A&P TEST 6

LAST ONE WOOHOOO

The minimum amount of voltage needed to open voltage-gated channels on an axon is called what?

threshold

At a synapse, the neuron that responds to the neurotransmitter is the ______ neauron

postsynaptic

Electrical currents in neurons are due primarily to the flow of which of the following through gated channels?

ions such as potassium or sodium

Which term refers to a synapse that releases acetylcholine from the presynaptic axon terminal?

Cholinergic

When GABA is used, more chloride channels open which makes the inside of the cell what?

More negative

Sodium ions flowing into a neuron cell membrane are most likely to produce what?

ESPS

What do inhibitory postsynaptic potentials do to postsynaptic membranes?

hyperpolarizes them

When a single synapse generates EPSPs so quickly that each is generated before the previous one fades, what is this process called?

temporal summation

The type of summation that occurs when EPSPs from several synapses add up to threshold at the axon hillock is called
_____ summation

spatial

The ability of synapses to change is called synaptic plasticity. Which term refers to the neuronal pathways formed during learning?

Memory traces

The ability of synapses to change is called synaptic

plasticity

Depolarization during an action potential occurs because

voltage gated sodium channels opened causing sodium to enter the cell

What is the suprathreshold stimulus?

The stimulus is super strong, but the action potential takes over.

Which membrane potential can die before reaching threshold?

local potentials

Which membrane potential is non decremental?

action potentials

What chemical has the greatest impact on RMP?

K+

What maintains the ion levels against concentration gradients in membrane potentials?

the sodium potassium pump

What is the threshold?

point of depolarization to trigger the action potential

What is the subthreshold stimulus?

stimulus in the local potential that isn’t strong enough to activate the action potential

What is the term for a synapse between a neuron and another neuron’s axon?

axoaxonic

What is the cauda equina?

A bundle of nerve roots occupying the vertebral canal from L2 to S5

Which are a series of fibrous connective tissue membranes covering the central nervous system?

Meninges

In which does cerebrospinal fluid circulate?

subarachnoid space

What is the order of the meninges from superficial to deep?

Dura mater, arachnoid mater, pia mater

Where are the neuron cell bodies, dendrites, and synapses found in the CNS?

Gray matter

White matter has a pearly white appearance due to the presence of which of the following?

Myelin

In the spinal cord, what is the space within the gray commissure that contains CSF?

Central canal

What is the site of synaptic integration in the spinal cord?

gray matter

In the spinal cord, where is the white matter in relation to the gray matter?

superficial

Within the spinal cord, which tracts carry motor signals down from the brain?

descending

Which nerve tracts do not decussate?

Ipsilateral

In a sensory pathway, which neurons run from the thalamus to the sensory cerebral cortex?

third-order

What does the central canal of the spinal cord contain?

cerebrospinal fluid

Which fibers are nerve fibers that innervate blood vessels, glands, and internal organs?

visceral

In a sensory pathway, the order neuron detects the ____ stimulus and transmits the signal to the spinal cord or brainstem.

first

A nerve containing both sensory and motor nerve fibers is called a(n) ______ nerve.

mixed

Which spinal nerve roots carry sensory nerve signals?

posterior

In a sensory pathway, which neurons run from the spinal cord or brainstem to the thalamus?

second-order

Moving peripherally from the spinal cord, which anterior and posterior structures form a spinal nerve?

roots

The somas of which neurons are found within the posterior root ganglion?

sensory

Which rami of spinal nerves T1-L2 connect to the sympathetic chain ganglia?

communicating

What is the function of a muscle spindle?

To detect muscle length and body movements

During a crossed extension reflex, which nerve fibers cross to the contralateral side?

afferent

In a contralateral reflex, the input and output are where?

on opposite sides of the body

In which reflex arc do the input and output occur at different levels of the spinal cord?

intersegmental

When are tendon organs stimulated?

when a muscle contracts

Efferent nerve fibers carry which of the following?

motor impulses

What is a tendon organ?

A tangle of nerve endings entwined in collagen fibers of tendon

What is the result of a tendon reflex response?

inhibition of muscle

What is repolarization and what happens during it?

stage of action potential where potassium channels open and leave

What is hyperpolarization and what happens during it?

stage of action potential where potassium channels start to close but membrane potential dips down to -90.

What is the absolute refractory period?

where no amount of simulus will trigger another action potential

What is the relative refractory period?

where larger than normal stimuli can trigger another action potential

Describe the direction of propagation of action potential

action potential travels in one direction down the axon

What is continous conduction?

step by step depolarization occuring in unmyelenated axons

What is saltatory conduction?

nerve impulse “leaps” from myelen sheath gap to gap.

What dictates if an axon has continous or saltatory conduction?

the structure of an axon and if its myelinated

Describe axodendritic?

axon connecting to dendrite of a neuron

Describe Axosomatic:

axon connecting to soma of neuron

Describe axoaxonic:

axon connecting to other axon terminal

What is cell adhesion molecules?

proteins that help connects neurons together

What is cehmical synapse?

junction between two neurons that allow neurotransmitters to be transmitted. requires synaptic cleft

What are electrical synapse?

requires gap junctions that allow ions and electrical currents to pass between each other

What is the postsynaptic density?

area where the receptors of neurons are present

What are examples of amino acids in neurons?

building blocks of proteins that include Glutamate, GABA, glycine.

Describe glutamate and what it causes:

an excitatory neurontransmitter in the brain and causes the excitatory postsynaptic potential

Describe GABA and Glycine and what it causes?

inhibitory neurotransmitters in the CNS. they cause inhibitory postsynaptic potentials

What are examples of monoamines?

histamine, serotonin, dopamine, adrenaline

What are examples of neuropeptides?

substance P, endorphins, cholecystokinin

If ACh is excitatory what is affected?

the NMJ

If ACh is inhibitory what is affected?

cardiac

is GABA inhibitory or exhitatory?

inhibitory

If GABA is released into the cell, will it make it more negative or positive?

negative

What is Gabapentin?

a synthetic form of GABA used to lower anxiety or nerve damage

What does Adrenergic Synapses use and need?

uses norepinephrine and needs adrenergic receptors

WHat do adrenergic synapses rely on ?

second messengers like cAMP or G proteins

What is the cessation of a cell?

when neurotransmitters stop being send out and reuptake is done.

What is neural integration?

Ability to process information, store, or recall it

What is temporal summation?

many stimuli in a small amount of time

What is spatial summation?

stimuli at the same tie from several different places

What does presynaptic facilitation do to the effects of summation?

enhances the effect

What does presynaptic inhibition do to the effects of summation?

reduces the effect

What is neural coding?

converting information to a meaningful pattern of action potentials

What is labeled line code?

relies on fact that each nerve fiber to the brain originates at specific type of receptor

What is neural pools?

group of interlined neurons of the CNS that all does one specific function

What is the discharge zone?

where the input neuron controls decisions

What is the facilitated zone?

where the input neuron has a vote in the action of postsynaptic cells

What is the neural circuit ?

pathway along the neuron of a neural pool

What is the diverging neural circuit?

signal merges inputs

What is reverberating neural circuit?

restimulate previous neurons to start process over again

What is the parallel after discharge type of neural circuit?

diverge after input but converges again before the output

What are memory traces?

physical basis of memory where new synapes are formed

What do memory traces rely on?

synaptic plasticity

What is the length of intermediate memory?

few seconds

What is the purpose of intermediate memory?

reading a sentence and making sense of things

What is short term memory length?

memory for a couple of hours

What is working memory?

a subtype of short term memory where you hold on to an idea long enough to carry it out

What does short term memory rely on?

synaptic facilitation

What is synaptic facilitation?

meakes signal easier to transmit across synapse

What is postsynaptic potentiation?

where elevated Ca2+ levels can cause release of a lot of neurotransmitters in response to new signal much later,