11 topics with brief reviews: definitions, key facts, and class questions.
Thermoregulation is the body's ability to maintain a constant internal environment temperature regardless of external conditions. In this section, we analyze in detail the functional system of thermoregulation, the body's temperature profile with its classical division into a stable "core" and a poikilothermic "shell", as well as the mechanisms of heat production and heat loss.
We will trace the entire pathway of the temperature signal: from peripheral thermoreceptors to the hypothalamic centers, and learn how these centers readjust the body's functioning under normal conditions, extreme environmental impacts, and pathology (hyperthermia and hypothermia).
What is most frequently asked in class? During seminars and exams, special attention is paid to the pathways of heat loss (radiation, conduction, convection, evaporation), the role of brown adipose tissue in non-shivering thermogenesis, and the hypothalamic set point. Also, be prepared to explain the difference between circadian physiological fluctuations in body temperature and true thermoregulatory disorders.
What does the term "plastic constant" mean in relation to temperature?
This means that body temperature is not a rigidly fixed figure. The organism allows its deviation from the optimum for a certain period of time to adapt to conditions, subsequently striving to return it to normal.
What is the body core?
These are the internal regions of the body (thoracic and abdominal organs, brain), the temperature of which is maintained at a strictly constant level, unlike the temperature of the "shell" (skin and extremities).
Where in the body is the reference core temperature recorded?
As a standard for the average core temperature, the temperature of the blood in the right ventricle of the heart is used, which is normally 37.5 °C.
At what time of day is human body temperature at its minimum?
The minimum (nadir) is reached during deep night sleep, usually between 04:00 and 06:00 AM.
At what rate do thermoreceptors generate impulses at rest?
Under comfortable resting conditions, they exhibit stationary (constant) background activity at a rate of 2–5 impulses per second.
What will happen to a warm-blooded animal upon destruction of the hypothalamus?
It will lose the ability to maintain a constant body temperature (homeothermy) and become poikilothermic. Its temperature will fluctuate following environmental changes.
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