3 Membranes & the Integumentary System Flashcards
Describe mucous membranes and their function
- aka mucosa
- line a body cavity that opens directly to the exterior
- Epithelium with a CT base
- Examples: G.I. tract, respiratory tract, reproductive tract
Functions (site dependent)
- Protection (Tight junctions, contains goblet cells)
- Absorption
Describe serous membranes
- Line a body cavity that does not open directly to the exterior
- Also cover organs within the cavity (E.g. thoracic and abdominal cavities)
- Serous membranes have two layers
- Parietal layer: lines the cavity wall
- Visceral layer: covers and adheres to the organs in the cavity
- The simple squamous epithelium secretes serous fluid (For lubrication)
- Examples: pleura, pericardium, peritoneum
Describe synovial membranes
- Line freely movable joint cavities
- Do not open to the exterior
- No epithelium
- Made up of a layer of synoviocytes with a CT base
- Synovial fluid lubricates and nourishes joint cartilage an contains macrophages that help fight infections and clean up within the joint cavity
What is the structure of the integumentary system from superficial to deep?
- Epidermis
- Dermis
- Subcutaneous tissue (superficial fascia, loose areolar, loose adipose)
What are the primary functions of the integumentary system?
- Protection
- Barrier
- Cushioning
- Monitoring
- UV
- Thermoregulation
- Blood reservoir
- Excretion
- Vitamin synthesis
The superficial layer of the integumentary system, this is avascular stratified squamous epithelium:
Epidermis
What are the four types of epidermal cells?
- Keratinocytes
- Melanocytes (produce melanin)
- Langerhans cells
- Merkel cells
Which type of cells form the majority of epidermal cells?
Keratinocytes
What’s the primary function of langerhans cells?
Responsible for recognizing foreign and harmful antigens in helping to remove them (they present the substance to the immune system so other immune cells can then kill it)
What are the five epidermal layers from deep to superficial?
- Stratum basale
- aka stratum germinativum
- Single row of keratinocytes anchored basement membrane
- Continuous mitosis (which pushes players up and creates several single layers)
- All epidermal cells originate here. Each following layer is a progressively dying version of the same (as distanced from the blood supply)
- Stratum spinosum cake
- Provide strength and flexibility to the skin
- Think anchoring junctions. When pulled apart, anchors look like spines.
- Stratum granulosum
- These cells are dying
- As cells die their organelles look granular
- Stratum lucidum
- Flat, dead, keratinocytes
- Cells of been dead/broken down long enough, they become clear/lucid
- Only appear on certain services like sole of the foot (thick)
- Stratum corneum
- Flat and dead keratinocytes that are shed
- To remember: flat cells start to curl up, which look like horns (cornu means horn)
Where is the dermis and what is made up?
- Connective tissue layer separating epidermis and underlying adipose later
- Made of collagen and elastin
What structures does the dermis contain?
- Blood vessels, nerves
- Meissner corpuscles: touch receptors
- Free nerve endings: pain, temperature
- Pacinian corpuscles: pressure, vibration
- Sweat and oil glands, and hair are also embedded in the dermis and continue through the epidermis
What is subcutaneous tissue made of and what function does it serve?
- aka hypodermis
- areolar and adipose tissue
- serves as shock absorber, insulator
What’s the name of the muscle that contracts to pull hair upright in the dermis?
arrector pili
These provide lubrication for hair
sebaceous glands
