Special Sense Flashcards
Tactile sensation
Touch, pressure,vibration(change in frequency) it is not a result of a single receptor
Touch sensation
Detected by tactile receptors which are found on the skin, close to the skin or deep
Pressure sensation
Result from deformation of deeper tissues, located in the skin or deep layers
Vibration sensation
Result from rapidly repetitive sensory organs, change in frequency of stimulation
Free nerve ending
Or sensory nerve ending, this is widely distributed on the skin, can detect touch and pressure, responds to different frequency
Meissener’s corpuscle
Located at the point where the dermis meets the epidermis, it is an elongated encapsulated nerve ending fiber usually myelinated sensory nerve fiber present in fingertips and surrounded by connective tissue
Dermeral papillae
The invagination of where the meissners corpuscle meets the epidermis
Meissners corpuscle is what kind of receptor
Mechano receptor and exterioreceptor, and it can detect vibration
Merkel’s disks
Found in the skin, tactile receptor, works with meissners corpuscle, the signal transmitted are adaptive therefore responsible for steady state signal that allow for determination of continuous touch of object against the skin..it is responsive to touch
Iggo dome receptor
It is Markels disk and neuron fiber
Hair end organ
Tactile receptor, sensory fiber wraps around the base of the hair follicle, movement of hair follicles activates the neuron, this a mechano and exterioreceptor
Ruffins end organ
Deep touch receptor in deep tissues, can be found in the visceral, and encapsulate, found in the joint corpuscle, important for proprial reception
Pacinian corpuscle
Pressure receptor, deep receptor, visceral eg pancreas, found in the dermis, the structure is layers of connective tissue, the sensory fiber are unmylinated. Pressure on this receptor causes the nerve fiber to fire giving a sensory pressure
Somatic sense
The nervous mechanism that collects sensory information from all over the body, that are not special sense, which touch, pressure, pain.
Somatic senses physiological types
Mechanoreceptive, thermo receptive, and pain
Mechanoreceptive
Mechanical distortion of the body tissues which gives rise to tactile and position sensation
Somatic sense location of receptors
Exteroreceptive, visceral, and deep
Sensory pathway to the somatosensory cortex
The information enters through the dorsal root to eithe the dorsal column medial lemniscal system or the antero-lateral system
Dorsal column medial lemniscal system
Defined information and important information come in through the dorsal root then travel up to the brain, first in the first order sensory Neuron, then second in the second order sensory neuron. In the medulla there is cross over to the opposite side of the brain, once in the medulla there is synapse then travel to thalamus to the sensory cortex
Anterol lateral system
Less defined information, crude information involving the ascending tracks, come into the dorsal root but afterward there is extensive synapsing and crossing over at the level of the spinal cord, afterwards ascending to the tract to the brainstorm , including the medulla synapses into the thalamus and sensory cortex
Somatosensory cortex
Located posterial to the centre sulcus or fissure, it has 50 distinct area called the brodman’s area, the different part of the body is associated with different brodman’s area
Somatosensory area 1
More critical and involves more information, for thigh, thorax, neck, shoulder,hands, finger, tongue etc
Somatosensory area 2
Information from the face, leg, face, arm
Association area
It’s function is to refine the signal that are already perceived
Amorphosythesis
Where the is damage to the association area leading to loss of definition of shape of something or texture
Lateral inhibition
As the signal goes up it can move in the lateral direction which can diminish the amount of the signal that moves up to the brain, interneurons prevents the radiation of the signals from moving laterally this strengthen the signal that the brain receives
Propriocetive sense
Involves the awareness of the body parts and position related to each other
Static proprioceptive sense
No movement and we can still detect our body parts
Kinesthesia or dynamic proprioceptive sense
Moving and knowing where your body parts are
