# SOS how to vertical align text with this specific \newcolumntype?

I would like to vertical align the text 'Muscular system', which is highlighted in color lavender. I defined a new column type and the correlated questions on this website couldn't help. Thank you in advance!

    \documentclass{book}
\usepackage{dcolumn}
\usepackage{tabularx}
\usepackage{color, colortbl}
\definecolor{LavenderBlue}{rgb}{0.85,0.85,1}

\newcolumntype{P}[1]{>{\centering\arraybackslash}p{#1}}

\begin{document}

\begin{table}[!h]
\renewcommand\arraystretch{1.1}
\centering
\small
\begin{tabular}{|P{4cm}|P{7cm}|}
\hline
System & Effects \\
\hline
Circulatory system & Pericarditis, heart failure, hypertension \\ \hline
Blood tissue & Anemia \\ \hline
Gastrointestinal system & Nausea, loss of appetite, diarrhoea, stomatitis \\ \hline
Nervous system  & Somnolence, apathy, amnesia \\ \hline
\rowcolor{LavenderBlue}
Muscular system & Cramps, alteration of sensitivity, alteration of neuromuscular excitability \\ \hline
Skeletal system & Changes in bone metabolism, joint inflammation \\ \hline
Integumentary system & Pallor, itching, yellowish colour \\ \hline
\end{tabular}
\caption{Effects caused by renal dysfunctions on the systems of the human body.}
\label{effectbody}
\end{table}

\end{document}

• you want to align where? top, bottom, center? – Michael Palmer Nov 16 '17 at 14:19
• center, please. But >{\centering\arraybackslash} didn't work for me – silvia26 Nov 16 '17 at 14:21

Replacing \newcolumntype{P}[1]{>{\centering\arraybackslash}p{#1}} by \newcolumntype{P}[1]{>{\centering\arraybackslash}m{#1}} in your MWE gives you the following result:
In general, p cells are top aligned, m cells are vertically centered and b cells align their contents to the bottom of the cell.