Related Experiment Video

Updated: Aug 18, 2026

Fetal Mouse Cardiovascular Imaging Using a High-frequency Ultrasound (30/45MHZ) System
07:34

Fetal Mouse Cardiovascular Imaging Using a High-frequency Ultrasound (30/45MHZ) System

Published on: May 5, 2018

The fetal response to changes in the composition of maternal inspired air in human pregnancy

K Ritchie

    Seminars in Perinatology
    |October 1, 1980
    PubMed

    The effect of hypoxia upon the fetus is dependent upon not only the degree of hypoxia induced but probably also upon gestational age and the initial level of fetal oxygenation. Mild hypoxia (12% or over) causes fetal tachycardia, while a more severe insult may cause bradycardia. The effect of hypoxia upon FBM in human pregnancy is uncertain, but depending upon the severity of the hypoxia, it is likely that FBM is reduced or abolished. Hyperoxia has little effect upon the fetal heart rate or FBM in normal circumstances, but an increase in FBM occurs in the presence of fetal hypoxia. No significant change in fetal heart rate in human pregnancy occurs during hypercapnia which is, however, a potent stimulus to fetal breathing. On the other hand, hypocapnia caused by hyperventilation is associated with a decrease in FBM with no obvious change in fetal heart rate. Smoking is associated with a fetal tachycardia and a decrease in FBM. The decrease in FBM is small, the effect being maximal at 30 min after smoking with recovery by 90 min.

    More Related Videos

    The Perinatal Asphyxiated Lamb Model: A Model for Newborn Resuscitation09:03

    The Perinatal Asphyxiated Lamb Model: A Model for Newborn Resuscitation

    Published on: August 15, 2018

    Continuous Telemetric In Utero Tracheal Pressure Measurements in Fetal Lambs05:40

    Continuous Telemetric In Utero Tracheal Pressure Measurements in Fetal Lambs

    Published on: December 22, 2023

    Related Concept Videos

    Physiological Control of Respiration01:23

    Physiological Control of Respiration

    Introduction
    Breathing, a seemingly passive process, is regulated by the respiratory center in the brainstem. This center coordinates the involuntary control of respirations, which means it occurs without conscious effort, ensuring a smooth and uninterrupted pattern.
    Regulation of Ventilation
    The body maintains ventilation by monitoring levels of carbon dioxide (CO2), oxygen (O2), and hydrogen ion concentration (pH) in the arterial blood. Among these factors, the level of CO2 plays a crucial...
    Pressure Relationships in Thoracic Cavity01:24

    Pressure Relationships in Thoracic Cavity

    Breathing, otherwise known as pulmonary ventilation, is the process of air movement into and out of the lungs. The main mechanisms propelling pulmonary ventilation are atmospheric pressure (Patm), intra-pulmonary (Ppul ) or intra-alveolar pressure (Palv) within the alveoli, and intrapleural pressure (Pip) within the pleural cavity.
    Breathing Mechanisms
    Both intra-alveolar and intrapleural pressures rely on specific lung properties. The ability to breathe—allowing air to enter the lungs during...
    Pulmonary Ventilation: Inhalation01:24

    Pulmonary Ventilation: Inhalation

    Pulmonary ventilation is a vital process that ensures the exchange of oxygen and carbon dioxide in the lungs. It refers to the movement of air into and out of the lungs, enabling the body to obtain oxygen and remove waste carbon dioxide. In this article, we will explore the intricacies of pulmonary ventilation, including its underlying principles, mechanisms, and the interplay of pressures within the respiratory system.
    Boyle's law becomes particularly pertinent when examining respiratory...
    Pulmonary Cycle: Exhalation01:17

    Pulmonary Cycle: Exhalation

    In terms of human respiration, the act of expelling air, known as exhalation (or expiration), operates on the principle of pressure gradients. During expiration, the pressure within the lungs exceeds that of the surrounding atmosphere. Under normal conditions, quiet breathing involves passive exhalation and is free of muscular contractions. This is because the exhalation process is driven by the natural elastic recoil of the lungs and chest wall, both of which have an inherent tendency to...
    Factors Affecting Pulmonary Ventilation01:19

    Factors Affecting Pulmonary Ventilation

    Besides the pressure difference between the external environment and the lungs, the airflow rate and ease of pulmonary ventilation are also influenced by three other factors: surface tension of the fluid in the alveoli, compliance of the lungs, and airway resistance.
    Alveolar Surface Tension
    The alveolar fluid lines the luminal surface of the alveoli and exerts a force called surface tension. This force is caused by the polar water molecules in the liquid being more strongly attracted to each...
    Chemical Factors Affecting Respiration Centers01:31

    Chemical Factors Affecting Respiration Centers

    Chemical factors such as changing CO2, O2, and H+ levels in arterial blood play a critical role in influencing respiration depth and rates. These variations are detected by chemoreceptors—specialized sensors located in two primary body areas. Central chemoreceptors are found throughout the brain stem, including the ventrolateral medulla, while peripheral chemoreceptors are located in the aortic arch and carotid arteries.
    CO2 has a potent influence on respiration and is strictly regulated. Under...