2A - nervous system

• Central nervous system (CNS) consists of the brain and spinal cord. It receives neural messages from and transmits neural messages from the PNS also processes information from internal and external environment.
• The brain is considered to the control center enabling us to perceive, interact and respond to our world. Coordinates mental processes and behavior. Regulates bodily activity and is involved in every sensation and movement we experience.
• The spinal cord is a cable of nerve tissue that extends from the brain, connects us to the PNS, is the route which neural information travels between the body and brain. Composed of afferent tracks that transmit motor messages from the brain to PNS.
• Peripheral NS connects the CNS to external world, transmitting neural messages between CNS and the body. Is comprised of all neurons outside the CNS. Divided into somatic and autonomic nervous system.
• Somatic NS has the important role in responding to sensory stimuli and initiating voluntary movement. Transmits neural messages that are related to voluntary motor movement. Comprised of sensory neural pathways that are made up of sensory neurons and motor neural pathways made up of motor neurons.
• How a neural message travels in the somatic nervous system begins when, motor neural messages travel from CNS to skeletal muscles via efferent pathways. The somatic NS is comprised of sensory neural messages travel from sensory receptors to the CNS via afferent neural pathways.
• The Autonomic NS does not require conscious control and is responsible for unconscious responses further divides into the sympathetic and parasympathetic NS. It controls visceral muscles, organs and glands that are not connected to the skeleton. Is predominately self-regulating.
• The sympathetic NS activates visceral muscles, organs and glands. Prepares the body to respond to threats or stressors.
• Parasympathetic NS maintains and returns the body to optimal and balanced functioning of visceral muscles, organs and glands. Maintains homeostasis.
• A neuron is a nerve cell that receives and transmits neural information. Is the basic functional unit of the NS, arranged in neural pathways that allow neural messages to be transmitted.
• A motor neuron transmits neural messages about motor movement from the CNS to PNS.
• Sensory neurons transmit neural messages about bodily sensations from PNS to CNS.
• Interneurons transfer neural messages between sensory neurons and motor neurons