CHAPTER 3 Flashcards
Define the nervous system
The interpreter of your experiences, the stimuli around you and the inner workings of your body. Creates behaviours. It can be subdivided into the central and peripheral nervous systems.
What makes up the central nervous system?
The brain and spinal cord
What is the function of the CNS
To process and relay information
What is the nervous system composed of?
Neurons and glial cells which can be arranged in different configurations to perform specific tasks.
Why do we differ as individuals?
Neural networks are varied and change based on an individual’s experiences.
What is the main nervous cell and what provides support?
Neurons are the main cell, while glial cells provide support
What are dendrites?
The branches of a neuron that receive messages through neurotransmitters binding to receptors in its membrane
What are neurotransmitters? Explain them and their connection to excitation and inhibition.
Neurotransmitters are chemical messengers that allow cells to communicate with each electrochemically. They trigger changes in the membrane potential, structure of neurons and their production of proteins as well as chemicals.
Excitation is the process of activating the neuron to send a message.
Inhibition is the process of preventing a neuron from sending a message/firing.
What happens to dendrites over the course of our lives?
Dendrites spread and branch, forming new connections with more neurons (the more connections, the better)
How do neurotransmitters function?
Neurons dispel their chemicals from the terminal buttons into the synaptic cleft, these neurotransmitters bind to the dendritic receptors and change the behaviour in the cell. This change will either be exciting the neuron to carry on a message or cease it
How does electricity come into play when considering action potentials and neuronal message transmission?
When neurotransmitters bind to the receptors of a neuron, it changes the action potential, either exciting it or inhibiting it. If exciting, the neuron will send an electrical pulse down its axon to release neurotransmitters in the synaptic cleft with another neuron, continuing transmission. If inhibiting, it will cease all such activity.
Where does the electricity in our bodies come from?
Ions, the opening and closing of sodium, potassium and chloride-gated channels along the membrane of an axon move an electrical charge to the end of a neuron
What is the initial charge of a neuron? What would you call this state of charge?
- 70mV, polarized
When would a cell be classified as depolarized?
When moving away from a charge of -70 (increasing), once it meets threshold, it will trigger the release of neurotransmitters into another neuron’s dendritic receptors
How do ions get into the cell?
Through various types of channels
What are the main 2 types of channels?
Chemically-gated channels only allow specific types of ionic chemicals through/require a specific type of neurotransmitter to be activated
Voltage-gated channels are only activated when threshold is met
What allows threshold to be reached?
When there are enough + charged ions present (usually Na+) outside the cell, voltage-gated sodium channels open attempting to balance charges. The sudden influx rapidly depolarizes the cell and fires it
Define propagation
The movement of an electric charge down an axon through the successive opening of sodium gated channels
What is repolarization?
When there is too much of a positive charge within the cell, voltage-gated K+ channels open, allowing for its efflux and resetting the membrane potential.
T/F: Neurons receive inhibitory OR excitatory neurotransmitters
False
Where are neurotransmitters released from?
Vesicles of a presynaptic neuron
How do inhibitory and excitatory neurotransmitters work?
Inhibitory: hyperpolarize the cell and change the membrane potential as a result
Excitatory: depolarize the cell and increase the likelihood of the neuron firing
What does GABA do and what channel does it bind with? What is its associated drug?
GABA binds with chloride channel receptors to inhibit an action potential. It makes the cell negative and more likely to remain inactive. It has to do with learning and anxiety regulation through inhibiting neurons. As a result, it has to do with valium for treating anxiety and flumazenil
What is the function of acetylcholine (Ach)? What is its associated drug?
It’s usually an excitatory neurotransmitter because it usually binds to Na+ channels, allowing for depolarization and making the cell more positive. Has to do with learning and muscle action, botox inhibits the release of Ach, thus preventing wrinkles and movement.