Professor Wong's Lecture on Anatomy and Physiology

Course Information

• Professor Bob Long's Human Anatomy and Physiology 2 course at Del Mar College.
• Converted to online due to COVID-19.
• Emphasis on active participation (writing and drawing) for better learning.
• Lecture 3 in Sensory Physiology series.

General Sensory Receptors

• Nociceptors (Pain Receptors):

  • Detect pain (nociception).
  • Free nerve endings without connective tissue.
  • Located in dermis, periosteum, blood vessels, joint capsules, muscles, and internal viscera.
  • Respond to mechanical distortion, extreme temperatures, and chemicals.
  • Two types: Type A (fast, sharp pain) and Type C (slow, dull ache).

• Neurotransmitter & Adaptation:

  • Substance P is used by pain fibers.
  • Tonic receptors with central adaptation filtering.

Types of Pain

• Referred Pain: Pain felt in a different location from stimulus.
• Phantom Pain: Pain in amputated limbs.

Thermoreceptors

• Detect rapid temperature changes; free nerve endings.
• Hot and cold receptors respond to increasing or decreasing temperatures, respectively.
• Fast adapting.

Tactile Receptors

• Free Nerve Endings: Include nociceptors and thermoreceptors.
• Root Hair Plexus: Around hair follicles; detect direction of movement.
• Merkel's Disk & Meissner's Corpuscle:
  • Merkel's: Fine touch in hairy skin.
  • Meissner's: Fine touch in hairless skin (e.g., palms).
• Pacinian and Ruffini's Corpuscles: Deep pressure and vibration.

Proprioceptors

• Muscle Spindle Fibers: Detect tension and stretch in muscles.
• Golgi Tendon Organs: Detect tension in tendons.

Baroreceptors

• Detect pressure changes in the digestive tract, urinary bladder, and cardiovascular system.
• Found in aorta and carotid arteries; monitor blood pressure to prevent vascular accidents.

Chemoreceptors

• Internal Chemoreceptors: Monitor ion concentrations, nutrients, and oxygen/carbon dioxide levels.
• Found in the hypothalamus and carotid/aortic bodies.
• Maintain homeostasis by adjusting pH and other critical levels.

Summary

• Covered general sensory modalities.
• Encouraged additional reading in the textbook for detailed understanding.
• Upcoming focus on special senses in future lectures.