What is Punctiform distribution?
It is established to-day that the cutaneous senses are not distributed uniformly over the whole skin, but are associated with discrete points or spots. The warm and cold spots, for example, have a distinctly punctiform distribution.
What are cutaneous sensations?
Definition of cutaneous sensation : a sensation (as of warmth, cold, contact, or pain) aroused by stimulation of end organs in the skin.
What type of receptors sense pressure and touch?
Mechanoreceptors: These receptors perceive sensations such as pressure, vibrations, and texture. There are four known types of mechanoreceptors whose only function is to perceive indentions and vibrations of the skin: Merkel’s disks, Meissner’s corpuscles, Ruffini’s corpuscles, and Pacinian corpuscles.
What does a Punctiform colony mean?
Punctiform colonies are distinguished from circular colonies by their very small size. Spindle colonies are lens-shaped. 3. Elevation. There are no clear distinctions among raised, convex, and pulvinate.
What is meant by Punctiform?
1 : having the form or character of a point. 2 : marked by or composed of points or dots : punctate. 3 : of or relating to tangible points or dots used for representing words for reading by the blind.
Where does cutaneous information go to in the brain?
Transmission of information from the receptors passes via sensory nerves through tracts in the spinal cord and into the brain. Processing primarily occurs in the primary somatosensory area in the parietal lobe of the cerebral cortex.
How does cutaneous sensation occur?
Cutaneous sensation is mediated by topographically distributed receptors of several kinds, innervated by different classes of afferent nerve fibers. These receptors are distributed in a grid pattern in the epidermis and dermis (Fig. 42-1; also see Chapters 8 and 34).
What are the main receptors that are sensitive to touch?
A number of receptors are distributed throughout the skin to respond to various touch-related stimuli (Figure 1). These receptors include Meissner’s corpuscles, Pacinian corpuscles, Merkel’s disks, and Ruffini corpuscles.
What are the 4 types of touch receptors?
The four major types of tactile mechanoreceptors include: Merkel’s disks, Meissner’s corpuscles, Ruffini endings, and Pacinian corpuscles.