• Autonomic motor pathways
  • involuntary control of smooth muscle, cardiac muscle, and glands
• Somatic motor pathways
  • voluntary control of skeletal muscles

• Affects cardiac muscle, smooth muscle, and glands
• Two divisions
  • Sympathetic division - thoracolumbar division
  • Parasympathetic division - craniosacral division
• Relay in the PNS (except for innervation of the adrenal gland)

• excitation
• fear
• physical activity

• rest

ANS

Cardiovascular system

• regulates heart rate
• regulates force of heartbeat
• regulates the rate of blood flow through the body
• regulates the diameter of various blood vessels
• regulates the amount of blood going to different organs

ANS - Sympathetic

Cardiovascular system

• Increases heart rate
• Increases the force of heartbeats
• Large effect on blood vessels

ANS - Parasympathetic

Cardiovascular system

• Decreases heart rate
• Has a small effect on decreasing the force of heartbeats
• Not much effect on blood vesses, except in genitals

ANS

Digestive System

• Motility
  • movement of products through GI tract
    • swallowing
    • vomiting
    • intestinal motility
    • defecation
• Secretions
  • saliva and other products that aid digestion
• Sympathetic - decrease the above
• Parasympathetic - increase the above

ANS

Respiratory System

• The ANS can change the diameter of airways
• Sympathetic
  • relaxes bronchial muscles, to dilate airways
• Parasympathetic
  • contracts bronchial muscles, to constrict airways

ANS

Urinary Systems

• Contraction of bladder
• Sympathetic
  • slightly relaxes muscle of bladder wall
• Parasympathetic
  • contracts muscle of bladder wall, to empty bladder during urination

ANS

Reproductive System

• erection and ejaculation in males
• uterine muscle activity in females
• Sympathetic
  • Helps stimulate contraction of uterus during childbirth
  • Stimulates ejaculation in males
• Parasympathetic
  • Stimulates erection in males

ANS

Sympathetic innervation of abdominal and pelvic organs

• Control of these organs is primarily discrete, so that the responses are normally specific to the organ being controlled

ANS

Sympathetic control of othe structures

(skin, heart, blood vessels and lungs)

• Control of these structures is sometimes discrete, to give specific responses
• these structures can also be activated all together, by the hypothalamus
  • Coordinates the body's ability to cope with the demands of exercise and/or threatening situations
    • an increase in the rate and force of heartbeats
    • a shift in blood flow, away from the GI tract, to skeletal and cardiac muscle

ANS

Sympathetic stimulation of adrenaline secretion by the adrenal glands

• flight or fight response
• promotes glycogenolysis in liver and in skeletal muscle

• Components of the parasympathetic division are usually activated separately, as needed to deal with some specific issue
  • decrease heart rate
  • cause urination
  • promote activity in the digestive system
  • to affect core body temperature

ANS

Conscious Activity

• Emotions
  • stress
  • fear
  • sexual arousal
  • embarrassement
  • nervousness

ANS

Reflexes

• occur when sensory information triggers ANS motor activity
• Many are classic negative feedback loops, which exist to maintain homeostasis
  • ex:  Medulla oblongatat detects that blood pressure is too low.  It activates sympathetic division to increase heart rate
  • ex:  Spinal cord detects that bladder is full of urine.  It activates parasympathetic division to cause urination.
  • ex:  Spinal cord and brainstem detect presence of food in GI tract.  They activate parasympathetic division to increase digestive activities.