bio cp 5

Apocrine Sweat Glands

  • Definition: Sweat glands that are sweatier and are known for producing a thicker, more odorous sweat.
  • Varied Pronunciation: Pronounced as either "apocrine" or "apocrine.
  • Location:
    • Axillary (underarms)
    • Anogenital (genital area)
  • Composition: Contains oils but is primarily a type of sweat gland.
  • Comparison: Not to be confused with sebaceous glands, which are oil-producing glands attached to hair follicles.

Functions of Skin

Protection

  • Mechanisms of Protection:
    • Chemical barriers (acidic components help inhibit bacterial growth)
    • Physical barriers (keratin and glycolipids blocking water penetration)
    • Biological barriers (immune cells present in the skin)

Regulation of Body Temperature

  • Mechanisms:
    • Sweating: Evaporation of sweat cools the body.
    • Vasodilation: Blood vessels near the skin surface dilate to release heat, causing a pink tone.
    • Vasoconstriction: Blood vessels tighten to retain heat when cold.

Cutaneous Sensation

  • Sensory Function: Hairs and nerve endings enable sensation through the skin.
  • Observation in Physical Exams:
    • Skin changes can indicate health status (e.g., sallow skin indicates poor health).

Metabolic Functions

  • Vitamin D Production: Skin is essential for sunlight absorption, converting UV rays into vitamin D.
    • Time recommended: 20 minutes in the morning without sunscreen (avoid midday sun for fair skin).
  • Blood Reservoir: Skin contains a significant number of blood vessels.

Excretion

  • Methods of Elimination:
    • Skin: Sweat eliminates waste (sodium, nitrogenous waste).
    • Other methods: Breathing, urination, defecation, and hepatic processing.
    • Connection to Health: Skin reflects overall health; changes may indicate toxicity or blockage.

Skin Color

  • Factors: Influenced by three pigments:
    • Melanin: Provides darker skin tones.
    • Carotene: Contributes yellow to orange hues.
    • Hemoglobin: Affects red coloration.
  • Skin tone results from the combination of all three pigments.

Skin Appendages

Types of Glands

  • **Eccrine Sweat Glands: **

    • Location: Found all over the body.
    • Function: Mainly responsible for temperature regulation through the secretion of water, salt, and metabolic waste.

  • Apocrine Sweat Glands:

    • Location: Concentrated in axillary and anogenital areas.
    • Composition: Water with some oils, begins functioning at puberty.
    • Possible Role: May influence pheromonal communication.

  • Sebaceous Glands:

    • Secretions: Oil (sebum) that keeps skin and hair soft.
    • Location: Associated with hair follicles, absent on palms and soles.

Hair

Structure:

  • Composed mainly of hard keratin, providing insulation and protection (especially for the head).
    • Types of Hair:
    • Vellus Hair: Fine hair covering much of the body.
    • Terminal Hair: Coarser hair found on the scalp, face, pubic areas, and other select locations.
  • Aging Effects: Decreased collagen and elastin production results in skin sagging and gray hair.

Hair Follicles

  • Description: Hair grows from follicles formed by the dipping epidermis.
  • Inner Layers:
    • Medulla: The inner part of the hair.
    • Cortex: The outer layer surrounding the medulla.

Alopecia

  • Definition: Hair loss that is not related to typical balding, can be due to various factors including hormonal changes, stress, or medication side effects.
  • Common Forms:
    • Psychological conditions like trichotillomania, where individuals pull out their hair.

Nails

Structure:

  • Protective covering for fingers/toes.
  • Composed of keratin; the cuticle protects the nail bed.
  • Involvement of blood vessels indicates injury.

Skin Cancer Recognition

Types of Skin Cancer:

  • Basal Cell Carcinoma: Most common, minimally malignant, generally requires surgical removal.
  • Squamous Cell Carcinoma: More aggressive than basal cell, needs more involved treatment.
  • Melanoma: Most dangerous form. Common symptoms include unusual moles or changes.

ABCDE Method for Self-Examination:

  • A: Asymmetry of the mole.
  • B: Border irregularity.
  • C: Color variations (greater than one color).
  • D: Diameter larger than a pencil eraser.
  • E: Evolving shape or size.

Burns

Classifications:

  • First Degree Burns: Affect only the epidermis; characterized by redness and minor swelling.
  • Second Degree Burns: Involve the epidermis and part of the dermis; result in blisters.
  • Third Degree Burns: Damage all skin layers and can be life-threatening; often require skin grafts.

Critical Conditions:

  • Over 25% of body has second-degree burns are at risk; 10% or more third-degree burns are life-threatening, especially on face, hands, or feet.

Physiological Impacts:

  • Damage affects tissue function, protein denaturation can lead to loss of vital bodily functions.