The human nervous system

The human nervous system flashcards

What is the average speed of an electrical impulse in nerve cells?

100 m/s

What is the largest and longest nerve in the body?

The sciatic nerve.

How many nerve cells does the brain contain on average?

86 billion nerve cells.

What life process is the nervous system related to that involves detecting changes in the environment?

Sensitivity.

What are the components of the nervous system?

Brain, spinal cord, and nerves.

What do receptor cells in the nervous system do?

They detect stimuli.

What is the function of an effector in the nervous system?

A muscle or gland that carries out a response to an electrical signal.

What is a reflex arc?

A means of automatically and rapidly integrating stimuli with responses of effectors.

What type of actions require conscious thought?

Voluntary actions.

What type of actions are automatic and do not require conscious thought?

Involuntary actions.

What are the three types of neurones?

Sensory neurones, motor neurones, and relay neurones.

What is the junction between two neurones called?

A synapse.

What does the myelin sheath do?

Acts as an electrical insulator, ensuring electrical signals only go where they are supposed to.

What is the role of the central nervous system (CNS)?

To process information and send signals between the brain and spinal cord.

What are the two main parts of the nervous system?

Central nervous system (CNS) and peripheral nervous system (PNS).

What happens to a muscle when it receives an electrical impulse from a motor neurone?

It contracts.

What is the purpose of the reflex arc?

To quickly respond to stimuli without involving the brain for immediate safety.

Name an example of a reflex action.

Knee jerk or withdrawing hand from a hot surface.

How do drugs like heroin or cocaine affect synapses?

They alter the transmission of impulses across synapses.

What do we call the cells that detect a stimulus?

Receptor cells.