Our Gemara on Amud Beis discusses the quantity of blood from a corpse that is sufficient to impart impurity as if a full corpse was present. This amount is known as a “revi’is”, which is a quarter log, approximately 3.8 ounces. The Gemara Chullin (72a) bases this amount on the amount of blood needed to maintain a form of life, thus it embodies the soul. (While this is scientifically difficult to understand, Tosafos Sotah 5a “adam” explains it as a minimum amount of unabsorbed blood which sustains the heart.)
Toldos Yaakov Yosef (Kedoshim) explains the idea of Revi’is and impurity with mystical depth:
The Gemara (Sotah 5a) states:
אֲמַר רַבִּי אֲלֶכְּסַנְדְּרִי כׇּל אָדָם שֶׁיֵּשׁ בּוֹ גַּסּוּת הָרוּחַ אֲפִילּוּ רוּחַ קִימְעָא עוֹכַרְתּוֹ שֶׁנֶּאֱמַר וְהָרְשָׁעִים כַּיָּם נִגְרָשׁ וּמָה יָם שֶׁיֵּשׁ בּוֹ כַּמָּה רְבִיעִיּוֹת רוּחַ קִימְעָא עוֹכַרְתּוֹ אָדָם שֶׁאֵין בּוֹ אֶלָּא רְבִיעִית אַחַת עַל אַחַת כַּמָּה וְכַמָּה
Rabbi Alexandri says: Concerning any person who has arrogance within him, even a slight wind disturbs him, as it is stated: “But the wicked are like the troubled sea, for it cannot rest” (Isaiah 57:20). And if with regard to the sea, which contains many quantities of quarters of a log of water, yet a slight wind disturbs it, certainly with regard to a person, who has in his body only one quarter-log of essential lifeblood, all the more so will a slight wind disturb him.
Says Toldos Yaakoiv Yosef, the Gematria numerical equivalent of the Hebrew word “Dam” “blood” is 44. A Revi’is of blood, is therefore a quarter of that, which is numerically 11, the same as God’s name E-hyeh אֶֽ-הְיֶ֑ה (found in Shemos 3:14.)*
(*You are legitimately wondering how this is numerically equal to 11? I’m not completely sure I understand it myself to be frank, however, Toldos Yaakov Yosef says it is based on a complicated mystical formula from Rav Chayyim Vital, found in: פרי עץ חיים חג המצות פרק א, here is how it goes: א’, א”ה, אה”י, אהיה, עולה גמטריא ד”ם, נמצא שהם י’ שמות אהיה ברבועם. If you add each pair אה, then אהי, then אהיה you get 44. But there are apparently four dimensions of this, I think the four different worlds of אצילות, בריה, יצירה ועשייה, so that is how it comes to equal 11. And because we’re not so smart and kabbalistica inclined, we could look at it more simply, the aggregate of the gematria of אה,אהי,א-היה equals 44 which is the same as דם blood. If a Revi’is of blood is life, then somehow a quarter of the holy name also equals life. )
Thus the “lifeblood” of a person is recognizing God’s presence within him. Any disruption of that caused by arrogance, unsettles this still soft voice within, just as small wind can rile up the vast sea. Man himself, in Hebrew “Adam” “אדם” is gematria-style “א-דם”, Dam plus one (also 45 is the aleph of Ehyeh plus the 44 of the other letter pairs.) That is, the recognition of the “One”, that is God, transforms the arrogant and idolatrous 44 into the revi’is dam, the quarter of blood, which is God’s name, numerically 11.
Moshe rhetorically asks the Jewish people (Devarim 10:12):
וְעַתָּה֙ יִשְׂרָאֵ֔ל מָ֚ה ה אלוקיך שֹׁאֵ֖ל מֵעִמָּ֑ךְ כִּ֣י אִם־לְ֠יִרְאָה אֶת ה אלוקיך לָלֶ֤כֶת בְּכָל־דְּרָכָיו֙ וּלְאַהֲבָ֣ה אֹת֔וֹ וְלַֽעֲבֹד֙ אֶת ה אלוקיך בְּכָל־לְבָבְךָ֖ וּבְכָל־נַפְשֶֽׁךָ
And now, O Israel, what does your God demand of you? Only this: to revere your God to walk only in divine paths, to love and to serve your God with all your heart and soul.
The Gematria of the Hebrew word “Mah” “what” is 45. Thus, Moshe says, all Hashem asks of you is “Mah” – to remove the arrogance and recognize the A-dam, the God force inside man, and then the rest of the Torah will be easy.