3 - Thermoregulation Flashcards
What two temperatures do not change much with their exposure to the environment?
Core temperature
Oral temperature
What two temperatures change a lot with body temperature and the environmental temperature?
Hand and feet temperature
Core temperature has a circadian rhythm to it. It varies 1-2 degrees over a 24 hour period. It is lowest at _______ and highest at ________.
6 AM
Early evening
A controlled variable, in this case the core temperature, is measured by _________ that are found in the skin, viscera, and brain. The different locations of these tell the brain about different temperatures that could potentially be a threat to the core temperature.
Thermoreceptors
Cutaneous thermoreceptors are important because they tell us about _________ conditions. They are often ________, meaning they can detect temperature and touch sensitivity. They also may be cold or warm sensitive (10x as many cold sensitive receptors).
Environmental
Bimodal
What would you have thermoreceptors in your gut?
They don’t just sense the core temperature, but also threats to the maintenance of the core temperature. Food ingested may change the body temperature, and the receptors will tell the hypothalamus about these threats.
The hypothalamus is the site for thermal regulation, specifically its _______ and _______ regions.
Pre-optic
Superoptic
Neuron cells bodies in the hypothalamus are sensitive to changes in temperature (in Pre-optic and Superoptic regions). There are 3x as many (COLD/WARM) sensitive neurons, and all the neurons relay their information to other areas of the hypothalamus.
Warm
The core temperature is measured by thermoreceptors, which send signals back to the “controller”, in this case the __________.
Hypothalamus
The hypothalamus has the connections to control the _________, _________, and _________ changes that are part of thermoregulation.
Hormonal
Autonomic
Behavioral
The hypothalamus has three functions as the controller for body temperature, which are…
1) Determining set point (for core temp.)
2) Receiving info about current temperature
3) “Deciding” what to do
The hypothalamus has a ________ for core temperature, that is decided by the brain.
Set-point
Set-point can be changed depending on the circumstances. With sleep, temperature (INCREASES/DECREASES) so this results in a (INCREASE/DECREASE) in set-point.
Decreases
Decrease
Set-point can be changed depending on the circumstances. With exercise, temperature (INCREASES/DECREASES) so this results in a (INCREASE/DECREASE) in set-point.
Increases
Increase
***Temp can increase as high as 40 degrees Celsius with exercise
What part of the hypothalamus deals with response to heat and heat loss behaviors?
Anterior hypothalamus
What part of the hypothalamus deals with response to cooling and heat production behaviors?
Posterior hypothalamus
________ tissue is a great insulator. Its thermal conductance is about 1/5 that of skin, muscle, etc. But in babies, the high surface area in proportion to their size means they lose _______ better than adults.
Adipose
Heat
***This is why babies are so chunky, it’s a thermoregulatory mechanism to keep them warmer.
Core temperature is measured by thermoreceptors, which signal to the hypothalamus (which adjusts set-point). The hypothalamus will then induce ______ ______ or ______ _______ depending on the situation. This will result in a change to the core temperature.
Heat loss
Heat production
What are the mechanisms of heat production?
- ANS (especially sympathetic)
- Endocrine (Thyroxine and Epinephrine)
- Muscular Activity
- Non-shivering Thermogenesis