Sensation, touch

Fiihlen, n. feeling, sensation, perception. Fiihler, m. feeler, antenna, tentacle probe. Fiihlung, /, feeling, sensation touch, contact, fuhr, pret. (of fahren) went, traveled, etc. Fuhre, /. carrying, carriage, cart, load, fiihren, v.t. lead, guide, conduct, carry, convey bear, wear construct carry on run (a machine) cause. 

The skin is responsive to four types of sensation— touch (pressirre), heat, cold, and pain. These sensations are detected by mechanoreceptors that are expanded nerve endings in the skin. Also present are some tmmyelinated, or free, nerve endings. All fom sensations are elicited in... 

Hold one end of the slip [of rubber]. . . between the thumb and forefinger of each hand bring the middle of the piece into slight contact with the lips . . . extend the slip suddenly and you will immediately perceive a sensation of warmth in that part of the mouth which touches it.. . . For this resin evidently grows warmer the further it is extended and the edges of the lips possess a high degree of sensibility, which enables them to dis-... 

Exts Trace pedal edema bilaterally decreased sensation in feet to light touch no lesions... 

Paresthesia An abnormal touch sensation, such as burning, tingling, or prickling, often in the absence of external stimuli. 

Most multicellular organisms exploit mechanoreceptors — specialized cells that detect external mechanical forces — to help construct their internal view of the external world. The senses of hearing, balance and touch all rely on mechanoreceptors, as do the proprioceptive sensations that tell an organism how it is situated in the environment. Mechanoreception is probably one of the most ancient of the senses. 

Suzuki, H. et al. In vivo imaging of C. elegans mechanosen-sory neurons demonstrates a specific role for the MEC-4 channel in the process of gentle touch sensation. Neuron 39 1005-1017,2003. 

Sensation provides the input to the system. The sources of sensory information can be outside your body through one of the five primary senses sight, sound, taste, smell, and touch. The source of information can also be inside your body. The nervous system receives and monitors information such as your blood pressure, blood sugar, and blood oxygen level. 

Peripheral nerve functions are not affected equally by local anesthetics. Loss of sympathetic function usually is followed by loss of temperature sensation sensation to pinprick, touch, and deep pressure and last, motor function. This phenomenon is called differential blockade. Differential blockade is the result of a number of factors, including the size of the nerve, the presence and amount of myelin, and the location of particular fibers within a nerve bundle. For conduction to be effectively blocked, the local anesthetic must exert its effects over the distance between several nodes of Ranvier. Since the smallest nerves (C fibers) have no myelin, they can be most easily blocked thus, sympathetic functions often are blocked soon after a local anesthetic is applied to a particular nerve bundle. Small myelinated nerves have correspondingly short distances between nodes of Ranvier and therefore are often blocked next. These nerves subserve temperature and sharp pain sensation. Larger nerves then become blocked, accounting for the loss of function up to and including motor innervation. 

However, because of lateral inhibition, you will recover the sensation of being stimulated by a sharp point. The various levels in Figure 7-6 show lateral connections between the neurons from the touch receptors. These connections have the prop erty of inhibiting one another s activities. The firing of the... 

I tested my tactile sensitivity. I worked my way back to the couch and found Alice. My exploration of the softness of the sweater and the warmth of her flesh was an ecstatic sensual experience. However, it was devoid of sexuality, devoid of passion. While on the couch, the stimulation of touch became less important to me as I began to experience the dichotomous sensation of sinking into the cushions and yet floating slightly above them. 

Cocaine and other local anesthetics abolish not only the sensation of pain, but other special sensations, if they are suitably applied. Here also there is some selection. In the skin, they paralyze first the vasoconstrictor reaction, then progressively the sensations of cold, warmth, touch, tickling, pressure, pain, and joint sense. In the nose, they abolish the olfactory sense. On the tongue, they destroy the taste for bitter substances but have less effect on sweet and sour taste and none on salty taste. When cocaine is applied to the appropriate nerves, it is found that the centrifugal vagus fibers are paralyzed before the centripetal, vasoconstrictor fibers before vasodilator, bronchial constrictors before the dilators, etc. (Sollmann, 1944). 

At doses of 20-100 mg, both BZP and TFMPP may produce a range of mental experiences lasting six to eight hours. Sought-after effects may include euphoria, alertness, reduced need for sleep, heightened sense of touch and other pleasurable sensations, and a sense of emotional bonding to others that is not necessarily based on shared experiences, common interests, or other reasons for close relationships. 

Flavour is a complex sensation, made up principally of smell and taste, but touch and hearing contribute as well. The human senses of smell and taste differ in sensitivity, between each other and depending on the nature of the component eliciting the sensation. Substances may have no impact at all (such as oxygen or carbon monoxide) or exhibit very low thresholds (such as 2 X 10 14g mL 1 water for the odour of bis-2-methyl-3-furyl disulfide).204 In general, odour thresholds are much lower than taste thresholds and so flavour tends to be dominated by odorous components, by substances able to reach the olfactory epithelium high up in the nose, that is, substances with at least some volatility. Hence, the emphasis on the volatile compounds derived from the Maillard reaction. 

Read the entire section (4) of the Procedure before carrying out the experiment so you understand what to do. The sensation of warmer or cooler temperature can be ascertained if you do the following experiment rapidly. Take a new rubber band. While holding it with your fingers between your two hands, let the rubber band touch your upper lip. Move the band away from your lip. Quickly extend the rubber band to about twice its length and touch your upper lip with the extended rubber band. Does the... 

When acupuncture needles are inserted into the skin, the patient feels a slight sensation of touch, but no pain (if there is pain, the needle is likely in the wrong place). Once inserted, the acupuncturist can manipulate the needles by rotating or vibrating them to achieve the desired effect, or may simply leave the needles in the skin for a set period of time. Most often, when acupuncture is used for the relief of pain, small wires are connected to the needles to deliver small electrical impulses (usually only a few microamps and at a frequency of 5-2000 Hertz (impulses per second). Higher frequencies are used for major surgical procedures, whereas lower frequencies are used for general pain relief. 

I found that now, too, I had a qualitatively different sensation in my fingertips. Then as I tried stronger stimulation of the finger ends, I experienced a peculiar phenomenon that I had never noted before nor have I noted it since, under any conditions. If you watch as you touch a tabletop with your finger, you will notice that the time when you hit it, as determined visually, and the time when you feel it are in essential coincidence. However, under this drug, I found that I first hit the table, and then felt it the feeling was a very definitely delayed phenomenon. I experimented with this for a half hour or more.. 

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