Exam #4 chapter 11 Flashcards
with graded potentials when channels close what happens?
the ions diffuse away and the membrane returns to the resting membrane potential
what will ions do with graded potentials?
flow through an open channel and make the membrane more polarized (hyperpolarized) or less polarized (depolarized)
what is the structure of a dendrite?
branched, short and tapering processes
what are glial cells of the CNS?
supporting cells
what is the cation, potassium level ?
intracellular: 148 and extracellular: 5
what is the structure of an axon?
usually unbranched, long and do NOT taper
what does the ANS do?
sends commands to the smooth and cardiac muscles and glands (involuntary)
what do axons do?
branch and form enlarged presynaptic (axon) terminals
why is the plasma membrane selectively permeable? (2) (PC)
1) proteins are too large to pass through
2) charged ions cannot pass through the membrane but they can pass through ion channels in the membrane
what does ependymal cells do?
produce, monitor and circulate CSF
what are the characteristics of bipolar neurons? (3) (HHS)
1) has one dendrite
2) has one axon
3) small sensory neurons
what is the functional classification of sensory (afferent) neurons?
they conduct action potential to the CNS
where is the enteric nervous system located?
part of the ANS in the wall of the GI tract that controls the GI tract.
what are some types of glial cells of the CNS? (4) (AEMO)
1) astrocytes
2) ependymal cells
3) microglia cells
4) oligodendrocytes
what can be done with graded potentials?
they can be summed or added together
what are unlyelinated axons in the PNS enclosed by?
schwann cells
what do schwann cells do?
wrap a portion of one axon and form a myelin sheath
what is the similarity and difference between the extracellular fluid and intracellular fluid?
they have the same amount of cations and anions but differ the concentrations of different ions
what does the sympathetic division do?
functions in stressful situation (or exercise)
with graded potentials what is the change at a distance from the site of ion flow?
smaller
what are the characteristics of leak channels? (3) (AAP)
1) always open
2) allow certain ions to pass through the membrane continuously
3) put in the membrane by the cell
what does the PNS consist of?
the nervous tissues outside the CNS
what does the motor (efferent) division consist of?
1) the somatic nervous system (SNS)
2) the autonomic nervous system (ANS)
why does the resting membrane potential exist?
because of an unequal distribution of ions
how are astrocytes shaped and where are they located?
they are star-shaped in the CNS
what are the characteristics of pseudo-unipolar (unipolar) neurons? (2) (SC)
1) has short dendrites attached to a long axon
2) cell body off axon- sensory
what are graded potentials?
electrical signals that do not travel far
what does astrocytes regulate?
the chemical enviornment around neurons
when is the membrane potential termed hyperpoloraization?
a change away from 0mV
what is the functional classification of motor (efferent) neurons?
they conduct action potentials from the CNS
what does the cytoskeleton of astrocytes provide?
structure in nervous tissue
what do myelin sheaths do?
increase the speed of an action potential considerably
if calcium channels open what happens?
calcium ions will flow into the cell (depolarization)
what are sensory receptors?
ends of neurons, or separate specialized cells that detect temperature, touch, pain, pressure etc.
what are ligand-gated channels opened by?
the binding of specific chemical, a ligand-
if sodium channels open what happens?
sodium ions will flow into the cell (depoloarization)
what are the causes of the resting potential? (3) (MIS)
1) more potassium leaves the cell than sodium enter the cell
2) the inability of most anions to leave the cell since they are large
3) the sodium- potassium exchange pump pumps 3 sodium out and 2 potassium in
what type of ligand opens ligand-gated channels?
sodium channels in the the neuromuscular junction
what does grey matter in the nervous system consist of? (4) (NDUG)
1) neuron cell bodies
2) dendrites
3) unlyelinated axons
4) ganglia in the PNS and nuclei in the CNS
what neurons are classified by structure?
1) multipolar neurons
2) bipolar neurons
3) pseudo-unipolar (unipolar) neurons
if chloride channels open what happens?
chloride ions will flow into the cell (hyperpolarization)
what nervous tissues does the PNS consist of? (4) (NGSP)
1) nerves
2) ganglia
3) sensory receptors
4) plexuses (nerve networks)
what is the section of the axon next to the axon hillock? and what occurs there?
the initial segment in which an action potential begins
what divisions does the PNS consist of?
1) sensory (afferent) division
2) motor (efferent) division
what functions does the CNS have? (3) (RPS)
1) receives sensory data
2) processes information
3) sends out major commands
what is the resting membrane potential of a neuron?
about -70mV
when ion channels open what do ions do?
diffuse down their concentration gradients
what type of stimuli opens other gated channels?
pressure
what do neuron cell bodies contain? (5) (PANMG)
1) prominent nucleus
2) abundant rough endoplasmic reticulum
3) nissle bodies
4) mitochondria
5) gogli apparatuses
what type of division is the sensory division and what does it do?
an afferent division and it sends information to the CNS
what is the functional classification of interneurons?
completely contained within the CNS
what does extracellular fluid consist of?
high in sodium and chloride
what are ‘electrical signals’ for the nervous system?
action potentials
what is a nerve?
a bundle of many axons that connects the CNS to sensory receptors, muscles and glands.
when are gated channels closed until?
a specific signal opens them.
what does the ventricles and canals of ependymal cells contain?
cerebrospinal fluid (CSF)
what is a myelin sheath?
layers of plasma membrane containing phospholipids
with graded potentials if more ions flow across the membrane what happens?
the change is greater
what can a cell’s resting membrane be measured in?
mV
what are neurons?
cells that are involved in neural activity
what does the parasympathetic division do?
functions in restful times
what does astrocytes limit?
the spread of inflammation and limit axon regeneration
what is the function of a dendrite?
to receive information and conduct it to the cell body
what will the flow of ions be influenced by when the channels open?
the charge of the ion and nearby charges
what do axons attach to?
a cone-shaped part of the neuron cell body called the axon hillock
what type of voltage opens voltage-gated channels?
calcium channels in presynaptic terminal membranes
what can concentration differences cause ions to do?
move across the membrane
what is the unequal distribution of ions due to?
the activity of the plasma membrane
what are voltage-gated channels opened by?
when the voltage reaches a certain voltage
what are other gated channels opened by?
stimuli
in graded potentials when ions flow across the membrane what happens?
the membrane potential changes
what are the characteristics of microglia cells?
small, mobile phagocytic cells in the CNS
what is an action potential
a quick change to the resting membrane potential
when does the membrane potential change in predictable ways?
when ions flow across the membrane through channels
what type of neurons are classified by structure?
1) sensory (afferent) neurons
2) motor (efferent) neurons
3) interneurons
what does the SNS do?
sends commands to skeletal muscles (voluntary)
what is the anion, chloride level?
I: 4 E: 103
what is the cation, sodium level?
I: 10 E: 142
when is the membrane potential termed depoloarization?
a change towards 0 mV
what does the CNS consist of?
the brain and spinal cord
what does white matter in the nervous system consist of?
1) myelinated axons
2) nerves in the PNS and nerve tracts (tracts) in the CNS
what does the ANS consist of?
1) the sympathetic division
2) parasympathetic division
3) the enteric nervous system
what do nerve tracts do?
propagate action potentials from one area of the CNS to another.
what do satellite cells do?
surround neuron cell bodies for protection and nourishment
what does the sodium-potassium ion exchange pump do?
moves 2 potassium ions in the cells and 3 sodium ions out
what is cation, calcium level?
I: less than 1 E: 5
what does astrocytes influence?
synapse formation
what does intracellular fluid consist of?
high in potassium, proteins and other anions (P)
what type of division is the motor division and what does it do?
an efferent division and it sends commands from the CNS
what do oligodendrocytes do?
wrap portions of several axons and form a myelin sheath
what are the characteristics of multipolar neurons? (3) (HHM)
1) has many dendrites
2) has one axon
3) most common neuron
what do cells in the nervous system include?
neurons and glial cells
where are ependymal cells located?
they line cavities (ventricles) and canals of the CNS
what are types of glial cells of the PNS?
1) schwann cells
2) satellite cells
what are the 2 divisions of the nervous system?
1) the central nervous system (CNS)
2) the peripheral nervous system (PNS)
if potassium channels open what happens?
potassium ions will flow out of the cell (hyperpolarization)
what type of permeability does the plasma membrane have?
it’s selectively permeable
what does astrocytes participate in?
the blood-brain barrier
