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55 Cards in this Set

  • Front
  • Back
What are the two types of cells in the nervous system?
Neurons and glions.
What are neurons?
They are cells that receive and transmit information to other cells.
About how many neurons are found in the human brain?
100 billion.
Who proved the existence of neurons?
Santiago Ramon y Cajal.
What 5 neuron structures are common with most animal cells?
1. Membrane

2. Nucleus

3. Mitochondrion

4. Ribosomes

5. Endoplasmic Reticulum
What is the structure and function of the cell membrane?
It is a double layer of fat that keeps most chemicals from flowing into and out of hte cell. It is wrapped around the cell like skin. Oxygen, Carbon Dioxide, and Glucose can flow freely through the membrane.
What is the structure and function of the nucleus?
This is the structure that contains the chromosomes. Cell division and all the other cool stuff occurs here. Like the brain.
What is the structure and function of the mitochondrion?
This is basically the stomach and lungs of the cell. Oxygen and suger go in, and energy for the cell comes out. This is a funny looking structure.
What is the structure and function of the ribosomes?
This is the structure where protein synthesis occurs. These are found almost anywhere in the cell. Proteins can become either structures or enzymes.
What is the structure and function of the endoplasmic reticulum?
This is the tube through which the new proteins get transported. Reticulated = network.
What are the six structures of the neuron that are specific to only neurons?
1. Dendrites

2. Dendritic spines

3. Cell body (soma)

4. Axon

5. Myelin Sheath

6. Presynaptic bulb
What is the dendrite?
The dencrites receive information from other cells. They are branchlike and come from the cell body. There can be many per each neuron.
What are the dendritic spines?
Thse are little outgrowths on the dendritic branches.
What is the cell body (soma)?
This is the housing for the common cell parts and is defined by the cell membrane.
What is the axon?
This is the channel through which info is sent to other cells.
What is the myelin sheath?
A fatty membrane that insulates the neuron, allowing the chemical signal to travel faster.
What is the presynaptic terminal?
The bulb from which chemicals are released. These are presynaptic clefts or bulbs.
How many axons does each neuron have?
Only 1, although it can branch. If it branches, it's like a splitter cable.
What type of communcation does the nervous system use?
Electrochemical communication.
What is the process of electrochemical communcation?
The dendrites pick up chemicals, the cell body fires and conducts down the axon. The presynaptic terminal receives the communcation and creates neurochemicals which are sent out through the presynaptic terminal.
Describe afferent axons.
These send information to the central nervous system.
Describe efferent axons.
These send information away from a structure.
Describe interneurons.
These stay inside a structure, just communicate with each other.
What is the relationship of neuron structure and function?
Structure is directly related to function.
What is the Central Nervous System made of?
Brain and spinal cord.
What is the main difference between glia and neurons?
Glia DO NOT transmit information. They only receive information. Neurons transmit and receive.
What are the four main types of glia?
1. Astrocytes.

2. Oligodendrocytes.

3. Schwann Cells.

4. Radial Glia.
What is the function of Astrocytes?
These are the largest of the glia. They are basically the vacuum cleaner and garbage disposal of the brain. They absorb neurotransmitters and relase them to help synchornize neurons. They also remove waste products (dead neurons.)
What is the function of Oligodendrocytes?
These build myelin sheaths in the central nervous system.
What is the function of Schwann cells?
These build myelin sheaths in the peripheral nervous system.
What are radial glia?
a type of astrocyte that regulates neuron migration and growth. It is critical during development. Most important prenatally, but a few stay throughout life.
What can happen if astrocytes mutate?
This is a bad type of brain cancer where the astrocytes destroy healthy tissue instead of dead neurons.
What is the ratio of glia to neurons?
There are 10 times more glia than neurons.
What is the relationship between glia and neurons?
Glia respond to or support the function of neurons.
How much blood does the brain contain?
Hardly any.
In what two main ways is the brain disconnected from the body?
1. The temperature regulation is independent from that of hte body.

2. The body's immune system doesn't work in the brain, since the body's immune system works by regeneration.
What is the blood-brain barrier composed of?
The walls of the capillaries in the brain are lined with endothelial cells (packed so tightly blood cannot pass).
What substances can pass through the blood-brain barrier?
Oxygen and carbon dioxide can squeeze through. A proten mediated transport system pulls glucose through.
How does glucose get to the brain?
A protein mediated transport system pulls glucose through. It forces the cells apart long enough to get glucose in.
How are neurons nourished?
What test can track the consumption of glucose in the brain?
PET Scan
What is Korsakoff's syndrome?
A genetic deficiency of thiamine (B1). This causes the brain and neurons to quit consuming glucose, leading to severe dementia.
What is the charge of the outisde of the membrane at resting state?
-70 mv.
What is polarization?
The resting potential of the neuron.
What is depolarization?
When the polarization moves toward zero. It sometimes becomes positive.
What is the threshold of excitation?
The point where voltage-activated sodium channels open all at once. The depolarization charge starts this process.
What happens as the cell is flooded with sodium, and what is the charge of the cell?
The charge goes up to about 50 mv almost instantly. In response, the cell purges potassium to bring the charge back to resting.
What is the all-or-none law?
Neurons are go/no go only. No matter how strong the stimulation is, they can only go as fast as they can.
What is the absolute refractory period?
The sodium gates can't reopen for a time, regardless of stimulus. This is when the cell is trying to get back to -50 mv.
What is the relative refractory period?
This is when the cell hyperpolarizes, so it takes a stronger signal to produce a new action potential. If it's at -85 mv, it would take a signal strong enough to bring that to zero to begin the influx of sodium.
Describe the propagation of the Action Potential.
Wen one node fires, it enters into a refractory period. Because the "upstream" node is refracting, it cannot fire again, and so the signal jomps to the next node. This is saltatory conduction.
What is the major benefit of the refractory period?
It keeps the action potential from going both ways.
What are local neurons and how are they different from other neurons?
Local neurons don't transmit and receive infromation. These are horizontal cells in the eye.
What are graded potentials?
Subtle electrical changes that can be detected by neighboring neurons. No transmitter is required for these types of communications.
How do local neurons transmit information?
In local neurons, the myelin sheath is so thin that polarization can be detected by other neurons.