These are also called the covering and lining membranes This organ though called Epithelial Membrane, is composed of epithelial and connective
Epithelial Membranes are further divided into more specialized membranes Cutaneous Membrane Composed of two layers, epidermis and dermis The cutaneous membrane is exposed to air and is a dry membrane For example: Skin
Mucous Membrane Composed of epithelial cells (varies depending on where the membrane is in the body) resting on connective tissue This membrane lines all body cavities that open to the exterior These are moist membranes that are almost continuously bathed in secretions Often adapted for secretion or absorption
Where do you think mucous membranes are located?
Serous Membranes Composed of simple squamous epithelium lying on connective tissue Serous membranes line compartments in the ventral body cavity that are closed to the exterior In the body the serous layers are separated by a thin clear fluid, known as serous fluid Specific names of the serous membranes depends on their locations Like the serous lining abdominal cavity and covering its organs is the peritoneum BE CAREFUL YOU DO NOT CONFUSE THIS WITH PERINEUM
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What is the role of mucous membranes?
Synovial Membranes Composed of connective tissue only These membranes line the fibrous capsules surrounding joints They also line small sacs of connective tissue called bursae Both of these structures cushion organs pushing against each other Think bone on bone?
Epithelial Membranes Simplified
Cutaneous Membranes Skin (Epidermis & Dermis) Mucous Membranes Lines all body cavities that open to the exterior Serous Membranes Lines body organs and provides fluid for easy movement Synovial Membranes Lines the fibrous capsules surrounding the joints
The pericardial sac falls into what membrane category?
The intestinal lining falls into what membrane category
The skin surrounding your mouth falls into what membrane category?
The Integumentary System
Skin is also known as your cutaneous membrane Skin is essential for maintaining your bodies boundary Keeps insides on the inside, and keeps the outside out The skin and its accessory structures, like oil, glands, hair, nails, etc.) is known as the integumentary system
Functions of the Integumentary System
The integumentary system performs a variety of functions but it mostly is used for protection This is from physical damage, chemical damage, thermal damage, ultraviolet radiation (UV), and microbes The uppermost layer of skin is hardened to prevent water loss from the body's surface The skin plays a large role in temperature regulation, while also acting as a small excretory system by sweating out urea, salts, and water The skin is also used to create several proteins through absorption of sunlight, and by producing acidic secretions
Name one day to day activity your skin protects you from
Structures of the Skin
Skin has three basic layers Epidermis Stratified squamous epithelium Dermis Made up of mostly connective tissue Epidermis and the dermis are firmly connected but friction or heat can cause these layers to separate and fill with interstitial fluid, this is known as a blister Subcutaneous Tissue or Hypodermis This is mostly adipose tissue (fat) Not considered part of the skin, but does anchor the skin to the underlying organs Protects and isolates
Most of the cells of the epidermis are keratinocytes which produce keratin Keratin is the fibrous protein that makes hair, skin, and nails tough These keratinocytes are connected by desmosomes throughout the epidermis Remember desmosomes are like anchors holding the cells together
Epidermis is avascular meaning it has no blood into five layers or strata
What do you think a third degree burn is?
This is a strong, stretchy envelope that helps bind the body together If you buy leather goods, you are purchasing treated animal dermis The deepest layer of the dermis contains blood vessels, sweat and oil glands, and receptors These receptors are different sensors for detecting touch, pressure, temperature, and pain Our receptors provide us with a lot of information about our environment What would happen without them?
Both collagen and elastic fibers are located in the dermis Collagen gives the skin its toughness and hydration Elastic fibers give the skin its elasticity As we age the number of collagen and elastic fibers decreases, and we lose subcutaneous fat causing our skin to wrinkle and sag
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Three pigments contribute to skin color: melanin, carotene, and hemoglobin Melanin Skins exposure to sunlight stimulates melanin production resulting in the tanning of the skin Melanin protects DNA from being damaged by the UV rays from the sun People with more melanin will have darker skin tones, while people with less melanin will have lighter skin tones
Carotene Carotene is an orange-yellow pigment found in carrots and other orange, deep yellow, or leafy green vegetables People who eat large amounts of carotene rich foods, the skin tends to take on a yellow-orange cast