Lets discuss questions of NBDE 1

[d dimps]

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1). .Which angle does a P Wave makes on ECG?
a). .45 degree
b). .180 degree
c). .0 degree
d). .-45 degree
e). .-180 degree.

2). .What is endogenous cholesterol? Most endogenous cholesterol is converted to?
a). .Glucose
b). .Cholic acid
c). .Steroid
d). .Oxaloacetete
e). .Ketone bodies

3). .Which of the following statement is correct regarding Glioblastoma multiforme?
a). .the tumor is most common before puberty
b). .it is classified as a type of meningioma
c). .it is most common type of Astrocytoma.
d). .Its prognosis is generally more favourablethan Grade 1 astrocytoma.
e). .It is derived from the epithelial lining of ventricles

4). .Which of the following pathological changes is irreversible?
a). .fatty changes in liver cells
b). .karyolysis in myocardial cells
c). .glycogen deposition in hepatocyte nuclei
d). .hydropic vacuolization of renal tubular epithelial cells.

5). .An example of Synergism is the effect of?
a). .insulin and glucagon on blood glucose
b). .estrogen and progesterone on uterine motility
c). .growth hormone and thyroxine on skeletal growth.
d). .Antidiuretic hormone and aldosterone on potassium excretion.

 

[bratdoc]

Hi guys,

pb 2007: the reference you mentioned from Monheims was not wrong , you only missed seeing a bracket there which meant that only B fibres do not have afferent function, it was not written for A delta fibres.
that book is not wrong.

A delta: large diameter , myelinated, due to large diameter, pain is sharp.
C fibres: small diameter, unmyelinated

Reference: check in anatomy decks#208, monheims local anesthesia, Grossman endodontics. I am confident that if you refer any other book, this information will be same.


Which of the following represents the correct size and characteristic of the nerve fibers that conduct sensory input of pain from the oral-facial region?
A) Large diameter, unmyelinated
B) Large diameter, myelinated--- correct answer. it is A-Delta fibres.
C) Intermediate diameter,. myelinated
D) Small diameter, myelinated
E) Small diameter, unmyelinated

Thank you so much teethie for clearing out the confusion!👍

 

[pb2007]

Thank you pb2007 ... i understand it now... since the question asked "RMP is maintained by" that is why it should be NA-K pump.... if the question was "RMP is caused by" then it should have been permeability of K ions!! Super👍

u r rtie bratdoc ,i didnt pay attention to word maintain.
one word can make such a big difference ...........

 

[teethie]

can u please mention the decks card #

Yea thats what I thought initially...but the decks say "Young pulp lacks collateral circulation"...so that means mature pulp contain collateral circulation which is not seen in the young pulp.Somebody clarify😕 please.

 

[bratdoc]

http://books.google.com/books?id=wm...CA#v=onepage&q=collateral circulation&f=false

It mentions from a clinical-practical point of view pulp is an end organ which lacks collateral circulation

 

[pb2007]

Yea thats what I thought initially...but the decks say "Young pulp lacks collateral circulation"...so that means mature pulp contain collateral circulation which is not seen in the young pulp.Somebody clarify😕 please.

found something relevant
http://books.google.com/books?id=wm...page&q=collateral circulation in pulp&f=false

 

[bratdoc]

found something relevant
http://books.google.com/books?id=wm...page&q=collateral circulation in pulp&f=false

Hehehe...we use the same sources it seems

 

[Cindrella]

ASDA dec. 1987

Q.50 .... Compared with syst circulation under normal conditions , pulmonary circulation is characterized by LOW pressure and

1. low flow and low resistance
2. equal flow low resistance.. ASDA's answer
3. low flow equal resistance
4. equal flow equal resistance... MY answer
5. high flow equal resistance.

I understand systemic and pulmonary circulation have equal flow throughout the circuit. So clearly , option 1 , 3 , 5 are out !!

Now, flow is entirely Dependant on resistance too right ?! so

Resistance increases --> flow and pressure decreases downstream

Resistance decreases --> flow and pressure increases downstream

bottom line... resistance should also be equal

pls help !!

 

[anniemirza]

We all use the same source guyz!🙂
N its there on decks-09 280 page anat.
Most of the sources say its not present....some say "limited collateral circulations"...Ahh why dont all the endodontists come to one conclusion and avoid all the confusion!!😛phewwww!

 

[teethie]

@anniemirza: this is what i remember that young pulp is highly vascular so we can see some collateral circulation there but in mature pulp, never. see next post
in mature pulp, you know that there is increased fibroblast activity and decreased vascularity.

 

[teethie]

well i checked that card it is mentioning abt young teeth and pulp so it is written as young pulp lacks collateral circulation. thats all.

this hdoes not mean that they are saying it in comparison to mature pulp specifically.
hope u got the point.

We all use the same source guyz!🙂
N its there on decks-09 280 page anat.
Most of the sources say its not present....some say "limited collateral circulations"...Ahh why dont all the endodontists come to one conclusion and avoid all the confusion!!😛phewwww!

 

[anniemirza]

@anniemirza: this is what i remember that young pulp is highly vascular so we can see some collateral circulation there but in mature pulp, never.
in mature pulp, you know that there is increased fibroblast activity and decreased vascularity.

According to decks...."Young pulp LACKS collateral circulation"

 

[anniemirza]

well i checked that card it is mentioning abt young teeth and pulp so it is written as young pulp lacks collateral circulation. thats all.

this hdoes not mean that they are saying it in comparison to mature pulp specifically.
hope u got the point.

Yea i know...but the whole page is about comparision between young and mature pulp...so got confused at that point.

 

[bratdoc]

ASDA dec. 1987

Q.50 .... Compared with syst circulation under normal conditions , pulmonary circulation is characterized by LOW pressure and

1. low flow and low resistance
2. equal flow low resistance.. ASDA's answer
3. low flow equal resistance
4. equal flow equal resistance... MY answer
5. high flow equal resistance.

I understand systemic and pulmonary circulation have equal flow throughout the circuit. So clearly , option 1 , 3 , 5 are out !!

Now, flow is entirely Dependant on resistance too right ?! so

Resistance increases --> flow and pressure decreases downstream

Resistance decreases --> flow and pressure increases downstream

bottom line... resistance should also be equal

pls help !!

Cindrella these are one of the things i mugged up.. thank u for bringing it up for discussion... basically u agree that pulmonary circulation has low pressure right(as the question also says) So think of it this way
(Though u already know this, but might be thinking off track)
Low pressure=Low resistance
High pressure= high resistance

 

[pb2007]

ASDA dec. 1987

Q.50 .... Compared with syst circulation under normal conditions , pulmonary circulation is characterized by LOW pressure and

1. low flow and low resistance
2. equal flow low resistance.. ASDA's answer
3. low flow equal resistance
4. equal flow equal resistance... MY answer
5. high flow equal resistance.

I understand systemic and pulmonary circulation have equal flow throughout the circuit. So clearly , option 1 , 3 , 5 are out !!

Now, flow is entirely Dependant on resistance too right ?! so

Resistance increases --> flow and pressure decreases downstream

Resistance decreases --> flow and pressure increases downstream

bottom line... resistance should also be equal

pls help !!

The Pulmonary versus Systemic Circulation
The atria of the left and right side of the heart are thin-walled, low pressure chambers. Note, the pulmonary arterial pressure is much lower than in the aorta (systemic arterial pressure). The pulmonary circulation is, overall, a much lower pressure system than is the systemic circulation. The systemic circulation has to work against gravity, especially when a person is standing, and the system needs more pressure to do this! Remember that the pulmonary circulation is only as tall as the lungs! The systemic circulation must also redirect blood according to the needs of the body using smooth muscle; in order to accomplish this task, the systemic circulation must be capable of generating significant resistance with smooth muscle. Remember, too, that systemic resistance generated primarily by arterioles is necessary to generate the high pressures required to drive blood through the high volume, long distance systemic circulation! The pulmonary circulation, on the other hand, only needs to get blood from the top to the bottom of the lungs which are perfused by constant low pressure; there is very little redirection of blood within the pulmonary circulation, other than from locally hypoxic pockets in the lung! Pulmonary arterioles have much less smooth muscle than systemic arterioles and, thus, pulmonary arterioles generate much less resistance than systemic arterioles.
http://faculty.etsu.edu/currie/pulmcirc.htm

 

[teethie]

thank u bratdoc and pb2007 for the info👍

 

[Cindrella]

@ bratdoc and pb2007 like the link 👍 but those pics aren't opening 🙁

Thankuuzz !! Yeah i knew i was missing something while thinking ! i gave less importance to " low pressure " as mentioned in the question, hoping it would make life easy 😉

 

[elmos]

i'm sorry i didn't understand why it's not C fibers they carry pain from the facial, cause i know that Adelta is in the teeth for sharp pain.
can anyone clarify the Cfibers?

 

[hot]

i'm sorry i didn't understand why it's not C fibers they carry pain from the facial, cause i know that Adelta is in the teeth for sharp pain.
can anyone clarify the Cfibers?

it should be C-fibers... there are 3-5x more C-fibers than A-delta. they are small diameter & unmyelinated.

 

[deck]

it should be C-fibers... there are 3-5x more C-fibers than A-delta. they are small diameter & unmyelinated.

Did u mean more C on oral than A-delta?? I am so confused now


Thanks a lot😍

 

[bratdoc]

...

 

[teethie]

key to that question is sharp pain.
pt. recognise sharp pain before dull pain.
c fibres cause dull pain due to small diameter.
a delta fibres is the answer.
if anyone has the logic different than this, most welcome to discuss here.



.

Did u mean more C on oral than A-delta?? I am so confused now


Thanks a lot😍

 

[anniemirza]

From the pain receptors, pain impulses​

are carried to the CNS by two fiber systems:
the large myelinated fibres (A-delta) conduct
impulses rapidly (15.25 m/sec), the small
unmyelinated fibres (C-fibres) conduct at a
slower rate (<1 m/sec).It is known that noxious​

stimulation exciting somatic and dental A

&#948;

​

​

afferents may exert a masking or inhibitory​

effect on C-fiber related sensations.
​

​

​

​

​

I read this in an endodontic journal...Explaining y the A delta fbers carry the impulse rather than the c fibers.
​

 

[hot]

don't freak out guys...

c-fibers was in response to elmos' question which is different than what you guys are talking about. there are 3-5x more C-fibers than A-delta. both of them provide pain from both the oral and facial region. the question doesn't specify which type of pain... so technically you all are correct.

seriously... this thread is getting a little out of hand.

 

[pb2007]

need to confirm my answer.
optic nerve fibres from nasal half of the retina cross the midline and enter the optic tract of the opposite side by way of the
1]optic chiasma...........answer
2]lateral geniculate body
3]bipolar cells of the retina
4]brachium of the superior colliculus
5]geniculocalcarine tract[optic radialis}

 

[bratdoc]

need to confirm my answer.
optic nerve fibres from nasal half of the retina cross the midline and enter the optic tract of the opposite side by way of the
1]optic chiasma...........answer
2]lateral geniculate body
3]bipolar cells of the retina
4]brachium of the superior colliculus
5]geniculocalcarine tract[optic radialis}

Optic chiasm- here is where the fibers cross over and form the optic tract upto the LGN

 

[teethie]

correct.👍
see this. http://thebrain.mcgill.ca/flash/d/d_02/d_02_cr/d_02_cr_vis/d_02_cr_vis.html

​

need to confirm my answer.
optic nerve fibres from nasal half of the retina cross the midline and enter the optic tract of the opposite side by way of the
1]optic chiasma...........answer
2]lateral geniculate body
3]bipolar cells of the retina
4]brachium of the superior colliculus
5]geniculocalcarine tract[optic radialis}

 

[elmos]

the last thing to disappear in down the respiratory chain :
cartilage, or cilia or smooth muscle?
pls can anyone answer this?

 

[pb2007]

the last thing to disappear in down the respiratory chain :
cartilage, or cilia or smooth muscle?
pls can anyone answer this?

i think it should be cilia coz bronchioles are lined by simple ciliated columnar epithelium n alveolar sacs have donot have cilia.

thns bratdoc n teethie for confirming the answer
hav another doubt
kaplan mentions that alveolar sacs have simple squamous alveolar epithelium while wikipedia mentions that alveolar ducts have nonciliated simple cuboidal cells.
does respiratory tract have cuboidal cells ,i thought was columnar only .

 

[bratdoc]

In the case of atrial fibrillation why is Digitalis given?
1. depresses AV conduction
2. increases SA node discharge
3. decreases SA node discharge


An Alkalinizing reaction is caused upon ingestion of Sodium Lactate due to which reason?
1. Sodium ion readily absorbed as compared to lactate ion
2. Kidney excretes lactic acid and conserves Sodium
3. Plasma becomes alkaline due to presence of Sodium lactate
4. Sodium Lactate is absorbed readily and lactate is rapidly metabolized

 

[pb2007]

In the case of atrial fibrillation why is Digitalis given?
1. depresses AV conduction
2. increases SA node discharge
3. decreases SA node discharge.............answer


An Alkalinizing reaction is caused upon ingestion of Sodium Lactate due to which reason?
1. Sodium ion readily absorbed as compared to lactate ion
2. Kidney excretes lactic acid and conserves Sodium
3. Plasma becomes alkaline due to presence of Sodium lactate
4. Sodium Lactate is absorbed readily and lactate is rapidly metabolized

is used to increase cardiac contractility (it is a positive inotrope) and as an antiarrhythmic agent to control the heart rate, particularly in the irregular (and often fast) atrial fibrillation. Digitalis is hence often prescribed for patients in atrial fibrillation, especially if they have been diagnosed with congestive heart failure

Digitalis works by inhibiting sodium-potassium ATPase. This results in an increased intracellular concentration of sodium, which in turn increases intracellular calcium by passively decreasing the action of the sodium-calcium exchanger in the sarcoplasmic reticulum. The increased intracellular calcium gives a positive inotropic effect. Digitalis also has a vagal effect on the parasympathetic nervous system, and as such is used in reentrant cardiac arrhythmias and to slow the ventricular rate during atrial fibrillation. The dependence on the vagal effect means that digitalis is not effective when a patient has a high sympathetic nervous system drive, which is the case with acutely ill persons, and also during exercise
http://en.wikipedia.org/wiki/Digitalis#Medicinal_use_and_mechanism_of_action

 

[bratdoc]

is used to increase cardiac contractility (it is a positive inotrope) and as an antiarrhythmic agent to control the heart rate, particularly in the irregular (and often fast) atrial fibrillation. Digitalis is hence often prescribed for patients in atrial fibrillation, especially if they have been diagnosed with congestive heart failure

Digitalis works by inhibiting sodium-potassium ATPase. This results in an increased intracellular concentration of sodium, which in turn increases intracellular calcium by passively decreasing the action of the sodium-calcium exchanger in the sarcoplasmic reticulum. The increased intracellular calcium gives a positive inotropic effect. Digitalis also has a vagal effect on the parasympathetic nervous system, and as such is used in reentrant cardiac arrhythmias and to slow the ventricular rate during atrial fibrillation. The dependence on the vagal effect means that digitalis is not effective when a patient has a high sympathetic nervous system drive, which is the case with acutely ill persons, and also during exercise
http://en.wikipedia.org/wiki/Digitalis#Medicinal_use_and_mechanism_of_action

Thanks pb2007 but the answer i have says option 1 is the answer.... 😕😕

 

[bratdoc]

thanks for the link pb2007... it lead me to another link which says
http://en.wikipedia.org/wiki/Cardiac_glycoside
Normally, sodium-potassium pumps in the membrane of cells (in this case, cardiac myocytes) pump potassium ions in and sodium ions out. Cardiac glycosides inhibit this pump by stabilizing it in the E2-P transition state, so that sodium cannot be extruded: intracellular sodium concentration therefore increases. A second membrane ion pump, NCX, is responsible for pumping calcium ions out of the cell and sodium ions in (3Na/Ca); raised intracellular sodium levels inhibit this exchange, so calcium ions are not extruded and will also begin to build up inside the cell.
Increased cytoplasmic calcium concentrations cause increased calcium uptake into the sarcoplasmic reticulum via the SERCA2 transporter. Raised calcium stores in the SR allow for greater calcium release on stimulation, so the myocyte can achieve faster and more powerful contraction by cross-bridge cycling. The refractory period of the AV node is increased, so cardiac glycosides also function to regulate heart rate....

So i guess this is why the answer is option 1?!!

 

[teethie]

hi, see below.

i think it should be cilia coz bronchioles are lined by simple ciliated columnar epithelium n
alveolar sacs have donot have cilia.--------------------agree👍

thns bratdoc n teethie for confirming the answer
hav another doubt
kaplan mentions that alveolar sacs have simple squamous alveolar epithelium while wikipedia mentions that alveolar ducts have nonciliated simple cuboidal cells.
does respiratory tract have cuboidal cells ,i thought was columnar only .

respiratory bronchioles( the site where gas exchange takes place) have cuboidal epithelium , portion above this is columnar epithelium.

 

[teethie]

hi,

In the case of atrial fibrillation why is Digitalis given?
1. depresses AV conduction--------------👍
http://books.google.ca/books?id=PaO...ial fibrillation Digitalis mechanism&f=false

2. increases SA node discharge
3. decreases SA node discharge

 

[elmos]

thks pb2007 a lot for the answer

 

[teethie]

Congrats to all, today is the second anniversary of this thread. Many future test takers will be benefitted from this thread.👍

bratdoc, what is the answer for this ques???

An Alkalinizing reaction is caused upon ingestion of Sodium Lactate due to which reason?
1. Sodium ion readily absorbed as compared to lactate ion
2. Kidney excretes lactic acid and conserves Sodium
3. Plasma becomes alkaline due to presence of Sodium lactate
4. Sodium Lactate is absorbed readily and lactate is rapidly metabolized

 

[bratdoc]

Congrats to all, today is the second anniversary of this thread. Many future test takers will be benefitted from this thread.👍

bratdoc, what is the answer for this ques???

Yea 2nd anniversary with 2100+posts!😀

my one month on SDN also

Teethie the answer to that question is
4. Sodium Lactate is absorbed readily and lactate is rapidly metabolized


but dont undertand why

 

[teethie]

Sodium Lactate is absorbed readily and lactate is rapidly metabolized😕😕
only way is craming this answer.

Yea 2nd anniversary with 2100+posts!😀

my one month on SDN also-------congrats-------👍👍👍👍

Teethie the answer to that question is
4. Sodium Lactate is absorbed readily and lactate is rapidly metabolized


but dont undertand why

 

[bratdoc]

Sodium Lactate is absorbed readily and lactate is rapidly metabolized😕😕
only way is craming this answer.

Yes that is what i tried to do 🙁 but ANY explanation would help........

 

[teethie]

some other queries:

1) what causes CNS inflammation due to meningitis?
is this question asking abt viral mechansim or what??

2) most common thyroid cancer???

3) amino acids which are not glycosylated???

4)thrombosis most commomly occur in which artery of brain??

 

[bratdoc]

some other queries:

1) what causes CNS inflammation due to meningitis?
is this question asking abt viral mechansim or what??

2) most common thyroid cancer???
Papillary cancer

3) amino acids which are not glycosylated???
basically the aminoacids not forming proteoglycans

4)thrombosis most commomly occur in which artery of brain??
internal carotids, vertebral, and the Circle of Willis.

..

 

[teethie]

thank u bratdoc🙂

 

[elmos]

some other queries:

1) what causes CNS inflammation due to meningitis?
is this question asking abt viral mechansim or what??

2) most common thyroid cancer???
bratdoc right papillary
3) amino acids which are not glycosylated???

4)thrombosis most commomly occur in which artery of brain??

i think the answer is middle cerebral artery

 

[teethie]

thank u elmos.🙂

i was thinking within circle of willis, is it not post cerebral?😕
if anyone clears my doubt, would appreciate.

i think the answer is middle cerebral artery

 

[elmos]

thank u elmos.🙂

i was thinking within circle of willis, is it not post cerebral?😕
if anyone clears my doubt, would appreciate.

teethie in released asda 1985 the artery most common in stroke is
lenticulostriate which is branche of middle cerebral artery.

 

[ibeflossin]

i think the answer is middle cerebral artery

middle cerebral artery is most often occluded in a stroke (#39 anatomic sciences 2009-2010 dental decks) so i think this is the most common OBSTRUCTIVE thrombosis.

however i know that ARTERIAL thrombosis --> the most susceptible arteries are aorta & coronary arteries. so since the question was asking about the brain specifically, i would say coronary artery.

FYI: MI is most often due to acute thrombosis due to coronary artery atherosclerosis, which results in myocyte necrosis.

 

[deck]

I have question on TMJ, on deck anatomy p63, it said the post. slope of eminence is covered with fibrous connective tissue, does that mean ant cover with fibrocartilage? I thought the one part cover with fibrocartilage is articular surface of glenoid fossa and condyle and disc....am I on the right????😕😕😕

Thank u guys!!!!

 

[ibeflossin]

I have question on TMJ, on deck anatomy p63, it said the post. slope of eminence is covered with fibrous connective tissue, does that mean ant cover with fibrocartilage? I thought the one part cover with fibrocartilage is articular surface of glenoid fossa and condyle and disc....am I on the right????😕😕😕

Thank u guys!!!!

i remember when taking my NBDE part I, they never had fibrous CT & fibrocartilage together in option choices. while i was studying i used them both synonymously. i think technically both fibrous CT & fibrocartilage are present on the disc, usually cartilage though is increased with age. at least this is how i understood it.

 

[deck]

Which following can immediately source of energy for muscle reaction?
1) creatine phosphate +ADP--> ATP+creatine
2)ATP-->ADP + phosphate...ans

but on deck bio chem p 34, it said creatine phosphate can derive its higher energy phosphate from ATP and donare the phosphate back to ADP to form ATP. The pool of creatine in fiber is about 10 times larger than that of ATP and thus serves as modest reservoir of ATP....why answer is not 1

My exam is coming less than 10 days.........plz help me ><

 

[teethie]

thank u soo much elmos and ibeflossin.👍 i appreciate your responses.
my doubt is clear now.