function dy = single_syn_coupled_equations(t,y)

dy=zeros(2,1); % a column vector
%seed_values=[membrane_potential_due_to_AP, number_ca_channels_total, number_ca_channels_open, ca_channel_conductance, ca_channel_close_tau, cytosolic_calcium_conc, , ...
%    7   cytosolic_calcium_decay_tau, RRP_size, RP_to_RRP_tau, RP_size,PEP_size, PEP_to_RP_tau, PEP_to_RRP_tau, glu_per_vesicle, cleft_glutamate_conc, glutamate_cleft_decay_tau];


if membrane_potential_due_to_AP>10 & number_ca_channels_open<number_ca_channels_total & rand>.8, number_ca_channels_open=number_ca_channels_open+1;end

dmembrane_potential_due_to_AP=-5*membrane_potential_due_to_AP;
 
dcytosolic_calcium_conc=-cytosolic_calcium_decay_tau*cytosolic_calcium_conc + ca_channel_conductance*number_ca_channels_open;

dnumber_ca_channels_open=-ca_channel_close_tau*number_ca_channels_open;

if cytosolic_calcium_conc*rand>1  & RRP_size>0
    cleft_glutamate_conc=cleft_glutamate_conc+glu_per_vesicle;
    RRP_size=RRP_size-1;
    PEP_size=PEP_size+1;

dy(5)=;

dy(6)=;

dy(7)=;

dy(8)=;

dRP_size=-RP_to_RRP_tau*RP_size;

dPEP_size=-PEP_to_RP_tau*PEP_size -PEP_to_RRP_tau;

dy(11)=;

dy(12)=;

dy(13)=;

dy(14)=;