Question

Thermoreceptors are:
A. End bulb of Krause
B. Ampullae of Lorenzini
C. Both A and B
D. None of the above

Answer 1

Hint: Thermoreceptors are specialized nerve cells that are able to detect differences in temperature. They are able to detect heat and cold and are found throughout the skin in order to allow sensory reception throughout the body. They are more densely packed in the fingertips and ear lobule. Hence, a slight increase in temperature brings about profound changes in the perception of temperature.

Complete answer: Thermoreceptors include the end bulb of Krause; it detects cold sensation in the surrounding and it is defined by capsules.
1. Warmth receptor contains unmyelinated C-fibers (they have a low conduction velocity), while those responding to cold have both C-fibers and thinly myelinated A-delta fibers (they have a faster conduction velocity).
2. The firing rate of cold receptors increases during cooling and decreases during warming and vice-versa in warm receptors.
3. Temperatures that are likely to damage an organism are sensed by sub-categories of nociceptors (pain receptors) that may respond to noxious cold, noxious heat, or more than one noxious stimulus modality (i.e., they are polymodal).

So the correct option is A: End bulb of Krause

Note: Elasmobranchs, such as rays and sharks, have distinctive sense organs, known as the ampullae of Lorenzini, that is a highly sensitive receptor to cooling. These organs consist of small capsules within the animals' heads that have canals ending at its skin surface. The ampullae of Lorenzini are special sensing organs called electroreceptors. They form a network of jelly-filled pores. Electroreceptors can detect minute electrical currents in living organisms. This is used to target and hunt for potential prey.