26 Questions
What is the role of astrocytes in the nervous system?
Regulating synapses
Which cells act as 'brain macrophages' and protect the brain from pathogens?
Microglia
What is the resting membrane potential of a neuron?
-70mV
What maintains the concentration gradient in neurons?
Sodium-potassium pumps
What type of channel is triggered by a change in membrane potential and is important for action potential?
Voltage-gated channel
What determines the driving force for ion movement across the neuron membrane?
Both concentration gradient and electrical gradient
Which cells are responsible for myelination of axons in the nervous system?
Oligodendrocytes
What is the role of ependymal cells in the nervous system?
Production and movement of cerebrospinal fluid
What type of cells allow communication with the rest of the body in the nervous system?
'Messenger cells', allows communication with rest of the body
What is the threshold value that needs to be reached to trigger an action potential?
-50mV
During which stage of the action potential do sodium channels become completely inactivated?
Depolarisation stage
What causes the membrane potential to go more negative than usual during action potential?
Overshoot
What type of conduction involves the AP 'jumping' from node to node where there is no myelin sheath?
Saltatory conduction
What helps the action potential to conduct quicker by reducing resistance?
Axon diameter
What causes the membrane to become more positive during depolarisation?
Na+ entering the cell
What happens to the membrane potential when the K+ channels are too slow to close?
'Overshoot'
During the action potential, the membrane potential becomes more negative than the resting potential due to the slow closure of K+ channels.
True
The threshold value to trigger an action potential is -70mV.
False
Saltatory conduction is the process by which the action potential jumps from one node of Ranvier to another along a myelinated axon.
True
Axon diameter has no effect on the speed of propagation of action potentials.
False
The resting membrane potential of a neuron is around -50mV.
False
Neurons are capable of sending signals themselves, in addition to allowing communication with the rest of the body.
True
The resting membrane potential of a neuron is primarily determined by the high concentration of sodium ions inside the cell.
False
Ependymal cells are responsible for both the production and movement of cerebrospinal fluid (CSF) in the nervous system.
True
Oligodendrocytes are responsible for the myelination of axons in the peripheral nervous system (PNS).
False
The driving force for ion movement across the neuron membrane is determined solely by the electrical gradient.
False
Study Notes
Astrocytes and Brain Macrophages
- Astrocytes play a crucial role in the nervous system.
- Microglia act as 'brain macrophages' and protect the brain from pathogens.
Neuron Membrane Potential
- The resting membrane potential of a neuron is around -70mV.
- The concentration gradient in neurons is maintained by the sodium-potassium pump.
- The driving force for ion movement across the neuron membrane is determined by both the electrical and concentration gradients.
Action Potential
- Voltage-gated channels are triggered by a change in membrane potential and are important for action potential.
- The threshold value that needs to be reached to trigger an action potential is -70mV.
- During the action potential, sodium channels become completely inactivated during the refractory period.
- The membrane potential becomes more negative than usual during the action potential due to the slow closure of K+ channels.
Myelination and Conduction
- Oligodendrocytes are responsible for the myelination of axons in the central nervous system (CNS), while Schwann cells are responsible for myelination in the peripheral nervous system (PNS).
- Saltatory conduction is the process by which the action potential jumps from one node of Ranvier to another along a myelinated axon.
- The myelin sheath helps the action potential to conduct quicker by reducing resistance.
- The diameter of the axon has an effect on the speed of propagation of action potentials.
Ependymal Cells and Cerebrospinal Fluid
- Ependymal cells are responsible for both the production and movement of cerebrospinal fluid (CSF) in the nervous system.
Neuron Functionality
- Neurons are capable of sending signals themselves, in addition to allowing communication with the rest of the body.
- The resting membrane potential of a neuron is not primarily determined by the high concentration of sodium ions inside the cell.
Test your knowledge of the components of the central and peripheral nervous systems, including cells such as astrocytes, ependymal cells, oligodendrocytes, microglia, and neurons. Explore how these cells contribute to the function of the nervous system.
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