Psyche AP Nervous system

What is the nervous system?

The body's communication network that receives, processes, and sends information.

What are the two main divisions of the nervous system?

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

What makes up the central nervous system (CNS)?

The brain and spinal cord.

What is the main function of the CNS?

Processes information and coordinates the body's responses.

What is the peripheral nervous system (PNS)?

All nerves outside the brain and spinal cord.

What is the main function of the PNS?

Carries information between the CNS and the rest of the body.

What are the two main divisions of the PNS?

Somatic nervous system and autonomic nervous system.

What does the somatic nervous system control?

Voluntary skeletal muscle movements and sensory information.

What does the autonomic nervous system control?

Involuntary functions such as heartbeat, digestion, and breathing regulation.

What are the two divisions of the autonomic nervous system?

Sympathetic and parasympathetic nervous systems.

What is the sympathetic nervous system responsible for?

Activates the fight-or-flight response during stress or danger.

What is the parasympathetic nervous system responsible for?

Promotes rest-and-digest activities and conserves energy.

What happens to heart rate during sympathetic activation?

Heart rate increases to prepare the body for action.

What happens to heart rate during parasympathetic activation?

Heart rate decreases toward its resting level.

How does the sympathetic system affect digestion?

Generally slows digestion so energy can support immediate action.

How does the parasympathetic system affect digestion?

Stimulates digestion and gastrointestinal activity.

How do the pupils respond to sympathetic activation?

Pupils dilate to let in more light.

How do the pupils respond to parasympathetic activation?

Pupils constrict toward their normal resting size.

How does sympathetic activation affect energy availability?

Mobilizes stored energy for rapid use.

How does parasympathetic activation affect energy use?

Supports energy conservation, recovery, and routine maintenance.

Which nervous system division controls voluntary movement?

The somatic nervous system.

Which nervous system division controls involuntary organ activity?

The autonomic nervous system.

What is the basic information pathway from sensation to response?

Sensory input travels toward the CNS

What are sensory (afferent) neurons?

Carry information from sensory receptors toward the CNS.

What are motor (efferent) neurons?

Carry commands from the CNS toward muscles and glands.

What is an interneuron?

A neuron that connects and processes information between neurons, especially within the CNS.

How do the CNS and PNS work together?

The PNS carries information to the CNS, and the CNS processes it and sends instructions back.

How do the sympathetic and parasympathetic systems interact?

They often have opposing effects that help regulate and balance organ activity.

Do sympathetic and parasympathetic systems always work in opposition?

No. Their effects can be complementary, and some organs receive mainly one type of input.

What is homeostasis?

Maintaining relatively stable internal conditions despite changes inside or outside the body.

How do the autonomic divisions help maintain homeostasis?

They adjust involuntary functions to meet the body's changing needs.

You pull your hand away from a hot surface. Which system controls the skeletal muscle movement?

Somatic nervous system. A spinal reflex can produce the movement rapidly.

Your heart beats faster when you feel threatened. Which division is active?

Sympathetic nervous system.

After eating, your digestive activity increases. Which division is active?

Parasympathetic nervous system.

You consciously decide to raise your arm. Which division is involved?

Somatic nervous system.

Your body automatically adjusts blood vessel diameter. Which division controls this?

Autonomic nervous system.

You hear a loud bang and become alert. Which division helps prepare your body?

Sympathetic nervous system.

After the danger passes, your heart rate settles. Which division helps?

Parasympathetic nervous system.

A sensory signal travels from your skin to your spinal cord. Which major division carries it?

Peripheral nervous system, through sensory neurons.

Your brain sends a command to your leg muscles. Which major division carries it outside the CNS?

Peripheral nervous system, through motor neurons.

Can the sympathetic and parasympathetic systems be active at the same time?

Yes. Their activity can overlap