ascending pathways Flashcards
types of senses
- special
- general
general senses
spread through the body
special senses
localized by their respective sensory organ
5 special senses and their CN
- olfaction (CNI)
- vision (CNII)
- taste (CNVII, IX)
- hearing (CNVIII)
- vestibular (CNVIII)
general sense types
- interoception
- exteroception
- proprioception
interoception
pain, temp, touch pressure of the viscera
exteroception
pain, temp, touch pressure of environmental stimuli
proprioception
position sense from joints, tendons, ligaments
general sense information detected via
- nociceptors
- thermoreceptors
- mechanoreceptors
- chemoreceptors
- baroreceptors
nociceptors
monitor tissue damage
thermoreceptors function and location
- monitor temperature
- found in skin, muscle liver and hypothalamus
mechanoreceptors
- monitor contact and pressure
- found mostly in the skin
chemoreceptors
monitor chemical composition of body fluids (O2, CO2, pH)
baroreceptors
- subset of mechanoreceptors
- monitor changes in pressure of tubular organs (vessels, ureters, bowel)
motor areas
- precentral gyrus of frontal lobe
- primary motor cortex (directs voluntary movements)
sensory areas
- postcentral gyrus of the parietal lobe
- primary somatosensory cortex (receives somatic sensory information)
somatic sensory information
touch, pressure, pain, vibration, taste, temp
dermatome
- area of skin supplied by a particular spinal nerve
- correspond to the entry or exit point of ventral (motor) and dorsal (sensory) rootlets
if a spinal nerve is cut …
sensation is lost in the dermatome
symptoms that follow a dermatome may indicate ?
pathology that involves the related nerve root
ganglia
cell bodies lining the nerves in the peripheral nervous system
nuclei
cell bodies in the central nervous system
types of ascending somatosensory pathway in the spinal cord
- spinothalamic (anterolateral)
- medial lemniscus (dorsal column-medial lemniscus pathway)
- spinocerebellar
spinothalamic (anterolateral) pathway function
pain and temp, crude touch
medial lemniscus (dorsal column-medial lemniscus) pathway function
- fine touch
- conscious proprioception
spinocerebellar pathway function
proprioception
somatosensory axons are relayed to the ?
primary somatosensory sortex
3 orders of neurons in the ascending pathways
- PNS (dorsal root ganglion)
- CNS (grey matter spinal cord)
- CNS (ventral posterolateral thalamus)