3.2 Integumentary System

System ​

• ​Protection from

  • ​Abrasions

  • ​Chemical damage

  • ​Dehydration

  • ​UV damage

• ​Temperature regulation

• ​Water Barrier

• ​Vitamin D Production

• ​Waste elimination

• Sensory Perception​

• ​Keratinocytes

  • ​build fibrous proteins that form a protective layer against mechanical stress

  • ​prevent water loss

• Melanocytes​

  • Prevent damage from UV radiations ​

• ​Capillaries

  • ​contract to conserve body heat

  • ​dilate to release heat

• ​Exocrine glands

  • ​release sweat to cause evaporative cooling

  • ​sweating rids the body of Urea and Uric acids

• ​Receptor cells

  • ​Pacinian cells

    • pressure/vibration

  • ​Free Nerve endings

    • temperature

  • nociceptors​

    • pain

  • Meissner's corpuscle​

    • ​touch

  • Merkel disks

    • light touch

• ​Cholesterol conversion

  • ​sunlight converts modified cholesterol into Vitamin D

• ​Epidermis

• ​Dermis

• ​Hypodermis

• ​

• ​Keratinocytes

  • ​produce keratin forming layers of the epidermis

• ​Epidermal dendritic cells

  • Langerhans cells

    • ​infection prevention

• ​Merkel Cells

  • ​touch receptors

• ​Stratum Basal

  • ​mitosis of a single layer cuboidal keratin producing stem cells

• ​Stratum Spinosum

  • ​stratified keratinocytes

    • bound by tight junctions and desmosomes​

• ​Stratum Granulosum

  • ​Keratohyalin granules

    • ​crosslinking keratin filaments

    • ​coarse surface

• ​Stratum Lucidum

  • ​thick skin only

  • ​densely packed keratinocytes and clear protein eleidin

• ​Stratum corneum

  • ​up to 30 layer of dead keratinized cells

  • ​durable surface protection from

    • ​abrasions

    • ​water loss

• ​Dust

  • ​mostly dead human skin

• ​Dermatophagoides

  • ​dust mites

    • ​thrive in humid areas

    • ​feed on dead skin cells

• ​Dust allergy

  • ​dust mite feces

• Dense fibrous connective tissue​

• ​Papillary

  • ​Areolar loose CTP

  • ​Finger prints

• ​Reticular Layer

  • ​Irregular dense CTP

  • ​deepest layer of the skin

• ​Fibrous connect tissue

  • ​adipose

• ​Larger blood vessels

• ​Macrophages

  • ​Large white blood cells