Divisions and subdivisions of the nervous system

What are the two major anatomical divisions of the nervous system?

• Central Nervous System (CNS)

• Peripheral Nervous System (PNS)

What does the CNS consist of?

• Brain

• Spinal cord

What is the main function of the CNS?

• Control centre

• Performs integration

What does the CNS control?

• Emotions

• Behaviours

• Personality

What intellectual functions does the CNS perform?

• Cognitive functions

• Memory storage

What does the PNS consist of?

• Sensory receptors

• Cranial nerves

• Spinal nerves

• Peripheral nerves

What do cranial nerves innervate?

• Head & neck structures

• Skin and muscles of head, neck, face; Salivary and tear glands

• 12 pairs

What do spinal nerves form?

• Peripheral nerves that innervate body below the head

• Skin and muscles of torso, arms, legs

• 31 pairs

Subdivisions of the peripheral nervous system

• Motor division (efferent division)

• Sensory division (afferent division)

What does the sensory division do?

• Conveys sensory input from receptors to the CNS

What does the motor division do?

• Conveys motor output from the CNS to muscles or glands

What are the two functional systems of the motor division?

• Autonomic Nervous System

• Somatic Nervous System

What does the somatic nervous system convey?

• Somatic motor output from CNS to skeletal muscles

What does somatic motor output control?

• Voluntary skeletal muscle movements

• Involuntary skeletal muscle movements (somatic reflexes)

What are somatic reflexes?

• Rapid, involuntary skeletal muscle movements in response to a specific stimulus

What does the autonomic nervous system convey?

• Autonomic motor output from CNS to glands, cardiac & smooth muscles

What does autonomic motor output control?

• Involuntary activities

What involuntary activities does the ANS regulate?

• Heart rate

• Respiratory airflow

• Blood vessel diameter

• Pupil diameter

• Digestion

• Urination

• Defecation

• Perspiration

• Salivation

What are the two divisions of the autonomic nervous system?

• Sympathetic division

• Parasympathetic division

What does the sympathetic division control?

• Fight-or-flight activities

What does the sympathetic division activate?

• Functions supporting physical activity

What does the sympathetic division inhibit?

• Functions that do not support physical activity

What are examples of sympathetic effects?

• Increases heart rate

• Increases respiratory airflow

• Increases blood flow to skeletal muscles

• Increases sweat gland activity

• Dilates pupils

• Inhibits digestion

• Inhibits urination & defecation

What does the parasympathetic division control?

• Rest and digest activities

What does the parasympathetic division activate?

• Functions that conserve and restore energy

What are examples of parasympathetic effects?

• Stimulates digestion

• Stimulates urination & defecation

• Constricts pupils

• Decreases heart rate

• Decreases respiratory airflow

What are the major divisions of the nervous system?

• Central Nervous System

• Peripheral Nervous System

Divisions of the CNS

• Brain

• Spinal cord

What are the divisions of the PNS?

• Sensory division

• Motor division

What are the divisions of the motor division?

• Autonomic nervous system

• Somatic nervous system

What are the divisions of the autonomic nervous system?

• Sympathetic division

• Parasympathetic division