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ISLAMIC MEDICAL EDUCATION RESOURCES 04

0012-SURFACE SENSORY SYSTEM

Lecture for 3rd year students on 8th December 2000 by Professor Omar Hasan Kasule, Sr.

A. PRESSURE AND TOUCH (LAMS)

TOUCH IN THE QUR'AN

The Qur'an has mentioned touch in some verses using the words lams or mass (p 382 4:34, 5:6, 6:7).  Those who are ritually impure should not touch the mushaf (56:79). In all these verses touch is understood to mean handling things and not as a sensory modality. It is however understood that touch sensitivity is a pre-requisite for handling objects.

 

ANATOMY

The sense of touch is mediated through touch receptors. The Qur'an has described the skin as sensory organ (p 382 4:56, 22:20, 39:23).  These receptors are most numerous on the skin of the fingers and lips and are scarce in the skin of the trunk. Parts of the body with hair rely a lot on touch receptors in hair follicles. In hairless regions such as the palm, plantar, lips, glans penis, tactile sense is in the meissner corpuscles.

 

PHYSIOLOGY

The threshold for touch is 0.5-1 g/square millimeters. Minimum separation between sensations varies by place and ranges 2-70 mm. The thigh and the upper arm are the least sensitive. Too much pressure causes pain instead of touch sensation.

 

THE HUMAN HAND

The hand is a sense organ. It can help explore and define size, shape, and texture of many objects. The hand can be said to be the basis of human civilization. The human hand is able to manipulate objects and make tools. Its fine movements are helped by its great tactile sensitivity. The Qur'an dealt with the hand not as a sense organ but as an organ of actions that may be good or bad (p 283 2:179, 2:249, 5:28, 5:94, 7:195, 14:9, 38:44, 111:1). Accurate mechanical manipulations by the hand require sensitive sensation.

 

FUNCTIONS OF THE TOUCH SENSATION

Touch provides humans with the ability to appreciate physical properties of objects. It can also help in avoiding obstacles for those not able to see them. Touch is a very powerful source of sensory input. It can also be used to show love and intimacy.  Touching marriageable women is forbidden. The Qur'an uses two terms, lams (p 1046 4:43, 5:6) and mass (p 1111 2:236-237, 3:47, 19:20, 33:49, 55:56, 55:73, 58:3-4) in both physical and metaphorical senses that are true for the action of touching women. The human lip has a very rich nervous supply that makes it very sensitive to touch. Babies use their lips and mouths extensively for 'feeling' and understanding objects. Kissing is a very intimate form of human touch and because it could excite passions was forbidden during fasting (KS 332: Bukhari K30 B23 & B24; Muslim K13 H62-74; Abu Daud K14 B34-36; Tirmidhi K6 B31 & B32, Ibn Majah K7 B19 & B20; Muwatta K18 H13-17; Muwatta K18 H18-20). Touch is also the basis for social intercourse. Baby is comforted by the touch of the mother's body. The prophet recommended kissing of children. Other forms of social interaction are shaking hands, hugging, and nose rubbing of the New Zealand Maori.

 

B. PAIN

PAIN IN THE QUR'AN

The Qur'an describes the sensation of pain in the context of the suffering of those being punished on earth (p 146 4:104, 8:32, 9:74, 11:102, 12:25, 24:19, 36:18, 46:24) and in the hereafter (p 144-145 2:104, 2:174, 2:178, 3:21, 3:77, 3:91, 3:177, 3:188, 4:18, 4:138, 4:161, 4:173, 5:36, 5:73, 5:94, 6:70, 7:73, 9:3, 9:34, 9:39, 9:61, 9:74, 9:79, 9:90, 10:4, 10:88, 10:11, 11:48, 14:22, 15:50, 16:63, 16:104, 16:117, 17:10, 22:25, 24:19, 24:63, 25:37, 26:201, 29:23, 31:7, 33:8, 34:5, 37:38, 41:43, 42:21, 42:42, 43:65, 44:10-11, 45:8, 45:11, 46:31, 48:16-17, 48:25, 51:37, 58:4, 59:15, 61:10, 64:5, 67:28, 71:1, 73:31, 76:31, 84:24). The physical pain of punishment in the hereafter will be more severe than earthly pain. 

 

TYPES AND SOURCES OF PAIN

Pain is a response to some insult to the body. The insult may be mechanical, chemical, thermal, or inflammatory injury. Some types of headache are pain with a psychogenic basis. Pain can be described as different qualities and intensities. The Qur'an has, for example, described the pain of pruritis (2:196) as an annoyance.

 

ANATOMICAL ASPECTS

Pain receptors are found all over the body. Their distribution reflects the wisdom of the creator. There are more pain receptors on epithelial surfaces than in the viscera. Pain sensation on the surfaces is protective from external injury. Pain sensation in the viscera would make normal life almost impossible because of excessive sensory stimulation. The diminished pain sensation in the viscera helps make surgery on internal organs easier.

 

Pain receptors are undifferentiated, unmyelinated or finely myelinated axons in the epidermis.

 

PHYSIOLOGICAL ASPECTS

Pain sensations are interpreted in the cerebral cortex. The cerebral cortex can inhibit pain sensation. Soldiers in battle experience stress analgesia, they do not feel pain of wounds until after the fighting is over. Pain can be relieved by counter irritation such as scratching or acupuncture.

 

FUNCTIONS OF THE PAIN SENSATION

Pain is a symptom. It is rarely is it considered a disease on its own. The prophet gave us an example of courage in withstanding pain during his terminal illness (KS 485: Bukhari K3 B39; Bukhari K75 B2, B13, B16; Bukhari K81 B42; Muslim K25 H22; Tirmidhi K8 B8; Nisai K21 B6; Ibn Majah K6 B63; Ahmad V6 p64, 70, 77, 172, 181, 369; Tayalisi H1536). Pain, a bounty from Allah, is protective. The feeling of pain warns the person of an injury so that measures can be taken to prevent further injury or mitigate the effects of the injury. If there were no pain sensation, humans would get injured without knowing.

 

C. HEAT

HEAT IN THE QUR'AN

The Qur'an discusses heat mostly in the context of punishment in hell (p 346-7 6:70, 9:35, 9:81, 10:4, 18:86, 22:19-20, 37:67, 38:75, 40:71-72, 44:45-46, 44:48, 47:1, 55:44, 56:42-43, 56:54, 56:93, 78:25, 88:4, 101:11). Heat is also discussed in the context of the discomfort of hot days (p. 346-7 15:2, 15:28, 15:33) or protection from heat (p.437 16:81). Shades are a bounty from Allah to protect humans from heat (p. 756 2:57, 4:53, 7:160, 16:18, 25:45, 28:24, 35:31, 36:56, 56:30, 56:43, 76:14, 77:30-31, 77:41). The heat of the day and fever are considered as blows from the heat of hell indicating that heat energy on earth is the same type of heat that will be in hell but in a milder form. Creation of humans was described as from hot clay (p. 347 15:2, 15:28, 15:33).

 

ANATOMY

Temperature receptors are peripheral or central. Peripheral temperature receptors are all over the body. Central temperature receptors are in the hypothalamus. The peripheral receptors are responsive to heat in the external environment. Central receptors are responsible to increases in the temperature of the blood.

 

PHYSIOLOGY

The threshold for heat is increase of 0.007 degrees in 3 seconds. The threshold for cold is decrease of temperature by 0.012 degrees. Optimal temperature discrimination is optimal at 28 degrees. Different parts of the skin have different sensitivity to temperature. The response to high environmental temperature is: sweating, heat syncope, anorexia, diarrhea, and fatigue. Efficiency of thermo-regulation decreases with age. Temperature regulation is impaired in the newborn.

 

TYPES AND SOURCES OF HEAT

The sensation of heat may arise out of contact with primary sources of heat such as the sun, fires, and other types of radiations. It may also arise out of entry into the body of pyrogens that are substances that will raise body temperature.  Pyrogens can be endogenous or exogenous.

 

IBADAT IN EXTREME HEAT

Human ability to withstand heat is limited. The prophet delayed salat al dhuhr in extreme heat (MB # 332 & 333 p 201)

 

D. COLD

COLD IN THE QUR'AN

The Qur'an treats cold as the opposite of hot. In an example of direct divine intervention to change the causal relations, sunan al llaah fi al kawn, Allah made the fire cold for Ibrahim (p. 189 21:69). The Qur'an describes rain as cold showers from clouds (p. 189 24:43). The Qur'an also describes cold drinking water (p. 189 38:42, 76:13). The drink of those punished in hell will not be cold (p. 189 56:44, 78:24).

 

ANATOMY

Cold receptors are found on the surface of the body. They outnumber warm receptors by a factor of 10:1.

 

PHYSIOLOGY

The response to low environmental temperature is diversion of blood away from the skin.

 

IBADAT IN EXTREME COLD

The law provides for special situations of difficulty such as fasting in winter (KS 326: Tirmidhi K6 B74), salat in extreme cold, and wudhu in extreme cold.

Professor Omar Hasan Kasule, Sr. December 2000