Module 3 Flashcards
What do the nervous system do?
Coordinates voluntary and involuntary actions and transmits signals to and from different parts of the body
What does afferent mean?
Carrying information towards the CNS (sensory)
What does efferent mean?
Carrying information away from the CNS (somatic and autonomic)
What are the two divisions of the nervous system?
PNS and CNS
What makes up the CNS?
brain and spinal cord
What makes up the PNS?
Nerve tissue outside the CNS (cranial nerves and branches, spinal nerves and branches, ganglia)
What is a neuron?
basic signaling units of the nervous system
What are glia?
Support cells known to communicate with neurons and provide biochemical support
Which part of the neuron receives incoming signals from neighboring cells?
Dendrites
Which part of the neuron carries outgoing signals from the integrating center?
Axon
What is the control center of the neuron?
Soma (cell body)
What is the name of the region where an axon terminal communicates with its postsynaptic target cell?
Synapse
What is a nerve?
A bundle of peripheral neurons
Why cant the axon produce proteins?
It lacks ribosomes and ER, proteins are produced in the soma and transported down the axon
If a substance was being transported toward the cell body, what is this called?
Retrograde transport
If a substance was being transported away from the cell body, what is this called?
Anterograde transport
Kinesins are an example of ___ transport, and dynein’s are an example of ___ transport.
Anterograde (move toward + charge), Retrograde (move toward - charge)
The space containing extracellular matrix that holds the pre and post synaptic cells is called ____.
Synaptic cleft
What is the moto that synapses tend to go by?
Use it or lose it
What is myelin?
Layers of phospholipid membrane wrapped around an axon
Important in structural stability of axon, insulation of axon and speeding up electrical signals
Which glial cell produces myelin the CNS, and which glial cell produces myelin the PNS?
CNS: Oligodendrocytes
PNS: Schwann cells
Which disorder results from demyelination in the CNS?
MS
What are the 6 types of glial cells and their functions?
Oligodendrocytes: myelin producers in CNS
Schwann cells: myelin producers in PNS
Satellite: supportive capsule around cell bodies of neurons (PNS)
Astrocytes: take up and release chemicals at synapses, provide neurons with substrate, main ECF homeostasis, surrounds vessels (CNS)
Microglia: CNS immune cells
Ependymal: line cerebrospinal fluid, circulate cerebrospinal fluid
What types of diseases are likely to occur if microglia remain activated past a certain time period or pass a certain threshold?
Alzheimer’s, ALS
Which division of the nervous system is more likely to repair neurons and why?
PNS. Schwann cells create a tube to guide the regenerating axon
What does the Nernst equation describe?
Describes the membrane potential that would result if the membrane were completely permeable to only one ion
What does the Goldman-Hodgkin-Katz equation describe?
Predicts the membrane potential that results from the contribution of all ions that can cross the membrane
What alters membrane potential?
Change in K+ concentrations or change in permeability to ions (Na+, K+, Ca2+, Cl-)
The ease with which ions flow through a channel is known as ___.
the channels conductance
Which gated channel opens in response to physical forces and is found in sensory neurons?
a) Voltage-gated
b) Mechanically-gated
c) Chemically-gated
b) mechanically-gated
Which gated channel responds to ligands?
a) voltage
b) mechanical
c) chemical
c) chemical
which gated channel responds to changes in the cells membrane potential?
a) voltage
b) mechanical
c) chemical
a) voltage
A mutation in a channel is called ____. What can this mutation do to the channel?
Alter permeation
Change channel activation
Change channel inactivation
What conditions can result from channelopathies?
cystic fibrosis, muscle disorders, congenital insensitivity to pain
What are the two sources of resistance in a cell?
membrane resistance
internal resistance of cytoplasm
What determines how far current will flow in a cell before the energy is dissipated?
Resistance
What is a graded potential?
Electrical signal that travel over short distances and lose strength as they travel
What induces an action potential?
a graded potential large enough that causes a large depolarization
What is an action potential?
brief, large depolarization that travel for long distances without losing strength (rapid signal over long distance)
Where do graded potentials typically occur?
Where do action potentials typically occur?
GP: soma+dendrites
AP: axon
What generates the graded potential?
Chemically gated ion channels or closure of leak channels
What causes graded potential to lose strength as they travel through the cell?
Leak channels
Cytoplasmic resistance
Which part of the neuron must a graded potential reach to initiate an action potential?
trigger zone (axon hillock)
Why is the movement of an action potential dominoes-like?
The movement of an AP results in sequential opening of voltage gated ion channels in each adjacent area of the axon creating a uniform depolarization
The movement of AP along an axon is referred to as ___.
Conduction
