Nervous System

• Neurons and Glial Cells are the 2 Types of Nervous Tissue
• The nervous system regulates, and coordinates functions of the body required to maintain homeostasis.
• Neurons are the electrically excitable cells of the nervous system. It consists of consists of a cell body with several processes.
• Neurons send electrical signals to other cells using long extensions called AXONS
• Nerve is a collection of many axons bundled together outside the brain and the spinal cord
• Cranial Nerves – 12 pairs, originated from brain
• Spinal Nerves – 31 pairs, originated from spinal cord.
• Some neurons form clusters of cell bodies outside the brain and spinal cord called GANGLIA.
• Glial cells are supportive cells that serve many functions for the neurons.
• The 5 types of functions of the nervous system are: Maintaining Homeostasis, Receiving Sensory Input, Integrating Information, Controlling Muscle and Glands, and Establishing and Maintaining Mental Activity
• The 2 Major Divisions of Nervous System are Central Nervous System (CNS) and Peripheral Nervous System (PNS)
• CENTRAL NERVOUS SYSTEM (CNS) receives information from and sends information to the body. it is the KEY DECISION MAKER and consists of the brain and the spinal cord
• Brain – housed within the skull.
• Spinal Cord – housed within the vertebral canal of the vertebral column.
• PERIPHERAL NERVOUS SYSTEM (PNS) is responsible for detecting stimuli in and around the body and sending that information to the CNS and then communicating messages from the CNS to the body. it is the MESSENGER and consists of all the nervous tissue outside the CNS, which includes nerves, ganglia, and sensory receptors.
• 2 Primary Divisions of PNS: Sensory Division and Motor Division
• SENSORY DIVISION (AFFERENT (TOWARD) DIVISION) transmits electrical signals from specialized receptors in the body toward the CNS.
• Sensory Receptors – detect stimuli and then send input along nerves, which extend from the receptor to the brain or spinal cord.