local anasthetic q

Prep for USMLE Forum

» Log in | Register

Forum

Step 1

Match

Prep4USMLE Forum » USMLE Step 1 Forum » Pharmacology Forum

local anasthetic q

Author

8 Posts

leen
Forum Guru

Topics: 79
Posts: 294

04/24/06 - 06:08 PM

which of the following statement is true for the nerve blockade with LA is true?

1 block is faster in nfected tissue

2 block is faser in myeinated tissue

3 faster in hypocalcemia

4 slower in hyperkalemia

5 slower in the periphery of bundle than in the center

robin082006
Forum Hero
avatar

Topics: 471
Posts: 5,123

04/24/06 - 07:37 PM

2?

___________________
The Key to Succeed is Patience.

gpsbrar
Forum Elite
avatar

Topics: 34
Posts: 278

04/24/06 - 07:45 PM

2

___________________
B+

leen
Forum Guru

Topics: 79
Posts: 294

04/25/06 - 12:34 AM

kapaln says type c fibres r more easily blocked than type a but if we see the degree of myelination type A fibres r myelinated while type C r less myelinated than type A .....

pl explain .....correct me where I m wrong

thanks

gpsbrar
Forum Elite
avatar

Topics: 34
Posts: 278

04/25/06 - 06:29 AM

The effect depends on the diameter and firing rates . The smaller diameter and high firing rate is preferred. The block is best in nonmyelinated nerve fibers. And the block is to inactive sodium channels.

The local anesthesia is better in the periphery and unifected cells, so rule out 1 and 5. 3 and 4 I don't know. So iwas left with 2.

typeB and C>type A delta.Type A beta and gamma > type A alpha. (from Kaplan book.)

___________________
B+

r_albayunen
Forum Senior
avatar

Topics: 0
Posts: 218

04/25/06 - 11:35 PM

leen
Forum Guru

Topics: 79
Posts: 294

04/28/06 - 11:28 AM

hey guys wat abt option 3 n 4?

gpsbrar
Forum Elite
avatar

Topics: 34
Posts: 278

04/28/06 - 11:48 AM

This is a good question. We all must think about this one coz it is very USMLE fave topic.

___________________
B+

You don't have permission to post.