speciak senses - touch Flashcards
sensory for smell
olfactory nerve
sensory for vision
optic nerve
motor fibers to eye muscles
oculomotor nerve
motor fiber to eye muscles
trochelar
sensory for the face; motor fibers for chewing muscles
trigeminal nerve
motor fibers to eye muscles (left to right)
abducens nerve
sensory for taste; motor fibers for the face
facial nerve
sensory for balance and hearing
vestibulocochlear nerve
sensory for taste; motor fibers to the pharynx
glossopharyngeal nerve
sensory and motor fibers for pharynx, larynx, and viscera (homeostasis)
vagus nerves
motor fibers to neck and upper back
accessory nerve
motor fibers to tounge
hypoglossal nerve
conscious awareness of incoming sensory information
sensation
receptors are distributed throughout the skin/organs
general sense
receptors are housed within complex organs in the head
special sense
• Receptors that respond to heat, mechanical stress, and chemicals—associated with tissue damage—help the body detect and react to potential harm.
• Are most concentrated in the skin but are also found in muscles, joints, and internal organs.
• Play a key role in pain perception, alerting the brain to injury or harmful stimuli.
• These receptors send signals to the brain, triggering protective responses such as reflex withdrawal, inflammation, or behavioral changes to avoid further damage.
nociceptors (trauma)
• receptors that respond to changes in temperature
help the body detect and react to variations in external and internal temperatures.
• are found in the dermis (the deeper layer of the skin), skeletal muscles, liver, and hypothalamus (the brain region responsible for regulating body temperature).
• cold receptors are more numerous than warm receptors, meaning the body is generally more sensitive to detecting cold temperatures than warm ones.
• these receptors send signals to the brain, particularly the hypothalamus, which then triggers responses like shivering (to generate heat) or sweating (to cool down) to maintain a stable internal temperature.
thermoreceptors
respond to physical distortion of cell membrane (stretching, twisting, compression)
mechanoreceptors
• Receptors that respond to stretching and pressure changes help regulate functions in the respiratory, cardiovascular, and digestive systems.
• Are found in the lungs (lung stretch receptors), blood vessels (baroreceptors), and digestive tract (mechanoreceptors).
• Detect expansion or tension in their respective organs, sending signals to the brain and nervous system to maintain balance and function.
• These receptors trigger responses such as adjusting breathing rate, regulating blood pressure, and controlling digestive motility to ensure proper physiological function.
baroreceptors
• Receptors that detect body position, movement, and muscle stretch help maintain balance and coordination.
• Found in muscles, tendons, and joints, including muscle spindles and Golgi tendon organs.
• Provide continuous feedback to the brain about limb position and movement.
• Enable posture control, coordinated movement, and reflexive adjustments.
proprioceptors
• Receptors that detect touch, pressure, vibration, and texture help the body sense physical contact.
• Found in the skin, especially in fingertips, lips, and other sensitive areas.
• Include Meissner’s corpuscles (light touch), Merkel cells (texture), Pacinian corpuscles (deep pressure), and Ruffini endings (skin stretch).
• Enable perception of touch, grip control, and responsiveness to external stimuli.
tactile receptors
• Receptors that detect light touch and texture help in fine tactile discrimination.
• Found in the skin, especially in fingertips, lips, and other sensitive areas.
• Provide slow-adapting, detailed information about shapes, edges, and textures.
• Enable precise touch perception and object recognition through sustained pressure detection.
merkel cells
• Receptors that detect light touch and vibration help in tactile sensitivity.
• Found in the skin, especially in fingertips, palms, lips, and soles of the feet.
• Rapidly adapting, allowing quick detection of changes in texture and movement.
• Enable sensitivity to gentle touch, contributing to grip control and object manipulation.
meissners corpuscles
• Receptors that respond to small concentration changes of specific chemicals help the body detect and regulate chemical signals.
• Internal chemoreceptors monitor blood composition, including levels of sodium (Na), pH, and partial pressure of carbon dioxide (pCO2).
• Found within the aortic and carotid bodies, which are located near major blood vessels.
• Play a crucial role in homeostasis by helping regulate respiratory and cardiovascular functions to maintain stable internal conditions.
chemoreceptors
The sensation of touch begins when tactile receptors in the skin are activated by physical stimuli like pressure, vibration, or temperature changes.
1. Stimulus Detection: When something touches the skin, tactile receptors such as Meissner’s corpuscles (for light touch) and Pacinian corpuscles (for pressure and vibration) detect the physical contact.
2. Signal Transmission: These receptors convert the mechanical stimulus into electrical signals. The signals are transmitted via sensory neurons to the spinal cord and then to the somatosensory cortex in the brain.
3. Processing in the Brain: The brain processes the signals, allowing you to perceive the type, location, intensity, and nature of the touch. For example, whether it’s a gentle touch, a sharp poke, or a vibration.
4. Perception: The brain interprets these signals, giving rise to the conscious experience of touch, allowing you to feel and respond to different sensations like pressure, texture, or temperature.
sensation of touch
