Kines 101 Exam 2

Sharples Section

motor control

how the central nervous system moves body segments and maintains posture to meet task goals

neuroscience

scientific study of the nervous system

connectome

complete wiring of the nervous system

Central Nervous System (CNS)

central nervous system: brain, spinal cord, retina

Peripheral Nervous System (PNS)

peripheral nervous system: nerves and ganglia outside the CNS

gray matter

regions rich in neuron cell bodies; processing

white matter

bundles of myelinated axons (tracts); communication

tract

bundle of axons inside the CNS

Nucleus (CNS)

cluster of gray matter deep inside the brain

afferent

sensory, carries information to the CNS

Afferent arrives

efferent

motor; carries commands from the CNS

Efferent Exits

somatic nervous system

voluntary movement and body sensation

autonomic nervous system

involuntary control (sympathetic and parasympathetic)

torque

rotational force produced across a joint

action potential

electrical signal across a cell membrane caused by ion movement

neuromuscular junction

synapse between a motorneuron and a muscle fibre

acetylcholine

neurotransmitter released at the NMJ

end plate potential

electrical response of the muscle to acetylcholine

motor unit

one motorneuron plus all the muscle fibres it controls

muscle twitch

contraction produced by a single impulse

rate coding

increasing force by increasing firing rate

recruitment

increasing force by activating more motorneurons

size principle

more units are recruited from small to large

sagittal plane

divides left from right

coronal plane

divides front from back

horizontal plane

divides top from bottom

rostral/caudal

towards the nose/toward the tail

dorsal/ventral

toward the back or top/toward the belly or bottom

medial/lateral

toward/away from the midline

gyrus

a ridge on the cortex

sulcus

a groove on the cortex

fissure

an especially deep groove

precrentral gyrus

primary motor cortex

postcentral gyrus

primary sensory cortex

corpus callosum

white matter bundle connecting the two hemispheres

brainstem

midbrain, pons, and medulla; connects brain to spinal cord

cranial nerves

12 pair or nerves leaving the brain and brainstem

cerebellum

“little brain”; coordination, balance, motor learning

circle of willis

ring of arteries supplying the brain

blood-brain barrier

tight junctions and astrocyte foot processes that limit what enters the brain

ventricles

4 fluid-filled spaces in the brain

cerebrospinal fluid (csf)

fluid that nourishes, protects, and clears waste from the brain

choroid plexus

structure that makes cerebrospinal fluid

glymphatic system

waste-clearance system that drains CSF, mostly during sleep

meninges

dura mater, arachnoid, pia mater (outer to inner)

neuron

main functional unit of the nervous system; carries electrical impulses

dendrite

input region of a neuron

soma

cell body; integrates (adds up) inputs

axon

conducts the signal out to other cells

axon terminal

output region; releases neurotransmitter

myelin

fatty insulation around axons that speeds conduction

node of ranvier

gap between myelin segments

oligodendrocyte/schwann cell

glia that make myelin in the CNS/PNS

astrocyte

glia that help from the blood-brain barrier and balance ions

microglia

immune cells of the CNS

ALS

disease in which motorneurons die

multiple sclerosis

autoimmune disease that destroys CNS myelin

resting membrane potential

voltage of a neuron at rest (about—70m)

ion channel

membrane protein pore that lets ions cross

Na+/K+ pump

uses ATP to move 3 Na+ out and 2 K+ in

threshold

voltage that triggers an action potential

depolarization

membrane becomes less negative (Na+ in)

repolarization

membrane returns toward rest (K+ out)

afterhyperpolarization

brief dip below resting potential

all or none

action potentials are always the same size

saltatory conduction

action potential jumps from node to node along a myelinated axon

tetrodotoxin (TTX)

puffer fish toxin that blocks voltage-gated Na+ channels

synapse

junction between two neurons

synaptic cleft

gap between presynaptic and postsynaptic membranes

ionotropic receptor

ligand-gated ion channel (fast)

metabotropic receptor

g-protein coupled receptor (slower)

EPSP/IPSP

excitatory/inhibitory postsynaptic potential

neuromodulator

molecule that adjusts excitability via G-protein coupled receptors