Introduction and The Central Nervous System Flashcards
Outline the nervous system. (NS)
Provides the biological basis of psychological experience.
Outline the central nervous system. (CNS)
Concerned with all life functions and processes.
Outline the autonomic nervous system. (ANS)
Comprised of motor pathway.
Outline the somatic nervous system. (SNS)
Comprised of sensory and moor pathways.
Conscious control of smooth muscle.
Outline the peripheral nervous system. (PNS)
Transmits information to and from the nervous system.
Outline the sympathetic nervous system.
Fight or flight.
Activates internal organs in situations that need arousal and energy.
E.g. pupil dilation, increased heart rate.
Outline the parasympathetic nervous system.
Rest and digest.
Body tries to conserve and store resources.
Opposite effect to sympathetic.
E.g. store glucose, decrease heart rate.
Outline the motor neuron.
Carry signals from the CNS which helps both organs, including glands and muscles, to function.
Outline the sensory neuron.
Tells the rest of the brain about the external and internal environment by processing information from any of the five senses.
Outline the relay neuron.
Carry messages from one part of the CNS to another.
They connect with sensory neurone.
Why does synaptic transmission only occur in one direction?
Receptor sites are only on a post synaptic neuron.
There are no vesicles on a post synaptic neuron.
Diffusion can only take place from a low concentration to a high concentration.
Outline the process of synaptic transmission.
Action Potential/ electrical impulse travels down the presynaptic neuron.
Stimulates the vesicles (containing NTs) to move down towards the terminal of the cell.
The vesicles fuse with the membrane of the presynaptic neuron.
NTs diffuse into the synaptic fluid/ cleft.
NTs then diffuse across the synapse to the receptor sites on the postsynaptic neuron, where they will bind to the complementary sites.
An action potential may or may not be initiated in the post synaptic neuron.
Inhibitory NTs reduce the likelihood of an action potential arriving in the post synaptic neuron.
Excitatory NTs increase the likelihood of an action potential arriving in the post synaptic neuron.
Finally, summation occurs, distributing the combined effect of the action potential on the post synaptic neuron.
If a threshold is reached, then a new action potential will form in the post synaptic neuron.
NTs can diffuse back into the synapse, broken down by enzymes or can be re-up taken by the presynaptic neuron.
What is exocytosis?
The fusion of vesicles with the membrane.
Can any NT only an ion channel in the receptor sites?
Only certain neurotransmitters can “unlock” an ion channel in certain receptors in the post-synaptic neuron.
Similar to the ‘lock and key theory’ with enzymes.
What happens when NTs bind to receptor sites?
Ions flow through the channel into the neuron along their specific pathways.
This flooding of ions can cause a ‘potential’ in the dendrites.
These potentials can be excitatory or inhibitory.
