

Chapter 1
The autopilot of your inner universe
Chapter 2
The body's internal construction crew
Chapter 3
The microscopic ecosystem keeping you alive
Chapter 4
Survival mode and extreme adaptations
Ch 1 · The autopilot of your inner universe

007skaty The brain's thermostat triggers blood vessels to constrict or dilate and muscles to shake, protecting cellular life during temperature fluctuations.
007skaty Kidney Fluid Balance
We filter your blood all day (day and night!) And save ninety-nine percent (bring it back!)

007skaty Specialized cells in the right atrium trigger about 100,000 heartbeats every day.

BETA
007skaty Time your morning alarms to discover how sleep cycles recharge your body.
Fun Fact
Heartbeat sync: Did you know that when people sing in a choir together, their heart rates actually synchronize and beat in unison?
Glossary
autonomic nervous system (noun)
The part of the nervous system responsible for regulating involuntary bodily functions like heart rate and digestion. British physiologist John Newport Langley coined the term in 1898 to describe these unconscious pathways.
The part of the nervous system responsible for regulating involuntary bodily functions like heart rate and digestion. British physiologist John Newport Langley coined the term in 1898 to describe these unconscious pathways.
Quiz
At what internal body temperature does severe hypothermia typically set in, causing the body's self-regulation systems to fail?
Quiz
Which part of the brain acts as the body's primary control center for regulating temperature and hunger?
Quiz
Which specialized group of cells serves as the natural pacemaker of the human heart?
Quiz
Which part of the brainstem is primarily responsible for automatically controlling your breathing rhythm?
Quiz
What chemical trigger in the blood primarily tells your brainstem that it is time to take another breath?
Quiz
Roughly how many times is your body's total blood volume filtered by your kidneys every single day?

