Nerves, Signaling, CSF, Membrane transport Flashcards
What is the endoneurium?
The tissue lining the innermost layer of a nerve, surrounding each individual cell
What is the perineurium?
The tissue surrounding each bundle (fascicle) of nerve cells
What is the epineurium?
The outermost tissue surrounding a nerve
What structures are part of the central nervous system?
Brain and spinal cord
What structures are part of the peripheral nervous system?
All the nerves of the body including the cranial nerves
What is an afferent nerve?
A nerve that receives sensory input (A= arrives)
What is an efferent nerve?
A nerve that produces motor output (E= exit)
True or false: electrical signals can travel up and down the same neuron
FALSE: an electrical signal can only travel one way through a certain neuron.
What is the functional unit of the nervous system?
The neuron
What are dendrites?
The branches off the soma that receive information from their environment
Where are the nucleus and organelles located in a neuron?
The soma (cell body)
What structure of the neuron carries information from the receiving end to the transmitting end?
The axon
What structure of the neuron transmits information from the neuron to the next cell?
Axon terminals
What type of neuron structure is found in the CNS and motor neurons?
Multipolar
What type of neuron structure is associated with the special senses like sight and smell?
Bipolar
What type of neuron structure is associated with the sense of touch?
Unipolar
Where do nerve bodies synapse (connect) in the brain?
Grey matter
Where do the axons travel through the brain?
White matter
What creates a resting transmembrane potential?
Difference in electrical charge inside vs. outside the cell
What maintains the transmembrane potential?
Sodium-potassium pumps
What quantity of ions does the sodium-potassium pump move?
3 Na out
2 K in
This is the first part of the axon that contains voltage-gated channels & is capable of creating an action potential
Trigger zone
This is a specific change in the transmembrane potential due to opening of sodium voltage gated channels and potassium voltage gated channels
Action potential
This is the transmembrane potential that causes a voltage gated channel to open
Threshold; -55mV
This is a depolarizing stimulus that changes the membrane potential but does not cause the membrane to reach threshold; no AP generated
Subthreshold stimulus
This is a depolarizing stimulus that causes the membrane to reach (or exceed) threshold; generates an AP
Suprathreshold/threshold stimulus
True or false: leak channels and sodium-potassium pump channels are always working
true
These channels are located on the dendrites
Chemically-gated channels
These channels are located on the axon
Voltage-gated Na-K channels
These channels are located on the axon terminals
Voltage-gated Ca channels
Describe graded potential
Depolarization that weakens the further it gets from the point of stimulus
What is the trigger zone?
the first place on the neuron to contain voltage-gated channels
Describe the relationship between graded potential and the trigger zone
A stimulus must be strong enough for the graded potential to travel all the way from the dendrites to the trigger zone and stay above the AP threshold
Axon terminals release neurotransmitter through what?
Synaptic vesicles
This glial cell is responsible for producing CSF
ependymal cell
Where are the ependymal cells located?
In the choroid plexus of the ventricles of the brain
How do substances cross a selectively permeable membrane?
Lipids and water can simply diffuse; proteins, ions, carbohydrates must travel through channels
What is endocytosis?
The method of bulk transport where a cell engulfs large molecules with a vesicle to transport into the cell
What is exocytosis?
The opposite of endocytosis; transport of large molecules out of a cell
What is an example of exocytosis?
Neurotransmitter being released from an axon terminal on a neuron
What is an example of endocytosis?
glial cells consuming neurotransmitter after the chemical has completed its task
What is required for the Na-K pump to move 3 Na+ and 2 K+ across the membrane?
1 ATP
What part of the neuron contains Na/K pump and leak channels?
Everywhere!!
What part of the neuron includes chemically gated channels?
Dendrites
What part of the neuron contains voltage-gated sodium and potassium channels?
Axon
What part of the neuron contains voltage-gated calcium channels?
Axon terminals
What path does CSF take through the brain/body?
Created in the choroid plexus, circulates through the ventricles of the brain, down through central canal of spinal cord, up into/through the subarachnoid space, pass through arachnoid granulations into superior sagittal sinus to be absorbed into venous circulation
