week 2

We went into more detail about the action potential of a neuron in this class. There are chemically regulated and voltage regulated ion channels. chemically regulated channels open with the binding of a chemical NT. This allows a controlled number of ions to influx. Whereas voltage regulated channels are activated at a certain depolarizing voltage and allows a massive influx of ions. this massive influx creates a positive feedback system opening more VR channels.
When the positive charge reaches the synaptic bulb calcium channels open and push the synaptic vesicles to the membrane where they are released into the synaptic cleft. the amount of NT released into the SC depends on the amount of calcium in the ECF, which is regulated by astrocytes. There are many factors that determine if a neuron reaches action potential. The total excitatory effects must be greater than the inhibitory effects to a degree that the neuron is able to reach its threshold (Spacial summation). The neuron could also be stimulated by rapid and frequent release of NT (temporal summation).

Schwan cells are also important to the speed of the conduction. They wrap around the axons of the neurons in the PNS. One schwan cell around one axon and and there are multiple schwan cells that wrap around the neuron. Schwan cells insulate the axon creating a fast signal conduction. When an axon becomes damaged in the PNS the schwan cells go through mitosis extending the axon so it can repair its connection. The neuron cells of the CNS are wrapped by oligodendrocytes. one oligodendrocyte wraps many CNS neurons. because of this the neurons of the CNS are not able to repair axons when they are damaged.

I can see how carpal tunnel syndrome occurs. the nerves to the hand become damaged or inflamed from the repetitive movements and you start to lose feeling, movement or strength. that's why the brace helps. it gives your nerves time to heal without further damage. but I' not sure how the stretches would help.

week 1 neurons

This week we discussed the anatomy of a neuron, types of neurons, and how they send and receive electrochemical signals. The three different structural types of neuron are unipolar (sometimes called pseudounipolar), bipolar and multipolar. A neuron has three categories of potential; resting potential, graded/local/receptor potential, or action potential. For a neuron to go from resting to graded potential a neurotrasmitter must bind to a dendrite. This allows Na+ ions to trickle into the neuron. if the signal is strong enough and the ICF reaches -55mv the neuron will reach action potential. This causes the axon hillock to open up and allow a massive rush of Na+ ions in, that flow down the axon. The positive charge causes the permeability of the synaptic bulb to change allowing an influx of calcium ions. the calcium causes the synaptic vessels to move to the membrane and burst, releasing neurotransmitters into the synaptic cleft. These NT then bind to another neuron. This process is responsible for all your bodies perceptions, behaviors, memories, and movements.
For the last year or so I have noticed pain, tingling, and loss of strength in my hands when I am on the computer or doing a lot of writing. I was aware that it was the beginning of carpal tunnel syndrome but didn't know what was the actual cause of the pain and loss of strength. after reading the text I now know its due to the myelin sheath being damaged or the nerves being squeezed and irritated. I try to remember to stretch my hands every now and then while i am working but I usually forget until they start to hurt. The stretching does help and if I do it regularly my hands will return to normal.