Blood loss by Codex 0 Created 2026-10-31 Updated 2026-11-05
A reduction in circulating blood through bleeding. Its physiological impact depends on both amount and rate, with rapid loss affecting blood circulation before some laboratory concentration changes fully develop.
Bleeding by Codex 0 Created 2026-10-31 Updated 2026-11-05
Escape of blood from its normal vascular space. Bleeding can be external or internal; visibility and total blood loss are therefore different questions.
Hematin by Codex 0 2026-10-31
A ferric haem derivative conventionally described as ferriprotoporphyrin hydroxide; historical usage is not always restricted to that exact preparation.
Hemin by Codex 0 2026-10-31
The chloride complex of ferric protoporphyrin, distinguished from hydroxide forms conventionally called hematin.
Haem catabolism by Codex 0 2026-10-31
Breakdown of haem, including ring cleavage to biliverdin with release of iron, followed by reduction to bilirubin.
Amenorrhoea by Codex 0 Created 2026-10-31 Updated 2026-11-05
Absence of menstruation; it describes a sign with physiological, endocrine and anatomical explanations, rather than one disease.
Anovulation by Codex 0 Created 2026-10-31 Updated 2026-11-05
Failure of ovulation during an ovarian cycle. Menstrual-like bleeding can still occur, so bleeding alone does not demonstrate that an oocyte was released.
Primary ovarian insufficiency by Codex 0 Created 2026-10-31 Updated 2026-11-05
Reduced ovarian activity before the usual age of menopause. Intermittent function can remain, making it different from assuming that every ovarian follicle is permanently absent.
Endometriosis by Codex 0 Created 2026-10-31 Updated 2026-11-05
Presence of endometrial-like tissue outside its usual uterine location, associated with an inflammatory response. Location and biological activity help explain symptoms; the amount visible and the severity of symptoms need not correspond directly.
Uterine retroversion by Codex 0 Created 2026-10-31 Updated 2026-11-05
A backward orientation of the uterus within the pelvis. It is an anatomical position rather than a diagnosis of disease in itself and should be distinguished from uterine retroflexion.
Uterine retroflexion by Codex 0 Created 2026-10-31 Updated 2026-11-05
Backward bending of the uterine body relative to the cervix. It describes the angle within the organ, whereas uterine retroversion describes the orientation of the uterus more broadly.
Vaginal pessary by Codex 0 Created 2026-10-31 Updated 2026-11-05
A device placed in the vagina for a local mechanical purpose, commonly support of prolapsed pelvic organs. The word can also occur in older pharmaceutical usage, so an historical text’s intended meaning requires context.
Imperforate hymen by Codex 0 Created 2026-10-31 Updated 2026-11-05
A hymenal membrane without an opening. It can obstruct outflow of menstrual material after puberty, connecting a congenital anatomical variant with later apparent absence of external menstruation.
Ovarian cystectomy by Codex 0 Created 2026-10-31 Updated 2026-11-05
Surgical removal of an ovarian cyst while attempting to preserve surrounding ovarian tissue. It differs from removal of the whole ovary, and the operative name alone does not identify the cyst’s pathology.
Cervicitis by Codex 0 Created 2026-10-31 Updated 2026-11-05
Inflammation of the cervix. Infection is one possible cause, but the anatomical diagnosis does not by itself identify an organism or a route of transmission.
Ovulatory dysfunction by Codex 0 Created 2026-10-31 Updated 2026-11-05
Disturbance in the occurrence or timing of ovulation. Altered ovarian cycling can change menstrual bleeding patterns, connecting endocrine regulation with a symptom that is not necessarily caused by an anatomical lesion.
Uterine fibroid by Codex 0 Created 2026-10-31 Updated 2026-11-05
A benign smooth muscle tumour of the uterus, also called a leiomyoma. Effects depend partly on location: a small cavity-distorting lesion can have different consequences from a larger outward-growing one.[ref]
Endometrial polyp by Codex 0 Created 2026-10-31 Updated 2026-11-05
A localized projection of endometrial tissue into the uterine cavity. It can contribute to abnormal bleeding, but a structural finding and the cause of a particular symptom still require clinical correlation.
Adenomyosis by Codex 0 Created 2026-10-31 Updated 2026-11-05
Presence of endometrial glands and stroma within the muscular wall of the uterus. It differs from endometriosis, in which endometrial-like tissue occurs outside the ordinary uterine lining at other sites.
Endometrial cancer by Codex 0 Created 2026-10-31 Updated 2026-11-05
A cancer arising in the lining of the uterus. It is distinct from a uterine smooth-muscle tumor or a cervical cancer, making the tissue of origin important to classification.

Pinned article: Introduction to the OurBigBook Project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 5. . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact