L71. Senses and Perception 2 Flashcards
Neurons with the same function are grouped into ________________.
Bundles / pathways
Where do neural pathways terminate?
Specific areas of the brain known as primary receiving areas.
What types of axons do peripheral nerves contain?
Either sensory axons only, or sensory and motor axons.
What substance surrounds the peripheral nerves?
Epineurium
What substance are peripheral nerves encapsulated by?
Perineurium
Do peripheral nerve bundles contain blood vessels?
Yes.
Name the above axons in relation to the following :
largest diameter Smallest diameter
slowest signal Fastest signal
A alpha
A beta
A delta
C
A alpha axons respond to what kind of stimulus?
Skeletal muscle
A beta axons respond to what kind of stimulus?
mechanoreceptors on skin
A delta axons respond to what kind of stimulus?
pain, temperature
C axons respond to what kind of stimulus?
Pain, temperature, itch
Give the name for the 31 pairs of structures which sit either side of the spinal cord (31 pairs).
Dorsal root ganglions
What type of neurons take a sensory signal from the stimulus to the dorsal horn?
Sensory afferents
What type of neurons take a motor signal from the ventral horn to the effector?
Motor efferents
For the 3 branches of the trigeminal nerve, name the type(s) of nerves.
Branch 1 (ophthalmic) - sensory Branch 2 (maxillary) - Sensory Branch 3 (mandibular) - sensory and motor
Do touch and pain have the same pathways?
No, they have separate pathways.
Give a vague region as to where each of the following neurons can be found:
- Primary sensory neuron
- Secondary sensory neuron
- Tertiary sensory neuron
- Periphery
- Spinal cord/brainstem
- Thalamus
What type of stimulus does the medial lemniscal pathway occur for?
Mechanoreception
Give the route of the medial lemniscal pathway.
- Afferent nerve fibre from stimulus
- Brainstem nucleus
- Thalamus
- Sensory cortex
What kind of receptor is the posterior dorsal trigeminothalamic tract used for?
Mechanoreception
Give the route of the posterior dorsal trigeminothalamic tract.
- Trigeminal ganglion
- brainstem nucleus
- thalamus
- sensory cortex
What kind of receptor is the spinothalamic pathway used for?
Nociception
Give the route of the spinothalamic pathway.
- Afferent nerve
- Spinal cord
- Thalamus
- Sensory cortex
What stimulus is the anterior ventral trigeminothalamic tract used for?
Nociception
Give the route of the anterior ventral trigeminothalamic tract.
- Trigeminal ganglion
- spinal nucleus
- thalamus
- sensory cortex
Why is the sensory homunculus image distorted?
The more sensory neurons that supply the area, the more “brain space” allocated in the cortex. ie. Areas of high density receptors (small receptive fields) are more represented in the cortex.
What is stereognosis?
The ability to recognise objects by touch alone.
What is proprioception?
Having knowledge of the positions of the body eg. balance from the inner ear.
