Mechano Recptors Flashcards
(41 cards)
What are the main classifications of sensations?
Physiological sensations, Epicritic sensations, Protopathic sensations, Kinesthetic sensation, Synthetic senses
Physiological sensations include somatic sensations, special senses, and organic sensations.
What are the types of somatic sensations?
- Pain
- Temperature (cold & hot)
- Mechanoceptive (Tactile, Proprioceptive)
Mechanoceptive sensations include tactile sensations, proprioceptive sensations, and various forms of touch.
Define epicritic sensations.
Mild or light sensations that are perceived more accurately
Epicritic sensations allow for fine discrimination of touch.
What are protopathic sensations?
Crude & primitive sensations
Protopathic sensations are less precise and include sensations such as pain and temperature.
What is kinesthetic sensation?
Sensation of position & movements of different parts of the body
Kinesthetic sensations arise from proprioceptors in muscles, tendons, joints & ligaments.
What are synthetic senses?
Sensations synthesized at cortical level by integration of impulses from basic sensations
Examples include vibratory sensation, stereognosis, and two-point discrimination.
What are the types of mechanoreceptive sensations?
- Tactile
- Touch
- Pressure
- Vibration
- Stereognosis
- Tickling & Itching
These sensations are detected by various types of mechanoreceptors.
What are the receptors for crude touch?
Free nerve endings, hair end organs, Pacinian corpuscles
Crude touch is poorly localized and detected by specific receptors.
True or False: Fine touch is well localized.
True
Fine touch allows for precise localization of tactile stimuli.
What is tactile localization?
Ability to localize touched point with both eyes closed
Tested by using a blunt object to touch the skin.
What is the threshold distance for two-point discrimination in fingertips?
2 mm
This is the best tactile discrimination found in the body.
What is the significance of vibration sense?
Loss of vibration sense is an early diagnostic sign in cases of degeneration of the posterior column
Conditions like uncontrolled diabetes mellitus and pernicious anemia can affect vibration sense.
What is tactile object recognition (TOR)?
Higher cerebral associative cortical function that integrates touch, vibration, texture & proprioceptive sensations
TOR allows individuals to identify objects by touch.
What triggers itching sensations?
Chemical substances secreted near the receptors, such as histamine and kinins
Itching is often associated with allergic reactions.
What is the role of slowly adapting mechanoreceptors?
They provide continuous information about a stimulus as it is maintained
Examples include Merkel’s discs and Ruffini endings.
What is the pathway for proprioceptive sensations?
Dorsal column and ventral spinothalamic pathway
Proprioceptive sensations are processed through specific neural pathways in the spinal cord.
What are the receptors for proprioception?
- Muscle spindles
- Golgi tendon organs
- Ruffini endings
- Spray type endings
These receptors help detect static and dynamic proprioceptive information.
What is the sensation produced by a sustained strong mechanical stimulus over a wide area of skin?
Deep touch or pressure
This sensation is often assessed in clinical examinations.
Fill in the blank: The ability to identify the nature of objects with both eyes closed is called _______.
Texture of materials
This ability is tested by feeling different materials with closed eyes.
Describe the role of first-order neurons in sensory pathways.
They are located in dorsal root ganglia and transmit sensory information to the spinal cord
First-order neurons have myelinated fibers and carry information from peripheral receptors.
What is the function of second-order neurons in the sensory pathway?
They relay signals from the spinal cord to the thalamus
Second-order neurons cross to the opposite side of the spinal cord.
What is the third-order neuron in the sensory pathway responsible for?
Transmitting sensory information from the thalamus to the somatic sensory cortex
Third-order neurons are crucial for processing sensory information in the brain.
What are the ascending tracts in the posterior white funiculus formed by?
Fibers of first order neurons
What does the trigeminal nerve (Cr-V) carry somatosensory information from?
Face, teeth, periodontal tissues, oral cavity, nasal cavity, cranial dura mater, major part of scalp
