AP Psych Unit 1.2

The Nervous System

Sensory neurons (afferant): send signals from sensory receptors to CNS

Motor neurons (efferant): sends signals from CNS to PNS

Nervous Systems: a communication network system that is made up of nerve cells (neurons) that controls our body’s functions

• made up of central nervous system and peripheral nervous system

Central Nervous System: Made of the brain and spinal cord, (headquarters) receives and processes sensory info from the rest of body. Sends out motor commands to control movement, behavior, and internal processes. Stores memories, enables learning

Peripheral Nervous System: all the rest of the nerves throughout our body that gather and collect sensory info from our receptors in our skin, muscles and organ and send it to our CNS.

Divided into 2 main subsystems: Autonomic and Somatic Nervous Systems

Somatic Nervous System: controls our body’s skeletal muscles and voluntary movements/behaviors.

• under conscious control

• allows us to perform actions based on our will and intentions

Autonomic Nervous System: controls the glands and the muscles of the internal organs and regulates involuntary unconscious processes to survive (heart rate, breathe) (autonomic= automatic!!)

divided into 2 more parts

Sympathetic nervous system: the emergency response system that arouses the body and helps it deal with stressful events. It triggers “fight or flight” responses that prepare the body for action.

Parasympathetic Nervous system: the default condition of ANS that maintains homeostasis. It calms the body after a sympathetic situation and conserves energy. “rest and digest”

Both the sympathetic and parasympathetic systems work together to maintain homeostasis.

Sympathetic Examples:

• pupils dilate

• heart rate increases

• slows digestion

Parasympathetic Examples:

• pupils contract

• heart rate slows

• increased digestion