The human body
The heart and blood vessels
The heart is a muscular pump with four chambers. Its valves direct blood forward through the pulmonary and systemic circuits.
The heart drives blood through the circulation. Arteries carry blood away from the heart to supply tissues or, in the pulmonary circuit, to the lungs.
Veins return blood toward the heart. Superficial and deep networks collect blood from the tissues; the pulmonary veins bring oxygenated blood back from the lungs.
The heart
A muscular pump in the chest. Its right side sends blood to the lungs; its left side sends blood to the rest of the body.
- MeasuredMass: 330 g in men, 250 g in women (840 / 620 g with its blood)
- MeasuredPumps about 5.6 L a minute at rest in men, 4.5 L in women (cardiac MRI)
- MeasuredResting rate: 50–80 beats a minute in 95% of men, 53–82 in 95% of women
In Endo-View
In the human atlas you can peel the body layer by layer down to these organs, turn it, take it apart and click any part for its card.
Every number is labelled measured, an estimate or drawn: how we know.
More of the body
The lungs and airways The digestive system The kidneys and the urinary system The brain and the nervous system
The journey to life
What Happens to Sperm After Ejaculation How Sperm Get Through the Cervix: Cervical Mucus Sperm in the Uterus: The Race and the White Blood Cells Sperm in the Fallopian Tube: Waiting for the Egg The Human Egg Cell: Its Size and Its Layers How Fertilisation Works: Sperm Meets Egg The Zygote and the First Cell Divisions What Is a Blastocyst? Days 3 to 6 How Implantation Works: Days 6 to 12 The Fetus from Week 10 to Week 20 Pregnancy Week by Week: The Fetus to Week 40 How Birth Works: Labour and the First Breath The Embryo Week by Week: Weeks 4 to 10