Related Experiment Video
Updated: Jun 29, 2026
09:29
2-Vessel Occlusion/Hypotension: A Rat Model of Global Brain Ischemia
Published on: June 22, 2013
[The distribution of cardiac output in waking rats with a decrease in body temperature to 2.3 degrees C through
Fiziologicheskii Zhurnal Imeni I.M. Sechenova
|December 1, 1996
Summary
Hypothermia significantly altered heart output distribution in rats, increasing skin blood flow and decreasing bone marrow flow. Altitude hypoxia alone did not cause these changes.
Area of Science:
- Physiology
- Cardiovascular Research
- Animal Models
Background:
- Understanding how physiological stressors like hypothermia and hypoxia affect organ blood flow is crucial for clinical applications.
- Previous research has explored organ perfusion under various conditions, but specific changes during combined cooling and hypoxia require further elucidation.
Purpose of the Study:
- To investigate the impact of hypothermia and altitude hypoxia on heart output distribution in alert rats.
- To quantify changes in regional blood flow to various organs under these experimental conditions.
Main Methods:
- Utilized 15-micron 131I-albumin microspheres to trace heart output distribution in alert rats.
- Induce experimental conditions of cooling (hypothermia) and altitude hypoxia.
- Quantified the distribution of microspheres in different tissues to assess regional blood flow.
Main Results:
- No significant changes in overall heart output distribution were observed in rats exposed solely to altitude hypoxia.
- Hypothermic rats exhibited a significant 1.5-fold increase in the proportion of heart output directed to the skin.
- A corresponding 1.5-fold decrease in bone marrow heart output was noted in hypothermic rats.
- Hypothermic rats also showed increased blood flow to skeletal muscles and skin areas compared to hypoxic rats.
Conclusions:
- Hypothermia, not altitude hypoxia alone, significantly alters regional blood flow distribution in rats.
- The observed redistribution favors superficial tissues (skin) and muscles at the expense of bone marrow during hypothermia.
- These findings highlight the specific cardiovascular adaptations occurring during hypothermia, with implications for understanding tissue perfusion under stress.
Related Concept Videos
01:29Decreased Body Temperature
A decreased body temperature can occur in patients with hypothermia and frostbite. Heat loss with extended cold exposure overpowers the body's ability to create heat, resulting in hypothermia. Core temperature readings help classify hypothermia. Mild hypothermia is temperatures between 32 °C (89.6 °F) and 35°C (95 °F) and is caused by impaired thermoregulation. Moderate hypothermia is temperatures between 28 C (82.4 °F) and 32 °C (89.6 °F) caused by sustained extreme cold exposure, and severe...
01:19Cardiac Output I:Effect of Heart Rate on Cardiac Output
Cardiac Output
Cardiac output (CO) refers to the total amount of blood ejected by one of the ventricles in liters per minute (L/min). In a resting adult, CO ranges from 5 to 6 L/min, adjusting according to the body's metabolic requirements.
Effect of Heart Rate on Cardiac Output
Cardiac output adapts to metabolic demands during stress, physical activity, or illness. The autonomic nervous system regulates heart rate via the sinoatrial node. The parasympathetic nervous system decreases heart rate...
Cardiac output (CO) refers to the total amount of blood ejected by one of the ventricles in liters per minute (L/min). In a resting adult, CO ranges from 5 to 6 L/min, adjusting according to the body's metabolic requirements.
Effect of Heart Rate on Cardiac Output
Cardiac output adapts to metabolic demands during stress, physical activity, or illness. The autonomic nervous system regulates heart rate via the sinoatrial node. The parasympathetic nervous system decreases heart rate...
01:22Cardiac Output II: Effect of Stroke Volume on Cardiac Output
Cardiac output (CO), the amount of blood the heart pumps per minute, is a parameter in cardiovascular physiology determined by stroke volume and heart rate. Stroke volume, the amount of blood pushed from one of the ventricles per heartbeat, is influenced by preload, afterload, and contractility.
Preload
Preload refers to the initial elongation of the cardiac myocytes before contraction and is related to the volume of blood filling the heart at the end of diastole, or end-diastolic volume. The...
Preload
Preload refers to the initial elongation of the cardiac myocytes before contraction and is related to the volume of blood filling the heart at the end of diastole, or end-diastolic volume. The...