Week 2: Neural Transmission and Intro to Psychopharmacology Flashcards
What is multiple sclerosis caused by?
Degradation of myelin sheaths
Extra: on average more than 10 Australians are diagnosed with MS every week
What are some of the symptoms of multiple sclerosis?
Vision: double, blurred, partial loss
NS: tremor, weakness, fatigue, heat sensitivity
Feelings: depression, personality changes, inappropriate laughing or crying
What do nerve cells do?
Generate electrical signals to transmit info
How are neurons with the conduction of electricity?
They are not intrinsically good but have evolved to create mechanisms to generate signals based on the flow of ions across the plasma membranes
It allows currents to pass electrical charges to go through in the forms of ion
What does the action potential do?
Transiently abolishes the negative resting potential and makes the transmembrane potential positive
What is the cell membrane?
It regulates the concentration of salts and other chemicals on either side. The Head is HYDROPHILIC (likes water and is a polar region) and the tail is HYDROPHOBIC (hates water, has no polar regions)
The phosphate group will bind to water, fatty acid tails heads have no binding sites for water
What are the 3 factors that influence the movement of ions in and out of cells?
Concentration gradient
Voltage gradient
Structure (permeability of the membrane)
What is the concentration gradient?
Describes the relative difference in the concentration of a substance at different locations in pace when the substance is not evenly dispersed
What is the voltage gradient ?
A measure of relative concentrations of electrical charge. Ions will move down a voltage gradient from an area of high charge to an area of lower charge.
What is a selectively permeable membrane?
Some molecules, but not all molecules will be allowed through the membrane
What are to 2 positively charged particles which interact to produce the resting potential?
Sodium ions (Na+) Potassium ions (K+)
What are to 2 negatively charged particles which interact to produce the resting potential?
Chloride ions (Cl-) Large protein anions (A-)
What is a ligand gated channel?
They bind Neurotransmitters which opens the channel allowing ions to move across
What is a mechanically gated channels?
Open when there is a force that activates it.
What is a voltage gated channel?
When the voltage changes, the channel opens up allowing movement.
What is a leakage channel?
Is a channel that randomly opens allowing a certain degree of leakage across the membrane.
What is the Sodium Potassium Pump?
The process of moving Na and K ions across the cells membrane is an active transport process against the concentration gradient. It involves hydrolysis of ATP to provide the necessary energy
What can the equilibrium potential can be predicted by?
Nernst equation
What is the Nernst Equation?
where Ex is the EP for any ion X, R is the gas constant, T is the absolute temperature (Kelvin scale), z is the valence (electrical charge) of the ion, F is the Faraday constant (electrical charge contained in one mole of univalent ion)
What is the post-synaptic potential?
Graded potential in the dendrites of a neuron that receives synapses from other cells
What is excitatory postsynaptic potential?
is depolarising (+) because it causes the membrane potential to move toward threshold
Driven in positive direction
What is a inhibitory postsynaptic potential?
is hyperpolarising (-) because it causes the membrane potential to move away from threshold.
Driven in a negative direction
What happens during an Action Potential?
Is a brief (approx. 1ms) change from negative to positive in trans-membrane potential.
Is said to be all-or-none as it occurs fully or not at all
The changes in voltage that produce an AP are caused by a brief, large influx of sodium ions and efflux of potassium ions
What is the movement of an action potential along an axon called?
Nerve impulse
