Let’s say your body temperature is 98.6 degrees, which has been accepted by most as being human body norms. (There’s evidence that it’s gotten progressively colder, but that’s a topic for another thread).
Does it necessarily follow that the temperature of your blood, spinal fluid, semen, urine, saliva, et cetera, is that temperature inside your body? What about when it comes out of you?
For saliva in your mouth, I’d assume it is slightly, slightly lower than the core temperature because of exposure to the airflow in your mouth. While still in the salivary gland itself, though, probably yes, 98.6.
As for semen, since the testicles are “outside” of most of the rest of your body (I’ve read that it’s specifically for the purpose of cooling,) I’d also assume that it’s a slightly, slightly lower temp than core temp - not the prostate-produced component of it, but at least the part that is stored in the epididymis.
For all other things like blood, urine, spinal fluid, I’d assume core temp, yes.
The reason that “98.6 degrees” (Fahrenheit) is claimed to be the typical body temperature is because it is a direct conversion from 37 ℃ without consideration for significant figures. In reality, average core body temperature is around 36.7 ℃ which is around 98.1 ℉, although it can vary by up to ±0.6 ℃ (±1 ℉) throughout the day. Fluids that are stored within the body will be at approximately at body temperature for obviously reasons.
Stranger
Even with the mouth closed prior to and during a thermometer jammed hard into the flesh under my tongue reads a couple of degrees below what I’d assume my core temperature is. There’s necessarily a gradient from the skin and into the core, and depending on your surroundings thermoregulation of your body can allow your arms and legs to get significantly colder than core, in which case blood returning from them will also be colder.
About how long does it take an ice-cold drink to assume your body’s core temperature once you’ve consumed it?
No. Different parts of the human body are at at different temperatures
“Heat generated in metabolically active organs is transported to the skin where it is removed from the body. In a warm environment, temperature variation is not large, ranging from 37 to 38 °C in metabolically active organs, such as the Brain, heart, and liver, to 30–32 °C on the skin of hands and feet. Temperature change in critical central organs is strongly resisted by thermoregulatory mechanisms, while appreciable variation occurs in peripheral regions.”
For mammals in general, there is a detailed article here. It presents temperature variation data of different organs during different ambient temperature, physical exercise, etc. etc. :
That’ll depend on whether that “ice-cold” drink actually contains ice, and if so, how much. The heat it takes to melt water is much less than the heat to vaporize it, but it’s still enough to correspond to a very big change in temperature.
Here’s more data than you probably wanted to see. 13 men were recruited and 11 men completed trials. They were given Ice slushies and asked to work out while their rectal (!) and skin temperatures were measured.
While, its not exactly linear, the way I read figure 2 in the cite below, it took 15-20 minutes for their rectal temperatures to reach their skin temperatures after consuming the ice cold drink.
Is that good enough data for you ?