What normal looks like

Keeping blood chemistry balanced

Blood is held very slightly alkaline, in a range so narrow that moving outside it is always significant. Lungs

Keeping calcium balanced

Blood calcium is held in an unusually narrow range, because both nerves and heart muscle depend on it. Bone ac

Making red blood cells

The marrow makes roughly two million red cells every second. Each one lasts about 120 days, so the whole popul

Filtering the blood

Healthy adult kidneys filter roughly 90 to 120 mL of plasma per minute, processing the body's entire blood vol

Keeping blood sugar steady

Blood sugar rises after a meal and settles back within about two hours. Overnight it sits in a narrow band. He

Processing drugs and waste

The liver continuously processes everything absorbed from the gut before it reaches the rest of the body, incl

Making blood proteins

A healthy liver makes around 10 to 15 grams of albumin a day, plus most of the proteins that let blood clot. I

Taking in and storing iron

The body has no way to actively get rid of excess iron, so it controls the amount it absorbs instead. Only a s

Getting oxygen into the blood

At rest most adults breathe about twelve to twenty times a minute without thinking about it, and blood leaves

Managing your body's water and salt

Most adults pass urine six to eight times in a day and usually sleep through the night without needing to go.

Setting your metabolic pace

A working thyroid keeps hormone levels remarkably steady day to day. The pituitary constantly adjusts its sign

Absorbing vitamin B12

B12 absorption needs two organs working together: the stomach makes a carrier protein, and the far end of the