University:
High School
Course:
High School Biochemistry
Academic year:

2023
Views:

64

Pages:

7
Author:

SpaceCadet101

Resting Potential – the neuron at REST • Sodium Ions (Na+)– – in high concentration OUTSIDE of neuron. • Potassium Ions (K+) – – in high concentration INSIDE of neuron. • This gives a charge of + outside and – inside! Action Potential = the nerve IMPULSE • The neuron is in “action” – a signal is transmitting • Sodium Gates (Channel proteins) – open to let Na+ rush into cell (move down concentration gradient) • Causes charge to change: + inside, - outside. • Change in charge signals next Sodium Gate to open... etc • Potassium moves in opposite direction • Dendrites  cell body  axon  end of neuron • Impulses move like falling Dominoes!! Returning to Resting Potential • So the neuron can send a signal again • Sodium/Potassium Pump – (protein pump) actively transports Na+ back out of cell and K+ back in the cell. • Pumps 3 Na+ out to 2 K+ in. • Requires ENERGY (ATP) – This is why eating helps you to think/perform better To speed up transmission of impulse • Myelin – lipid/protein molecule that wraps around some neurons • Speeds up impulse transmission by covering up most of the sodium gates • Sodium gates open at beginning of axon and then at end of axon • Speed of impulse is increased from 1 m/sec to 100 m/sec with Myelin! How 2 neurons communicate! • Neurons line up dendrite to axon • Synaptic cleft/ Synapse – gap between axon of one neuron and dendrite of the next. • Neurotransmitter – chemicals that carry impulse across the synaptic cleft. – Stimulate Channels to open – Ex: Dopamine, seratonin, endorphins, adrenaline • Legal and illegal drugs alter these neurotransmitters Essential Questions 1. Where are the sodium and potassium ions during resting potential? 2. How does the impulse move between two neurons? 3. Describe the difference between resting potential and action potential in a neuron. 4. Explain how a neurotransmitter can cause action potential in a receiving neuron.