Biology: Neuron Structure and Nervous System

Neuron Structure

• A neuron consists of:
  • Dendrites: receive signals from other neurons
  • Cell body: contains the nucleus and maintains the cell's function
  • Axon: carries signals away from the cell body
  • Terminal buttons: release neurotransmitters into the synapse
• Neurons communicate through electrical and chemical signals
• The myelin sheath, composed of fatty tissue, insulates and facilitates signal transmission

Cerebral Cortex Function

• The cerebral cortex is the outermost layer of the brain, responsible for:
  • Processing sensory information
  • Controlling movement and behavior
  • Facilitating thought, perception, and memory
• The cortex is divided into four lobes:
  • Frontal lobe: motor control, decision-making, and language
  • Parietal lobe: spatial awareness and processing sensory information
  • Temporal lobe: auditory processing and memory
  • Occipital lobe: visual processing

Nervous System Development

• The nervous system develops from the ectoderm layer in the embryo
• The neural tube forms and eventually closes to create the central nervous system
• The neural crest cells migrate and differentiate to form the peripheral nervous system
• The neural tube differentiates into:
  • Forebrain (prosencephalon): develops into the cerebrum and thalamus
  • Midbrain (mesencephalon): develops into the midbrain
  • Hindbrain (rhombencephalon): develops into the cerebellum, pons, and medulla oblongata

Brainstem Function

• The brainstem connects the cerebrum to the spinal cord
• It regulates essential functions, including:
  • Breathing
  • Heart rate
  • Blood pressure
  • Body temperature
  • Hunger and thirst
• The brainstem consists of:
  • Midbrain
  • Pons
  • Medulla oblongata

Synaptic Transmission

• Synaptic transmission is the process of neurons communicating with each other
• Steps involved in synaptic transmission:
  1. Neurotransmitter release: terminal buttons release neurotransmitters into the synapse
  2. Neurotransmitter binding: neurotransmitters bind to receptors on the postsynaptic neuron
  3. Signal integration: the postsynaptic neuron integrates the signal and generates an action potential
• Factors affecting synaptic transmission:
  • Neurotransmitter type and concentration
  • Receptor density and type
  • Synaptic plasticity: the strengthening or weakening of synaptic connections