Lecture 2 - CNS Structure and Function Flashcards
Where is acetylcholine secreted from?
Is it excitatory or inhibitory?
L2 S4 LO1
Secreted by:
- pyramidal cells
- basal nuclei (some)
- alpha motor neurons
- preganglionic neuron (ANS)
- postganglionic neurons (parasympathetic)
- some postganglionic (sympathetic)
Typically excitatory
Where is norepinephrine secreted from?
Is it excitatory or inhibitory?
L2 S5 LO1
Secreted by:
- brain stem and hypothalamus (many)
- pons (some)
- most postganglionic neurons (sympathetic)
Both excitatory and inhibitory
Where is dopamine secreted from?
Is it excitatory or inhibitory?
L2 S5 LO1
Secreted by:
-neurons in the substantia nigra
Typically excitatory
Where is glycine secreted from?
Is it excitatory or inhibitory?
L2 S7 LO1
Secreted by:
-synapses in the spinal cord
Always inhibitory
Where is GABA secreted from?
Is it excitatory or inhibitory?
L2 S7 LO1
Secreted by:
-spinal cord and cerebral cortex
Always inhibitory
Where is glutamate secreted from?
Is it excitatory or inhibitory?
L2 S7 LO1
Secreted by:
- sensory pathways entering CNS
- cerebral cortex
Always excitatory
Dendrites do not conduct __________, instead they use __________.
L2 S9 LO2
Action potentials; electronic conduction
What is decremental conduction and where does it occur?
L2 S9 LO9
Due to the partial permeability of dendrite membranes to potassium and chloride, potential gradually decreases as it moves away from the site of initiation.
Because of this, a more positive potential gradually falls back towards baseline as it moves towards the cell body.
THIS DIRECTLY OPPOSES ACTION POTENTIAL FORMATION IN DENDRITES
What is electronic conduction?
Why does this occur in the dendrite instead of an action potential>
L2 S14 LO2
It is the direct spread of potential due to diffusion of ions.
Action potentials don’t form due to sparsity of voltage-gated sodium channels and that threshold potential is typically not achieved.
What factors affect firing rate?
L2 S18 LO2
If excitatory rate is above threshold, the neuron will fire repetitively. Addition of excitatory or inhibitory signals will increase or decrease the firing rate respectively.
What is synaptic delay and what factors effect it?
L2 S19 LO2
The time to transmit a signal form a presynaptic neuron to postsynaptic neuron.
Minimal time is 0.5 msec
Factors:
- time to release neurotransmitter
- time neurotransmitter takes to diffuse
- effect neurotransmitter has on postsynaptic membrane
- rate of receptor action
- time of sodium ion diffusion
What are the two sources of blood to the brain?
What is the Circle of Willis?
L2 S20-22 LO3
- vertebral arteries
- internal carotid
Circle of Willis:
-anastomosis of internal carotid arteries and basilar artery (fusion of vertebral arteries
What are the cerebral lobes and what are their functions?
L2 S28-29;31 LO4
Occipital lobe:
- eye focusing movements
- correlates visual images w/ memory
- conscious perception of images
Parietal lobe:
- somatesthetic interpretation
- understanding speech (Wernicke)
- formulating words
Frontal lobe:
- voluntary movement
- personality
- cognitive processes
- verbal communication (Broca)
Temporal lobe:
- olfactory and auditory sensation
- olfactory and auditory memory
Insula:
- memory
- highest level of brain function (ie. abstract thought and judgement)
What are the nuclei located in the corpus striatum and what are the functions of each?
L2 S32 LO4
Caudate nucleus:
-subconscious movements of skeletal muscles
Lentiform nucleus:
- Putamen: subconscious movements of oskeletal muscles
- Globus pallidus: regulation of muscle tone
What are the functions of the thalamus?
L2 S41 LO4
- relays all sensory information (except smell) to cerebrum
- crude awareness
- initial autonomic responses to intense pain
- interprets crude pain, temperature, light touch, and pressure
- role in arousal and alerting
- role in complex reflex movements
