Lecture Review on Skin Anatomy and Functions

Sebaceous and Sweat Glands

• Sebaceous Glands:

  • Location: Associated with hair follicles.
  • Function: Secretes sebum, which lubricates the skin and hair.

• Sweat Glands:

  • Types:
  • Apocrine Glands: Attached to hair follicles and secrete sweat that can produce odor.
  • Ecrine Glands: Discharge sweat directly through skin pores and are responsible for regulating body temperature.

Hair Structure

• Composition of Hair: Made of keratin, a tough protein.

• Functions of Hair:

  • Helps conserve body heat when raised (related to the arrector pili muscle).

• Visible Hair Parts:

  • Visible sections on anatomical diagrams (possibly shown in class).

Nails

• Description:

  • Located at distal ends of fingers and toes; made of keratin.
  • Grows from proximal to distal, meaning it grows from the base outwards.

• Nail Anatomy:

  • Nail Plate: The visible part of the nail.
  • Nail Root: Underground part from which the nail grows.
  • Lunula: The crescent-shaped area at the base of the nail, appears white.

• Functions of Nails:

  • Protection for distal ends of fingers and toes.
  • Assists in gripping and manipulation of objects.
  • Can be used for gathering DNA (from skin cells).

• Ingrown Toenails:

  • Occur when the nail grows into the surrounding skin.
  • Can result in infections and pain, treated by might include procedures to remove or correct the nail's growing direction.

Skin Functions

• Barrier to Infection:

  • Intact Skin: Provides primary defense against infection by keeping pathogens out.
  • Importance of Hygiene: Regular washing can prevent infection.

• Structural Description:

  • The skin has interlocking patterns that help prevent penetration by sharp objects.
  • Constant shedding of skin cells helps remove bacteria.

• Regulation of Water:

  • Skin retains moisture through keratin and sebum.

• Temperature Regulation:

  • Vasoconstriction: Blood vessels narrow to conserve heat when cold.
  • Vasodilation: Blood vessels widen to release heat when hot.

• Sensory Functions:

  • Collects sensory information through nerve endings:
  • Pain (free nerve endings).
  • Temperature (hot/cold).
  • Touch Sensation (Meissner corpuscles).
  • Pressure Sensation (Pacinian corpuscles).

Skin Color and Melanin

• Melanin Production:
  • Produced by melanocytes as a response to UV radiation from the sun; protects skin.
• Skin Color Variation:
  • Primarily influenced by genetic factors and ancestral geographic location.
  • Individuals from sunnier regions typically have darker skin due to higher melanin levels.

Vitamin D and Skin Health

• Vitamin D Synthesis:
  • Skin synthesizes Vitamin D when exposed to sunlight, essential for mood and muscle function.
• Seasonal Affective Disorder (SAD):
  • Lack of sunlight can lead to decreases in mood due to lower Vitamin D levels.

Conclusion

• Key Points to Remember:
  • Sebaceous and sweat glands play critical roles in skin function and health.
  • Understanding hair and nail structure is essential for overall dermatological knowledge.
  • Skin acts as a vital barrier and regulatory organ for temperature and sensation.
  • Melanin is crucial for protection against UV radiation, while Vitamin D contributes to overall health.