sphincters of metarterioles regulate the flow of blood into the capillary beds they supply. The smooth muscle cells are sensitive to chemical signals, including those released by endothelial cells.

4

A researcher is investigating the pathology produced by a newly discovered jungle microbe. This bacterium releases a toxin that produces dramatic leakage of fluid and cells from capillaries and postcapillary venules. The researcher determines that this reaction is not associated with an increase in the release of histamine or other known vasoactive molecules. To her surprise, studies using cultures of purified human endothelial cells indicate that the toxin does not bind to these cells and has no noticeable effect on their physiology. Which of the following would be the researcher’s next logical cellular target? A. Atrial myocytes B. Fibroblasts C. Pericytes D. Smooth muscle E. Sympathetic neurons

C -- Pericytes are the only cells listed that are routinely associated with capillaries and postcapillary venules. These cells provide many important activities, including the production of factors involved in maintaining the integrity of microvessels.

5

Ehlers– Danlos syndrome is a group of inherited disorders. One form of this syndrome apparently involves the inability to produce type III collagen. In this case, death often results from massive internal bleeding due to spontaneous rupture of the aorta. Which portion of the aorta should be most affected by this form of the syndrome? A. Tunica intima B. Internal elastic lamina C. Tunica media D. Tunica adventitia E. External elastic lamina

C -- The smooth muscle cells of the tunica media produce the type III collagen fibers and elastic fibers found in this layer. Recall that fibrillin mutations in Marfan syndrome, which perturb elastic fiber assembly, can also result in the rupture of large vessels.

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CBDA

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A systolic

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1. A prenatal ultrasound of a 35-year-old 
woman in her 12th week of gestation reveals 
an abnormal image of the fetal heart. Instead 
of a four-chambered view provided by the 
typical cross, a portion just below the crosspiece is missing. What structures constitute 
the cross, and what defect does this infant 
probably have?

Sadler, T. W. (2014-10-07). Langman's Medical Embryology (Longmans Medical Embryolgy) (Page 217). LWW. Kindle Edition. 

1. A four-chambered view is sought in ultrasound scans of the heart. Th e chambers are 
divided by the atrial septum superiorly, the 
ventricular septum inferiorly, and the endocardial cushions surrounding the atrioventricular canals laterally. Together, these 
structures form a cross with integrity readily 
visualized by ultrasound. In this case, however, the fetus probably has a ventricular 
septal defect, the most commonly occurring 
heart malformation, in the membranous portion of the septum. Th e integrity of the great 
vessels should also be checked carefully because the conotruncal septum dividing the 
aortic and pulmonary channels must come 
into contact with the membranous portion of 
the interventricular septum for this structure 
to develop normally.

Sadler, T. W. (2014-10-07). Langman's Medical Embryology (Longmans Medical Embryolgy) (Page 377). LWW. Kindle Edition. 

20

2. A child is born with severe craniofacial defects and transposition of the great vessels. 
What cell population may play a role in both 
abnormalities, and what type of insult might 
have produced this eff ect?

 

2. Because neural crest cells contribute to much 
of the development of the face and to the 
conotruncal septum, these cells have probably 
been disrupted. Crest cells may have failed to 
migrate to these regions, failed to proliferate, 
or may have been killed. Retinoic acid (vitamin A) is a potent teratogen that targets neural crest cells among other cell populations. 
Because retinoids are eff ective in treating acne, 
which is common in young women of childbearing age, great care should be employed 
before prescribing the drug to this cohort.

Sadler, T. W. (2014-10-07). Langman's Medical Embryology (Longmans Medical Embryolgy) (Page 377). LWW. Kindle Edition. 

21

A patient complains about having difficulty 
swallowing. What vascular abnormality or 
abnormalities might produce this complaint? 
What is its embryological origin?

 

22

3. What type of tissue is critical for dividing 
the heart into four chambers and the outflow 
tract into pulmonary and aortic channels?

 

3. Endocardial cushion tissue is essential for 
proper development of these structures. In 
the common atrioventricular canal, the superior, the inferior, and two lateral endocardial 
cushions divide the opening and contribute 
to the mitral and tricuspid valves in the left 
and right atrioventricular canals. In addition, the superior and inferior cushions are 
essential for complete septation of the atria 
by fusion with the septum primum and of 
the ventricles by forming the membranous 
part of the interventricular septum. Cushion 
tissue in the conus and truncus forms the 
conotruncal septum, which spirals down to 
separate the aorta and pulmonary channels 
and to fuse with the inferior endocardial 
cushion to complete the interventricular septum. Th erefore, any abnormality of cushion 
tissue may result in a number of cardiac defects, including atrial and ventricular septal 
defects, transposition of the great vessels, and 
other abnormalities of the outflow tract.

 

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47


1. Which of the following hormones are released primarily through humoral regulation? (Humoral regulation means that the hormone is secreted by cells that directly detect changes to concentrations of compounds in the blood.)
  
A. ADH (anti-diuretic hormone) and insulin
 
  
B. Epinephrine and norepinephrine
 
  
C. Follicle-stimulating hormone and luteinizing hormone
 
  
D. Thyroid hormone and thyroid-stimulating hormone
 

A. ADH (ant-diuretic hormone) and insulin

48

Glucagon is a hormone secreted by pancreatic alpha cells primarily in response to decreased blood glucose to help increase and maintain normal blood glucose levels. It signals through a G-protein coupled receptor. Which of the following will most directly alter the amount of glucagon signaling that occurs within a specific cell at a specific moment?

 

Number of glucagon receptors on the cell surface

Concentration of protein tyrosine phosphatases in the cell

Glucagon concentration in the blood

A.

Yes

Yes

No

B.

Yes

No

Yes

C.

Yes

No

No

D.

No

Yes

Yes

E.

No

Yes

Yes

B: Yes, No , Yes,

49

Draw out thyroid hormone regulation, including the roles of the hypothalamus, anterior pituitary, thyroid gland, TRH, TSH and T3/T4 (thyroxine).

50

A major component of the regulation of thyroid hormone secretion is:

A. adrenal medulla involvement

B. negative feedback regulation

C. positive feedback regulation

D. steroid hormone regulation

B. Neg. Feedback

51

Thyroid-stimulating hormone (TSH) binds what type of receptor?

A. G-protein coupled (7-transmembrane helical)

B. Ion channel coupled

C. Nuclear hormone

D. Tyrosine kinase

A. G-protein coupled

52

Cells found where are most likely to express the TSH receptor?

A. Anterior pituitary

B. Common carotid artery

C. Hypothalamus

D. Liver

E. Posterior pituitary

F. Thyroid follicle

F. Thryoid Flollicle

53

What is the relationship between thyroglobulin and thyroxine?

A. Thyroglobulin is made from thyroxine.

B. Thyroglobulin transports thyroxine in the blood

C. Thyroxine is made from thyroglobulin

D. Thyroxine positively regulates the production of thyroglobulin

C. thryroxine is made from thyroglobulin

54

Where is thyroxine (T4) primarily made?

A. In the anterior pituitary

B. In the hypothalamus

C. In the tissues where it is active

D. In thyroid follicular lysosomes

D. In thryoid flollicular lysosomes

55

What is the most immediate response that results from TSH binding to its receptor?

A. Increased secretion of T3 and T4 (thyroxine)

B. Increased synthesis of thyroglobulin colloid

C. Inhibition of TSH release

D. Inhibition of thyrotropin-releasing hormone secretion

A. Increased secretion of T3/T4

56

Which of the following is the correct structure for active thyroid hormone, T3?

D. D is right

57

Based on the information in the previous figure, what can you most logically conclude about the thyroid hormone receptor ?

A. It is expressed in many cell types throughout the body.

B. It is expressed primarily in liver cells (hepatocytes).

C. Its expression is induced by TSH binding to a G-protein coupled receptor. 

A. many cell types!

58

A 44-year-old woman presents with unexplained weight loss and increased anxiety. Vital signs were notable for a heart rate of 105. Physical exam showed a diffuse goiter, moist skin and hyperactive bowel sounds. Eye exam showed bilateral exophthalmos, upper lid lag and retraction, periorbital edema. Laboratory studies showed that serum TSH was undetectable (unusually low) and free T4 was 12 ng/dL (ref 0.8- 2.3). A test with radioactive iodine showed that her thyroid uptake was almost twice normal. 

Her symptoms (and low TSH, high T4)

are most likely caused by an auto-

antibody that:

A. Causes the destruction of the thyrotrope cells (TSH- producing cells) of the pituitary.

B. Acts as a TSH receptor agonist.
C. Binds with high affinity to T4 in the serum.
D. Lowers the affinity of serum binding proteins for T4. 

B. acts as a TSH receptor Agonist.

59

We extract energy from macronutrients primarily from which of the following types of chemical reactions?

hydrogenation of carbon

hydrolysis of carbon

oxidation of carbon

phosphorylation of carbon

reduction of carbon

Oxidation of carbon

60

We need functioning hearts and lungs primarily to deliver oxygen and nutrients to all cells, and remove the waste products of metabolism. Our metabolism, and that of most other organisms living on Earth, has evolved to be based on oxygen because this element has what property?

a high affinity for electrons

a molecular weight between that of carbon and phosphorous

the ability to be converted to the free radical superoxide

the ability to bind and be released from hemoglobin with positive cooperativity

High affinity for electrons

61

Energy expenditure (caloric needs) can be determined by measuring the amount of oxygen one utilizes. This is because the majority of oxygen we consume is:

attached directly to the carbons of carbohydrates, fats and amino acid fuels

incorporated into the structure of ATP

required for anaerobic glycolysis

used by the terminal oxidase in the mitochondrial electron transport chain

 

Used by the terminal oxidase in the mitochondrial elecron transport chain.

62

A researcher was studying the metabolism of a 34-year old healthy man. She measured the volume of O2 he consumed (VO2, mL/min) and the volume of CO2 he produced (VCO2, mL/min) using a spirometer. The results indicated that his respiratory quotient (RQ, VCO2/VO2) was 0.87 while he was at rest. This indicates that during the test his body was primarily oxidizing:

carbohydrates

cholesterol

fat

carbohydrates and fats

Carbohydrates and fats

63

One hour after a meal, the RQ for this same 34-year old man increased to 0.94. This change most likely indicates:

an increase in carbohydrate oxidation.

that he was exercising when this second measurement was made.

that the meal contained a large percentage of fat.

the thermic effect of food.

An increase in carbohydrate oxidation

64

Adenylate kinase is expressed in essentially all human cells and is a crucial enzyme for cellular energy balance. When a cell becomes stressed for energy, resulting in the increased production of ADP, adenylate kinase transfers a phosphate from one ADP to another, generating ATP and ___________.

Adenine

AMP

Creatine

Creatine phosphate

AMP!

65

An example of when your cardiac creatine kinase would primarily phosphorylate ADP is most likely:

  
when you first start sprinting up the stairs
 
 
after you’ve completed sprinting up the stairs and you are catching your breath

When you first start sprinting up the stairs

66

An example of when your cardiac creatine kinase would primarily phosphorylate creatine is most likely:

when you first start sprinting up the stairs

after you’ve completed sprinting up the stairs and you are catching your breath

After you've completed sprinting up the stairs

67

Which of the following processes is most likely to be activated by AMP-activated protein kinase phosphorylation of a key regulatory enzyme?

Fatty acid synthesis

Fatty acid oxidation

Gluconeogenesis (as the name indicates, this is the creation of new glucose)

Protein synthesis

Fatty Acid Oxidation

68

Which of the following processes is most likely to be inhibited by AMP-activated protein kinase phosphorylation of a key regulatory enzyme?

Fatty acid synthesis

Glycolysis

Ketone body oxidation

TCA cycle

Fatty Acid Synthesis!

69

The Nonna’s Toasted Pound Cake at Maggiano’s Little Italy restaurant has 1170 kcal, 36 g of saturated fat and 111 g of sugar. For a man who uses 2500 kcal of energy per day, approximately what percentage of his daily caloric needs are provided by this dessert? What percentage is provided by just the saturated fat in this dessert? By just the sugar in the dessert?

47%, 13%, 18%

47%, 36%, 11%

47%, 6%, 40%

47%, 22%, 25%

A. 47%, 13%, 18%

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71

Activation of AMP-activated protein kinase is most likely to inhibit which of the following processes in liver?

A. Fatty acid oxidation
B. Glucose synthesis (gluconeogenesis) C. Glycolysis
D. Mitochondrial respiration
E. TCA cycle (Kreb’s cycle) 

A. fatty acid oxidation.

72

A baby is born with a congenital defect in the integrins expressed in her neutrophils. She presents in clinic with a severe bacterial skin infection. What is the most likely situation regarding neutrophil numbers in her blood and at the site of the infection?

A. High in blood, low at the infected site B. High in blood, high at the infected site C. Low in blood, low at the infected site D. Low in blood, high at the infected site 

A. high in blood and low at the infected site.

73

NADPH oxidase catalyzes the formation of superoxide radicals, reactive molecules that are also substrates for the synthesis of hydrogen peroxide. People born with inherited defects in NADPH oxidase activity suffer from numerous, long lasting bacterial infections. This is likely due to reduced effectiveness of their:

A.  Basophils

B.  B lymphocytes

C.  Eosinophils

D.  Monocytes

E.  Platelets

F.  Polymorphonuclear neutrophils 

I believe it is F!

74

this is a posterior anterior or PA x-ray.  You can see this by the sharper shape of the acromial bone, and the sharper image of the vertibrate, and the lack of the edge of the scapula.

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There are 10

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Right middle lobe pneumonia – notice the right heart border is obscured 

77


The aortic arch:
1.  passes from the posterior mediastinum to the anterior mediastinum as it arches over the right primary bronchus and right pulmonary artery.


2. connects the dorsal vascular plane with the ventral vascular plane as it arches over the left primary bronchus and left pulmonary artery.


3. is located within the middle mediastinum and connects the ventral vascular plane with the dorsal vascular plane.

4. connects the dorsal vascular plane with the ventral vascular plane as it arches over the right primary bronchus and right pulmonary artery.
 

ans:  2

Teaching Point: The aortic arch connects the descending aorta in the dorsal vascular plane of the posterior mediastinum with the ascending aorta in the ventral vascular plane in the superior and middle mediastina. It arches to the left over the left pulmonary artery and left primary bronchus.

78

After a normal regimen of exercise, a 16-year-old girl experiences shortness of breath. She undergoes a clinical exam followed up by echocardiography, which reveals a patent ductus arteriosus. Which structure is most likely involved?


Coronary sinus
Left subclavian artery
Pulmonary artery
Right atrium
Fossa ovalis
 

Pulmonary artery.

Teaching Point: The ductus arteriosus serves as an arterial shunt that transports pulmonary blood to the aorta in fetal circulation. In the normal neonate, the ductus arteriosus may begin to close between 10 and 15 hours after birth, with the majority being closed by 72 hours after birth. Sometimes, however, the ductus arteriosus does not close, and a patient may be asymptomatic for several years.

79

An otherwise asymptomatic patient states that he feels a shortness of breath when mildly exercising. The patient's history is reviewed, and it is thought that the patient is experiencing a unilateral diaphragmatic paralysis. One cause may be compression of the:


glossopharyngeal nerve roots.
C1, C2, and C3 nerve roots.
vagus nerve roots.
T1, T2, and T3 nerve roots.
C3, C4, and C5 nerve roots.
T3, T4, and T5 nerve roots.
 

C3,C4,C5

Teaching Point: Unilateral diaphragmatic paralysis results from a lack of contraction of the diaphragm. The phrenic nerve innervates the diaphragm; it arises from the C3, C4, and C5 nerve roots.

80


The lateral boundaries of the mediastinum are formed by the:
fibrous pericardium.
medial walls of the right and left pleural sacs.
intercostal muscles.
lateral aspect of the true ribs.
 

medial walls of the right and left pleural sacs.

Teaching Point: The medial walls of the parietal pleura are called the mediastinal pleura because they border the mediastinum.

81

The horizontal plane that corresponds to the top of the heart, and the approximate level for the bifurcation of the trachea and the pulmonary trunk, the beginning and end of the aortic arch, the junction of the azygos vein with the superior vena cava, and the origin of the recurrent laryngeal nerve is:


the transverse plane from the sternal angle anteriorly to the T4-T5 intervertebral disc posteriorly.
 

Teaching Point: The plane that divides the superior mediastinum from the inferior mediastinum passes immediately above the heart and pericardial sac. The plane spans from the sternal angle to the T4-T5 intervertebral disc (plane of Ludwig at the angle of Louis).

82


The sympathetic trunk and its ganglia are:


in the anterior mediastinum and project into the superior mediastinum.


located within the fibrous pericardium along with the internal thoracic arteries and veins.


body wall nerves located between the internal and external investing fascia.


the deepest structural plane of the posterior and superior mediastina.
 


the deepest structural plane of the posterior and superior mediastina.

Teaching Point: The sympathetic trunks and ganglia parallel the vertebral column on both sides, and these autonomic nerves carry sympathetic neurons to all levels of the body. They communicate with the body wall spinal nerves via white and gray communicating rami, which leave the mediastinum and perforate the body wall. They send splanchnic nerves forward into the mesenteric plane.

83


An 18-year-old man presents to the emergency department following a vehicular accident. Physical exam reveals that he is hypotensive and tachycardic and has fractures in ribs 9 and 10 on the left side. He complains of abdominal pain. Identify an additional likely finding in this patient.
Pain radiating to the penis and scrotum
Bloody diarrhea
Abnormal liver function test
Pain in the left shoulder
Peritoneal irritation at the McBurney point
 

Teaching Point: This patient has a ruptured spleen (due to fracture of ribs 9 and 10 on the left side) resulting in blood hemorrhaging into the right side of the abdomen and causing a decrease in blood pressure (hypotension) and an increase in heart rate (tachycardia) attempting to restore the pressure. Blood pooling in the left upper quadrant of the abdomen irritates the parietal peritoneum, causing diffuse pain in the abdomen. The diaphragmatic parietal peritoneum is innervated by the phrenic nerve, and pain refers to the C3-C5 dermatomes, resulting in left shoulder pain.

84


A 58-year-old man complains of dysphagia (difficulty swallowing). Imaging reveals that the anterior wall of his esophagus in the midthorax region is compressed. Identify the structure most likely responsible for his dysphagia.
Left atrium
Pulmonary trunk
Right atrium
Left ventricle
Right ventricle
 

Teaching Point: The left atrium forms the majority of the base and posterior surface of the heart. The esophagus courses vertically behind the heart. Enlargement of the left atrium compressed the esophagus of the patient and results in dysphagia.

85


Question:A 56-year-old steelworker with a 40-pack-year smoking history visits his family doctor complaining of a persistent ache in his right shoulder and weakness in his right arm that is affecting his work. The physician, who has known the patient for many years, notices that his voice is considerably hoarser than it has been in the past. She also notices that the patient seems to be coughing frequently, but weakly and ineffectively. Concerned, she orders a chest X-ray, which reveals a Pancoast tumor in his right lung. Which of his symptoms are likely explained by this finding?
Weak coughing due to a paralyzed right hemidiaphragm
Right shoulder pain due to degenerative arthritis of the glenohumeral joint
Hoarseness due to paralysis of his right intrinsic laryngeal muscles
Right arm weakness due to paralysis of the muscles innervated by the superior roots of the brachial plexus
 

Teaching Point: The intrinsic muscles of the larynx are responsible for the movements of the vocal folds. When these muscles are paralyzed on one side, patients exhibit hoarseness and weak, ineffective coughing. A Pancoast tumor is one that is in the apex of the lung. These tumors can compromise the vagus nerve, recurrent laryngeal nerve, or sympathetic trunk. Injury to the vagus nerve or recurrent laryngeal nerve may result in paralysis of the vocal folds on the same side. The patient's weak coughing is also partially due to the paralysis of his vocal folds; paralysis of a hemidiaphragm would be due to a compromised phrenic nerve, which is rarely affected by Pancoast tumors. Pancoast tumors can cause weakness of the ipsilateral arm muscles on the ulnar side of the arm; however, this would be due to invasion of the inferior (not superior) roots of the brachial plexus. His right shoulder pain is likely due to degenerative arthritis, but this is unrelated to his tumor.

86


A 5-year-old boy is rushed to the ER after being stabbed in the anterior thorax with a sharp stick during recess. After initial examination, it is noted that the wound is superficial and located just below and lateral to the sternal angle. Had the wound been deep enough to puncture the thoracic wall, which of the following median structures would be harmed first?
Thymus
Parietal pericardium
Oblique cardiac sinus
Visceral pericardium
Fibrous pericardium
 

Teaching Point: The inferior aspect of the thymus occupies the space anterior to the heart in the pediatric population; it is in the anterior mediastinum. The 3 pericardia and the oblique cardiac sinus are in the medial mediastinum, deep to the thymus.

87


A 71-year-old male presents with hypotensive shock from a dissecting thoracic aneurysm. During surgical repair, a posterior approach was used (patient prone). What is the correct order (superficial to deep) of structures that the surgeon needs to be aware of during the procedure?
Thoracic descending aorta, azygos vein, thoracic duct
Azygos vein, thoracic lymph duct, thoracic descending aorta
Thoracic duct, hemiazygos vein, thoracic descending aorta
Accessory azygos vein, thoracic descending aorta, thoracic duct
 

Teaching Point: The basic structural pattern in the embryonic body cavity consists of structural planes from the dorsal aspect of the body cavity toward the vertical aspect. Within the vascular plane, the order, from dorsal to ventral, is veins, lymphatics, and arteries. Thus, the correct answer on a posterior approach is azygos vein (vein), thoracic lymph duct (lymphatics), and thoracic descending aorta (artery).

88

Aortic coarctation is defined as a congenital narrowing of the aortic arch lumen that causes a variable degree of obstruction to normal blood flow. Which of the following conditions would likely occur in a patient with aortic coarctation?

Teaching Point: The left ventricle hypertrophies in response to the high systemic vascular resistances resulting from the coarctation.

89


Question:Which structure is not located in the superior mediastinum?
Thymus
Trachea
Esophagus
Heart
 

Teaching Point: The heart occupies the middle mediastinum, which is a subset of the inferior mediastinum.

90


During cardiac surgery, a ligature is passed through a passageway posterior to the ascending aorta and pulmonary trunk. Identify the sinus the ligature was most likely passed through.
Oblique pericardial sinus
Retroperitoneal sinus
Horizontal pericardial sinus
Transverse pericardial sinus
Frontal pericardial sinus
 

Teaching Point: The transverse pericardial sinus is located posterior to the ascending aorta and pulmonary trunk, anterior to the superior vena cava, and superior to the left atrium. Both the transverse and the oblique pericardial sinuses can be used during cardiac surgeries to pass ligatures.

91


A 47-year-old man presents with fever and right-sided flank back pain. Ultrasound imaging reveals bright echogenic foci with acoustical shadowing indicative of renal calculi within the right renal pelvis. Identify the nerve that is most likely relaying the sensory information from the kidney to the spinal cord.
Greater splanchnic nerve
Sacral splanchnic nerve
Lesser splanchnic nerve
Pelvic splanchnic neve
T11 intercostal nerve
 

Teaching Point: The lesser, least, and 1st lumbar splanchnic nerves provide sympathetic innervation to the kidney. Visceral sensory neurons course from the kidney to the spinal cord via the same pathways. Therefore, pain from kidney stones is referred to the T10-T11 (lesser splanchnic), T12 (least splanchnic), and L1 (1st lumbar splanchnic) dermatomes along the flank and back.

92


After experiencing dizziness and vertigo while doing bicep curls, a 33-year-old man visits his doctor. The patient's history is taken, and duplex ultrasound and contrast-enhanced neck MR angiography are ordered. Based on these, the physician suspects that the patient has a reversal of blood flow in his right vertebral artery most likely resulting from an occlusion of which structure?
Right subclavian artery
Dorsal scapular artery
Right common carotid artery
Thyrocervical trunk
Costocervical trunk
 

Teaching Point: This patient presents with subclavian steel syndrome; the most common cause of this condition is arterial occlusion or a hemodynamically significant stenosis just proximal to the origin of the ipsilateral vertebral artery. The vertebral artery is the 1st branch off the subclavian artery.

93


Question:A 63-year-old man with a 40 pack year history of smoking complains that food seems to "get stuck" after he swallows. Conventional chest x-ray and CT scan reveal that the man has lesions throughout his lungs, pleural cavities, and posterior mediastinum. Lesions on which of the following plexuses best explain his chief complaint?
Superior mesenteric plexus
Intermesenteric plexus
Inferior mesenteric plexus
Esophageal plexus
Celiac plexus
 

Teaching Point: The metastatic lesions in the posterior mediastinum with accompanying heartburn and indigestion indicate a failure of the esophageal plexus to properly innervate the lower esophagus.

94

A patient participating in a triathlon in St. George, Utah is airlifted to the University Hospital and admitted into the emergency room with adverse cardiovascular complications.  When a blood sample was taken and the hematocrit was reported at nearly 80%.  The physician on call suspected that the patient was illegally taking which of the following:

Erythropoietin.

Cortisol.

Hemoglobin.

Interleukin 3.

Transforming growth factor beta

95

The pluri-potential stem cell of hematopoiesis is also called the "CFU-S" — this latter term is based on:

  

Detection of a unique surface antigen.

   

Electron microscopy.

   

Tissue culture experiments.

   

Whole animal experiments.

Whole animal experiments

CFU-S is an abbreviation for “colony forming unit of the spleen.” Experiments involving the injection of healthy bone marrow cells into X-irradiated mice, which had lost the capacity to make blood cells, identified foci, or colonies, of specific lines blood cell production in the spleen. These experiments eventually indicated that there is a bone marrow cell capable of producing all blood cells.

96

Endomitosis is involved in the formation of what blood cells?

  

Lymphocytes

   

Monocytes

   

Platelets

   

PMNs

   

RBCs

 

Platelets

Megakaryocytes are the differentiated bone marrow cells that produce platelets. Their development involves the process of endomitosis: these cells replicate their DNA and chromosomes without undergoing cell or nuclear division. This produces extremely large cells with immense, lumpy nuclei.

97

If you could mark and count all the neutrophils released from the hematopoietic marrow of a normal, healthy individual in 10 minutes and then 5 minutes later inventory the marked cells free in the blood and that entered connective tissue, you'd find a deficit: far more cells are released than show up in your inventory. The most likely explanation for this would be:

  

Apoptosis.

   

Differentiation.

   

Endomitosis.

   

Hemostasis.

   

Margination.

Margination

A large fraction of the neutrophils in the circulation is marginated: they are rolling along the surface of endothelial cells due to adhesion to selectins. Thus, they won’t show up in your inventory of free blood cells and cells in tissue. These marginated cells represent a pool of cells that can be rapidly released from endothelial cells into bulk blood fluid. It is true that neutrophils have a short life span once they enter the blood, but 5 minutes is too short to make cell death a reasonable explanation for a major deficit. Epinephrine and cortisol are examples of compounds that cause demargination. It is assumed that this release represents a mechanism for rapidly increasing the number of neutrophils available to combat an infection or tissue damage. It is also possible that prolonged stress, which raises the levels of epinephrine and cortisol, can interfere with neutrophil action by interfering with their ability to roll along endothelial cells.

 

98

The GEMM hematopoietic progenitor cell can give rise to three more restricted progenitors in hematopoietic marrow. The relative frequencies with which the three are produced are influenced most directly by:

  

Adventitial reticular cells.

   

Cytokines present in the marrow.

   

Random genetic events.

   

The relative balance of mature cells in the marrow.

   

The relative balance of mature cells in the blood.

Cytokines present in the marrow

 

99

The primary granules seen in the promyelocyte stage by Wright staining are no longer visible in the neutrophilic myelocyte. This is because they have:

  

Been extruded from the cell by exocytosis.

   

Been resorbed back into the Golgi apparatus.

   

Fused with the nucleus to begin segmentation.

   

Stopped staining so intensely.

   

Transformed into secondary granules.

Stopped staining so intensely

Dark staining primary granules are a defining feature of the promyelocyte stage of neutrophil production. These granules do not disappear, but they normally loose components responsible for their dark staining at the promyelocyte stage. In patients suffering from a prolonged and serious infection, neutrophils are sometimes found in the blood with dark staining granules, assumed to be primary granules that haven’t lost these components, possibly due to more rapid production induced by cytokine signaling. Observing these cells is called “toxic granulation” by hematopathologists and considered to be a sign in the blood of the body’s response to a significant infection.

100

The bone marrow of a 70 kg adult weighs approximately:

  

3.5 g

   

35 g

   

350 g

   

3.5 kg

   

35 kg

3.5 kg

 

101

The dark staining precipitate formed in reticulocytes by vital staining with dyes such as cresyl blue or methylene blue consists mostly of residual:

  

Chromatin fragments.

   

Golgi complexes.

   

Nucleoli.

   

Polyribosomes and mRNA.

   

Smooth endoplasmic reticulum.

Polyribosomes and mRNA.

102

What organelles are missing from platelets?

  

Membrane bound vesicles.

   

Microfilaments.

   

Microtubules.

   

Mitochondria.

   

Nuclei.

 

Nuclei

Platelets are pinched off of slender processes that extend from megakaryocytes into the vascular sinuses found in bone marrow. They lack nuclei, but contain all of the other organelles listed. When these cells, or cell fragments, are able to bind to a surface they undergo shape changes, can move, and release factors stored in vesicles.

103

If the incidence of cystic fibrosis is 1/2500 among a population of Europeans, what is the predicted incidence of heterozygous carriers of a cystic fibrosis mutation in this population?

  

A. 1/25

   

B. 1/50

   

C. 2/2500

   

D. 1/2500

   

E. (1/2500)2

1/25

104

A man is a known heterozygous carrier of a mutation that causes hemochromatosis.  Suppose that 1% of the general population consists of homozygotes for this mutation.  If the man mates with somebody from the general population, what is the probability that he and his mate will produce a child who is an affected homozygote?

A. .025

B. .045

C. .09

D. .10

E. .25

  

B. .045

 

Correct!.  One must first determine the probability that the man’s mate will also be a heterozygous carrier.  This is done by applying the Hardy-Weinberg rule.  If the frequency of affected homozygotes is 1%, then the gene frequency of the hemochromatosis mutation is the square root of 1%, or 0.10.  Then the estimated frequency of heterozygous carriers in the population, 2pq, is 2 x 0.10 x 0.9 = 0.18 (notice that we do not use the 2q approximation in this case because p is not approximately equal to 1).  The probability that two heterozygous carriers will produce an affected offspring is ¼, so the probability that the man mates with a carrier and the probability that they will in turn produce an affected offspring is obtained by multiplying the two probabilities together:  ¼ x .18 = 0.045.

105

Your class, which has 100 individuals, has been typed for a locus that has three possible alleles, labeled 1, 2, and 3.  The genotypes and their counts are:

 

Genotype

Count

1,1

10

1,2

5

1,3

15

2,2

20

2,3

20

3,3

30

 

Based on these genotype counts, which is the gene frequencies of alleles 1, 2, and 3?

 

106

 

 

Answer: New Mutation

            Incomplete penetrance

            Autosomal recessive

            X-linked recessive

107

A man and woman are both affected by an autosomal dominant disorder that is lethal in the embryonic period in homozygotes.  The disease has 50% penetrance in heterozygotes.  On average, what proportion of their live-born offspring will be affected?

Your Answer:

 

108

A man who has Neurofibromatosis type 1 (autosomal dominant) marries a phenotypically normal woman.  If they have five children, what is the probability that none of the children will be affected with this disorder?  What is the probability that all of the children will be affected?

109

110

111

112

113

114

115

116

117

118

119

120

Do C!

121

this will show F

122

123

Shows A,D,F, SVC

124

This shows D,B

125

126

127

128

129

130

131

How does rhumatic fever lead to increased vascular pressure in the pulmonary arteries