Chapter 3 pt 1 Flashcards
Exam 1
neurophysiology
the study of life processes within neurons that use electrical and chemical signals
How can information be processed by the nervous system?
- For info to be processed by the nervous system, it must first be gathered (ex. from the sensory system) and then relayed from neuron to neuron
- Each neuron in the chain (circuit) sequentially processes the signals given to them
Intercellular communication
- signals travel from one cell to another
- movement of info between cells/neurons
Intra-cellular communication
- signals travel within a single cell
- movement of info within cells/neurons
Inter-cellular transmission
- Info is transmitted through circuits from neuron to neuron to neuron
- this happens through neurotransmitters, which are chemical messengers
- the sensory neurons release a nt that will then bind to the receptors of the receiving neuron and activate it, this goes down a chain
What is a neurotransmitter?
a chemical messenger between neurons
Intra-cellular transmission
- info is received- dendrites
- info is integrated and processed- axon hillock
- info is transmitted/conducted- axon
- action potential
What is an action potential?
a rapid electrical signal that travels along the axon of a neuron
What does the membrane of the neuron look like?
- neurons are surrounded by extracellular fluid, separated from the intracellular fluid by a phospholipid bilayer
- Neuron membranes has a phospholipid bilayer (two layers w phosphate groups w lipid tails that are kind of joined together)… the tails are hydrophobic and are fats
- membrane also contains embedded proteins w hydrophilic (outside) part and hydrophobic (inside) part
How do electrical forces act on the membrane?
membrane voltage differential
- The is a membrane voltage differential due to inside of cell being more negatively charged than the space immediately outside of the cell
- This property is not unique to neurons (ex. cardiac cells)
- Ions are dissolved in intracellular fluid, separated from the extracellular fluid by the cell membrane
Neuron at rest (not receiving input)
- Concentration of ions is different inside vs. outside the cell
- Na+, K+, Ca2+, and Cl- are very important ions to neurons, as well as negatively charged proteins (most heavily negatively charged particle inside of a neuron)
- Ions are dissolved in intracellular fluid, separated from the extracellular fluid by the cell membrane
- Ions are hydrophilic and lipophobic
- Na+, Ca2+, Cl- are found primarily outside the cell
- K+ and many negatively charged proteins found inside the cell
protiens allow ions to go inside and outside of the cell
What two forces cause ions to move through a neuron/ what are the push/pull forces on molecules?
- Concentration force/gradient: ions move from high conecntration to low concentration (think of diffusion through a semi-permeable membrane)
- Electric force: opposite charges attract while like charges repel (think polarity)
- These two forces can collaborate or oppose one another
Resting membrane potential
- Rest/resting means in the absence of any other external input (waiting around for things to happen)
- Neuron is around -60 to -70 mV, which is more negative than the outside
How is the resting membrane potential maintained?
- Sodium-potassium pumps
- The pump sits in the membrane and uses energy to push ions against their concentration gradient
- Na+/K+=ATPase pump moves sodium and potassium ions… moves 3Na+ ions out and 2K+ ions in for every molecule of energy that is utilized