Chapters 32 & 37 Flashcards
(65 cards)
What is the resting potential of a neuron?
Resting potential is the membrane potential of a neuron that is not sending signals
Where is the concentration of Na+ higher? K+?
(Inside of neuron is more neg. than outside). This is because there is a lot of Na+ ions on the outside which are positive and a bunch of K+ on the inside which make it more negative.
Inside of membrane is -70 mV.
What must you do to achieve an action potential?
A certain level of depolarization must occur.
What is depolarization? How does it occur?
Reducing the membrane potential making it more positive. How it occurs: Sodium channels stimulated to open. Sodium moves into the cell. Causes change in membrane potential.
What membrane conditions are primarily responsible for maintaining the resting membrane potential?
The gated Na+ and K+ channels are closed. Ungated channels maintain the resting state.
What events are primarily responsible for the depolarization or the membrane?
A couple sodium channels are opened by stimulus. The inflow of Na+ through those channels depolarizers the membrane. An action potential is triggered if depolarization reaches the threshold.
What events are primarily responsible for the repolarization of the membrane?
K+ outflow is responsible for the repolarization of the membrane. Remember that in the repolarization zone, the sodium channels are inactivated.
What events are primarily responsible for the hyper polarization of the membrane?
Hyper polarization is caused from anything that increases the outflow of positive ions or the inflow of negative ions. Close K+ channels.
What forms the myelin sheath?
Schwann cells
Hormones
Chemical signal secreted into body fluids (blood) communicating regulatory messages
Target cells
Body cells that respond to hormones. The receptors might be on the outside of the target cell or they could be inside the target cell.
Endocrine system/glands
Sum of all an animals hormone secreting cells and tissues
Endocrine glands
Are ductless and secrete hormones directly into body fluids
Feedback mechanisms
Negative and positive that regulate most of the endocrine secretion.
Excitatory synapse
making a neuron less negative on the inside. Sodium channels are opened to cause this.
Inhibitory synapse
turns off the cell, has it not send signals, and potassium channels are opened
Neurotransmitters
chemical messengers that help pass information between pre and postsynaptic cells.
Dendrite
One of usually numerous, short, highly branched extensions of a neuron that receive signals from other neurons.
Axon
A typically long extension, or process, of a neuron that carries nerve impulses away from the cell body toward target cells.
Synapse
The junction where a neuron communicates with another cell across a narrow gap via a neurotransmitter or an electrical coupling.
Resting potential
The membrane potential characteristic of a nonconducting excitable cell, with the inside of the cell more negative than the outside.
Action potential
An electrical signal that propagates (travels) along the membrane of a neuron or other excitable cell as a nongraded (all-or-none) depolarization.
Sodium potassium pump
A transport protein in the plasma membrane of animal cells that actively transports sodium out of the cell and potassium into the cell.
Hyperpolarization
A change in a cell’s membrane potential such that the inside of the membrane becomes more negative relative to the outside. Hyperpolarization reduces the chance that a neuron will transmit a nerve impulse.