MCB 461 Exam 2 || 100% Accurate Answers.
Modes of Neuronal communication correct answers 1. Chemical synaptic transmission
(Neurotransmitters)
2. Electrical synaptic transmission via gap junctions
3. Interneuronal communication by gases (NO)
4. Interneuronal communication by hormones (longest range) --> short term effect *neuronal
activity* versus long term effect *changes in gene expression*
5. Interneuronal communication by endocannabinoids
6. Autocrine versus paracrine
Coined the Tern "synapse" correct answers Charles Sherrington 1897. Information transfer at a
synapse plays critical roles in all the operations of the nervous system
Who did research on Chemical synapses? correct answers Otto Loewi in 1921
Who did research on Electrical synapse? correct answers Edwin Furshpan/David Potter 1959
Gap Junction Channel Structure correct answers Composed of two connexons (one on each
cytoplasm). Six connexins per one connexon
Pore size of Connexon correct answers d=1-2 nm
What passes through electrical synapses? correct answers Small molecules less than 1 kDa in
both directions!
Where are gap junction channels found? correct answers In both non-neuronal cells, and in
neurons. More in embryonic than mature cells.
Pros and Cons of electrical synapses correct answers pros: No synaptic delay; very fast
transmission
Cons:only changes the voltage of the PSP one mV (small!!)
Direction of Electrical Synapses correct answers Bidirectional!
Evidence of Chemical Transmission experiment correct answers Otto Loewi: frog hearts .
Donor heart vagus nerve is stimulated and fluid is collected.
Recipient heart receives the fluid and its heart rate slows down.
Pacemaking slows within 100ms of stimulation of parasympathetic vagal nerves (inhibitory)
What was in the fluid of the frog hearts experiment? correct answers Acetylcholine (slowed
down rate, stimulated parasympathetic vagal nerves)
Synapses at the NMJ correct answers Chemical: occur between axons of neurons and muscle.
Modes of Neuronal communication correct answers 1. Chemical synaptic transmission
(Neurotransmitters)
2. Electrical synaptic transmission via gap junctions
3. Interneuronal communication by gases (NO)
4. Interneuronal communication by hormones (longest range) --> short term effect *neuronal
activity* versus long term effect *changes in gene expression*
5. Interneuronal communication by endocannabinoids
6. Autocrine versus paracrine
Coined the Tern "synapse" correct answers Charles Sherrington 1897. Information transfer at a
synapse plays critical roles in all the operations of the nervous system
Who did research on Chemical synapses? correct answers Otto Loewi in 1921
Who did research on Electrical synapse? correct answers Edwin Furshpan/David Potter 1959
Gap Junction Channel Structure correct answers Composed of two connexons (one on each
cytoplasm). Six connexins per one connexon
Pore size of Connexon correct answers d=1-2 nm
What passes through electrical synapses? correct answers Small molecules less than 1 kDa in
both directions!
Where are gap junction channels found? correct answers In both non-neuronal cells, and in
neurons. More in embryonic than mature cells.
Pros and Cons of electrical synapses correct answers pros: No synaptic delay; very fast
transmission
Cons:only changes the voltage of the PSP one mV (small!!)
Direction of Electrical Synapses correct answers Bidirectional!
Evidence of Chemical Transmission experiment correct answers Otto Loewi: frog hearts .
Donor heart vagus nerve is stimulated and fluid is collected.
Recipient heart receives the fluid and its heart rate slows down.
Pacemaking slows within 100ms of stimulation of parasympathetic vagal nerves (inhibitory)
What was in the fluid of the frog hearts experiment? correct answers Acetylcholine (slowed
down rate, stimulated parasympathetic vagal nerves)
Synapses at the NMJ correct answers Chemical: occur between axons of neurons and muscle.
