Group
Ventricular system
Also called Ventricular system
A hidden network of fluid-filled chambers that cushions and cleans the brain.
The ventricles are four connected, fluid-filled spaces deep inside the brain. They make and hold cerebrospinal fluid (CSF), a clear, watery liquid that bathes the brain and spinal cord. This fluid cushions the brain, lets it float, and helps wash away waste. It is made constantly, flows through the chambers into the space around the brain, and is then soaked back up into the blood.
Where it is
Deep in the center of the brain. The two large lateral ventricles sit in the left and right halves, and connect down through the third ventricle and a narrow canal to the fourth ventricle at the back of the brainstem.
What it does
Making fluid
Tissue inside the ventricles, the choroid plexus, makes most of the roughly 500 ml of cerebrospinal fluid produced every day.
Floating the brain
The brain floats in this fluid, so its effective weight drops from about 1.2 to 1.4 kg to only about 50 grams. This stops it from pressing hard on its own nerves and blood vessels.
Cushioning
The fluid acts like a shock absorber, softening bumps to the head.
Cleaning
As the fluid flows and drains away, it carries off waste products from the brain.
Keeping conditions steady
It keeps a stable chemical environment around brain cells, which they need to work properly.
Think of it as the brain's plumbing and water bed in one: a set of connected tanks that make, move and drain the fluid the brain floats in.
Inside the ventricular system
- Lateral ventriclesTwo big C-shaped fluid chambers, one curling through each half of the brain.
- Third ventricleA thin, slit-like fluid chamber squeezed between the two halves of the thalamus.
- Cerebral aqueductA narrow canal through the midbrain that links the third and fourth ventricles.
- Fourth ventricleA tent-shaped chamber between brainstem and cerebellum where fluid flows out.
- Choroid plexusThe brain's fluid factory: frilly tissue that makes cerebrospinal fluid.
Works with
- Choroid plexusThe choroid plexus, found inside every ventricle, is the factory that makes most of the fluid.
- Lateral ventriclesThe two lateral ventricles are the largest chambers and the start of the fluid's journey.
- Cerebral aqueductThe cerebral aqueduct is the narrowest point, a tiny canal linking the upper and lower chambers.
- Fourth ventricleThe fourth ventricle is the exit, where fluid escapes to surround the brain and spinal cord.
- Spinal cordThe same fluid flows down around the spinal cord, cushioning it too.
When it goes wrong
Hydrocephalus
If fluid cannot drain properly, it builds up and the ventricles swell, pressing on the brain. It is often treated with a thin tube called a shunt, which drains the extra fluid to another part of the body, such as the belly.
Normal pressure hydrocephalus
In older adults, a slow buildup of fluid can cause trouble walking, memory problems and bladder leaks. It can look like dementia, but it is sometimes treatable.
Spinal tap
Doctors can take a small sample of this fluid from the lower back to check for infections like meningitis and other conditions.
For learning only, not medical advice. If you have a health concern, talk to a doctor.
Surprising facts
- Your body makes about 500 ml of this fluid a day, but only about 150 ml is present at any time. That means it is fully replaced several times a day.
- Around 1508, Leonardo da Vinci injected melted wax into the ventricles of an ox brain to cast their shape, one of the earliest uses of this trick in anatomy.
- For centuries, scholars believed the ventricles were where thinking happened, and assigned imagination, reasoning and memory to different chambers.
By the numbers
Where the name comes from
From the Latin "ventriculus", meaning little belly, a word anatomists used for small hollow chambers in the body.
Quick quiz
3 questions. Your answers are saved and come back in your daily review.
Which of these is a job of the ventricular system?
Show the answer
Making fluid. Tissue inside the ventricles, the choroid plexus, makes most of the roughly 500 ml of cerebrospinal fluid produced every day.
Making fluid. Tissue inside the ventricles, the choroid plexus, makes most of the roughly 500 ml of cerebrospinal fluid produced every day.
The ventricular system is part of which larger structure?
Show the answer
Inside the brain. It belongs to the deep parts of the brain.
Inside the brain. It belongs to the deep parts of the brain.
Which part fits this description? "Like the brain's plumbing and water bed in one: a set of connected tanks that make, move and drain the fluid the brain floats in."
Show the answer
Ventricular system. It is the ventricular system. A hidden network of fluid-filled chambers that cushions and cleans the brain.
Ventricular system. It is the ventricular system. A hidden network of fluid-filled chambers that cushions and cleans the brain.
These parts now come back in your daily review, just before you would forget them.
Practice these parts in 3DSources
- Neuroanatomy, Ventricular System, StatPearls, NCBI Bookshelf
- Physiology, Cerebral Spinal Fluid, StatPearls, NCBI Bookshelf
- Leonardo di ser piero da Vinci - a bridge between ancient and post-Galenic anatomy based on studies of the ventricular system of the brain, Frontiers in Neuroanatomy
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