Topic.5.TheNeuron.powerpoint.5.0.the-neuron-an-overview Flashcards
What are the 3 classes of neurons?
Interneuron
Afferent neuron
Efferent neuron
CNS
brain and spinal cord
interneurons
Interneurons
integrate information and formulate a response
PNS
All other neurons
Afferent: picks up sensory stimuli through sensory neurons and transmits to interneurons in CNS; one axon with peripheral branch(cell body to peripheral) and central branch(cell body to spinal chord)
Efferent: sends directions from your brain to muscles and glands
T/F Motor neuron is afferent
False: carries signals to skeleton muscle, meaning that it is efferent and not afferent
T/F In the sense-integrate-act loop, the brain is always where signals are integrated
True because integration involves interneurons which include the brain and spinal cord
Sense: Afferent
Integrate: Interneurons
Act: Efferent
What is the basic anatomy of a neuron?
Dendrites on cell body with a nucleus connected to axon terminals through a axon
What is the difference between a neuron and a nerve?
Neuron is one cell ( 1 body, 1 axon, dendrites)
Nerve: cordlike bundle of MANY axons as a common pathway for electrochemical impulses to travel only in PNS
The nerve in the PNS is analogous to the __ in the CNS
tracts
t/f radial neuron are part of CNS
False, part of PNS; provides a common pathway for transmitted impulses in the arm
What is the difference between the grey and white matter?
Gray: Neuron somas/cell bodies
White: myelinated axons
Spinal nerve made out of what two roots?
Dorsal Root-afferent
Ventral root-efferent
Glial Cells
non-neuronal cells that provide nutrition and support to neurons
List types of glial cells
ependymal cells
microglia
astrocytes
satellite cells
Schwann cells
Oligodendrocytes
Acronym for glial cell types
EMASSO
ependymal cells
Type of glia cell that produces cerebrospinal fluid
microglia
Type of glial cell,
phagocytic cells that ingest and break down pathogens and waste
products in the CNS
Astrocytes
types of glial cell found in CNS, it covers the surfaces of blood vessels for structural support and helps maintain ion concentrations in the interstitial fluid surrounding it
Satellite cells are similar to _
astrocytes but they are found in the PNS
Schwann cells
Forms myelin sheath around axons in PNS
Oligodendrocytes:
form myelin sheath in CNS
What is the myelin sheath?
have a high lipid content; serve to insulate the electrical impulse as it
travels along an axon.
What can speed rate that electric impulses travel along axons?
Node of Ranvier
The tiny gaps between adjacent Schwann cells are called
node
In signal transduction what are the names for transmitting and receiving?
Presynaptic(transmitting)
Postsynaptic(receiving)
In signal conduction what is the role of axon hillock?
Emerging from soma has a high concentration of voltage-activated sodium channels, considered the spike initiation zone for action potentials.
What is a synapse?
The junction between the axon terminals of a neuron and the receiving cell(any type)
If uniform contractile activity is needed among cells, what type of synapse is involved?
Electrical synapse
Electrical synapse found in …
pulp of tooth, cardiac muscle cell/smooth muscle
What are electrical synapse?
it’s a gap junction where the membrane between two neurons is separated by a gap but connected by proteins tubes called connexons.
-gap junctions allow current to flow between adjacent cells, which is important for a chain of action potentials
Chemical synapse
information is transferred via the release of a neurotransmitter from one cell that diffuses along a synaptic cleft and is detected by an adjacent cell
T/F electrical synapse can be better modulated
False, chemical synapse can be better modulated
Which is faster, chemical or electrical synapse?
Electrical synapse because gap junctions are instantaneous
Electrical synapse enables ___ among population of neurons
synchronized electrical activity
What is resting membrane potential?
equilibrium condition, no
net flow of ions across the plasma membrane
Does a resting membrane potential have an electrical impulse?
NO
An electrical potential difference (or voltage) can be
generated across a plasma membrane by the separation of
positive and negative charges. Which is true of a resting
membrane potential?
Cell inside is negative; cell outer surface is positive
Resting membrane potential is expected to have a ___ of charged particles inside and outside the cell
uneven distribution
What gives rise to uneven ion distribution in resting membrane potential?
- Membrane more permeable to potassium (K+) than to sodium (Na+), more (Na+) outside the cell than (K+) inside the cell,3 Na+ out, 2 K+ in
- selective permeability, The plasma membrane lets ions move down a concentration gradient.
Na+ passively moves in and K diffuses out; more K+ leaves than Na+ enters, leaving net positive charge outside and negative inside
What does it mean to have a membrane potential?
Difference in electrical charge on two sides of a membrane
What creates a membrane potential?
membrane potential caused by the movement of ions across a membrane can result from diffusion(due to gradient) and electric fields.
What is the resting membrane potential in mV?
-70mV
Equilibrium potential:
The equilibrium potential for an ion is defined as the potential at which there is no net movement of that ion across the membrane, and this exists when the electrical gradient balances the concentration gradient.
Electrochemical gradient
electro-chemical gradient: net driving force that drives the flow of any ion
through a membrane channel protein; consists of a concentration
gradient and electrical gradient
Nerst equation can
predicting the equilibrium potential across the membrane of a cell for a singly charged
positive ion
Goldman equation
prediction of membrane
potential (Vm) when the membrane is permeable to more than one
ion.
-concentration gradient and the permeability determine
the contribution of a particular ion to the membrane potential
