A&P 1 Test 4

Generation of a resting membrane potential depends on 

1. Differneces in ___ and ___ concentrations inside and outside of the cell.
2. Differences in ____ of the plasma membrane to those ions.

The ____pumps maintian the concentration gradiants of their elements across the membrane.

More K+ diffuses ___ than Na+ diffuses __ because the resting membrane is 25X more.

Maintenance of the resting membrane potential is possible due to ____.

Membrane potentials that act as signals : ____, ____, ____.

Neurons use changes in their membrane potentials as '_____' to detect or recieve, integrate, and send information.

Neuron changes come from anything that chances ___ concentrations on either side of the membrane or anything that changes ion ___ across a membrane.

Only permeability changes are important for transferring ____.

Types of signals that can be generated  are

Graded Potentials are incoming signals operating over ___ distances. 
i.e. dendrites to cell bodies.

Action potentials are ___ distance signals of axons .

Changes relative to the resting membrane potential are either 


Depolarize: ____ potential (more postive) i.e. -70mV to -40mV

Hyperpolarize: ____ potential ( more Neg.)
ie. -70mV to -90 mV

How does a depolarization of the membrane affect the charge?

What does a hyperpolarization membrane affect the charge?

During Depolarization there is an increased permeability to ___.

Hyperpolarization increases membrane permeability to ___ or __.

Graded potential are ____, local changes( shits) in membrane potential: Depolarization or hyperpolarization signals. 

____ opens gaed ion channels.

Short 

Graded potentials are named according to ____ and ____.

Postsynaptic potential: neurons graded potential

Stimulated by a _____.

Depolarization: a small patch of the membrane ( red area) has become depolarized. 
Spread of depolarization: the local currents that are created depolarize adjacent membrane areas and allow the wave of depolarization to ___.

Decay of membrane potential with distance:

Because current is lost through the leaky plasma membrane, the voltage ____ with distance from the stimulus ( the voltage is ___ ) Consequently, graded potential are ___ - distance signals.

Degrade of graded potential is rapid, as charge is lost across the ____. But short distance signals are critial for initialing an _____.

Action potentials occur only in ___ and ____.

Action potential is a brief change in membrane potential in a patch of membrane that is ____ by local currents. Totals change in charge is ____ mV.

During action potential's repolarization there is a ___ outflow and during hyperpolarization the ___ continues to flow out.

During action potentials, the membrane permeability depends on its membrane ___ and vise Versa.

At rest, only ____ channels for Na+ and K+ are open; maintaining the resting membrane potential.

The key players in an action potential are the _____ channals.

Voltage-gated Na+ channels have ___ gates and alternate between ___ different states.

Voltage-gated K+ channels have ___ gate and ___ states.

Voltate gated Na+ channels are closed during ____ states, and open by ____ .

Voltage-gated K+ channels are closed during ___, and open during ___.

Neurons generally repolarize once the membrane potential reaches approximately +30 mV because . . .

Action potential is generated at the ___ .

In Action potential, ions move ___; establishing a current flow & opening a ____ channel.

Action potential:
Original channel is ____ thus propagation is away from the point of origin and in one diection only.

Action potentials move in one direction from the point of origin

After AP, Na+ channels _____.

During action potentials, there is a Na+ influx during ____. and a K+ during ____.

For axon to fire, depolarization must reach ___.

Graded Potentials may be ___-threshold.

An action potential either happens completely, or it ____ happen at all. 

But once generated, the ___ does not vary( all APs are identical).

During refractory periods 
Voltage-gated Na+ channels are ___. Neurons cannot respond to ___.

During absolute refractory period, 

Time form ___ of Na+ channels until ___ of the channels. 
Ensures that _____ and enforces ____ transmission.

Relative refractory periods, 

Inside of membrane is more ___ than resting . . . so ___ of AP generation is elevated.

During the relative refractory period, the ___ is substantially elevated and exceptionally ___ stimuli could trigger action potentials.

Conduction velocities in Axon depend on what two factors?

In bare plasma membrane, voltage ____. Without volage-gated channels, as on a dendrite, voltage ___ because current leaks across the membrane.

In non-myelinated axons, conduction is ___.

IN myelinated axons, APs are generated only in the ____ and appear to jump rapidly from gap to gap.

_____ AP:
AP travels in one direction because it jumps to the next gap the Na+ channels are inactivated.

A local current produces a 'graded' depolaization that brings the ____ at the next node to ____.

Information gets between neurons via ____. 

_____: axon to dendrite
_____: axon to cell body.

Most neurons function as ____ and postsynaptic neurons.

2 types of synapses:

____: (rare)
____: (common)

Chemical synapses transmit signals from one neuron to another using ______.

Neurotransmitter effects are _____ by reuptake throught proteins, enzymatic degradation, or diffusion away from the synapse.

Postsynaptic potentials ____ or ____ the receiving neuron

Neurotransmitter receptors cause ____ potentials that vary in ____ with

1: ____ of neurotransmitter released

2: ___ neurotransmitter stays in synaptic cleft

2 Types of chemical synapses

1: ___ Postsynaptic Potential (EPSP)

2: ___ Postsynaptic Potential (IPSP)

An excitatory postsynaptic potential is a local _____ of the postsynaptic membrane.

Bring neurons ____ to AP threshold.

Excitatory Postsynaptic potentials:


Neurotransmitters binding opens chemically gated ion channels, allowing ___ and ___ to pass at the same time.

Na+

Inhibitory postsynaptic potentials are _____.

Generally speaking, opening chloride channels in the postsynaptic membrane  will result in an _______.

A single EPSP ___ induce an AP

EPSPs can ___ (add together) to influence the '___ neuron’

IPSPs can also summate, but ___ the probability

Most neurons receive both ‘excitatory and inhibitory’ inputs from thousands of other neurons
Only if EPSPs ____ & bring to it threshold will an AP be generated

2 types of summation:

Chemicals used for neural transmittion are classified ____ or ___.

Functionally classified Chemicals:

Excitatory or Inhibitory
Direct or indirect (ion channels or via 2nd messengers)

Ex., Direct: acetylcholine (excitatory, EPSP); Indirect: norepinephrine (either), Substance P (excitatory), endorphins (inhibitory), nitric oxide (either)
Depends . . .

Neurotransmitter Function: Direct promotes ___ in membrane potentials. 1: Channel-linked (_____) receptors
2: ____-gated ions channels
3: 
Rapid, simple, brief.

Neurotransmitter Function: Indirect through ___ messenger systems 

G-protein coupled (___) receptorsComplex, slow, prolonged

Neurons function in ‘___.

1st level of neural integration:

Neuronal Pools

Functional groups of neurons

‘___ ’ incoming information received from receptors or other neuronal pools; ‘Process’, &

‘____’ information to other destinations

1st level of neural integration:


Circuits

Patterns of synaptic connections in neuronal pools

Determine pool’s . . .

What occurs in the discharge zone of a neuronal pool?

Diverging circuit:
___input, ___ outputs.

____ circuit

Converging Circuit:

____inputs, ____output.

_____ circuit

Reverberating circuits (_____)
control _____ activity.

Parallel after-discharge circuit: 
Arranged in ___ arrays that eventually ____ on a single output cell. 

Impulses reach output cell at ____ times.

Serial Processing for a simple reflex arc: 
1-5?

Patterns of Neural Processing: 


Serial: Input travels along ___ pathway to a specific destination


Works in a ‘predictable’ all-or-nothing manner

Ex., reflex arc (spinal reflexes)

Patterns of Neural Processing: 

Parallel: Inputs ___ into many ____ pathways

Ex., higher level thought processing

A ___ neuron sends information along  several pathways

So a large amount of information is processed more quickly