Understanding the Nervous System and Hormones

Sep 24, 2024

Lecture Notes: The Nervous System and Hormones

Introduction

  • Scenario of fear response: sudden noise causes a chemical reaction
  • Mental activities are intertwined with biological processes
  • "Everything psychological is biological"

Neurons

  • Neurons (Nerve Cells): Building blocks of the nervous system
    • Electrochemical transmission of messages
  • Components of Neurons:
    • Soma (Cell Body): Life support of the neuron (nucleus, DNA, etc.)
    • Dendrites: Receive signals from other cells; act as listeners
    • Axon: Transmits electrical impulses; encased in myelin sheath for speed
  • Myelin Sheath: Insulates axons and speeds up transmission
    • Degradation leads to diseases like multiple sclerosis

Neural Communication

  • Neurons transmit signals through sensory input or neighboring neurons
  • Action Potential: Electrical charge firing down the axon
  • Synapse: Contact points between neurons
    • Synaptic Gap: Space between axons and dendrites
  • Neurotransmitters: Chemical messengers that bridge the synaptic gap
    • Process of reuptake: Neurons reabsorb extra neurotransmitters

Types of Neurotransmitters

  • Excitatory Neurotransmitters
    • Norepinephrine: Controls alertness and arousal
    • Glutamate: Involved in memory; excess can lead to migraines
  • Inhibitory Neurotransmitters
    • GABA (gamma-aminobutyric acid)
    • Serotonin: Affects mood, hunger, sleep; linked to depression
  • Dual-role Neurotransmitters
    • Acetylcholine: Muscle action, learning, memory; linked to Alzheimer's
    • Dopamine: Learning, movement, pleasure; linked to schizophrenia, addiction

Endocrine System

  • Hormones: Chemical messengers like neurotransmitters, but slower
    • Affect moods, arousal, metabolism, and reproduction

Glands and Hormones

  • Adrenal Glands: Secrete adrenaline (fight or flight)
  • Pancreas: Insulin and glucagon for sugar absorption
  • Thyroid/Parathyroid Glands: Regulate metabolism and calcium levels
  • Sex Hormones: Estrogen and testosterone from testicles/ovaries
  • Pituitary Gland: "Master gland," controls other glands, releases growth hormone and oxytocin
    • Controlled by the hypothalamus

Nervous and Endocrine Interaction

  • Feedback loop: nervous system directs endocrine system and vice versa
  • The next lesson will delve deeper into brain components and usage

Credits

  • Written by Kathleen Yale
  • Edited by Blake de Pastino
  • Consultant: Dr. Ranjit Bhagwat
  • Directed and edited by Nicholas Jenkins
  • Script supervisor: Michael Aranda, also sound designer
  • Graphics by Thought Cafe

Note: This lesson is part of a series on Crash Course Psychology.