questions

[rtvj]

---

Members don't see this ad.

can someone gimme explanation for the answers:

1.The largest vol of blood flow thro the left coronary artery takes place:

a. during systole
b. during diastole
c. during ventricular ejection

ans given is b. diastole

2.In 3rd degree heart block, the ECG shows:

a.increased PQ interval
b.Increased ht of QRS complex
c.Dis-association of P wave and QRS complex.

ans given is c

3. The depolarization of skeletal muscle cell membrane by motor nerves is caused by:

a.shift of Na ions out of the end plate
b.change in EPP to a critical value.
c.presence of AchE

ans given is b.

4.Other factors being equal one should expect N2O-O2 sedation to be be induced more slowly than normal in a person:

a.with larger TV than normal
b. with Smaller RV than normal
c.With small VC than normal
d.with FRC larger than normal

ans given is d.



thanks

rtvj

 

[drarch]

ans for 1st q is during diastole
reason is during systole......... there is high compressive forces within the myocardium which causes endocardial vessels to collapse & so coronaray vascular resistance becomes high...results in diminished blood flow.

during diastole........... intramyocardial pressure drops which allow these endocardial vessels to reopen. cvr also decreased which allow more coronary blood flow.

hope this help u.

 

[rtvj]

thanks for the explanation for the 1st answer..makes sense now!

ans for 1st q is during diastole
reason is during systole......... there is high compressive forces within the myocardium which causes endocardial vessels to collapse & so coronaray vascular resistance becomes high...results in diminished blood flow.

during diastole........... intramyocardial pressure drops which allow these endocardial vessels to reopen. cvr also decreased which allow more coronary blood flow.

hope this help u.