During life in utero,oxygenation of the fetus occurs through transplacental gas exchange.When birth occurs,four factors combine to stimulate the respiratory center in the medulla.The initiation of respiration then follows.What are these four essential factors?
(Select all that apply).
A) Chemical
B) Mechanical
C) Thermal
D) Psychologic
E) Sensory

Question

Quizplus · Accepted Answer

Chemical factors are essential to initiate breathing.During labor,decreased levels of oxygen and increased levels of carbon dioxide seem to have a cumulative effect that is involved in the initiation of breathing.Clamping of the cord may also contribute to the start of respirations and results in a drop in the level of prostaglandins,which are known to inhibit breathing.Mechanical factors are also necessary to initiate respirations.As the infant passes through the birth canal,the chest is compressed.After the birth,the chest is relaxed,which allows for negative intrathoracic pressure that encourages air to flow into the lungs.The profound change in temperature between intrauterine and extrauterine life stimulates receptors in the skin to communicate with the receptors in the medulla.The stimulation of these receptors also contributes to the initiation of breathing.Sensory factors include handling by the health care provider,drying by the nurse,lights,smells,and sounds.Psychologic factors do not contribute to the initiation of respirations.

During Life in Utero,oxygenation of the Fetus Occurs Through Transplacental