Neuron Structure
The function of a neuron is to maintain...
Homeostasis
What are glial cells?
Neuron supporters; glial cells do not signal. Empty space where a neuron dies is filled in by glial cells.
What is an action potential?
Large, sudden and transient changes in membrane potential along the axon of a neuron.
What part of the neuron initiates an action potential?
Axon hillock
Astrocytes: what is the blood-brain barrier
Controls what is exchanged between nervous tissue and neurons.
What are the two "transport" mechanisms? How do they open?
Ion leak channels (always open) (more K leak channels = more electronegative in the cell.
Ion pumps (opened via ATP)
What are the 3 regions of a Neuron?
Receptive region
Conducting region
Secretory region
What is the importance of microglia?
Phagocytic cells. Keeps the area clean of debris and potential threats to the cell.
Explain the sodium-potassium pump
3 Na ions OUT, 2 K ions IN
maintains high Na outside the cell and high K inside the cell.
What are the parts of the axon?
axon hillock, axon collaterals, telodendria, axon terminal/synaptic bulb
What are ependymal cells?
Secretory cells. Produce/secrete CSF which allows for protection in the brain.
Action potential step by step:
1. local potential
2. depolarization
3. repolarization4. hyperpolarization
What are the functions/features of dendrites?
transmits input from other neurons toward the cell body; motor neurons: many dendrites; sensory neurons: few dendrites
What is the importance of schwann cells?
Cells that produce the myelin sheath. Schwann cells wrap themselves around an axon. Provide insulation around the axon. Insulation enhances electrical signals.
Explain the neuronal synapse