#6.4 Peripheral Nervous System PNS

Somatic Nervous System (SNS)

transmits messages about sights, sounds, smells, temperature, body positions etc. to the central nervous system

Somatic Nervous System (SNS)

control purposeful body movements and tiny almost imperceptible movements that maintain our balance and posture

Somatic Nervous System (SNS)

Part of PNS that interacts with external environment - sensory and motor

afferent nerves

Somatic NS:

carry sensory signal from organs to CNS

efferent nerves

Somatic NS:

carry motor signals from CNS to skeletal muscles

Autonomic Nervous System (ANS)

regulates/controls the body's internal environment (organs)

Autonomic Nervous System (ANS)

Critical in regulatory functions: blood circulation, secretion, digestion, urination, defecation, etc.

Autonomic Nervous System (ANS)

activities can occur automatically, even while sleeping

Sympathetic Division

ANS <

most active during processes that involve spending body energy from stored reserves, such as a fight-or-flight response

Sympathetic Division

ANS <

active during arousal

Sympathetic Division

ANS <

Autonomic nerves projected from CNS in lumbar and thoracic regions of spinal cord.

Sympathetic Division

ANS <

Prepares the body for action

Sympathetic Division

ANS <

Stimulate, organize, and mobilize energy sources in threatening situations

Sympathetic Division

ANS <

Fight-or-flight system

Sympathetic Division

ANS <

its changes are indicative of psychological AROUSAL

Parasympathetic Division

ANS <

most active during processes that replenish reserves of energy, such as sleeping

Parasympathetic Division

ANS <

active during relaxation

Parasympathetic Division

ANS <

Autonomic nerves projected from brain and sacral regions of spinal cord

Parasympathetic Division

ANS <

Act to conserve energy and provide rest, repair, and energy storage

Parasympathetic Division

ANS <

rest & digest

Parasympathetic Division

ANS <

its changes are indicative of psychological RELAXATION

each (all)

___________ autonomic target organ receives opposing sympathetic and parasympathetic input