First answer is , as the work of ventricle is to push blood to he whole body , so it has to be strong or it can not pump blood to head to the toe !
as in frog (an amphibian ) it has only three chambers as two artia and one ventricle, so the oxygenated blood from left artia and deoxygenated blood from right , combines and thus partial oxygenated blood is circulated !
Adrenaline
Nicotine is a substance that is addictive in nature commonly
found in cigarette, that affect the nervous system by binding to the receptors
in the brain and other part of the body. Atherosclerosis is the loss of
elasticity or thickens of arteries walls. However, nicotine increases the
release of neurotransmitter adrenaline into the blood which subsequently cause
the development of atherosclerosis.
Microtubules are tiny, hollow, bead-like tubular structures that help cells maintain their shape. Along with microfilaments and intermediate filaments, they form the cytoskeleton of the cell, as well as participate in a variety of motor functions for the cell.
Second messenger systems: The amino acid-derived hormones epinephrine and norepinephrine bind to beta-adrenergic receptors on the plasma membrane of cells. Hormone binding to receptor activates a G protein, which in turn activates adenylyl cyclase, converting ATP to cAMP.
