MUSCLES Flashcards
extrafusal muscle fiber
big fibers, that make movement possible. Firing rate of alpha motor neurons determine strenght of contraction
intrafusal muscle fiber
sensory information to CNS about lenght of muscle. Use gamma motor neurons
golgi tendon organ
stretch or tension
pacinian corpuscles
compression during contraction
free nerve endings
waste products after period of contraction
myofibrils
make muscle contraction possible
alpha motor neurons
spread acetylcholine on the muscle, calcium channels will open
myosin and actin
displacement of myosin relative to actin resulting in muscle contraction
monosynaptic stretch reflex
automatic contraction in response to a certain stretch, only one synapse is encountered
inhibition of alpha neuron
by golgi tendon organ, prevents excessive tension on muscle
medial side
movement of lower limbs
lateral side
hands and then face
motor homunculus
size of limbs indicate the amount of mort cortex involved
corticospinal tract
motor pathway carries efferent information from cerebral cortex tot he spinal cord to muscles
lateral group pathways
for independent limb movements
ventromedial group
for balance and walking
red line
cerebellum receives information on planned movements from cortex via pontine nucleus
blue line
cerebellum sends info on which muscles via dentate nucleus and thalamus to cortex and red nucleus
damage cerebellum
problem with timing muscles results in tremor
supplementary motor are (SMA)
plan specific movement sequence such as typing, piano, riding a bike. medial side of the cortex
premotor cortex
planning of all kinds of movements, plannng to pick something up
parietal lobe in higher order processing
perception and sensation
Parietal reach region (PRR)
reaching to object
anterior intraparietal sulcus (aIPS)
grabbing object
damage to parietabl lobe leads to (2)
- limb apraxia (left lobe): use wrong body parts, wrong sequence of moving
- constructional appraxia (right lobe): problems with copying figures, building larger objects from smaller elements.
basal ganglia 3 nuclei
caudate nucleus, putamen and globus pallidus
direct path
promotes movement plans of the motor cortex
direct path pathway
cortex activates caudate nucleus and putamen, more firing, more inhibition of globus pallidus, less firing, thalamus more active, excitatory activation to the cortex, positive feedback loop
indirect path
inhibits movement plans of motor cortex
indirect path pathway
cortex activates caudate nucleus and putamen, more firing, more inhibition of globus pallidus, subthalamic nucleus more active, thalamus more inhibited, less excitatory activation, negative feedback loop
D1 dopamine receptor
open sodium channels, more inclined to fire, excite direct path
D2 dopamine receptor
open chloride channels, resting potential more negative, less firing, inhibit indirect path
