IC1- CNS Flashcards
What does the forebrain consist of?
- Cerebrum
- Diencephalon (thalamus and hypothalamus)
What does the hindbrain consist of?
- Medulla oblongata
- Pons
- Cerebellum
What does the brainstem include?
- Midbrain
- Pons
- Medulla oblongata
Midbrain- cranial nerves, nuclei associated with, and fiber tracts?
Cranial nerves
- 3, 4
Nuclei associated with
- 3, 4, 5
- Visual and auditory pathways
Fiber tracts
- Ascending and descending fibers
Hindbrain- cranial nerves, nuclei associated with, and fiber tracts?
Cranial nerves
- 5, 6, 7, 8
Nuclei associated with
- 5, 6, 7, 8
Fiber tracts
- Ascending and descending fibers
What do the fast and slow component of the axon transport?
State how fast/ slow in (mm/day)
- Fast component (50 - 400mm/day) transports the
cytoplasmic proteins and macromolecules that are
required for metabolic and synaptic activity - The slow component (1 - 4mm/day) transports the
cytoskeletal components down the axon
Medulla oblongata- cranial nerves, nuclei associated with, and fiber tracts?
Cranial nerves
- 9, 10, 11, 12
Nuclei associated with
- 5, 9, 10, 11, 12
- Cardiovascular and respiratory function
Fiber tracts
- Ascending and descending fibers
What are the 2 types of cells in the brain? Elaborate on their function.
- Neurons
- Structural and functional
unit of the nervous system
- Generate/ conduct
impulses and are excitable - Non-neuronal cells (glial cells)
- Non-conducting
- Support and protect neurons
- 10x the number of neurons
What cellular components do the axonal cytoplasm lack? (3)
What happens as a result?
- Lack ribosomes, RER and Golgi apparatus
- As the axon terminus lacks components for
synthesizing new proteins or degrading old ones,
materials must be transported back and forth between
the cell body and the terminus
Which normal cell component do dendrites NOT have?
They contain all the cytoplasmic components found in the cell body except the golgi apparatus
What are dendritic spines and their functions?
Little protrusions coming out of dendrites (increased surface area → increase ability of dendrites to receive more information)
Which channel does the presynaptic terminal contain?
Voltage-gated Ca2+ channels
Explain what happens at the excitatory synapse. Include which channel is involved.
Binding of neurotransmitter
to its receptors -> opening of Na+ channels in the
postsynaptic membrane depolarization of the
membrane, action potential in the postsynaptic cell
State the process of what happens upon arrival of an action potential at axon terminal. State which channel is involved.
- Arrival of an action potential at an axon terminal → opening of Ca2+ channels → influx of Ca2+ ions → rise in the cytosolic Ca2+ level
- Triggers exocytosis of the neurotransmitter into the synaptic cleft
Explain what happens at the inihibitory synapse. Include the channel(s) involved.
Neurotransmitter binding → opening of K+ or Cl- channels in the postsynaptic membrane → hyperpolarization of the membrane → no action potential in the postsynaptic neuron
List the 3 types of glial cells in the CNS (list from the most numerous to the least numerous one)
- Oligodendrocytes (60-80%)
- Astrocytes (25%)
- Microglia (5-10%)
State the important functions of oligodendrocytes (1), astrocytes (2) and microglia (2).
The rest just read through
Oligodendrocytes:
- *Myelin sheath formation
Astrocytes:
- *BBB
- *Structural support, scar formation
- Secretion of nerve growth factors
- Water transport
- Excess transport – cerebral edema
Microglia:
- *Brain macrophages
- *Immunocompetent cells of CNS
- Phagocytosis
- Secretion of proinflammatory cytokines (TNF-α and IL1β), chemokines
What is the difference between fibrous and protoplasmic astrocytes?
Fibrous astrocytes:
- Located primarily in the
white matter; long,
spindly processes with
few branches
Protoplasmic astrocytes:
- Located in the gray
matter; thick, lightly
branched processes;
closely apposed to
neuron cell bodies