Bad lectures Flashcards
What are sensory receptors?
Sensory ending of an afferent neuron or specialized receptor cell
What is adaption in a sensory receptor?
Gradually reduce their response to a constant stimulus
What is modility?
The sensory endings of one sensory unit is the same, and are sensitve to one type of sensation, which is the modality.
–> Some are touch sensitive while some are temperature sensitive
What codes for intensity of the ap?
Frequency of AP and number of axons or motor units acitve
What codes for modality and location?
By the selection of particular axons or motor units to be active along a specific pathway.
What is the receptive feild of the axon?
The area of the body that if stimulated will result in the firing of that axon. Can be characterised by size and density.
What is the difference between small and large receptive fields?
Small ones allow for good localisation of stimulus and large ones allow for bad localisation of stimulus
How many vertabrae are there?
Cervical - 7 Thoracic - 12 Lumbar - 5 Sacrum - 5 fused coccxyx - 2 to 5 fused
How many ribs are there?
24
What bones does the scapula articulate with?
clavicale + humerous
What does the pelvic girdle consist of?
Consists of two hip bones artculating with the sacrum
What does the cerebellum do in movement?
The cerebellum coordinates movements. It does this by using information about current body position to compute movements needed to achieve a new body poistion and check planned movements against actual movements to compute corrections
Brain volventary movement?
Activation of the primary motor cortex is assited by input from the cerebellum and the basal ganglia.
The axons of primary motor cortex neurons project to the spinal cord.
The sensory pathway (dorsal/posterior) pathway?
Three neurons.
1: Cell body in dorsal root ganglion (unipolar), so the peripheral fibre from sensory recptor in skin and central fibre ascends towards brain in spinal cord white matter.
2: Cell body in medulla oblongata, axon crosses to opposite side and ascends
3: Cell body in the thalamus, axon ascends to somatosensory cortex.
The corticospinal pathway –> for volentary movement
Two neurons, upper motor and lower motor
Upper: cell body in primary motor cortex (precentral gyrus), axon extends from motor cortex to spinal cord on opposite side
Lower: Cell body in ventral horn (grey matter) of spinal cord, extends out of the ventral root and into the body –> synapses on skeletal muscle
What is the commisural tract?
Axons cross from side to side
What is the projection tract?
Axons extend between cortex and other CNS areas outside cerebrum
What is the association tract?
Axons on same side within cerebral cortex
Communication between brain areas (short or long distance)
Particular regions for the motor cortex?
Foot –> hand –> face –> tounge