L1 Flashcards
The visceral motor division is also known as what part of the nervous system?
The autonomic division
What two subdivisions is the visceral motor division divided into?
Sympathetic (fight or flight) and Parasympathetic (rest and digest)
Which type of neurons make up 90% of all human neurons?
Interneurons
T/F Interneurons are only located in the CNS?
True
Where are interneurons positioned relative to sensory and motor neurons?
In between them
Which type of neurons process, store and retrieve information?
Interneurons
What is the longevity of individual neurons that differentiate during fetal development?
They can function the entire life of an individual
T/F Most neurons stop dividing after fetal development.
True. The few exceptions include olfactory neurons and neurons in some areas of the brain
T/F It is a truism that axon are generally covered by glial cells
True
What percentage of cells in the CNS are glial cells? How much volume do all these glial cells make up?
90%. 50%
What are the four glial cells of the CNS?
Astrocytes, Oligodendrocytes, Microglia, and Ependymal cells.Mnemonic: Another One May Enter
What is the sole glial cell type in the PNS?
Schwann cell
What is the cell that acts like a macrophage in the CNS?
Microglia
Which is the most abundant glial cell in the CNS?
Astrocyte
Which glial cells form an important part of the blood-brain barrier by separating neurons from capillaries?
Astrocytes
Which glial cells help to regulate the composition of brain tissue intercellular fluid by selectively absorbing ions and nutrients from blood and removing waste?
Astrocytes
What does each dendritic process of an oligodendrocyte do in the CNS?
Myelinates part of an axon
Which glial cells form a ciliated simple columnar epithelium that lines ventricles and circulates CSF in the CNS?
Ependymal cells
When does myelination start and how long does it continue?
Starts during embryonic and fetal development of the nervous system and continues into adulthood
What is the composition of the glial cell plasma membrane?
About 20% protein and 80% lipid
True/False Axons can be covered by oligodendrocytes but not myelinated?
True
How many axons can one schwann cell cover? How many can one oligodendrocyte cover?
Only one region of one axon..Oligodendrocytes can cover regions of axons of more than one axon
What is neuronal communication based on?
Mechanisms for producing electrical potentials and currents
What is the electrical potential in neuronal communication? What units is it measured in?
The difference in charge (mostly due to ion concentration) across a membrane. Millivolts (mV)
What is the electrical current in neuronal communication? What units is it measured in?
Movement of charge (carried by ions) across a membrane. Milliamps (mA)
What is the electric potential of living cells measured with?
A sensitive voltmeter with two glass microelectrodes
Where must the microelectrodes be placed to measure the membrane potential of cells?
One microelectrode must be placed inside the cell and the other one outside the cell as a reference
What is the instrument used to make thin electrodes from glass tubes?
Microforge
What is the ratio of ion transport by the Na+/K+ pump?
3 Na+ : 2 K+
How many ATP are needed for each cycle of the Na+/K+ pump?
one ATP per cycle
High use of ATP requires which two molecules to be continuously supplied to the nerve tissue?
Glucose and oxygen
In which direction to K+ leak channels allow K+ ions to move? Na+ leak channels?
Out of the cell. Inside the cell.
Which leak channels are more numerous, K+ or Na+?
K+ leak channels are more numerous
How does the leaking out of K+ affect the membrane potential? Leaking in of Na+?
Makes the membrane potential more negative. Leaking in of Na+ makes the membrane potential only slightly more positive since there are very few Na+ leak channels
Which areas of a neuron have ligand-gated receptors?
The soma membrane and dendrites