PNB 2XB3 Questions and Answers | Latest Update 2024/2025

Merkell cells - ~~> - slowly adapting - 25% of mechanosensory afferents in hand - highest spatial resolution - edges, points, corners, curvature - static indentation ** Meissener - ~~> - rapidly adapting -40% of mechanosensory innervation in hand - skin motion, indentation, lo...

What are the three ways in which the head can rotate in? ~~> Yaw: z axis (saying no) Pitch: y axis (saying yes) Roll: x axis What are the semicircular canals filled with? ~~> endolymph What is the vestibular labyrinth composed of? what are the functions of each? ~~> - utricle ...

Sound waves are ___; compression is __ of a wave, rarefaction is ___ ~~> longitudinal - move like a slinky; top; bottom Period ~~> the time taken for one up-down cycle (wavelength) Wavelength ~~> the distance b/w two peaks/an up-down cycle Universal wave equation ~~> speed = d...

For an on-center ganglion cell, what causes it to maximally fire? ~~> light in the center and darkness in the surround What is the spontaneous level of activity or baseline for a ganglion cell? ~~> when the entire field is in the dark color opponency ~~> the center and surround cone...

A-alpha conduction velocity? ~~> 80-120 m/s A-beta conduction velocity? ~~> 35-75 m/s A-delta conduction velocity? ~~> 5-30 m/s C-fibers conduction velocity? ~~> 0.5-2 m/s A-alpha axon diameter? ~~> 13-20 microns A-beta axon diameter? ~~> 6-12 microns A-delta axon...

dermatome - ~~> the area of skin supplied by the sensory axons of a single spinal nerve dorsal horn - ~~> the POSTERIOR column of grey matter in the spinal cord (shape differs depending on spinal segment) - contains SENSORY neuron cell bodies ventral horn - ~~> the ANTERIOR co...

4 Sections of the spinal cord ~~> 1. Cervical 2. Thoracic 3. Lumbar 4. Sacral A beta Fibers ~~> Large sensory fibers involved in rapidly transmitting sensation. Responds to touch (around 50 m/s) A delta Fibers ~~> Slower fiber that responds to sharp pain ( around 10m/s) C f...

Central Nervous System (CNS) ~~> all parts of the nervous system within bone (spinal cord, brainstem, thalamus, cortex, etc) Peripheral Nervous System (PNS) ~~> all parts not within bone (spinal nerves, cranial nerves) Cranial nerve ~~> One of twelve pairs of nerves arising from t...

Neuroscience ~~> study of the neurons and nervous systems how many neurons are in the brain and what is the power of the brain ~~> 100 billion neurons, and it is about 20W how large are neurons ~~> 10 microns Central Nervous System (CNS) ~~> all the parts within bone (spinal c...

Mitosis ~~> process of one cell dividing in two (Embryonic) Stem Cells ~~> precursors to all types of cells Pluripotent ~~> potential to become any type of cell Ectoderm ~~> brain and skin (outer layer) Mesoderm ~~> muscle, blood, bone, cartilage (middle layer) Germline...