The Nervous System

​What are the two major divisions of the nervous system, and what are their basic functions?

​Two systems work to send and take in information from the surrounding environment

​1. Central Nervous System - Brain and spinal cord bundled with nerves is the body's decision maker

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​2. Peripheral Nervous System - Gathers information from other body parts and transmits CNS decisions to the rest of the body

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​Nerves - Electrical cables formed of bundles of axons that send and receive these messages

​Link CNS to sensory receptors, muscles, and glands

​- Sensory neurons: Carry messages from your body's tissues and sensory receptors inward to your spinal cord and brain for processing

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​- Motor neurons: Carry instructions from your central nervous system out to your body's muscles and glands

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​- Interneurons - Within your body and spinal cord communicate with one another and process information between the sensory input and motor output

​- Two subdivisions of the peripheral system: Somatic and Autonomic

​- Somatic: Monitors sensory input and triggers motor output (Moving muscles, taking step, lifting weights: Control over skeletal and muscles)

-Autonomic Nervous System: Controls glands, muscles of your internal organs, including heart and digestive systems

​TWO SUBDIVISONS OF THE AUTONOMIC NERVOUS SYSTEM - Sympathetic and Parasympathetic

​Sympathetic - More alert - Increases your heart rate, blood pressure, and blood sugar level

​Parasympathetic - calms down - conserve your energy and decrease your heart rate

​- The brain is the control center for sending and receiving signals to the body

​-Estimates of over 86 billion neurons make up the complexity of your brain

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​- Brain takes up 2% weight but 20% of energy

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​- Brain neurons try to cluster or be closer together to make the connection easier (learning piano, or history, or riding a bike)

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​- Neurons that fire together wire together

​- The spinal cord is a two way highway. Information going up to the brain and down to the body

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​- Connects the brain to everything which is why we have reflexes (Knee tap is one of these connections)

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​- Spinal cord damage can lead to loss of connection which can lead to paralysis and loss of feelings