Nervous system
11 questions tagged Nervous system — spanning every one of the seven Ws.
Why do some people get motion sick in cars or boats?
Motion sickness happens when the brain gets conflicting signals from the eyes, inner ear, and body. That mismatch can trigger nausea, dizziness, and sweating.
What is the myelin sheath?
The myelin sheath is a fatty insulating layer around nerve fibers that helps electrical signals travel faster. It is produced by different supporting cells in the brain and body.
What is myelin?
Myelin is a fatty insulating layer around many nerve fibers. It helps electrical signals travel faster and more efficiently.
Which is the longest nerve in the human body?
The sciatic nerve is the longest and widest nerve in the human body. It runs from the lower spine through the buttocks and down each leg.
How do nerves send messages so quickly?
Nerves send signals as electrical impulses called action potentials. Many signals travel at speeds of roughly 50–100 meters per second, and some myelinated fibers are even faster.
Where is the blood-brain barrier located?
The blood-brain barrier is located in the capillaries of the brain and spinal cord. It is not a single organ, but a protective barrier around the central nervous system.
Whose name is linked to the body’s largest nerve, which runs from the spine into the leg?
The sciatic nerve is the body’s largest nerve, but it is named for its anatomical location rather than a person.
Whose name is attached to the network of nerves that powers the arm and hand?
The brachial plexus is the nerve network that supplies the shoulder, arm, and hand.
Whose name is attached to the large nerve that runs from the lower spine into the leg?
The sciatic nerve is not named after a person, but it is the body’s largest nerve. It runs from the lower back through the buttock and down the leg.
How many cranial nerves are there in humans?
Humans have 12 pairs of cranial nerves. They emerge from the brain and brainstem and control sensation, movement, and some internal functions.
How many pairs of spinal nerves are there in humans?
Humans have 31 pairs of spinal nerves. They branch from the spinal cord and carry signals between the body and the central nervous system.