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Psych Somatosense
Somatosensation
Question | Answer |
---|---|
The 3 systems of somatosensory information are: | 1. Exteroceptive System 2. Proprioceptive 3. Interoceptive |
Exteroceptive system | External stimuli |
The 3 subcategories of the exteroceptive system are: | 1. Mechanical stimuli 2. Thermal stimuli 3. Nociceptive stimuli |
Exteroceptive system Mechanical stimuli | touch |
Exteroceptive system Thermal stimuli | temperature |
Exteroceptive system Nociceptive stimuli | pain |
Proprioceptive system | Body position |
Interoceptive system | body conditions |
Somatosensory info is transduced by ________. | cutaneous receptors |
The 4 different cutaneous receptors | 1. Free nerve ending 2. Pacinian Corpuscles 3. Merkel's disks 4. Ruffini endings |
Transduced | changing one type of energy into another type of energy |
Cutaneous Receptors A simple receptor that responds to pain and temperature | Free nerve ending |
Cutaneous Receptors Pacinin corpuscles | -Located deep in the skin -have a layered capsule surrounding the nerve ending -sense fine touch (details) and rapid vibrations -adapt rapidly and respond to the onset/offset of stimulus but not constant stimulus |
Decusate | (of two or more things) Cross or intersect each other to form an X |
Cutaneous Receptors Pacinian Corpuscles transductions | -Carbohydrate chains are linked to cation (e.g. Na+) channels in the cell membrane -Touch (mechanical force) on the chains causes the channel to open -Positive ions can enter the cell --> depolorization; if beyond threshold, action potential will occur |
Cutaneous Receptors Merkel's disks | -disk shaped receptor -located near surface of skin -respond to indentations of the skin; info about fine detail -adapt slowly; continue to fire while stimulus is present |
Cutaneous Receptors Ruffini endings | -have many branched fibers inside a cylindrical capsule -located deep in skin -respond to stretch of skin -adapt slowly; continue to fire in response to continuous stimulation |
What is the difference between Pacinian corpuscles and Merkel's disks and Ruffini endings? | -Pacinian corpuscles adapt rapidly, responding immediately to sudden displacements of the skin. -Merkel's disks and Ruffini endings adapt slowly and respond best to gradual skin indentation and gradual skin stretch, respectively. |
Signals from somatosensory receptors are sent via 1 of ___ spinal nerves. | 31 |
The spinal nerves enter the spinal cord via the ___________. | dorsal root |
Spinal nerves are made up axons of the _______. Their cell bodies are in the _________. | -Cutaneous receptors -Dorsal root ganglia |
Each spinal nerve connects to a limited area of the body. The area connected to a single spinal nerve is called a _________. | Dermatome |
Two different pathways that carry somatosensory info from the skin to the brain: | 1. Dosral column-medial lemniscal path 2. Anterolateral path |
Dorsal column-medial lemniscal path | tends to carry info about fine touch and proprioception |
Anterolateral path | tends to carry info about pain and temperature |
Damage to the spinal cord: If both pathways are completely transected by injury to the spinal cord, there will be ____ sensation where? | - no sensation below the level of the injury |
Damage to the thalamic nuclei Ventral posterior nucleus gets input from where? | From dorsal-column medial lemniscal path and anterolateral path) |
Damage to the thalamic nuclei Damage to the ventral posterior nucleus will result in what? | -some loss to sensitivity to touch, temperature, and sharp pain. -no effect on sensitivity to touch, temperature, and sharp pain |
Damage to the thalamic nuclei Parafasicular and introlaminar nuclei get inputs from where? | From spinoreticular tract of anterolateral path |
Damage to the thalamic nuclei Damage to parafasicular and introlaminar nuclei results in what? | -Reduced sensitivit to deep, chronic pain -No effect on sensitivity to touch |
Association cortex | association area: cortical areas that are neither motor or sensory but are thought to be involved in higher processing of information. |