The Biological Basis of Behaviour 10/22/2012 8:02:00 AM
Introduction: Texting while driving.My position on this thing is it should be
legal; good reasons to support it!! Not necessarily have to focus on all
aspects of the reasons for the topic; focus on something and pursue it !
Nerve cells specialized for communications
100 billion cells with – 160 trilion connections among them,
Support cells in the nervous system.
Much smaller than neurons, but 10 times more numberous that neurons.
Essential for myelinations of neurons, blood-brain barrier, repair , removal of
PARTS OF NEURON.
Myelinization creates insulation of current on the neurons; and also helps
speed neural impulses. Spaces b/w myelin sheath on the neurons are called
Nodes of Ranvier
Cell Body function is to figure out if it has enough message to create a new
message and process an action potential at the action potential. “All-or-
ACTION POTENTIAL -A neural message; a brief shift in a neurons electrical charge that travels
along an axon.
Axon can be considered as a hose; pipe. When nothing; no stimulation is
going on; negative charged particles are inside the cell and positive ones are
on the outside. The resting potential is (-70mV). (+ Sodium) (-Potassium)
Through action potential, the ion channels open; sodium flows in and
potassium out through the semi-permeable membrane on the axons.
Repetition of this occurs as the current travels along the axon.
Absolute Refractory Period
-A brief time period (-2ms) during which another action potential cannot
occur; when system is “over polarized.”
Coding Stimulus Intensity
Stimulus intensity if focused on the frequency can influence the levels of
Alzhemires disease is because acetyl choline asterase is inhibiters. Changing
the number of receptors can influence the the biologhical and behaviours of
humans; via drugs etc or increasing or decreasing the inhibition of receptors.
COMMUNICATION WITHIN & B/W NEURONS
-Action potentials travel along the axon and arrive at the terminal buttons
-Chemical Messengers (neurotransmitters=NT) are stored in sunaptic
-When the action potential reaches the terminal button, vesicles fuse with
-NT is released into the synaptic cleft the microscopic gap b/w the terminal
button of one neuron and the cell membrane of another neuron.
-NT binds to receptors in a lock-and-key fashion.
-The activity of the NT is halted via (1) chemical breakdown or (2) reuptake
into the pre-synaptic axon terminal.
POST-SYNAPTIC POTENTIALS (PSPs)
-Action potential has to occur at the threshold point at a certain point and it
shoots upto +40mV, from the resting potential of -70mV.
-Excitary neurotransmitters cause to go to +40 while inhibitory will cause to
go lower than -70mV; eg -80 or -90.
In the soma the potential is always changing.
-PsPs are voltage changes at a receptor site on the post synaptic cell
Integrating Postsynaptic Potentials: -SPATIAL SUMMATION (summing from inputs from different areas of the
Occurs when two or more post synaptic potentials occur simultaneorusly at
different receprotr sites at the same neuron.
-TEMPORAL SUMMATION (build up over time of voltage potentials)