chapter 10 a and p

what does the soidum/potassium pump transport

3 sodium ions out of the cell and 2 potassium ions into the cell

when the membrane potential reaches threshold in the neighboring membrane, voltage-gated channels open, triggering a(n) ? at the location

action potential

this local current alters the membrane potential nearby, and stimulates the ? to reach its threshold

adjacent membrane

the cytoplasm contains many ? such as phosphate, sulfate, and proteins. these contribute to the negative charge within the cell

anions

the star-shaped ? are found in the cns. they have several functions, from providing support to forming the ?

astocytes; blood-brain barrier

found between neurons and blood vessels (blood-brain barrier); regulate ion concentration in nervous tissue

astrocytes

the effectors of the ? nervous system include cardiac muscle, smooth muscle and glands

autonomic

associated with schwann cells sends outgoing impulses single process ends with synaptic knobs may have collaterals supported by neurofibrils

axons

rough endoplasmic reticulum with neuron cell body

chromatophilic substance

contains the interneuron and motor neuron

cns

branches of an axon

collaterals

branched processes thorn-like spines maybe present receives incoming signals

dendrites

as these ions enter the cell, the cell membrane undergoes ?, with the membrane potential increasing to a peak of approximately +30mV

depolarization

if the membrane potential becomes less negative than the resting membrane potential, the membrane is

depolarized

Covers the choroid plexus; lines space in the brain (ventricles)

ependymal cells

cells called ? line the spaces of the cns, called ? and form a membrane that covers the choroid plexuses

ependymal cells; ventricles

some sensory receptors act to gather info about the ? environment such as light and sound intensities. other monitor the ? environment, detecting changes in temp, blood pressure ect.

external; internal

composed of axons and neurons

gray matter

unmyelinated axons, dendrites, neuronal cell bodies, and synapses are found within nervous system tissue called

gray matter

the membrane potential actually dips lower than -70mV because the potassium channels do not close quickly enough. this phase is called ?

hyperpolarization

if the membrane potential becomes more negative than the resting membrane potential, the membrane is

hyperpolarized

this cycle continues, resulting in action potentials traveling down the axon. this propagation of action potentials is also called ? conduction

impulse

relay impulses between neurons in cns

interneurons

the distribution of ions across a plasma membrane is important to the functioning of neurons. potassium ions are more abundant in the ? space, white sodium ions are more abundant in the ? space. thus, when ion channels open, potassium will flow ? the cell and sodium will flow ? the cell

intracellular; extracellular out of; into

the fastest impulse conduction would occur in a what type of axon

large diameter myelinated axon

cells called ? act as phagocytic cells within the central nervous system, removing bacterial cells and cellular debris

microglia

phagocytes; supportive function

microglia

carry impulses from the cns to effectors

motor neurons

in a resting neuron, the inside of the membrane has a more ? charge than the outside of the membrane. this charge difference is called the resting membrane potential, which is the result of several factors

negative

provide support for axon hillock and axon

neurofibrils

the large group of cells within the central and peripherla nervous system, called ?, serve a supportive function for nervous tissue

neuroglia

the myelin sheath along an axon is not continuous. what are the gaps between schwann cells called

nodes of ranvier

form myelin in cns

oligodendrocytes

in the central nervous system, myelin is formed by cells called ?

oligodendrocytes

myelin is formed by two cell types: ? in the cna and ? in the pns

oligodendrocytes; schwann cells

the impulses that originate at sensory receptors will then be conducted along ? to the central nervous system where the info is integrated

peripheral nerves

contains the sensory neuron, sensory receptor and the effector

pns

the cell membrane of a resting neuron is described as being ?

polarized

as cations leave the cell, the membrane potential at that part of the membrane is reestablishing resting membrane potential. this phase of the action potential is called ?

repolarization

cells called ? cells wind and wrap around axons, forming the myelin sheath of myelinated axons in the peripheral nervous system

schwann

in the peripheral nervous system, myelin is formed by cells called

schwann cells

carry impulses from receptors to cns

sensory neurons

an action potential begins with the opening of ?. these channels open when the membrane potential reaches a level called ?. this sets up a local current

sodium channels; threshold

there is a higher concentration of ? ions outside of the cell, while ? ions are more abundant inside the cell. as a result, ? ions want to diffuse from outside into the cell and ? ions want to diffuse from inside to outside of the cell

sodium; potassium potassium; sodium

the effectors of the ? nervous system are skeletal muscles

somatic

release neurotransmitter molecules

synaptic knobs

membrane permeability differs for sodium and potassium, the membrane has more channels for ? than it has for ?. therefore, as the ions follow their diffusion gradient, more positive charges leave the cell than enter the cell

three; two

the sodium-potassium pump actively transports ? sodium ions out of the cell for every ? potassium ions transported into the cell. this reestabilishes the ion distribution and helps maintain the resting membrane potential

three; two

whether the factors detected are light, pressure, temp, or chemical concentrations, sensory receptors will ? that info into nervous ?

transduce; impulses

an action potential will not occur unless the membrane potential at the ? reaches a level called

trigger zone; threshold

as the peak of the action potential is reached, the sodium channels close and the ? open, allowing these ions to diffuse out of the cell

voltage-gated potassium channels

repolarization phase hyperpolarization phase

voltage-gated potassium channels

depolarization phase

voltage-gated sodium channels

when threshold is reached, ? of the initial segment open briefly, allowing ? to diffuse into the cell

voltage-gated sodium channels; sodium

bundles of myelinated axons form nervous system tissue called ?

white matter