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\usepackage{seqsplit}           % Splits long words.
%\usepackage{opensans}          % Can't make this work so far. Shame. Would be lovely.
\usepackage[normalem]{ulem}     % For underlining links
% Most of the following are not required for the majority
% of cheat sheets but are needed for some symbol support.
\usepackage{amsmath}            % Symbols
\usepackage{MnSymbol}           % Symbols
\usepackage{wasysym}            % Symbols
%\usepackage[english,german,french,spanish,italian]{babel}              % Languages

% Document Info
\author{piigmy}
\pdfinfo{
  /Title (cardiac-muscle.pdf)
  /Creator (Cheatography)
  /Author (piigmy)
  /Subject (Cardiac Muscle Cheat Sheet)
}

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% Header and Footer
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\fancyhead[L]{
\noindent
\begin{multicols}{3}
\begin{tabulary}{5.8cm}{C}
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    \vspace{-7pt}
    {\parbox{\dimexpr\textwidth-2\fboxsep\relax}{\noindent
        \hspace*{-6pt}\includegraphics[width=5.8cm]{/web/www.cheatography.com/public/images/cheatography_logo.pdf}}
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\end{tabulary}
\columnbreak
\begin{tabulary}{11cm}{L}
    \vspace{-2pt}\large{\bf{\textcolor{DarkBackground}{\textrm{Cardiac Muscle Cheat Sheet}}}} \\
    \normalsize{by \textcolor{DarkBackground}{piigmy} via \textcolor{DarkBackground}{\uline{cheatography.com/213581/cs/46487/}}}
\end{tabulary}
\end{multicols}}

\fancyfoot[L]{ \footnotesize
\noindent
\begin{multicols}{3}
\begin{tabulary}{5.8cm}{LL}
  \SetRowColor{FootBackground}
  \mymulticolumn{2}{p{5.377cm}}{\bf\textcolor{white}{Cheatographer}}  \\
  \vspace{-2pt}piigmy \\
  \uline{cheatography.com/piigmy} \\
  \end{tabulary}
\vfill
\columnbreak
\begin{tabulary}{5.8cm}{L}
  \SetRowColor{FootBackground}
  \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Cheat Sheet}}  \\
   \vspace{-2pt}Not Yet Published.\\
   Updated 27th May, 2025.\\
   Page {\thepage} of \pageref{LastPage}.
\end{tabulary}
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  \vspace{-5pt}
  %\includegraphics[width=48px,height=48px]{dave.jpeg}
  Measure your website readability!\\
  www.readability-score.com
\end{tabulary}
\end{multicols}}




\begin{document}
\raggedright
\raggedcolumns

% Set font size to small. Switch to any value
% from this page to resize cheat sheet text:
% www.emerson.emory.edu/services/latex/latex_169.html
\footnotesize % Small font.

\begin{multicols*}{3}

\begin{tabularx}{5.377cm}{x{1.9908 cm} x{2.9862 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Intro}}  \tn
% Row 0
\SetRowColor{LightBackground}
Myocardium & middle of heart wall, contains cardiac muscle \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
How are CM cells connected? & intercalated discs, forms desmosomes and gap-junctions \tn 
% Row Count 5 (+ 3)
% Row 2
\SetRowColor{LightBackground}
Functional Syncytium & group of CM cells that contract in coordination with each other (gap junctions) \tn 
% Row Count 9 (+ 4)
% Row 3
\SetRowColor{white}
Autorhythmicity & creates its own electrical activity (no NS input) \tn 
% Row Count 12 (+ 3)
% Row 4
\SetRowColor{LightBackground}
Pacemaker Cells & creates pacemaker activity, grouped together in nodes \tn 
% Row Count 15 (+ 3)
% Row 5
\SetRowColor{white}
Cardiac Contractile Cells & 99\% of cardiac muscle cells, actually performs contraction but is not autorhythmic \tn 
% Row Count 19 (+ 4)
% Row 6
\SetRowColor{LightBackground}
Other Characteristics & involuntary (autonomic neuro fibers), striated, lots of mito + myoglobin, longer AP than smooth/skeletal muscle \tn 
% Row Count 24 (+ 5)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.18988 cm} x{2.78712 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Pacemaker Flow}}  \tn
% Row 0
\SetRowColor{LightBackground}
SA Node & 70 APs/min, main node \tn 
% Row Count 1 (+ 1)
% Row 1
\SetRowColor{white}
Where is SA node? & right atrium near superior vena cava \tn 
% Row Count 3 (+ 2)
% Row 2
\SetRowColor{LightBackground}
AV Node & 50 APs/min, follows SA node \tn 
% Row Count 5 (+ 2)
% Row 3
\SetRowColor{white}
Where is AV node? & base of right atrium \tn 
% Row Count 6 (+ 1)
% Row 4
\SetRowColor{LightBackground}
Bundle of His & tract of pacemaker cells that start at AV node -\textgreater{} ends at left and right ventricles \tn 
% Row Count 10 (+ 4)
% Row 5
\SetRowColor{white}
Purkinje Fibers & 30 APs/min, follows SA node \tn 
% Row Count 12 (+ 2)
% Row 6
\SetRowColor{LightBackground}
Where are Purkinje Fibers? & from end of Bundle of His through ventricular myocardium \tn 
% Row Count 15 (+ 3)
% Row 7
\SetRowColor{white}
Interatrial Pathway & pacemaker pathway from right to left atrium \tn 
% Row Count 17 (+ 2)
% Row 8
\SetRowColor{LightBackground}
Internodal Pathway & pacemaker pathway from SA node to AV node \tn 
% Row Count 19 (+ 2)
% Row 9
\SetRowColor{white}
AV Nodal Delay & activity delay of 100ms going through AV node \tn 
% Row Count 22 (+ 3)
% Row 10
\SetRowColor{LightBackground}
Why is AV Nodal Delay important? & allows for ventricles to contract after atrial contraction \tn 
% Row Count 25 (+ 3)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.28942 cm} x{2.68758 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Pacemaker Activity}}  \tn
% Row 0
\SetRowColor{LightBackground}
Nodes & controls rate and coordination of contractions \tn 
% Row Count 3 (+ 3)
% Row 1
\SetRowColor{white}
How many nodes? & 2 nodes, SA and AV \tn 
% Row Count 4 (+ 1)
% Row 2
\SetRowColor{LightBackground}
Pacemaker potentials & depolarization of membrane potential until threshold (triggers AP) \tn 
% Row Count 8 (+ 4)
% Row 3
\SetRowColor{white}
First half of pacemaker potential & funny channels open -\textgreater{} Na+ in, K+ channels close (K+ remains inside) \tn 
% Row Count 12 (+ 4)
% Row 4
\SetRowColor{LightBackground}
Second half of pacemaker potential & funny channels close, T-type Ca2+ channels open -\textgreater{} takes potential to threshold \tn 
% Row Count 16 (+ 4)
% Row 5
\SetRowColor{white}
Threshold & T-type Ca2+ channels close, L-type Ca2+ channels open -\textgreater{} potential reaches peak \tn 
% Row Count 20 (+ 4)
% Row 6
\SetRowColor{LightBackground}
Falling Phase & K+ channels open (K+ out), L-type Ca2+ channels close -{}-\textgreater{} fall back to original potential \tn 
% Row Count 25 (+ 5)
% Row 7
\SetRowColor{white}
Major ions for pacemaker activity & K+, Na+, Ca2+ \tn 
% Row Count 27 (+ 2)
% Row 8
\SetRowColor{LightBackground}
Timing & both Ca2+ channels are crucial for keeping rhythm (T-type channels: gradual depolarization, L-type: fast depolarization) \tn 
% Row Count 33 (+ 6)
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\par\addvspace{1.3em}

\vfill
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\begin{tabularx}{5.377cm}{x{2.28942 cm} x{2.68758 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Pacemaker Activity (cont)}}  \tn
% Row 9
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Pacemaker potential value & -60mV \tn 
% Row Count 2 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
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\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
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\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Contractile Cardiac Muscle Cells}}  \tn
% Row 0
\SetRowColor{LightBackground}
Resting potential value & -90mV \tn 
% Row Count 2 (+ 2)
% Row 1
\SetRowColor{white}
Rapid rise & opening fast Na+ channels, Na+ in \tn 
% Row Count 4 (+ 2)
% Row 2
\SetRowColor{LightBackground}
Brief repolarization & limited K+ efflux, coupled with inactivation of Na+ channel \tn 
% Row Count 7 (+ 3)
% Row 3
\SetRowColor{white}
Plateau Phase & Ca2+ entry (opens L-type channels), coupled with reduced K+ efflux (K+ channels close) \tn 
% Row Count 11 (+ 4)
% Row 4
\SetRowColor{LightBackground}
Rapid falling & opening ordinary voltage-gated K+ channels (K+ out) \tn 
% Row Count 14 (+ 3)
% Row 5
\SetRowColor{white}
Resting potential & back to resting potential by closing ordinary K+ channels and opening leaky K+ channels \tn 
% Row Count 18 (+ 4)
% Row 6
\SetRowColor{LightBackground}
AP and Contractile response & contraction happens during plateau phase \tn 
% Row Count 20 (+ 2)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
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\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{X}
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\mymulticolumn{1}{x{5.377cm}}{\bf\textcolor{white}{Contractile AP vs. Pacemaker AP}}  \tn
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\par\addvspace{1.3em}

\begin{tabularx}{5.377cm}{x{2.23965 cm} x{2.73735 cm} }
\SetRowColor{DarkBackground}
\mymulticolumn{2}{x{5.377cm}}{\bf\textcolor{white}{Excitation-Contraction Coupling}}  \tn
% Row 0
\SetRowColor{LightBackground}
Dyhydropyridine receptors & acts like voltage-gated Ca2+ channels. When AP reaches T-tubules, these receptors activate and allows Ca2+ flow \tn 
% Row Count 6 (+ 6)
% Row 1
\SetRowColor{white}
Sarcoplasmic Reticulum & entry of Ca2+ causes calcium release from Sarcoplasmic Reticulum \tn 
% Row Count 9 (+ 3)
% Row 2
\SetRowColor{LightBackground}
Contraction & number of activated cross-bridges is proportional to Ca2+ conc. in cytosol \tn 
% Row Count 13 (+ 4)
% Row 3
\SetRowColor{white}
Calcium-Induced Calcium-Release & opening of L-type Ca2+ channels -\textgreater{} activation of dyhydropyridine receptors -\textgreater{} amplified release of Ca2+ from sarcoplasmic reticulum \tn 
% Row Count 19 (+ 6)
% Row 4
\SetRowColor{LightBackground}
Refractory Period and Contraction & refractory period and length/strength of contraction is directly proportional (longer refractory period = contractile length/strength increases) \tn 
% Row Count 26 (+ 7)
\hhline{>{\arrayrulecolor{DarkBackground}}--}
\end{tabularx}
\par\addvspace{1.3em}


% That's all folks
\end{multicols*}

\end{document}