Chap4: Body Membranes And Skin Flashcards
Epithelial membranes subdivisions?
- cutaneous membrane
- mucous membrane
- serous membrane
Characteristics of body membrane
- cover and line body surfaces
- protect body cavities
- lubricate body cavities
Cutaneous membrane
Dry membrane
Outermost protective membrane –> skin
Divided into 2 diff regions:
- superficial epidermis (keratinized stratified squamous ep)
- underlying dermis (mostly dense conn)
Mucous membrane
Line body cavities that open to the outside
Adapted for absorption or secretion (digestive , respiratory, excretory, reproductive tracts)
Serous membrane
Line body cavities that do not open directly to the outside + cover these organs
Covered by thin layer of serous fluid (secreted by ep) + used for protection (cushion)
Special names according to location :
- peritoneum (abdominal cavities)
- pleura (lungs cavities)
- pericardium (around the heart)
Connective tissue membrane?
Synovial membrane : lines fibrous capsules surrounding joints
Integumentary system definition and constituents
Def: helps the body maintain a constant state of balanced internal conditions (homeostasis)
Const: skin, hair, nails, glands ( sweat or oily)
Dermis constituents
Blood vessels
Receptors
Glands
Receptors in dermis
Types of receptors:
- thermoreceptors
- meissners corpuscle (touch)
- nociceptor (pain)
- pacinian corpuscle (pressure)
Fct:
Work with other tissues to detect change in environment
Glands in dermis
Enable body to maintain homeostasis (remove waste)
Help ensure body’s temperature remains the same
Sweat glands : emit moisture on skin surface + removes waste
Oil glands / Sebaceous glands : secrete lubricating liquid at base of hair follicle (activated during puberty)
Skin function
Protection (from ext env)
- mechanical damage (keratinized cells)
- chemical damage (melanin’s uv protection+skin secretions)
- bacterial damage (macrophage of dermis + DNA
- thermal damage
- uv radiation
- desiccation (water loss)
Vitamin D synthesis
Aids in thermal regulation (sweat glands + hair)
Aids in excretion of urea and uric acid
Sensory receptors (nerves that receive msg)
Fct of blood vessels in dermis
Provide dermis with blood
Enable the skin to grow and heal itself
Skin structure
Epidermis
Dermis
Subcutaneous / hypodermis
Epidermis definition
Outer thin layer of skin
Stratified squamous epithelium
Often keratinized
Keratin = fibrous protein that protects epidermis + connected by desmosomes
Arise from stratum basale and die along the way to surface
Layers of epidermis
Stratum basale
-next to dermis
-cells undergo mitosis
-melanocytes (cells containing melanin)
Melanin= pigment that varies between yellow, brown and black
Amount of melanin produced depends on sun exposure or genes
Stratum spinosum
- 8 to 10 layers of keratinized cells connected by desmosomes
- cells phagocytose melanin progressively
Stratum granulosum
3 to 5 layers of cells connected by desmosomes
Stratum lucidum
ONLY IN THICK SKIN ( Palm of hands, feet, tip of fingertips)
2 to 3 layers of clear flat dead keratinocytes
(Cells start to detach and lose desmosomes)
Stratum corneum
Dead cells that protect the skin from water loss and gain