Central Nervous System & Neurotransmitters

Central Nervous System & Neurotransmitters

• The nervous system in humans controls bodily functions and responses to the surrounding environment
• The nervous system comprises the brain, spinal cord, spinal nerves, and specialized sense organs
• Sense organs detect stimuli and convert them into nerve impulses, which are transmitted to the central nervous system
• Nerve impulses are electrical signals that travel through the peripheral nervous system to the central nervous system.
• The body contains approximately 1 trillion nerve cells, and 100 chemicals, called neurotransmitters, facilitate communication between these cells.
• The nervous system is divided into central (CNS) and peripheral (PNS) components
• CNS encompasses the brain and spinal cord
• PNS includes all nerves and sensory structures outside the CNS
• The PNS further subdivides into somatic and autonomic systems
• The somatic system controls voluntary skeletal muscle movements
• The autonomic system regulates involuntary functions like gland and smooth muscle activity
• The autonomic system further divides into sympathetic ("fight or flight") and parasympathetic ("rest and digest") branches
• A neuron, or nerve cell, has components like dendrites, cell body, axon, myelin sheath, and synaptic terminals that contribute to neuronal functions and communication
• Neurotransmitters are chemical messengers that transmit signals across synapses between neurons
• Synapses are junctions between neurons or between neurons and effectors (muscles or glands)
• Nerve impulses are transmitted across the synapse by chemicals called neurotransmitters
• Neurotransmitters bind to receptors on the postsynaptic neuron, initiating a response
• Neurotransmitters are classified into various categories:
  • Excitatory: Glutamate, Acetylcholine, Histamine, Dopamine, Norepinephrine, Epinephrine
  • Inhibitory: GABA, Glycine
  • Modulatory: Various neuropeptides, hormones
• The four criteria for identifying neurotransmitters include:
  • Synthesis within the neuron
  • Release upon neuronal activity, triggering responses in target cells
  • Exogenous application elicits similar responses in target cells
  • Mechanisms for inactivation/removal after function completion

Introduction to the Nervous System

• Living organisms react to environmental changes (stimuli)
• An organism's reaction to a stimulus is called a response
• The ability to respond to stimuli is sensitivity, or irritability

Neurotransmitter Function

• Neurotransmitters influence neurons in three ways: excitatory, inhibitory, and modulatory
• Examples: glutamate (excitatory), glycine/GABA (inhibitory), neuropeptides/hormones (modulatory)
• Certain neurotransmitters, like dopamine, are crucial for various functions, including motivation and movement
• Others, like serotonin, play essential roles in mood regulation

Specific Neurotransmitters (and related info)

• Acetylcholine is involved in muscle movement, heart rate and memory. Deficiencies can manifest in major symptoms like forgetfulness and difficulty with daily tasks
• Dopamine is associated with pleasure, reward, and motor control. Parkinson's disease (and schizophrenia) is linked with abnormal dopamine levels
• Serotonin plays a role in mood regulation
• Norepinephrine and epinephrine are involved in the "fight or flight" response
• GABA and Glycine are primarily inhibitory neurotransmitters
• Endorphins are associated with pain relief and euphoria

How to Improve Acetylcholine

• Adapt to stress better by improving coping mechanisms.
• Balance blood sugar levels
• Use caffeine strategically
• Eat nutrient-rich, choline-rich foods
• Practice neuro-exercises (mental exercises to stimulate brain function)
• Cleanse the body. Get enough sleep
• Examples of choline-rich foods: Pastured poultry liver, grass-fed meats, grass-fed beef liver, pasture-raised eggs, wild-caught salmon, broccoli/cauliflower, rosemary.

Impact of neurotransmitter imbalances

• Parkinson's disease arises from the death of dopamine-producing brain cells leading to movement problems (shaking, difficulty moving)

Additional Notes

• The exact number of neurotransmitters is unknown, but more than 200 have been identified
• Neurotransmitters can act through different receptors. (e.g. muscarinic, nicotinic)
• Scientists initially thought synaptic communication was mainly electrical; Otto Loewi discovered chemicals called neurotransmitters.