Nervous System (13.2)

Such Great Potential

100

Charge inside nerve is -70mV; higher concentration of potassium inside the cell and a higher concentration of sodium ions outside the cell; the movement of K⁺ is mainly responsible for creating the electrical potential

Resting Potential

200

K⁺ gates close slowly, so more K⁺ ions move out than normal; more negative charge inside neuron than normal

Hyperpolaztion

300

Nerve becomes more permeable to highly concentrated Na⁺ than K⁺; rapid influx of Na⁺ causes -70mV to jump to 40mV

Depolarization

400

DAILY DOUBLE (2 answers)

Time required before a neuron can return to resting potential; this time is required to produce another action potential

Refractory Period; Recovery Time

500

Na⁺ channels close, K⁺ gates open, and K⁺ diffuses out of cell restoring original polarization

Repolarization

Axon, Ax-off

100

Neurons either fire maximally or not at all

All or None Response

200

Improves the ability of electrical charge to flow far enough down the axon to reach the next node of Ranvier

Myelin Sheath

300

Different for each neuron; a potential stimulus must be above this critical value in order to produce a response

Threshold Level

400

When action potentials jump from node to node without depolarizing the region under the myelin sheath

Saltatory Conduction

500

Organisms which don't have myelinated neurons, so they have an increased axon diameter to speed up conduction; the larger the cross-sectional area of a neutron, the further it can conduct electrical charge along the axon

Invertebrates

You Can Find Me in the Space Between

100

Space which divides at least 2 neurons

Synapse

200

DAILY DOUBLE

1 answer

Carry impulses away from synapse

1 answer

Carry impulses to the synapse

Postsynaptic Neuron; Presynaptic Neuron

300

Enzyme which follows acetylcholine and destroys it; sodium channels are closed, and neuron begins recovery phase

Cholinesterase

400

Daily Double

1 answer

Triggers potassium channels to open; hyperpolarization; increased threshold level

1 answer

Triggers receptor proteins in post synaptic cleft to allow positive ions (eg. sodium) in; depolarization; lowered threshold level

Inhibitory Neurotransmitters; Excitatory Neurotransmitters

500

Chemicals which brave the gap; released by the end plate of presynaptic neuron; move by diffusion

Neurotransmitters 

That's Dope

100

Excitatory or inhibitory; released as rewarding of a behaviour; pleasure

Dopamine

200

Generally inhibitory; impacts mood; happiness

Seretonin

300

Can act as an excitatory transmitter chemical on many postsynaptic neurons by opening Na⁺ channels, causing depolarization; may also act an an inhibitory transmitter chemical on a different postsynaptic membrane by opening more K gates, K⁺ on inside of neuron follow concentration gradient and diffuse out of neuron

Acetylcholine 

400

Found in CNS and PNS; is excitatory in PNS; excitatory or inhibitory in CNS

Norepinephrine (noradrenaline)

500

DAILY DOUBLE

1 answer

Inhibitory; reduces pain perception

1 answer

Excitatory; memory

1 answer

Inhibitory; calms the body

Endorphins; Glutamic Acid; GABA

Too Much, Too Little

100

Associated with decreased levels of seretonin

Depression

200

Excess dopamine

Schizophrenia

300

Deterioration of memory and mental capacity; related to decreased production of acetylcholine 

Alzheimer's Disease

400

Involuntary muscle contractions and tremors; inadequate production of dopamine

Parkinson's Disease

500

DAILY DOUBLE (1 answer) Theme: Threshold Levels

Theory which dictates that the message (stimulus) priority is determined by the frequency of impulses; some neurons have higher threshold levels, and are only set off with an increased stimulus

Spinal Gate Theory