Login

Join for Free!
118908 members


Help! Cutting the vagus nerve and force of contraction

For discussing the functions of different structures of all organisms.

Moderator: BioTeam

Help! Cutting the vagus nerve and force of contraction

Postby Vangeek » Fri Feb 13, 2009 1:26 am

Cutting the vagus nerve to the heart increases heart rate. What effect would it have in the force of contraction of the heart? Please explain the answer, anyone????????
Vangeek
Garter
Garter
 
Posts: 18
Joined: Thu Sep 25, 2008 3:11 am

Postby mith » Fri Feb 13, 2009 6:16 pm

well, what's the force controlled by?
Living one day at a time;
Enjoying one moment at a time;
Accepting hardships as the pathway to peace;
~Niebuhr
User avatar
mith
Inland Taipan
Inland Taipan
 
Posts: 5345
Joined: Thu Jan 20, 2005 8:14 pm
Location: Nashville, TN

Postby Vangeek » Fri Feb 13, 2009 7:29 pm

If contractile strength is independent of muscle stretch and EDV ,but rather controlled by bloodborne chemicals (epinephrine, excess of Ca,thyroxine) which has little to do with the vagus (parasympathetic division) nerve, even if it's cut; then, yes, HR will increase, reflecting inherent rate of SA note (100beats/min), but the force of contraction will remain the same? Am I on the right path??
Vangeek
Garter
Garter
 
Posts: 18
Joined: Thu Sep 25, 2008 3:11 am


Postby behzad » Mon Aug 10, 2009 8:14 am

Vangeek is right. If we bring out the heart from body and cut its nerves thoroughly you can see that HR will increase. Vagus is a parasympathetic nerve. It shows that heart in normal situation is more affected by parasympathetic nerves. Now I think it's clear why cutting vagus can increase HR
behzad
Garter
Garter
 
Posts: 2
Joined: Mon Aug 10, 2009 8:04 am


Return to Physiology

Who is online

Users browsing this forum: No registered users and 0 guests