Nervous System Control of Behavior Flashcards
Nerve Net
few neurons, minimal density, sparse connections; no “brain,” but still perform simple behaviors, like response to environmental stimuli
Nerve Net Example: simple invertebrates (w/radial symmetry) -> Jellyfish
Complex Nervous System
as the name says, more complex lol, greater number of neurons, other cell types present, greater density; more robust connections; has “brain” and specialized neurons that respond to specific stimuli
Complex nervous system examples: vertebrates (so mammals, birds, amphibians)
Santiago Ramon y Cajal
Histologist
Saw cells of various shapes and sizes, predicted they had different purposes (and was right!), did the research before humans had knowledge of neurons; had extensively detailed drawings of neurons
Name the parts of the neuron and its function
Parts: nucleus, cell body, dendrites, axon, myelin sheath, axon terminal
Cell body
soma, responsible for electrical signal generation
Dendrites
where chemical info is received
Axon
transmits electrical signals
Myelin Sheath
a type of fat that wraps around the axon to speed up an electrical signal
Axon terminal
where a signal exits a neuron to the designated part of the body (an example being muscle)
Describe neuron process/function
info enters dendrites, goes through cell body, to axon/myelin sheath, and exits at the axon terminal
Name the 3 categories of neurons
multipolar, bipolar, and unipolar
Multipolar Neuron
major cell type of complex neurons system, produce more complex behaviors
Bipolar neuron
processes sensory info, seen in vertebrates and higher order invertebrates
Unipolar neuron
most simple neuron type, processes simple behaviors (nothing complex), associated with nerve nets, seen in simple invertebrates
Describe the research of Dr. Kenneth Roeder
Ultrasonic processing in moths
Saw it Outside of the CNS(central nervous system), local circuit
Accompolished by pattern generator (NOT BRAIN); brain modulates but does not control this
Figured out moths can hear echolocation of bats, their main predator, through A1 and A2 receptors
Describe experiments done by Dr. Kenneth on A1 and A2 receptors
Activation of A1 and A2 sustained
Moths exposed to volume increasing in intensity; Central pattern generator normally responsible for rhythmic movements, inhbiting this creates erractic wing beats/flying
This will throw off the pattern the bat(predator) would expect
If the bat is not fooled: Continued activation of A1 and A2, or Complete shutdown of central pattern generator (then bat cannot detect moth)
Central pattern generators
responsible for rhythmic movements
Aplysia
aquatic species aka the sea hare
has unipolar neurons
displayed to have learning ability in research
Describe the research of Dr. Eric Kendel
showed Aplysia has learning ability to an extenet
showed learning of habituation and sensitization in Aplysia
Aplysia habiutation
When the Aplysia is poked, the sensitive parts of the body are draw in/back towards the body (gills, head); once it goes back to “normal, “ this is repeated
Eventually displays habituation (no response to poking)
Neurotransmitters of Aplysia under normal conditions
Vesicles and neurotransmitters are just waiting for signals
Electrical signals are sent down the axon
Signals bring in Calcium ions into the channels
Then capsules work as chemical messengers (neurotransmitters), to cross the synapse to the motor neuron it will activate
Neurotransmitters under habituation in Aplysia
The voltage gated Calcium ion channels will not open
The electrical signal stops there, will then not allow capsules to release chemical messages
Note: remember these signals are ALL OR NOTHING signals; This means poking harder does not change effect, voltage stays the same and does not open ion channels
Sensitization in Aplysia
they receive a poke and then are shocked (done with strong continuity); they will then flinch after a poke since they expect a shock to follow
Describe one neurotransmitter pathway of sensitization in Aplysia
Poking and shocking releases serotonin 5-HT, G-coupled 5-HT receptor grabs onto serotonin 5-HT in axon
Serontonin 5-HT has three major parts: the alpha section moves on to Adenylate cyclase (other areas don’t matter here); Alpha section and Adneylate cyclase create the cyclic AMP (2nd messenger); This leads to protein kinase
Protein kinase phosphorylates (adds phosphate group) potassium channels; This changes potassium channel states (in this case on -> off, open -> close, but can go either way); Phosphorylated potassium channels stay closed longer
Overall, the electrical signal will have no where to go, since channels are closed; the longer they are closed, the longer the calcium ion channels are open
Name another pathway of neurotransmitters in sensitization in Aplysia
Poking and shocking releases serotonin 5-HT; G-coupled 5-HT receptor grabs onto serotonin 5-HT in axon
Serontonin 5-HT has three major parts: the alpha section moves on to phospholipase C (other areas don’t matter here); Alphas section and phospholipase C create the DAG(diacylglycerol); This leads to protein kinases
Protein kinase phosphorylates calcium ion channels and synapsin activates; This changes their state from off -> on, close -> open
Syapsin facilitates movement of vesicles and capsules
Neuron
send and receive electrical & chemical info; receive chem, send electrical
Glia
10x more numerous than neurons, support the function of neurons
Interneurons
: modulate (fine tune) signaling by neurons
Cerebellum
responsible for fine motor activities
Size/distinguishable-ness of it increases from reptile to bird to cat to human
Olfactory lobe/bulb
responsible for sense of smell
Near front of face in vertebrates (which makes sense lol)
