Skin and Body Membranes
Epithelial Membranes
- Include the cutaneous membrane (skin), the mucous membranes, and the serous membrane
Cutaneous Membrane
- Is your skin
- Its superficial epidermis is composed of a keratinizing stratified squamous epithelium
- It is exposed to air and is a dry membrane
Mucous Membrane
- Composed of epithelium resting on a loose connective tissue membrane called Lamina Propria
- Lines all body cavities that open to the exterior like the hollow organs of the respiratory, digestive, urinary, and reproductive tracts
Serous Membrane
- Composed of a layer of simple squamous epithelium resting on a thin layer of areolar connective tissue
- Line body cavities that are closed to the exterior
Cutaneous Membrane
- Is your skin
- Its superficial epidermis is composed of a keratinizing stratified squamous epithelium
- It is exposed to air and is a dry membrane
Mucous Membrane
- Composed of epithelium resting on a loose connective tissue membrane called Lamina Propria
- Lines all body cavities that open to the exterior like the hollow organs of the respiratory, digestive, urinary, and reproductive tracts
Serous Membrane
- Composed of a layer of simple squamous epithelium resting on a thin layer of areolar connective tissue
- Line body cavities that are closed to the exterior
Connective Tissue Membrane
- Synovial membranes are composed of soft areolar connective tissue and contain no epithelial cells at all.
- Line the fibrous capsules surrounding joints where they provide a smooth surface and secrete a lubricating fluid.
- Synovial membranes are composed of soft areolar connective tissue and contain no epithelial cells at all.
- Line the fibrous capsules surrounding joints where they provide a smooth surface and secrete a lubricating fluid.
Integumentary System
Definition: the organ system that protects the body from various kinds of damage, such as loss of water or abrasion from outside.
*Watch this video to get a good visual about what the Integumentary System is really all about.
Functions of the Integumentary System
- Also called the integument which it is "covering" the skin multitasks
- Keeps water and other precious molecules in the body and also keeps water out
*** With out skin we would quickly fall prey yo bacteria and perish from water and heat loss
Protects deeper tissues from:
- Mechanical Damage: Physical barrier contains keratin, which toughens cells; fat cells to cushion blows; and pressure receptors, which alert the nervous system to possible damage
- Chemical Damage: Has relatively impermeable keratinized cells; contains pain receptors, which alert the nervous system to possible damage
- Bacterial Damage: Has an unbroken surface and "acid mantle". Phagocytes ingest foreign substances and pathogens, preventing them from penetrating into deeper body tissues.
- UV: Melanin produced by melanocytes offers protection from UV damage
- Thermal Damage: Contains heat/cold/ pain receptors
- Desiccation: Contains a water-resisting glycolipid and keratin
Aids in body heat loss or heat retention
- Heat loss: By activating sweat glands and by allowing blood to flush into skin capillary beds so that heat can radiate from the skin surface.
- Heat retention: By not allowing blood to flush into skin capillary beds.
Aids in excretion of urea and uric acid
- Contained in perspiration produced by sweat glands
Synthesizes vitamin D
Modified cholesterol molecules in skin converted to vitamin D by sunlight
- Also called the integument which it is "covering" the skin multitasks
- Keeps water and other precious molecules in the body and also keeps water out
*** With out skin we would quickly fall prey yo bacteria and perish from water and heat loss
Protects deeper tissues from:
- Mechanical Damage: Physical barrier contains keratin, which toughens cells; fat cells to cushion blows; and pressure receptors, which alert the nervous system to possible damage
- Chemical Damage: Has relatively impermeable keratinized cells; contains pain receptors, which alert the nervous system to possible damage
- Bacterial Damage: Has an unbroken surface and "acid mantle". Phagocytes ingest foreign substances and pathogens, preventing them from penetrating into deeper body tissues.
- UV: Melanin produced by melanocytes offers protection from UV damage
- Thermal Damage: Contains heat/cold/ pain receptors
- Desiccation: Contains a water-resisting glycolipid and keratin
Aids in body heat loss or heat retention
- Heat loss: By activating sweat glands and by allowing blood to flush into skin capillary beds so that heat can radiate from the skin surface.
- Heat retention: By not allowing blood to flush into skin capillary beds.
Aids in excretion of urea and uric acid
- Contained in perspiration produced by sweat glands
Synthesizes vitamin D
Modified cholesterol molecules in skin converted to vitamin D by sunlight
Structures of the Skin
Dermis
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Epidermis
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Skin Color
Three pigments contribute to skin color:
Three pigments contribute to skin color:
- The amount and kind of melanin in the epidermis. (yellow, reddish brown, or black)
- The amount of carotene deposited in the stratum corneum and subcutaneous tissue. Skin tends to take on a yellow-orange cast when the person eats large amounts of carotene-rich foods.
- The amount of oxygen-rich hemoglobin in the dermal blood vessels.