Lecture on the Nervous System

Lesson Plan Overview

• What is the nervous system?
• Components of the nervous system
• Central Nervous System (CNS)
• Brain structures and functions
• Nervous tissue and types of neurons
• Reflex arc vs reflex action
• Peripheral Nervous System (PNS)
• Types of receptors
• Summary of the lesson

Nervous System Overview

• Responsible for processing and transmitting information
• Coordinates body activities like walking, hearing, seeing
• Divided into:
  • Central Nervous System (CNS)
  • Peripheral Nervous System (PNS)

Central Nervous System (CNS)

• Composed of the brain and spinal cord
• Brain:
  • Protected by the cranium and meninges (3 layers: dura mater, arachnoid, pia mater)
  • Consists of gray matter (cortex) and white matter (medulla oblongata)
  • Structures: cerebrum, corpus callosum, medulla oblongata, hypothalamus, cerebellum
• Spinal Cord:
  • Protected by vertebral column and cerebrospinal fluid
  • Pathway for impulses between body and brain

Brain Structures and Functions

• Right hemisphere controls left body side; left hemisphere controls right body side
• Cerebrum: Voluntary actions, interprets sensory data, higher thought processes
• Corpus Callosum: Connects hemispheres, communication between hemispheres
• Hypothalamus: Controls hunger, thirst, sleep, temperature, emotions
• Medulla Oblongata: Manages involuntary actions like heartbeat, breathing
• Cerebellum: Coordinates voluntary movements, maintains balance

Types of Neurons and Nervous Tissue

• Sensory Neurons: Conduct impulses from receptors to CNS
• Motor Neurons: Carry impulses away from CNS to effectors
• Interneurons (Connector Neurons): Connect sensory and motor neurons within CNS

Reflex Arc vs Reflex Action

• Reflex Action: Quick, involuntary response, protects from harm, involves spinal cord
• Reflex Arc: Pathway taken by impulse during reflex action

Peripheral Nervous System (PNS)

• Includes all nerves outside the brain and spinal cord
• Divisions:
  • Autonomic Nervous System (automatic functions)
    • Sympathetic (fight or flight)
    • Parasympathetic (rest and digest)
  • Somatic Nervous System (voluntary control)

Types of Receptors

• Exteroceptors: Respond to external stimuli (skin, nose, tongue, eyes, ears)
• Photoreceptors: Sensitive to light (eyes)
• Chemoreceptors: Respond to chemical stimuli (tongue, nose)
• Mechanoreceptors: Sensitive to pressure, sound, touch, gravity (ears, skin, muscles)
• Interoceptors: Respond to internal body changes
• Thermoreceptors: Detect temperature changes
• Osmoreceptors: Sensitive to osmotic pressure changes
• Baroreceptors: Detect changes in blood pressure

Summary

• Nervous system has two main parts: CNS and PNS
• CNS: Brain and spinal cord
• PNS: Sensory and motor pathways
• PNS divisions:
  • Somatic (voluntary)
  • Autonomic (involuntary): Sympathetic and parasympathetic systems

Important Concepts to Remember:

• Functions and roles of different brain parts
• Differences between sensory, motor, and interneurons
• Reflex action and reflex arc dynamics
• Distinctions between sympathetic and parasympathetic systems
• Types and roles of different receptors

Thank you for attending the lecture, and I hope these notes help in your study and understanding of the nervous system.