Nervous System Lecture Notes

Overview of the Nervous System

• The nervous system is a complex network that controls all functions in the body.
• Composed of the central nervous system (CNS) and the peripheral nervous system (PNS).

Central Nervous System (CNS)

• Components:
  • Brain
  • Spinal Cord
• CNS Function:
  • Serves as the main control center for processing information.
  • Cranial Nerves: Nerves that stem from the brain (inside the cranium).
  • Spinal Nerves: Nerves that stem from the spinal cord.

Peripheral Nervous System (PNS)

• Components:
  • Cranial Nerves
  • Spinal Nerves
• Divisions of PNS:
  • Somatic Nervous System: Controls voluntary actions.
  • Autonomic Nervous System: Controls involuntary actions such as heart rate, digestion, respiratory rate, etc.

Brain Structure

• Cerebrum:
  • Largest part of the brain.
  • Involved in voluntary actions, sensory perceptions (sight, hearing), emotions, personality, learning, and memory.
• Medulla Oblongata:
  • Located at the brainstem. Controls involuntary actions (heartbeat, breathing, swallowing).
• Cerebellum:
  • Coordinates muscle movements and maintains balance.
• Hypothalamus:
  • Governs homeostasis (regulating body temperature, hunger, thirst, etc.).
  • Connects nervous system with the endocrine system via the pituitary gland.

Pituitary Gland

• Known as the master gland of the endocrine system.
• Releases hormones that control other endocrine glands.
• Connected to the hypothalamus, which regulates its production and secretion of hormones.

Spinal Cord

• Structure:
  • Cross-section shows gray matter (cell bodies) in the center and white matter (nerve fibers) surrounding.
  • Contains dorsal roots (sensory) and ventral roots (motor).
  • Dorsal Root Ganglion: Collection of sensory neuron cell bodies.
• Function of Neurons:
  • Sensory Neurons: Carry information from sensory receptors to the spinal cord.
  • Motor Neurons: Carry information from the spinal cord to effectors (muscles/glands).

Key Takeaways

• The nervous system is crucial for controlling body functions both voluntarily and involuntarily.
• Understanding various parts of the nervous system helps in learning how they interact and function together to maintain homeostasis and respond to stimuli.

Conclusion

• The nervous system consists of various components that work together. Understanding them provides insight into human physiology and responses.

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