Lecture 4 Flashcards
sensory receptors for GENERAL senses include _____(x3) and are mostly found ______. They are MAINLY transmitted via ____ to the ____.
- nociceptors (pain)
- mechanoreceptors (touch and proprioception)
- thermoreceptors (temperature)
- on the surface of the skin
sensory receptors for SPECIAL senses include _____(x3) and are found in the ________. They are ONLY transmitted via ____ to the ______.
- chemoreceptors (smell, taste)
- mechanoreceptors (hearing and balance)
- photoreceptors (vision)
- head
- cranial nerves
- brain
pain temperature and itch are conveyed via the ______
which is considered an ____ and ____ system.
- anterolateral (spinothalamic) pathway
- old
- slow (small and less or unmyelinated axons)
touch and proprioception are conveyed via the ___ which is considered a ___ and ___ system.
- DCML pathway
- new
- fast (large myelinated axons)
spinal nerves give rise to (x2)
dorsal and ventral roots (further rootlets)
dorsal rootlets enter the spinal cord via
the dorsolateral sulcus
ventral rootlets exit the spinal cord via
the ventrolateral sulcus
Aα and Aβ axons are ____
Aδ axons are _____
C axons are_____
- highly myelinated and fast (touch and prop.)
- slow and least myelinated (pain,temp,itch)
- unmyelinated and slow (pain,temp,itch)
The grey matter of the spinal cord is divided into (x3)
- ventral, lateral and dorsal horns
The white matter of the spinal cord is divided into (x3)
- ventral, lateral and dorsal funiculus
The lateral horn is only present at ____ and carries _____.
- T1 - L2, S1 - S3
- autonomous information for visceral organs
where are α-Motoneurons located?
in the ventral grey horns
each spinal root carries information to/from _____
a specific part of the body
how many nerves are present at each segment of the spinal cord?
cervical - 8 thoracic - 12 lumbar - 5 sacral - 5 coccygeal - 1
where are the spinal enlargements?
cervical (shoulder and upper limbs) and lumbar (pelvis and lower limbs) spinal cord
the spinal cord ends at ______
L1 - L2 of vertebral column
Why is there a disparity between the vertebral columns and spinal cord?
Because the spinal cord stops growing during childhood (spinal cord stops at L3 at birth), whilst the vertebral column continues growing into adulthood (spinal cord stops at L1-2).
The white matter at the cervical level is the largest because
it contains all the axons to and from the brain
the grey matter is expanded at cervical, lumbar and sacral spinal segments because
they contain motor neurones and sensory information from the upper and lower limbs.
which thalamic nuclei relay to the primary somatosensory, visual and auditory cortices?
- VPL, VPM, PO
- LGN
- MGN
sensory (afferent) fibres enter the cortex via the _____limb of the internal capsule.
posterior
The cerebrum and diencephalon fuse during development, allowing…
axons from the cerebrum to leave via the internal capsule.
the gracile and cuneate fasciculi are separated by the
dorsal intermediate sulcus
the fibres of the DCML tract decussate at the ___as the ___
- caudal medulla
- internal arcuate fibres
the cortex is made up of how many layers? where do sensory axons terminate?
- six
- layer four (IV)
fibres from layers II and III project to…
fibres from layer V project to…
fibres from layer VI project to…
- contralateral and ipsilateral sensory and motor areas
- basal ganglia, brainstem and spinal cord
- thalamus (VPN)
the anterolateral system consists of the (x3)
- anterior and lateral spinothalamic tracts
- spinomesencephalic tract
- spinoreticular tract
fibres of the anterolateral system enter the spinal cord via ____and decussate at the ______.
- Lassuer’s tract
- ventral commissure
where are pyramidal cells/Giant cells of Betz found?
in layers III and V (output layers)
The cuneate fasciculus is only present from
T6 and above (mid-thoracic)
the reticular formation is….
- a collection fo nerve fibres which make up most of medial portion of the brainstem, responsible for regulating arousal
spinothalamic tract terminating in the VPL, MD, VMP nuclei of the thalamus ascend to:
primary sensory cortex, cingulate cortex (emotional response), insular cortex (visceral response)
the spinoreticular pathway mediates____and terminates in_____
- emotion and arousal related to pain
- nuclei of reticular formation (Raphe nuclei, parabrachial nucleus)
third order neurons of the spinoreticular pathway from the parabrachial nucleus projects to…
the amygdala
The Spinomesencephalic tract mediates
- head, eye and hearing orientation towards pain stimuli (tectum)
- pain feedback to spinal cord (periaquaductal gray)
how does the periaquaductal grey mediate pain feedback?
the periaquaductal gray recieves input from the cortex, then sends excitatory axons to the raphe nuclei which then sends excitatory neurons to the dorsal horn of the spinal cord which enhances inhibitory function of interneurons to directly suppress nociceptors.
The spinocerebellar tract mediates ____and consists of___and ascends______.
- unconscious proprioception
- Clarke’s nucleus (C8, T1-12) or Accessory Cuneate nucleus (located at caudal medulla next to cuneate nucleus)
- ipsilaterally
