Smooth muscles depolarize as a result of a transmembrane current of Calcium ions. When an action potential depolarizes the muscle cell membrane, it also travels into the body of the cell via the t-tubules. Unlike skeletal muscle, smooth muscle is dependent in two sources of calcium in order to intiate contraction. These two sources are calcium sequestered in the S.R. of the smooth muscle cell.
Well, A humans brain is bigger than a Sheeps brain, And a human has more Ridges and Contours also, Hope this helps
There are high risk of following abnormalities or mis- happening if chorionic villus sampling (CVS) are performed before 10th week of pregnancy:
a) Fetal defects
b) Miscarraige
c) Fetal anomalies.
d) Risk of infection
As per the standard recommended by American Congress of Obstetricians and Gynecologists, the standard time to perform this test is between 10th & 12th week as at that time the chances of risk to fetus is very negligible. In no case CVs shall be conducted before 9th week of gestation.
It is estimated that there is a risk of 0.5 to 1 % of miscarriage after CVs which usually happens within the 3rd day of test.
