22/10/2026
Sensory, Motor and Integrative Systems!
Each unique type of sensation-touch, pain, vision or hearing is called a sensory modality.
The general senses: refer to both somatic senses and visceral senses. Somatic senses include: tactile sensations (touch, pressure, vibration, itch, tickle), thermal senses (warm and cold), pain sensations and proprioceptive sensations: allow perception of both the static (nonmoving) positions of limbs and body parts (joint and muscle position sense) and movements of the head and limbs. Visceral senses provide information about conditions within internal organs e.g. pressure, stretch, chemicals, nausea, hunger and temperature.
The special senses include the sensory modalities of smell, taste, vision, hearing and equilibrium or balance.
Exteroceptors: are located on or near the external surface of the body; they are sensitive to stimuli originating outside the body and provide information about the external environment. The sensations of hearing, vision, smell, taste, touch, pressure, vibration, temperature and pain.
Interoceptors or visceroceptors are located in blood vessels, visceral organs, muscles and the nervous system and monitor conditions in the internal environment.
Proprioceptors: are located in muscles, tendons, joints and the inner ear. They provide information about body position, muscle length and tension and the position and movement of joints.
Mechanoreceptors: are sensitive to mechanical stimuli such as: deformation, stretching, bending of cells, Provide sensations of touch, pressure, vibration, proprioception and hearing and equilibrium. They also monitor the stretching of blood vessels and internal organs.
Thermoreceptors: detect changes in temperature.
Nocioreceptors: respond to painful stimuli resulting from physical or chemical damage to tissue.
Photoreceptors: detect light that strikes the retina of the eye.
Chemoreceptors: detect chemicals in the mouth (taste), nose (smell) and body fluids.
Osmoreceptors: detect the osmotic pressure of body fluids.
Fast pain: the perception occurs very rapidly, usually within 0.1 second after a stimulus is applied. This type of pain is also known as: acute, sharp or pricking pain. E.g. the pain felt from a needle or knife cut to the skin. Is not felt in deeper tissues of the body. Slow pain: begins a second or more after stimulus is applied. It then gradually increases in intensity over a period of several seconds or minutes. This type of pain, which might be excruciating is also referred to as: chronic, burning, aching or throbbing pain. Can occur both in the skin and in deeper tissues or external organs. E.g. the pain associated with a toothache. You can perceive the difference in onset of these 2 types of pain best when you injure a body part that is far from the brain because the conduction difference is long. E.g. when you stub your toe you first feel the sharp sensation of fast pain and then feel the slower, aching sensation of slow pain. Superficial somatic pain: pain that arises from receptors in the skin. Deep somatic pain: stimulation of receptors in the skeletal muscles, joints, tendons and fascia. Visceral pain: results from stimulation of noiceptors in visceral organs.
Fast pain is very precisely localised to the stimulated area. E.g. if you get pricked by a pin you know exactly which part of your body was stimulated. Somatic slow pain is also well localised but more diffuse (involves large areas); it usually appears to come from a larger area of the skin. In some instances of visceral slow pain, the affected area is where the pain is felt. E.g. inflamed pleural membranes around the lungs causes chest pain.
Proprioceptive sensations: allow us to know where our head and limbs are located and how they are moving even if we're not looking at them, so that we can walk, type of dress without using our eyes. Kinesthesia: is the perception of body movements.
NREM Sleep: Stage 1-transition stage between wakefulness and sleep that normally lasts 1-7 minutes. The person is relaxed with eyes closed and has fleeting thoughts. people awakened during this stage often say they have not been sleeping. Stage 2/light sleep: first stage of true sleep. A person is a little more difficult to awaken. Fragments of dreams might be experienced and the eyes might slowly roll from side to side. Stage 3-a period of moderately deep sleep. Body temperature and blood pressure decrease and it is difficult to awaken the person. This stage occurs about 20 minutes after falling asleep. Stage 4-deepest level of sleep. Although brain metabolism decreases significantly and body temperature drops slightly at this time, most reflexes are intact and muscle tone is decreased only slightly. If you sleepwalk it occurs during this stage.
Typically, a person goes from stage 1-4 of NREM sleep in less then an hour. During a typical 7 or 8 hour sleep period there are 3-5 episodes of REM sleep, during which the eyes move rapidly back and forth under closed eyelids. The first episode of REM sleep lasts 10-20 minutes. Then another interval of NREM sleep follows. REM and NREM sleep alternate throughout the night. REM periods, which occur approximately every 90 minutes, gradually lengthen, until the final one lasts about 50 minutes. In adults, REM sleep totals 90-120 minutes during a typical sleep period. As a person ages, the average total time spent sleeping decreases and the percentage of REM sleep declines. As much as 50% of an infants sleep is REM sleep, as opposed to 35% for 2 year olds and 25% for adults.
Principles of Anatomy & Physiology, 13th Edition, Gerard J Tortora & Bryan Derrickson, 2012
