Question

1. What are the functions of the nociceptors, thermoreceptors, mechanoreceptors (including barroreceptors, proprioceptors, and chemoreceptors) and all of the tactile receptors.  Be able to identify the following for each type of receptor:
   1. Size of receptive field
   2. Type of adaptation (if any)
   3. Is the receptor tonic or phasic, and what allows them to be activated or deactivated

Answer 1

nociceptors is pain receptor
thermoreceptors are specialized receptors that detect the changes in temperature.
Mechanoceptors detect stimuli such as touch, pressure, vibration, and sound from the external and internal environments. They are of the following types:
barroreceptors, proprioceptors, and chemoreceptors.
Baroreceptors are mechanoreceptors located in the carotid sinus and in the aortic arch. Their function is to sense pressure changes by responding to change in the tension of the arterial wall.
Proprioceptors primarily give detailed and continuous information about the position of the limbs and other body parts in space.
Chemoreceptors detect the chemical signals or they tranduce chemicals from the surroundings and generate the biological signals.
Tactile receptors are sensory receptors which respond to touch. four types of receptors: Meissner, Merkel, Pacinian, Ruffini. The density of Meissner and Merkel receptors determines the two-point discrimination. Pacinian corpuscles are quite big to be seen with naked eye, and they respond to pressure.

a. Receptive field of the nociceptors, thermoreceptors and baroreceptors is large, and of chemoreceptors and proprioceptors is small.

b. Time of adaptation of nociceptors and chemoreceptors is less, whereas for remaining receptors it is more.

c.

nociceptors, chemoreceptors and proprioceptors are tonic receptors, which are slow receptors.
Baroreceptors and thermoreceptors are the phasic or fast receptors.