Chapter 5 Review - Integumentary System Flashcards
Integument consists of:
Cutaneous Membrane (skin) serving as a barrier along with Accessory structures (hair, nails & glands).
Integument functions
Along w/subcutaneous fascia, the integument functions include:
- Protection
- Excretion
- Maintenance of body temperature
- Synthesis of Vit. D3
- Storage of lipids
- Detection of environmental changes
Protection
prevents water & heat loss and protects mechanical & chemical damage
Excretion
water, salts and organic wastes by integumentary glands.
Maintenance of body temperature
cooling by evaporation of sweat along w/heat loss
Synthesis of Vit. D3
UV radiation stimulation increasing - - Vit D synthesis which is later converted to the hormone Calcitriol (stimulates calcium absorption in gut).
Storage of Lipids
in dermal and subcutaneous (hypodermal) layers
Detection of environmental changes
receptors monitoring changes in touch, pressure, pain and temperature.
Cutaneous membrane
skin consists of outer epidermis (epithelium) and inner dermis (CT)
Epidermis
water-resistant stratified squamous epithelium with 4 stratum (layers) in thin skin which covers most of the body, and 5 layers in thick skin as present on the sole of feet and palm of hands.
Stratum (deep to superficial)
- Stratum Germinativum (Basale)
- Stratum Spinosum
- Stratum Granulosum
- Stratum Lucidum*
- Stratum Corneum
Epidermis
Stratum Germinativum (Basale)
mitotically active keratinocytes attached to basement membrane by hemidesmosomes. Underlying dermis projects dermal papillae to interlock with epidermal ridges which reflects outward as fingerprints.
Epidermis
Keratinocytes
Young keratinocytes have many tonofilaments necessary for desmosomes and hemidesmosomes.
Epidermal Growth Factor (EGF)
ocal hormones which promote mitosis for growth & repair.
Melanocytes
cells which release melanosomes (vesicles w/melanin) which are release to higher layers to protect nuclei from DNA damage from UV radiation during mitosis.
Merkel Cells
specialized epithelium that respond to light touch stimulating neurons.
Stratum Spinosum
8-10 layers of keratinocytes which appear spiny owing to tonofilaments and shrinkage of cells during staining process.
- Langerhan Cells
Epidermis
Stratum Granulosum
3-5 layers of thin keratinocytes packed w/lipogranules & keratohyalin (which serve to convert tonofilaments to keratin). Cells undergo apoptosis at this level.
Epidermis
Stratum Lucidum
3-5 layers of flat dead keratinocytes found only on thick skin (palms of hand & soles of feet).
why thick skin has another layer
Epidermis
Stratum Corneum
15-30 layers of dead keratinocytes on the outermost, exposed surface.
a. Cornification
b. Insensible perspiration
c. sensible perspiration
Epidermis
tonofilaments
intermediate filaments
Langerhan Cells
Stratum Spinosum.
-stimulate body defenses activating lymphocytes.
Cornification
process of keratinization which occurs during a 15 to 30 day journey from the germinativum to the corneum. Mitosis increases w/Psorasis (typically 10 day journey and cells not fully keratinized in the corneum).
Insensible Perspiration
1 pt./day evaporates through skin goes unnoticed
Sensible Perspiration
active sweat glands utilized to cool down the body.
Dermis
contains all the cells of CT Proper w/blood & nerve supply. There are two distinct layers of dermis that blend together seamlessly. Sits on top of hypoderims (subcutaneous).
- Papillary
- Reticular
Hypodermis
subcutaneous
Papillary Layer
superficial layer of areolar CT which secretes lamina densa of basement membrane. Areas subject to abrasion have more dermal papillae (finger tips).
a. Decubitus ulcers (bed sores)
b. Transdermal patches
c. Tactile discs
d. Free-nerve endings
Decubitus ulcers (bed sores)
Dermis - Papillary Layer
- from compression of papillary capillary against boney surface (like ilium) causing necrosis of epithelium.
Transdermal patches
Dermis- Papillary Layer
- deliver pharmaceuticals into dermal layer & blood vessels.
Free-nerve endings
Dermis - Papillary Layer
-detect pain & temperature.
Tactile Discs
Dermis - Papillary Layer
- sensory terminal for Merkel receptors.
Reticular Layer
Dermis.
- deeper dermis is mainly dense irregular CT w/ collagen & elastin.
a. Striae
b. Lines of cleavage
c. Blood & lymph supply
d. Pacinian corpuscles
e. Accessory organs
Striae
Dermis - Reticular Layer
- stretch marks from overcoming elastic barrier of reticular layer.
Lines of Cleavage
Dermis - Reticular Layer
- direction of collagen & elastic fibers arranged in pattern.
Blood and Lymph supply
Dermis - Reticular Layer
- receives blood & lymph from deeper layers traveling up to dermal papillae.
Pacinian Corpuscles
Dermis - Reticular Layer
- deep-pressure receptors that are fast to adapt so good for sensing vibrations.
Accessory Organs
Dermis - Reticular Layer
- hair follicles and sweat glands.
Subcutaneous layer
Hypodermis Layer. - mainly adipose and areolar CT, it blends with reticular dermis to allow skin & muscles to move independently. Contains: Blood Reservoir Carotene pigment Subcutaneous fat
Blood Reservoir
Subcutaneous Layer
- Very rich blood & lymph supply.