Nervous System: Structure, Function, and Cell Types

What is the primary function of the nervous system?

Coordinates and controls all activities of the body.

What happens when the brain stops functioning?

The body dies.

What are the major organs of the nervous system?

Brain, spinal cord, senses, and nerves.

What are the two main divisions of the nervous system?

Central Nervous System (CNS) and Peripheral Nervous System (PNS).

What does the Central Nervous System consist of?

The brain and spinal cord.

What does the Peripheral Nervous System consist of?

All nerves not in the brain or spinal cord.

What is the role of the Motor Division of the PNS?

Sends impulses away from the CNS to muscles and glands.

What is the difference between the Autonomic and Somatic Nervous Systems?

The Autonomic Nervous System controls involuntary muscles, while the Somatic Nervous System controls voluntary muscles.

What is the function of the Sympathetic Division?

Used in emergency situations ('fight or flight').

What is the function of the Parasympathetic Division?

Reduces sympathetic response and provides resting functions such as digestion and urination.

What are the two major types of nerve cells?

Neurons and neuroglia.

What is the primary function of neurons?

Conduct impulses around the body.

What is the role of neuroglia?

Support, insulate, and protect neurons.

What are the three main parts of a neuron?

Cell body, dendrites, and axon.

What is the function of dendrites?

Bring impulses towards the cell body.

What is the function of axons?

Send impulses away from the cell body.

What is myelin and its function?

A waxy insulation that helps nerve impulses travel more quickly.

How is the myelin sheath created?

By Schwann cells wrapping around the axon.

What are the gaps in the myelin sheath called?

Nodes of Ranvier.

What is a nerve impulse?

An electrical signal that travels along the neuron.

What is resting potential?

The state where a neuron's intracellular space is negatively charged and the extracellular space is positively charged.

What occurs during depolarization?

Sodium rushes into the neuron, reversing the charges.

What is the all-or-none response in nerve impulses?

Either the threshold is met and the impulse proceeds, or it never starts.

What is a synapse?

The junction where two neurons meet.

What is the synaptic cleft?

The space between two neurons at a synapse.

What happens at a synapse when an impulse reaches the axon terminal?

Neurotransmitters are released across the synaptic cleft.

What are the three layers of connective tissue that protect the CNS?

Dura mater, arachnoid membrane, and pia mater.

What is the function of cerebrospinal fluid (CSF)?

Protects the brain, maintains the blood-brain barrier, and prevents infection.

Where is cerebrospinal fluid produced?

In the ventricles of the brain.

What are the four ventricles of the brain?

Two lateral ventricles, third ventricle, and fourth ventricle.