Study guide: Reflex Behaviors and Nervous System

📋 Course Outline

1. Nervous System Organization
2. Neurons and Glial Cells
3. Reflex Behaviors and Pathways

📖 1. Nervous System Organization

🔑 Key Concepts & Definitions

• Nervous system: a rapid communication system between organs, continuously connecting all organs through nerve fibers.

★ Must-know

• The encephalon contains:
  • the brain
  • the brainstem
  • the cerebellum

Further detail

• Nerves contain sensory fibers, motor fibers, or both, including 12 pairs of cranial nerves and 31 pairs of spinal nerves.

• The nerve centers are protected by three membranes called the meninges.

💡 Memory Hook

Centers → nerves → muscles or glands

📖 2. Neurons and Glial Cells

🔑 Key Concepts & Definitions

• Neuron: an excitable, stimulable, and information-conducting cell.

★ Must-know

• Dendrites receive and integrate information from other neurons or sensory receptors, and a myelinated axon sends the message toward another neuron, a muscle cell, or a glandular cell.

Further detail

• The human encephalon contains approximately 100 billion neurons, while glial cells are approximately 20 times more numerous than neurons.

• The neuron includes: dendrites, a cell body containing the nucleus, an axon, a myelin sheath with Schwann cells and nodes of Ranvier, terminal arborization ending at synapses

💡 Memory Hook

Neurons transmit information; glial cells protect and nourish them

📖 3. Reflex Behaviors and Pathways

🔑 Key Concepts & Definitions

• Reflex behavior: an innate, involuntary, and stereotyped movement that occurs in response to a given stimulus.
• Myotatic reflex: a postural reflex in which a muscle contracts in response to its stretching, helping a person remain standing or sitting without conscious thought.

★ Must-know

📌 A conditioned reflex follows learning, whereas an innate reflex occurs without prior learning.

Further detail

📌 A withdrawal reflex in response to pain is a medullary reflex because it involves the spinal cord rather than the encephalon.

💡 Memory Hook

Stimulus → nervous message → involuntary stereotyped movement

📊 Synthesis Tables

Comparison of Reflex Types