NBEO PART 1 COMPREHENSIVE EXAMS UPDATED
ALL QUESTIONS AND ANSWERS SURE A+
✔✔Which of the following is the correct pathway for the drainage of tears through the
nasolacrimal drainage system?
Nasolacrimal duct, lacrimal sac, valve of Hasner, lacrimal canaliculus, ampulla, lacrimal
punctum
Lacrimal punctum, lacrimal canaliculus, ampulla, lacrimal sac, nasolacrimal duct, valve
of Hasner
Lacrimal sac, lacrimal punctum, lacrimal canaliculus, ampulla, nasolacrimal duct, valve
of Hasner
Lacrimal punctum, lacrimal canaliculus, ampulla, valve of Hasner, nasolacrimal duct,
lacrimal sac - ✔✔The lacrimal punctum is a small aperture located in the lacrimal
papilla, the slight elevation at the junction of the lacrimal and ciliary portions of the
eyelid margin. Initially, the tear film drains through this aperture. The lacrimal punctum
leads into the lacrimal canaliculus, the tube connecting the punctum to the lacrimal sac.
The ampulla is a slight dilation in the initial portion of the lacrimal canaliculus. The
canaliculi from the upper and lower lids run horizontally along the lid margin, connecting
into a common canaliculus that then enters the lateral aspect of the lacrimal sac located
in the anterior portion of the medial orbital wall. The lacrimal sac empties into the
nasolacrimal duct in the maxillary bone. The valve of Hasner is located at the terminus
of the nasolacrimal duct in the inferior nasal meatus. The Valve of Hasner is a fold of
mucosal tissue that ensures that fluid flows anterograde out of the duct.
,Ref: Remington, LA. Clinical Anatomy of the Visual System, 1998 pp 153-154
✔✔Which of the following skin conditions is considered to be benign and has the
LOWEST risk of malignancy?
Squamous cell carcinoma
Keratoacanthoma
Actinic keratosis
Basal cell carcinoma - ✔✔Keratoacanthoma appears very much like squamous cell
carcinoma (SCC) in that it tends to progress rapidly and appears to ulcerate. This
condition typically occurs in middle-aged and elderly patients of Caucasian descent on
areas of the skin that are exposed. The lesion appears elevated, and eventually the
center will produce a scab-like plug of keratin. The margins surrounding the plug will be
rolled. At some point the keratin plug will fall out, resulting in the formation of a pit, and
the lesion will regress. Most patients and clinicians do not like to wait this condition out
due to its similarities to SCC.
Actinic keratosis is a pre-cursor to squamous cell carcinoma and appears as scaly, dry
skin that does not heal. People with skin that is of lighter pigmentation along with
excessive exposure to ultraviolet light tend to be most at risk for development of this
condition.
Squamous cell carcinoma (SSC) is thankfully one of the rarest malignancies but due to
its ability to metastasize can be quite dangerous. This malignancy has the ability to
progress rapidly and has a high affinity for people who spend a lot of time in the sun,
especially those who are light-skinned. The only way to definitively diagnose SCC is to
refer for a biopsy and ensuring the use of Mohs technique. This strategy takes more
time but ensures that the lesion is removed. Essentially, Mohs procedure calls for
removal of tissue and biopsy of the surrounding borders. If the borders prove to be
malignant then more tissue is removed and biopsied. This continues until the borders
prove to be free of any carcinoma.
Basal cell carcinoma (BCC) is the most common malignant lid lesion and mercifully
tends to be very slow-growing. BCC generally appears as a waxy, translucent nodule.
Eventually the nodule will ulcerate. Patients may bring these to your a
✔✔Which patient would be considered legally blind?
A wet macular degeneration patient with best central acuities of 10/120 OD and 10/200
OS
A patient with a total retinal detachment of the right eye, no light perception and a best
corrected central acuity of 8/60 due to wet macular degeneration
A patient with Best's disease with best corrected central acuities measure OD 10/80 and
OS 10/100
A myopic patient with acuities of 20/400 OD and OS uncorrected
A retinitis pigmentosa patient who has 20/20 central vision in each eye and a 30 degree
in diameter visual field - ✔✔Legal blindness must take into account central best
,corrected visual acuity, with the better eye 20/200 or worse. If the central acuity is
normal such as in the RP patient then the field would be the restricting qualification,
which, at 30 degrees, does not qualify.
✔✔What term describes the phenomenon in which a bacterium directs its movement
TOWARD a chemical in its environment?
Apoptosis
Transposition
Chemotaxis
Phagocytosis - ✔✔Many bacteria possess flagella, or thread-like appendages, which
allow for movement. Certain chemicals attract bacteria (chemoattractants), while others
repel them (chemorepellents). Chemotaxis refers to the response of the bacteria to
either chemoattractants or chemorepellents. In the absence of either of the
aforementioned chemicals, bacteria will move in random patterns. Some bacteria
possess genes and proteins which allow for the sensing of concentration gradients in
their environment. In the presence of a chemoattractant, bacteria will have longer runs
in the appropriate direction.
Apoptosis is defined as programmed cell death.
Phagocytosis refers to the engulfment of a particle (for example, bacteria) by a
phagocyte (for example, a macrophage).
Transposition refers to the rare phenomenon in which genes move from one place on
the genome to another position.
✔✔What type of agar is commonly used to culture fungi?
Cetrimide agar
Hay infusion agar
Thayer-Martin agar
Sabouraud's agar
Blood agar plate - ✔✔Sabouraud's agar is useful for culturing fungi. Culturing and
sensitivity testing are important diagnostic tools used to determine the offending
pathogen and help to select the appropriate medication for treatment. Sabouraud's agar
is unique in that it possesses a low pH that causes the inhibition of most bacterial
growth, allowing for better isolation of the fungus. Hay infusion agar is frequently utilized
to culture slime moulds.
Cetrimide agar is designed to isolate Gram-negative bacteria.
Blood agar plates are useful for the detection of pathogenic organisms via the presence
of hemolytic activity (the ability of organisms to lyse or destroy red blood cells). Blood
agar plates are not a selective medium, as many different types of organisms are
capable of growth on this type of agar.
Thayer-Martin agar is a type of chocolate agar used to isolate Neisseria gonorrhoeae.
, ✔✔Which of the following classifications refers to an organism that can survive in an
environment with or without oxygen?
Facultative anaerobe
Microaerophile
Strict anaerobe
Obligate aerobe - ✔✔Facultative anaerobes are capable of using oxygen as a life
source but can also thrive using anaerobic respiration. When culturing this type of
bacteria in a test tube of liquid media, one would observe the bacteria dispersed
throughout the entire tube but with greatest concentration at the top, as aerobic
respiration yields a more favorable energy result.
Obligate aerobes require oxygen to survive. Test tube culturing would display bacteria
gathering at the top of the tube where the oxygen levels are greatest.
Microaerophiles are capable of utilizing oxygen, but only at lower concentrations. A test
tube culture of microaerophillic bacteria would result in the greatest concentration of
bacteria towards the upper portion of the test tube, but not at the very top.
Strict anaerobes cannot tolerate oxygen and rely on anaerobic respiration to survive. A
test tube culture of strict anaerobes would display the greatest concentration of bacteria
towards the bottom of the tube where the least amount of oxygen is present.
Aerotolerant organisms are capable of growing in the presence of oxygen but do not
actually utilize it for respiration. One would observe these bacteria evenly distributed
throughout a test tube liquid culture.
✔✔Which of the following genus of organisms is responsible for tuberculosis and
leprosy?
Salmonella
Klebsiella
Mycobacterium
Borrelia - ✔✔Mycobacterium is an aerobic, Gram-positive (although this is somewhat
debatable) genus that includes several pathogenic species. Mycobacteria are extremely
difficult to treat due to the nature of their cell walls which are truly neither Gram-negative
nor Gram-positive (although they are classified as Gram-positive because they are acid-
fast). M. tuberculosis is responsible for causing tuberculosis. M. leprae is the culprit that
causes Hansen's disease (also termed Leprosy). A species of Borrelia can cause Lyme
disease. Salmonella has been known to cause food poisoning. Contraction of Klebsiella
can lead to the development of pneumonia.
✔✔Which of the following microorganisms is associated with peptic ulcer formation?
Vibrio cholerae
Clostridium tetani
Campylobacter spp
ALL QUESTIONS AND ANSWERS SURE A+
✔✔Which of the following is the correct pathway for the drainage of tears through the
nasolacrimal drainage system?
Nasolacrimal duct, lacrimal sac, valve of Hasner, lacrimal canaliculus, ampulla, lacrimal
punctum
Lacrimal punctum, lacrimal canaliculus, ampulla, lacrimal sac, nasolacrimal duct, valve
of Hasner
Lacrimal sac, lacrimal punctum, lacrimal canaliculus, ampulla, nasolacrimal duct, valve
of Hasner
Lacrimal punctum, lacrimal canaliculus, ampulla, valve of Hasner, nasolacrimal duct,
lacrimal sac - ✔✔The lacrimal punctum is a small aperture located in the lacrimal
papilla, the slight elevation at the junction of the lacrimal and ciliary portions of the
eyelid margin. Initially, the tear film drains through this aperture. The lacrimal punctum
leads into the lacrimal canaliculus, the tube connecting the punctum to the lacrimal sac.
The ampulla is a slight dilation in the initial portion of the lacrimal canaliculus. The
canaliculi from the upper and lower lids run horizontally along the lid margin, connecting
into a common canaliculus that then enters the lateral aspect of the lacrimal sac located
in the anterior portion of the medial orbital wall. The lacrimal sac empties into the
nasolacrimal duct in the maxillary bone. The valve of Hasner is located at the terminus
of the nasolacrimal duct in the inferior nasal meatus. The Valve of Hasner is a fold of
mucosal tissue that ensures that fluid flows anterograde out of the duct.
,Ref: Remington, LA. Clinical Anatomy of the Visual System, 1998 pp 153-154
✔✔Which of the following skin conditions is considered to be benign and has the
LOWEST risk of malignancy?
Squamous cell carcinoma
Keratoacanthoma
Actinic keratosis
Basal cell carcinoma - ✔✔Keratoacanthoma appears very much like squamous cell
carcinoma (SCC) in that it tends to progress rapidly and appears to ulcerate. This
condition typically occurs in middle-aged and elderly patients of Caucasian descent on
areas of the skin that are exposed. The lesion appears elevated, and eventually the
center will produce a scab-like plug of keratin. The margins surrounding the plug will be
rolled. At some point the keratin plug will fall out, resulting in the formation of a pit, and
the lesion will regress. Most patients and clinicians do not like to wait this condition out
due to its similarities to SCC.
Actinic keratosis is a pre-cursor to squamous cell carcinoma and appears as scaly, dry
skin that does not heal. People with skin that is of lighter pigmentation along with
excessive exposure to ultraviolet light tend to be most at risk for development of this
condition.
Squamous cell carcinoma (SSC) is thankfully one of the rarest malignancies but due to
its ability to metastasize can be quite dangerous. This malignancy has the ability to
progress rapidly and has a high affinity for people who spend a lot of time in the sun,
especially those who are light-skinned. The only way to definitively diagnose SCC is to
refer for a biopsy and ensuring the use of Mohs technique. This strategy takes more
time but ensures that the lesion is removed. Essentially, Mohs procedure calls for
removal of tissue and biopsy of the surrounding borders. If the borders prove to be
malignant then more tissue is removed and biopsied. This continues until the borders
prove to be free of any carcinoma.
Basal cell carcinoma (BCC) is the most common malignant lid lesion and mercifully
tends to be very slow-growing. BCC generally appears as a waxy, translucent nodule.
Eventually the nodule will ulcerate. Patients may bring these to your a
✔✔Which patient would be considered legally blind?
A wet macular degeneration patient with best central acuities of 10/120 OD and 10/200
OS
A patient with a total retinal detachment of the right eye, no light perception and a best
corrected central acuity of 8/60 due to wet macular degeneration
A patient with Best's disease with best corrected central acuities measure OD 10/80 and
OS 10/100
A myopic patient with acuities of 20/400 OD and OS uncorrected
A retinitis pigmentosa patient who has 20/20 central vision in each eye and a 30 degree
in diameter visual field - ✔✔Legal blindness must take into account central best
,corrected visual acuity, with the better eye 20/200 or worse. If the central acuity is
normal such as in the RP patient then the field would be the restricting qualification,
which, at 30 degrees, does not qualify.
✔✔What term describes the phenomenon in which a bacterium directs its movement
TOWARD a chemical in its environment?
Apoptosis
Transposition
Chemotaxis
Phagocytosis - ✔✔Many bacteria possess flagella, or thread-like appendages, which
allow for movement. Certain chemicals attract bacteria (chemoattractants), while others
repel them (chemorepellents). Chemotaxis refers to the response of the bacteria to
either chemoattractants or chemorepellents. In the absence of either of the
aforementioned chemicals, bacteria will move in random patterns. Some bacteria
possess genes and proteins which allow for the sensing of concentration gradients in
their environment. In the presence of a chemoattractant, bacteria will have longer runs
in the appropriate direction.
Apoptosis is defined as programmed cell death.
Phagocytosis refers to the engulfment of a particle (for example, bacteria) by a
phagocyte (for example, a macrophage).
Transposition refers to the rare phenomenon in which genes move from one place on
the genome to another position.
✔✔What type of agar is commonly used to culture fungi?
Cetrimide agar
Hay infusion agar
Thayer-Martin agar
Sabouraud's agar
Blood agar plate - ✔✔Sabouraud's agar is useful for culturing fungi. Culturing and
sensitivity testing are important diagnostic tools used to determine the offending
pathogen and help to select the appropriate medication for treatment. Sabouraud's agar
is unique in that it possesses a low pH that causes the inhibition of most bacterial
growth, allowing for better isolation of the fungus. Hay infusion agar is frequently utilized
to culture slime moulds.
Cetrimide agar is designed to isolate Gram-negative bacteria.
Blood agar plates are useful for the detection of pathogenic organisms via the presence
of hemolytic activity (the ability of organisms to lyse or destroy red blood cells). Blood
agar plates are not a selective medium, as many different types of organisms are
capable of growth on this type of agar.
Thayer-Martin agar is a type of chocolate agar used to isolate Neisseria gonorrhoeae.
, ✔✔Which of the following classifications refers to an organism that can survive in an
environment with or without oxygen?
Facultative anaerobe
Microaerophile
Strict anaerobe
Obligate aerobe - ✔✔Facultative anaerobes are capable of using oxygen as a life
source but can also thrive using anaerobic respiration. When culturing this type of
bacteria in a test tube of liquid media, one would observe the bacteria dispersed
throughout the entire tube but with greatest concentration at the top, as aerobic
respiration yields a more favorable energy result.
Obligate aerobes require oxygen to survive. Test tube culturing would display bacteria
gathering at the top of the tube where the oxygen levels are greatest.
Microaerophiles are capable of utilizing oxygen, but only at lower concentrations. A test
tube culture of microaerophillic bacteria would result in the greatest concentration of
bacteria towards the upper portion of the test tube, but not at the very top.
Strict anaerobes cannot tolerate oxygen and rely on anaerobic respiration to survive. A
test tube culture of strict anaerobes would display the greatest concentration of bacteria
towards the bottom of the tube where the least amount of oxygen is present.
Aerotolerant organisms are capable of growing in the presence of oxygen but do not
actually utilize it for respiration. One would observe these bacteria evenly distributed
throughout a test tube liquid culture.
✔✔Which of the following genus of organisms is responsible for tuberculosis and
leprosy?
Salmonella
Klebsiella
Mycobacterium
Borrelia - ✔✔Mycobacterium is an aerobic, Gram-positive (although this is somewhat
debatable) genus that includes several pathogenic species. Mycobacteria are extremely
difficult to treat due to the nature of their cell walls which are truly neither Gram-negative
nor Gram-positive (although they are classified as Gram-positive because they are acid-
fast). M. tuberculosis is responsible for causing tuberculosis. M. leprae is the culprit that
causes Hansen's disease (also termed Leprosy). A species of Borrelia can cause Lyme
disease. Salmonella has been known to cause food poisoning. Contraction of Klebsiella
can lead to the development of pneumonia.
✔✔Which of the following microorganisms is associated with peptic ulcer formation?
Vibrio cholerae
Clostridium tetani
Campylobacter spp
