Part One Physiology

[foxydentist]

Hey guys I thought of arranging the forum a bit by making a thread for each section for NBDE part one.... so if any body got any questions or need help in or got new useful infromation wana share in Physiology writes here......... hope that would make it easy for everybody planning to take part one soon .. (like me )

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[confused tooth]

Preganglionic automnomic nere fibres are exclusively
1. somatic
2. adrenergic
3.sympathetic
4. cholinergic(ans)
5. parasympathetic

I always thought it was 5 .......any explanation?

 

[Ankylosed]

Preganglionic automnomic nere fibres are exclusively
1. somatic
2. adrenergic
3.sympathetic
4. cholinergic(ans)
5. parasympathetic

I always thought it was 5 .......any explanation?

It's 4.. all preganglionics use acetylcholine as neurotransmitter. It can't be 5 because sympathetic autonomic nerves use preganglionic and postganglionic neurons also.

 

[confused tooth]

hey thanks.......I got a bit confused there.....read ANS again

heres a briefing for ppl who are intrested:-

ANS divided as 1.PNS and 2. SNS

PNS:- "rest and digest"
- mostly cholinergic as utilise Ach which act on muscarinic receptors(ionotropic post synaptic)
- ganglia located in brain stem and spinal cord.

SNS;- "fight or flight"
- use adrenalie or noradrenaline
- nor adrenalie acts on adreno receptors, excpt swaet glands which have muscarinic receptors
- ganglia loacted in thorasic and lumbar segments

Hope this is help for a quick refrence jaut to get the gist of it

 

[industrious1]

Hello, I agree with what "Ankylosed" said, because almost all preganglionic fibers are cholinergic. The thing that u mentioned "about the adrenergic, the receptors,, etc" is related to the post ganglionic fibers which has nothing to do with what the question was asking about,,,

I mean,,, all preganglionic fibers are cholinergic,,,,, while post ganglionic fibers are either cholinergic(parasympathetic) or adrenergic(sympathetic)

I hope that helps Good luck

 

[confused tooth]

YES..........got it :0

Thanks Ankylosed and Industrious

 

[bubbly]

hi guys ! i m gonna start studying for the part 1 exam .. so b4 i start i 'd like to confirm what topics/syllabus i sud study.. i went thru ada.org and i found this
http://www.ada.org/prof/ed/testing/n...ifications.pdf

is this enuf or do we have to study some other topics as well .. if yes then where can i get them ?

 

[tooth germ]

Is second (pharyngeal)part of swallowing is voluntary or involuntary?

 

[wireless_doc]

An analysis of EKC shows P-waves occuring in the S-T segment. This would indicate ectopic beats originating in the
A. atria
B. AV node
C. Lower portion of bundle of His
D. Upper portion of bundle of His

My choice is A since P-wave is generated from atrial depolarization. But the last two choices concern me. When they have two choices like this, it's quite often it's one or the other. Could someone please confirm? Thanks.

 

[amrita1]

An analysis of EKC shows P-waves occuring in the S-T segment. This would indicate ectopic beats originating in the
A. atria
B. AV node
C. Lower portion of bundle of His
D. Upper portion of bundle of His

My choice is A since P-wave is generated from atrial depolarization. But the last two choices concern me. When they have two choices like this, it's quite often it's one or the other. Could someone please confirm? Thanks.

hi
i think its A.atria..normally such waves are termed P' waves,which originates from atria,but,since not a part of regular SA rythm,is coming up at its own
i think last two choices are just to confuse

 

[wireless_doc]

Thanks for the reply. Got another question.
The main factors directly involved in maintenance of systemic arterial blood pressure are:
A: cardiac output, blood viscosity and peripheral resistance
D: cardiac output, peripheral resistance and tissue colloid osmotic pressure

Both sound right to me. Which one do you think? Thanks.

 

[prerna]

Hi there..the answer to your question is A. can someone help me out with these questions ...i am sorry i dont have the options for them.
1. which event preceeds the calcification of matrix.
2. papiloma 13 causes which disease.
3. pressure in large veins at right atrium is?
4. which is constant throughout the cardiovascular system..endothelium,smooth muscle or vaso vasorum.
5. spheno occipital synchondrosis has which type of cartilage?
6. what is the epithelium of gallbladder..simple columnar,simple cuboidal or ciliates pseudostratified?
7. which amino acid cannot have gycosalation..serine,proline,ariginine?
8. what happes to tooth morphology if ameloblasts fails to form?
9. which connective tissue has more ground substance than fibes...cartilage, dense regular ct or dense ireegular ct?
10. what are the products of hydrolysis of lecithin?
11. how does p/o ratio alter in mitochondria if an uncoupler is added?
12. a patient gets a full dentire and comes back in a few days complaining of burning sensation in anterior region..what could be the cause?
13. what structure causes buccal vestibule to decrease in size when jaw is opened wide? condyle / coronoid/hamular/styloid?

any ideas about any of these answers would be greatly appreciated and sorry that i dont have the proper choices. Thanks!

 

[dentist33]

cardiac output, blood viscosity and peri resistance is correct

 

[wireless_doc]

Thanks for the confirmation.

 

[Ruchig]

5. spheno occipital synchondrosis has which type of cartilage?
Hyaline cartilage
6. what is the epithelium of gallbladder..
simple columnar
7. which amino acid cannot have glycosalation ..proline
10. what are the products of hydrolysis of lecithin?
I think its choline.

 

[swetha_dentist]

what is p/o ratio what does that mean?

 

[swetha_dentist]

8. what happes to tooth morphology if ameloblasts fails to form?
enamel hypoplasia i suppose
9. which connective tissue has more ground substance than fibes...cartilage, dense regular ct or dense ireegular ct?
i think it is cartilage
12. a patient gets a full dentire and comes back in a few days complaining of burning sensation in anterior region..what could be the cause?
improper denture fitting i suppose
13. what structure causes buccal vestibule to decrease in size when jaw is opened wide? condyle / coronoid/hamular/styloid?
condyle i suppose

 

[tom_servo_dds]

Is second (pharyngeal)part of swallowing is voluntary or involuntary?

involuntary

 

[tom_servo_dds]

Thanks for the reply. Got another question.
The main factors directly involved in maintenance of systemic arterial blood pressure are:
A: cardiac output, blood viscosity and peripheral resistance
D: cardiac output, peripheral resistance and tissue colloid osmotic pressure

Both sound right to me. Which one do you think? Thanks.

A

 

[swetha_dentist]

3. pressure in large veins at right atrium is?
is it RHF??

 

[swetha_dentist]

11. how does p/o ratio alter in mitochondria if an uncoupler is added?
ATP synthesis decrease.correct me if i am wrong.

 

[Ruchig]

what do you mean by p/o ratio?

11. how does p/o ratio alter in mitochondria if an uncoupler is added?
ATP synthesis decrease.correct me if i am wrong.

 

[swetha_dentist]

what do you mean by p/o ratio?

The P/O ratio, or ATP yield of respiration, is a measure of the efficiency of oxidative phosphorylation in energy metabolism. The P/O ratio is calculated as the relative amount of ATP molecules produced per pair of electrons donated to the ETS.

 

[Ruchig]

thanx! I didnt have any clue about it.

The P/O ratio, or ATP yield of respiration, is a measure of the efficiency of oxidative phosphorylation in energy metabolism. The P/O ratio is calculated as the relative amount of ATP molecules produced per pair of electrons donated to the ETS.

 

[prerna]

thanks ruchi and shwetha for the answers....there are still some unanswered ...do pass on any ideas anyone has. exam in a week...worried !

 

[wireless_doc]

116. At which stage in the process of gene cloning are restriction nucleases used?
A. Isolation of mRNA
B. Synthesis of double-stranded cDNA
C. Insertion of the cDNA into the vector DNA
D. Expression of the cloned gene by the bacteria
E. Introduction of recombinant DNA into bacterial cell
I think it's C, but not sure

128. Which of the following statements BEST describes the activity of DNA ligase?
A. Seals single-stranded nicks in DNA
B. Proofreads the DNA proper base pairing
C. Prevents the polymerase from falling off the DNA
D. Removes the RNA primer from the lagging strand
A sounds OK, but that is more a role of DNA polymerase

147. Which of the following represents the sensory organs concerned with maintenance of skeletal muscle tonus?
A. Sarcomeres
B. Muscle spindles
C. Gamma efferents
D. Pacinian corpuscles
E. Golgi tendon organs
B and E both sense changes (length vs. tension). Which one is it?

What do you think? Thanks.

 

[swetha_dentist]

8. what happes to tooth morphology if ameloblasts fails to form?

enamel hypocalcification

 

[Ruchig]

At which stage in the process of gene cloning are restriction nucleases used?
A. Isolation of mRNA
B. Synthesis of double-stranded cDNA
C. Insertion of the cDNA into the vector DNA
D. Expression of the cloned gene by the bacteria
E. Introduction of recombinant DNA into bacterial cell
I will go with C as restriction nuclaese braek the nucleic acids to produce sticky ends where the vector DNA strands attach.( recombinant DNA technology)

128. Which of the following statements BEST describes the activity of DNA ligase?
A. Seals single-stranded nicks in DNA
B. Proofreads the DNA proper base pairing
C. Prevents the polymerase from falling off the DNA
D. Removes the RNA primer from the lagging strand
You are right A is the work of DNA polymerase. Can it be C as DNA ligase helps DNA polymerase to fully repair DNA? ( I dont know)

147. Which of the following represents the sensory organs concerned with maintenance of skeletal muscle tonus?
A. Sarcomeres
B. Muscle spindles
C. Gamma efferents
D. Pacinian corpuscles
E. Golgi tendon organs
The answer is E as tonicity is mainatined by golgi tendons.

 

[wireless_doc]

Thank you very much for your prompt reply. I left out one question from this test.

184. Production of phosphoenolpyruvate carboxykinase is stimulated by
A. insulin
B. cortisol
C. aldosterone
D. somatotropin

I looked it up and found that phosphoenolpyruvate carboxykinase is regulated by insulin, glucocorticoids, cAMP and diet to maintain glucose homeostasis. So, are A and B both correct?

 

[Ruchig]

I think the answer is B. phosphoenolpyruvate carboxykinase is used in gluconeogenesis and insulin inhibits gluconeogenesis.

Thank you very much for your prompt reply. I left out one question from this test.

184. Production of phosphoenolpyruvate carboxykinase is stimulated by
A. insulin
B. cortisol
C. aldosterone
D. somatotropin
I think the answer is B. phosphoenolpyruvate carboxykinase is used in gluconeogenesis and insulin inhibits gluconeogenesis.
I looked it up and found that phosphoenolpyruvate carboxykinase is regulated by insulin, glucocorticoids, cAMP and diet to maintain glucose homeostasis. So, are A and B both correct?

 

[swetha_dentist]

I think the answer is B. phosphoenolpyruvate carboxykinase is used in gluconeogenesis and insulin inhibits gluconeogenesis.

ruching is right cortisol usually has tendency to increase glucose level

 

[wireless_doc]

You two are right! I double-checked my note. PEP carboxykinase catalyzes the conversion of oxaloacetate into phosphoenolpyruvate which is one of the steps of gluconeogenesis. Thank you. This biophys test is the hardest I ever took so far.

 

[swetha_dentist]

can anybody explain hyperpolarization??

 

[prerna]

hi guys..some misc questions...pls help!
1. arch of aorta vs brachiocephalic artery..the differnce would be tunica media?
2. viscosity is greatest at SVC,pulmonary atery,pulmonary vein, aorta or vasa recta?
3. direct source of atp is creatinie phosphate or gtp?
4. streptococcus pyogens cause which kind of necrosis...liquefactive,coagulative, caseous?
5. most common anomaly of max canine is tubercle or second canal?
6. when saivary gland is destroyed what replace sit ..epitheilum or firbrous tissue?
7. contents of synovial fluid?
8. which part of tmj is most sensitive...capsule ,peripehery or synovial fluid.

thanks a ton guys!

 

[Ruchig]

swetha,
Hyperpolarisation is when Na channels are closed but K channels (leaky channels) are still open . Although the voltage-activated channels are closed, potassium leaks through other open channels to return the cell to the resting potential.Hyperpolarisation is below the resting membrane potential.

can anybody explain hyperpolarization??

 

[swetha_dentist]

swetha,
Hyperpolarisation is when Na channels are closed but K channels (leaky channels) are still open . Although the voltage-activated channels are closed, potassium leaks through other open channels to return the cell to the resting potential.Hyperpolarisation is below the resting membrane potential.

you are right but how does AP is produced in this realtive refractory period??so does the cell comes to RMP due to Na K pump and K , Na exchange??

 

[Ruchig]

. Leaky channels are few in number so flow of K channels accross the membrane is less.In relative refratory period K leaky channels are still open but the Na channels (that were earlier closed) open that change the polarity.

you are right but how does AP is produced in this realtive refractory period??so does the cell comes to RMP due to Na K pump and K , Na exchange??

 

[swetha_dentist]

. Leaky channels are few in number so flow of K channels accross the membrane is less.In relative refratory period K leaky channels are still open but the Na channels (that were earlier closed) open that change the polarity.

but i read some other theory anyway thanks for explanation but do you know about hyperpolarization and AP thresh hold for second AP. I mean how does AP occur in case of hyperpolarization its because it comes to RMP or does it occur in hyperpolarization state? If it occur in RMP it wont be called as second AP. If it occur in hyperpolarity how does it occur??
thanks

 

[Ruchig]

Swetha,
Action potentials occur only when the membrane in stimulated (depolarized) enough so that sodium channels open completely.
In relative refractory period, another action potential can be produced, but only if the stimulus is greater than the threshold stimulus.IThis corresponds to the period when the potassium channels are open (leaky channels) and the nerve cell membrane becomes progressively more 'sensitive' (easier to stimulate) as the relative refractory period proceeds. So, it takes a very strong stimulus to cause an action potential. This is known as second action potential.
For AP to occur the membrane has to be depolarized. The potential becomes less negative.
Hyperpolarisation (potential = -80mv apx) to RMP(-70mv) to AP(+40-50mvappx).
This is what I know. If anybody else has some information please add.........

but i read some other theory anyway thanks for explanation but do you know about hyperpolarization and AP thresh hold for second AP. I mean how does AP occur in case of hyperpolarization its because it comes to RMP or does it occur in hyperpolarization state? If it occur in RMP it wont be called as second AP. If it occur in hyperpolarity how does it occur??
thanks

 

[swetha_dentist]

Swetha,
Action potentials occur only when the membrane in stimulated (depolarized) enough so that sodium channels open completely.
In relative refractory period, another action potential can be produced, but only if the stimulus is greater than the threshold stimulus.IThis corresponds to the period when the potassium channels are open (leaky channels) and the nerve cell membrane becomes progressively more 'sensitive' (easier to stimulate) as the relative refractory period proceeds. So, it takes a very strong stimulus to cause an action potential. This is known as second action potential.
For AP to occur the membrane has to be depolarized. The potential becomes less negative.
Hyperpolarisation (potential = -80mv apx) to RMP(-70mv) to AP(+40-50mvappx).
This is what I know. If anybody else has some information please add.........

(potential = -80mv apx) to RMP(-70mv) to AP(+40-50mvappx).This is what i am searching for. thanks for your time.

 

[Ruchig]

you are welcome....

 

[swetha_dentist]

1. arch of aorta vs brachiocephalic artery..the differnce would be tunica media?
i think it is tunica media because it has to bear the tension produced during ventricular systolebut correct me if i am wrong
2. viscosity is greatest at SVC,pulmonary atery,pulmonary vein, aorta or vasa recta?
i think it is pul artery not sure
8. which part of tmj is most sensitive...capsule ,peripehery or synovial fluid
i think it is periphery correct me if i am wrong
thanks a ton guys![/QUOTE]

 

[mrswinidm]

hi guys..some misc questions...pls help!
1. arch of aorta vs brachiocephalic artery..the differnce would be tunica media?
2. viscosity is greatest at SVC,pulmonary atery,pulmonary vein, aorta or vasa recta?
3. direct source of atp is creatinie phosphate or gtp?
4. streptococcus pyogens cause which kind of necrosis...liquefactive,coagulative, caseous?
5. most common anomaly of max canine is tubercle or second canal?
6. when saivary gland is destroyed what replace sit ..epitheilum or firbrous tissue?
7. contents of synovial fluid?
8. which part of tmj is most sensitive...capsule ,peripehery or synovial fluid.

thanks a ton guys!

Acc to me
4. liquefactive necrosis
5. tubercle
6. fibrous tissue

 

[Ruchig]

i because tunica media has more smooth and elastic muscle. More clser to heart more elastic and smooth muscle
2 pulmonary vein (I am not sure)
3 creatine phosphate
4 liquefative
5 tubercle
6 fibrous
7 hyalaronic acid
8 periphery
Please let me know if I am wrong

hi guys..some misc questions...pls help!
1. arch of aorta vs brachiocephalic artery..the differnce would be tunica media?
2. viscosity is greatest at SVC,pulmonary atery,pulmonary vein, aorta or vasa recta?
3. direct source of atp is creatinie phosphate or gtp?
4. streptococcus pyogens cause which kind of necrosis...liquefactive,coagulative, caseous?
5. most common anomaly of max canine is tubercle or second canal?
6. when saivary gland is destroyed what replace sit ..epitheilum or firbrous tissue?
7. contents of synovial fluid?
8. which part of tmj is most sensitive...capsule ,peripehery or synovial fluid.

thanks a ton guys!

 

[dental doc80]

cud some one plz tell me the ans to this question....

the antidiuretic harmone is synthesized in the
1)cells of posterior hypophysis
2)hypothalamic nuclei
3)anterior pituitary
4)pars intermedia
5)none of the above

thnx guys

 

[mrswinidm]

cud some one plz tell me the ans to this question....

the antidiuretic harmone is synthesized in the
1)cells of posterior hypophysis
2)hypothalamic nuclei
3)anterior pituitary
4)pars intermedia
5)none of the above

thnx guys

2. hypothalamic nuclei (synthesized in supraoptic nucleus of hypothalamus and released from post. pituitary)

 

[swetha_dentist]

2. hypothalamic nuclei (synthesized in supraoptic nucleus of hypothalamus and released from post. pituitary)

supraoptic ans paraventricular nuclei of hypothalamus if i am not wrong

 

[swetha_dentist]

over use leads to depression of CNS-low B.P.,LOW heart rate
,dizziness,cold clammy skin
vomiting after this will for a short phase increase pulse rate,i guess...........
i dont think the rest of the options go well for such a case
its just a guess,do let us know the correct answers

you are rigt but sympathetic system get activated to increase blood pressure.

 

[swetha_dentist]

1. which event preceeds the calcification of matrix.
depostion of ECF and collagen fibers correct me if i am wrong

 

[swetha_dentist]

4. which is constant throughout the cardiovascular system..endothelium,smooth muscle or vaso vasorum.

endothelium