The Nervous System

1. The Nervous System

2. What Is The Nervous System? • It is a communication system between the brain and the body. • It controls your body’s emotions, movements, thinking, and behavior.

4. The Nervous System is… • Made up of two major systems: • Central Nervous System (CNS) • Peripheral Nervous System – Relays messages between the CNS and the rest of the body.

5. Central Nervous System (CNS) • Consists of the brain and the spinal chord – enclosed in bone. • Every voluntary action involves the CNS. • Walking, Taking Notes, Throwing A Football

6. Peripheral Nervous System (PNS) • Made up of nerve cells called neurons • Responsible for transmitting messages (electrical impulses) between the CNS and the body. • Made up of 2 major systems: • Somatic Nervous System • Autonomic Nervous System

7. Neurons • 3 types of neurons: • Sensory Neurons – Pick up stimuli inside the body or in the world and sends signals INTO the brain. • Motor Neurons – Send OUT signals from the brain and spinal chord to the glands, muscles, and organs. • Interneurons – Connects neurons to one another.

8. Neurons • 5 parts to a neuron: • Cell Body – Produces the energy for the cell. • Dendrites – Thin branch-like fibers that receive information from other neurons. • Axon – Tube-like extension that carries a signal away from the cell body. • Myelin Sheath – White fat cells that protect the axon and speeds of the transmission of signals. • Axon Terminals – Small branch-like fibers that send messages to other neurons.

9. Neuron Structure

10. Neuron Synapses • Synapse – The space between the axon terminals and dendrites where signals are sent across using neurotransmitters. • Neurotransmitters – Chemicals released by the axon terminal that travel across the synapse to another neuron’s dendrites. • 3 Key Neurotransmitters: • Serotonin • Dopamine • Endorphins

11. Synaptic Gap

12. Neurotransmitters • Serotonin • Involved in mood control, appetite, and sleep • Low levels of serotonin are linked with depression and anxiety disorders.

13. Neurotransmitters • Dopamine • Involved with movement and emotional arousal (alertness) • Deficiency in dopamine is linked with Parkinson Disease • Excess dopamine is linked to schizophrenia • Antipsychotic Drugs block dopamine receptors • Cocaine, nicotine & amphetamines increase dopamine activity

14. Neurotransmitters • Endorphins • Regulates pain control and perception during stressful or traumatic events. • Also important in experiencing pleasure. • Can give a sort of “high” or euphoric feeling to the individual. • We can become addicted to endorphin causing feelings. • Ex. Acupuncture • Similar to opiate addiction (morphine, heroin, codeine)

15. 2 Parts To The Peripheral Nervous System • Somatic Nervous System • Controls the voluntary muscles & transmits sensory information the CNS. • Autonomic Nervous System • Controls the involuntary functions of the body • Ex. Heartbeat, Breathing, Digestion, Blood Pressure • Has two parts: • Sympathetic • Parasympathetic

16. 2 Parts To The PNS • Sympathetic Nervous System • Prepares the body for stressful or threating situations. • Slows digestion, raises heart rate, raising blood pressure, sweating • “Fight Or Flight” Response • Stay and confront or turn and run • Sympathetic starts with “S” like Stress

17. 2 Parts To The PNS • Parasympathetic Nervous System • Calming mechanism for the body. • Heart rate & blood pressure return to normal, • Acts to conserve & maintain the body’s energy resources. • Parasympathetic begins with a “P” just like Peace.

18. 2 Parts To The PNS