Crash Course Psychology: Nervous and Endocrine Systems

Introduction

• Scenario: Sudden banging at the door while drifting to sleep triggers a chemical response in the brain.
• The brain and nervous system operate through complex chemical reactions.
• Everything psychological is biological.

Neurons: The Building Blocks

• Neurons are the nerve cells that make up the nervous system.
• Neurons transmit messages through electrochemical processes.
• Brain consists of billions of neurons.

Types and Structure of Neurons

• Neurons vary in size and length.
• Parts of a neuron:
  • Soma (Cell Body): Life support containing nucleus, DNA, etc.
  • Dendrites: Receive messages from other cells.
  • Axon: Transmits electrical impulses.
  • Myelin Sheath: Insulates axons, speeds up transmission.

Neuron Communication

• Neurons transmit signals through sensory input or neighboring neurons.
• Synapses: Contact points between neurons.
• Synaptic Gap: Space between neurons where neurotransmitters travel.
• Neurotransmitters: Chemical messengers that cross synaptic gaps.

Types of Neurotransmitters

• Excitatory Neurotransmitters: Increase likelihood of neuron firing.
  • Examples: Norepinephrine, Glutamate.
• Inhibitory Neurotransmitters: Decrease likelihood of neuron firing.
  • Examples: GABA, Serotonin.
• Dual-role Neurotransmitters: Can excite or inhibit.
  • Examples: Acetylcholine, Dopamine.

The Endocrine System

• Hormones act on the brain and affect mood, arousal, and circadian rhythms.
• Endocrine vs. Nervous System: Endocrine system is slower but longer-lasting.
• Adrenal Glands: Release adrenaline, affecting fight-or-flight response.
• Pancreas: Regulates blood sugar with insulin and glucagon.
• Thyroid/Parathyroid Glands: Regulate metabolism and calcium levels.
• Sex Glands: Produce sex hormones.
• Pituitary Gland: Master gland controlling other glands.

Feedback Loop

• Nervous system and endocrine system interact in a feedback loop.
• Sensory input triggers a response through nervous and endocrine interactions.
• Feedback loop: Brain → Gland → Hormone → Brain.

Conclusion

• Next lesson will explore deeper into the nervous system and brain components.
• Acknowledgement of contributors to the episode.