Overview of the Nervous System

Overview of the Nervous System

• Both the nervous system and the endocrine system are responsible for the body's internal coordination.
• The endocrine system uses hormones to communicate throughout the body.
• The nervous system uses neurons to send messages from cell to cell, via electrical and chemical methods.
• The nervous system receives stimuli from the external environment and transmits messages to the CNS.
• The CNS processes information and determines a response.
• The CNS issues commands to muscles and gland cells to execute the response.

Central and Peripheral Nervous Systems

• The CNS includes the brain and spinal cord.
• The PNS includes nerves and ganglia.
• A nerve is a bundle of neuron axons wrapped in connective tissue.
• Ganglia are clusters of neuron cell bodies concentrated in the PNS.

Functional Divisions of the Peripheral Nervous System

• The PNS is functionally divided into sensory and motor systems, each with further somatic and visceral categories.
• The sensory (afferent) division carries signals from receptors to the CNS.
  • The somatic sensory division carries signals from receptors in the skin, muscles, bones, and joints.
  • The visceral sensory division carries signals from the viscera (heart, lungs, stomach, and urinary bladder).
• The motor (efferent) division carries signals from the CNS to effectors.
  • The somatic motor division carries signals to skeletal muscles and causes voluntary muscle contraction and reflexes.
  • The visceral motor division (autonomic nervous system or ANS) carries signals to glands, cardiac, and smooth muscle. It is involuntary.
    • The sympathetic division of the ANS stimulates and prepares the body for action.
    • The parasympathetic division of the ANS has a calming effect on the body.
    • The enteric nervous system is a network of nerves located within the digestive tract wall that assists with digestive function.

Properties of Neurons

• Neurons are made excitable by their ability to respond to stimuli.
• Neurons have the ability to conduct electricity, sending signals along their length.
• Neurons can secrete neurotransmitters at their tips.
• There are three types of neurons:
  • Sensory neurons detect stimuli and send messages to the CNS.
  • Interneurons receive signals from other neurons and send signals to other neurons.
  • Motor neurons receive signals from the CNS and send signals to an effector organ.

This quiz covers the basic components and functions of the nervous system and endocrine system. It examines the distinctions between the central nervous system (CNS) and peripheral nervous system (PNS), including their structures and roles in body coordination. Delve into the functional divisions of the PNS to enhance your understanding.