Nervous system

• The central nervous system includes the brain and spinal cord and is responsible for processing and coordinating information.
• Neurons are specialized cells that communicate with one another through electrical impulses called action potentials.
• Interneurons connect different parts of the CNS and play a role in integrating and modulating neural activity.
• Sensory neurons carry signals from sensory receptors to the CNS, while motor neurons transmit signals from the CNS to effector organs such as muscles or glands.
• The Nervous System is the "Highway" along which the brain sends and receives information about what is happening inside and outside the body
• The Nervous System is made up of billions of neurons throughout the body that join together to make nerves
• The Nervous System has 2 major divisions: Central Nervous System (CNS) and Peripheral Nervous System (PNS)
• Central Nervous System (CNS) is made up of the brain and the spinal cord
• The brain is the control center of the entire body and the most important organ of the nervous system
• The brain is divided into three major parts: cerebrum, cerebellum, and brainstem
• Cerebrum is the largest part of the brain that controls thoughts, senses, thinking, and imagination
• Cerebellum is located below the cerebrum and is responsible for controlling motion, balance, learning, and acquiring new things
• Brainstem, also known as "Medulla Oblongata," regulates automatic functions such as breathing, heart rate, digestion, and blood pressure
• The Spinal Cord is a cylindrical bundle of nerve fibers that is enclosed in the spine and connects all parts of the body to the brain
• The Spinal Cord is protected by a bony vertebral column and surrounded by cerebrospinal fluid (CSF) that acts as a cushion against trauma and damage
• Ascending Tract carries stimulus from the body towards the brain to interpret
• Descending Tract carries response from the brain to initiate movement and control body functions
• Cervical nerves "C" supply movement and feeling to the arms, neck, and upper trunk, and also control breathing
• Thoracic Nerves "T" supply the trunk and abdomen
• Lumbar nerves "L" and Sacral Nerves "S" supply the legs, bladder, bowel, and sexual organs
• Spinal nerves are categorized from C1 to C7, T1 to T12, L1 to L5, and the Sacral Nerve
• Peripheral in computers refers to devices like printers and scanners that are external and controlled by the central processing unit
• The Peripheral Nervous System (PNS) carries messages, signals, stimulus, and responses to and from the Central Nervous System
• The PNS performs nervous system activities outside the brain
• The PNS has 2 divisions:

  • Autonomic Nervous System: carries automatic or involuntary functions from the brainstem to different organs/parts of the body
  • Somatic Nervous System: carries voluntary functions into and out from the brain, specifically the cerebrum and cerebellum
• Autonomic Nervous System has 2 divisions:

  • Sympathetic Nervous System: prepares the body for action and stress
  • Parasympathetic Nervous System: restores normal functions or relaxes the body
• PNS has 2 major parts:

  • Cranial Nerves: located in the head, carries signals into and out of the brain
  • Spinal Nerves: located in all body parts (except the head), carries signals into and from the spinal cord
• Somatic Nervous System has 2 major parts:

  • Sensory Nerve: carries stimulus from different body parts to the spinal cord
  • Motor Nerve: collects responses from the spinal cord produced by the brain and carries them to different body organs/parts
• 3 types of Spinal Nerve:

  • Sensory Nerve
  • Motor Nerve
  • Associative Nerve: located between the sensory and motor nerves
• Stimulus is anything acquired through the five senses

  • Response can be voluntary or involuntary actions responding to a specific stimulus
• Diagram scenarios:

  1. Ball about to hit your face

  2. Receiving a chat from your crush saying "hi!"