The Nervous System

Mind Map: Nervous System

Central Idea

• Nervous System

Main Branches

1. Structure

• Central Nervous System (CNS)

  • Brain

    • Cerebrum

    • Cerebellum

    • Brainstem

  • Spinal Cord

    • Cervical Region

    • Thoracic Region

    • Lumbar Region

• Peripheral Nervous System (PNS)

  • Somatic Nervous System

    • Sensory Neurons

    • Motor Neurons

  • Autonomic Nervous System

    • Sympathetic Division

    • Parasympathetic Division

2. Function

• Sensory Input

  • External Stimuli

  • Internal Stimuli

• Integration

  • Processing Information

  • Decision Making

• Motor Output

  • Voluntary Movements

  • Involuntary Reflexes

3. Types of Neurons

• Sensory Neurons

  • Afferent Neurons

• Motor Neurons

  • Efferent Neurons

• Interneurons

  • Relay Signals

4. Neurotransmitters

• Types

  • Dopamine

  • Serotonin

  • Acetylcholine

• Functions

  • Mood Regulation

  • Muscle Control

  • Sleep-Wake Cycle

5. Disorders

• Neurological Disorders

  • Alzheimer's Disease

  • Parkinson's Disease

  • Epilepsy

• Mental Health Disorders

  • Depression

  • Anxiety Disorders

  • Schizophrenia

6. Protection

• Meninges

  • Dura Mater

  • Arachnoid Mater

  • Pia Mater

• Cerebrospinal Fluid (CSF)

  • Cushioning

  • Nutrient Transport

7. Development

• Embryonic Development

  • Neural Tube Formation

• Neuroplasticity

  • Learning and Memory

  • Recovery from Injury

This mind map provides a comprehensive overview of the nervous system, covering its structure, function, types of neurons, neurotransmitters, disorders, protection mechanisms, and development.

8. Anatomy of the Nervous System

Central Nervous System (CNS)

• Brain

  • Cerebrum

  • Cerebellum

  • Brainstem

• Spinal Cord

  • Ascending Tracts

  • Descending Tracts

Peripheral Nervous System (PNS)

• Somatic Nervous System

  • Controls voluntary movements

  • Connects to skeletal muscles

• Autonomic Nervous System

  • Sympathetic Division

  • Parasympathetic Division

9. Brain Regions and Functions

Cerebrum

• Frontal Lobe

  • Decision making

  • Problem-solving

• Parietal Lobe

  • Sensory perception

  • Spatial orientation

• Temporal Lobe

  • Auditory processing

  • Memory formation

• Occipital Lobe

  • Visual processing

Brainstem

• Midbrain

  • Vision and hearing

• Pons

  • Relays signals between cerebrum and cerebellum

• Medulla Oblongata

  • Controls autonomic functions (e.g., heart rate, breathing)

Cerebellum

• Coordination

  • Balance and motor control

• Learning

  • Motor learning and timing

10. Neuroplasticity

Mechanisms

• Synaptic Plasticity

  • Strengthening or weakening of synapses

• Structural Changes

  • Growth of new neurons (neurogenesis)

  • Formation of new synaptic connections

Importance

• Learning and Memory

  • Adaptation to new experiences

• Recovery from Injury

  • Reorganization of neural pathways

11. Research and Advances

Neuroimaging Techniques

• MRI (Magnetic Resonance Imaging)

  • Detailed images of brain structure

• fMRI (Functional MRI)

  • Measures brain activity by detecting changes in blood flow

Emerging Therapies

• Gene Therapy

  • Targeting genetic causes of neurological disorders

• Stem Cell Therapy

  • Potential for repairing damaged neural tissue

12. Conclusion

Understanding the nervous system is crucial for recognizing how it influences behavior, cognition, and overall health. Ongoing research continues to uncover the complexities of neural functions and their implications for treating various disorders, enhancing

Neuron Structure

• Parts of a Neuron

  • Soma (Cell Body)

    • Houses important cell bits like the mitochondria, nucleus, endoplasmic reticulum (ER), etc.

    • The main body of the neuron

  • Nucleus

    • The brain of the neuron

    • Holds genetic data for protein synthesis

    • Houses and builds DNA

  • Dendrites

    • Receivers of the neurotransmitters’ electrical signals from other neuron (axon terminals)

  • Myelin Sheath

    • Protects and insulates the axon

    • Allows for efficient and quick transport

    • impermeable to Na+ (sodium)

  • Node of Ranvier

    • Spots where Na+ (sodium) can enter and cause a nerve impulse (action potential)

  • Axon

    • Part that carries electrical signals away from the soma and towards other neurons, muscles and glands.

    • Axon Terminal + Bulb

      • Place where the electrical signals depart from on the neuron (via neurotransmitters)

Nerve Impulses

Nerve Impulses: The 4 Stages

Polarized/Resting State

• charge difference is now called resting membrane potential (RMP)

• RMP = -70mV

1. Resting State & the Sodium-Potassium pumps

   • inside resting cell = K⁺ concentration > Na⁺ concentration

   • outside resting cell = Na⁺ concentration > K⁺ concentration

2. K⁺ > Na⁺ @ passively moving out of cell

   • (K⁺ = “leaky ion channels”)

   • Sodium struggles

   • Counteracts concentration gradient

3. To balance the difference, sodium-potassium (Na⁺-K⁺) pumps move 3Na⁺ inside → 2K⁺ outside

4. + charge accumulates outside cell membrane (-70mV inside)

Depolarization

• stimulus → action potential

• impulse causes sodium gates → open

  • Na⁺ diffuse freely across membrane

• Na⁺ rushes into cell (decreases concentration gradient)

  • (small) + inside > outside

• reverse membrane potential -70mV → +40mV (inside)

• Depolarization & Threshold Potential

  • All or nothing

  • Break -55mV threshold to have effect

  • ↑ stimulus strength ≠ ↑ impulse strength

  • ↑ frequency of nerve impulses + ↑ stimulus strength (intensity)

Repolarization

• back 2 normal

• action potential peak → Na⁺ gates close → K⁺ gates open

  • K⁺ rushes out

• restores ‘+’ charge outside membrane

  • Na⁺ & K⁺ concentrations briefly reversed (Na⁺ > K⁺ inside, K⁺ > Na⁺ outside)

• sodium-potassium pumps start!

  • Na⁺ ←→ K⁺, restores -70mV

  • Like a wave down axon

Refractory Period (Hyperpolarization)

• Na⁺-K⁺ pumps overdo it and → -90mV (hyperpolarized)

• resting needs to be restored by 2^nd action potential

• Right now membrane ≠ permeable to Na⁺ ≠ depolarize

  • Stronger the stimulus/impulse, the longer the refractory period