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How contraction of alary muscles results in expansion of pericardial sinus in cockroach?
alary muscles are traingle shaped, the pointed side is connected to tergum and its broad face is connected to dorsal diaphragm. When alary muscles are contracted, the pricardial sinus is enlarged. My question is how this pericardial sinus enlarges? contraction should result in decrease of pericardial sinus!
1 Answer
- Anonymous9 years agoFavorite Answer
the alary muscles contract resulting in expansion of pericardial sinus. becoz, as the alary muscles contract they pull the part of pericardial sinus towards them..imagine if u r in compact place whose walls u can push behind so as to get more space to stand..now if these walls are connected to springs from outside and the other end of spring attached to a rigid support they will CONTRACT..
in same way as the blood enters it pushes the sinus back and frm outside the allary muscles contract!