Normal cell division in the body depends on a precisely regulated set of events that determine when a cell will divide. two specific genes, proto-oncogenes and tumor-suppressor genes, are responsible for cell cycle regulation. when mutated, proto-oncogenes can become what scientists call stimulating excessive cell division.

Oncogenes

Explanation:

Oncogenes are defined as genes linked to the appearance of tumors, both malignant and benign. They are derived from normal cellular genes, known as proto-oncogenes, responsible for regulating cell growth and differentiation. Proto-oncogenes have the function of coding elements involved in different pathways and include molecules such as growth factors and their receptors, cell cycle regulators, DNA binding proteins, transcription factors, protein kinases, among others.

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.