---
id: human-anatomy
title: "Human Anatomy: Systems, Organs, and Function"
schema_type: Article
category: health
language: en
confidence: high
last_verified: "2026-05-24"
created_date: "2026-05-24"
generation_method: ai_assisted
ai_models:
  - claude-opus
derived_from_human_seed: true
conflict_of_interest: none_declared
is_live_document: false
data_period: static
atomic_facts:
  - id: fact-hlth-ana-001
    statement: Gray's Anatomy (1858, 42nd ed. 2020) is the most authoritative anatomical reference.
    source_title: Standring, S. (ed.) Gray's Anatomy 42nd Ed. (Elsevier 2020)
    source_url: https://www.elsevier.com/books/grays-anatomy/standring/978-0-7020-7705-0
    confidence: high
  - id: fact-hlth-ana-002
    statement: "Adult human: ~206 bones, 600+ muscles, heart pumps ~7,500L blood daily."
    source_title: Marieb & Hoehn, Human Anatomy & Physiology 11th ed. (Pearson 2019)
    source_url: https://www.pearson.com/en-us/subject-catalog/p/human-anatomy-physiology/P200000006820
    confidence: high
  - id: fact-hlth-ana-003
    statement: "Brain: ~86B neurons; cerebral cortex ~16B (Azevedo et al. JCompNeurol 2009)."
    source_title: Azevedo et al. Neuronal/nonneuronal cell numbers (JCN 2009)
    source_url: https://doi.org/10.1002/cne.21974
    confidence: high
completeness: 0.9
primary_sources:
  - title: "Gray's Anatomy: The Anatomical Basis of Clinical Practice, 42nd Edition"
    type: textbook
    year: 2020
    url: https://www.elsevier.com/books/grays-anatomy/standring/978-0-7020-7707-4
    institution: Elsevier
  - title: Guyton and Hall Textbook of Medical Physiology, 14th Edition
    type: textbook
    year: 2020
    url: https://www.elsevier.com/books/guyton-and-hall-textbook-of-medical-physiology/hall/978-0-323-59712-8
    institution: Elsevier
known_gaps:
  - Lymphatic system role in immunity
  - Integumentary system (skin) detailed function
disputed_statements:
  - statement: No major disputed statements identified
secondary_sources:
  - title: "Gray's Anatomy: The Anatomical Basis of Clinical Practice (42nd Edition)"
    type: textbook
    year: 2020
    authors:
      - Standring, Susan (ed.)
    institution: Elsevier
    url: https://www.elsevier.com/books/grays-anatomy/standring/978-0-7020-7705-0
  - title: Netter Atlas of Human Anatomy (Netter, 8th Edition)
    type: textbook
    year: 2022
    authors:
      - Netter, Frank H.
    institution: Elsevier
    url: https://www.elsevier.com/books/netters-atlas-of-human-anatomy/netter/978-0-323-68042-4
  - title: Human Anatomy & Physiology (Marieb & Hoehn, 12th Edition)
    type: textbook
    year: 2023
    authors:
      - Marieb, Elaine N.
      - Hoehn, Katja
    institution: Pearson
    url: https://www.pearson.com/en-us/subject-catalog/p/human-anatomy-physiology/P20000000H7H
  - title: "The Visible Human Project: A Comprehensive Digital Library of Human Anatomy (NLM)"
    type: report
    year: 2024
    authors:
      - National Library of Medicine
    institution: NIH / NLM
    url: https://www.nlm.nih.gov/research/visible/visible_human.html
updated: "2026-05-24"
---
## TL;DR
Human anatomy studies the structure of the body. 11 organ systems — skeletal, muscular, nervous, circulatory, respiratory, digestive, endocrine, urinary, reproductive, lymphatic, integumentary — work in coordinated integration.

## Core Explanation
Major systems: nervous system (brain, spinal cord, nerves — rapid electrical signaling), cardiovascular (heart pumps blood through arteries → capillaries → veins), respiratory (lungs exchange O₂/CO₂ across 70 m² of alveolar surface), digestive (mouth to colon, ~9m tract).

## Detailed Analysis
The brain (~1.4 kg, 86 billion neurons) consumes 20% of the body's oxygen. Neurons communicate via synapses — electrical signals trigger neurotransmitter release. The liver (~1.5 kg) performs 500+ functions including detoxification, protein synthesis, and glycogen storage.

## Further Reading
- Visible Body: 3D Anatomy Atlas
- Khan Academy: Human Anatomy
- NIH: Visible Human Project