2-Integumentary system Flashcards
Part of the Integument
- Skin
- Sweat Glands
- Sebaceous glands
- Hair
- Nails
Skin Functions
- Reception
- Protection
- Regulation of body temp
- Excretion
- Absoprtion
Specialized Receptors
- Mechano receptors-Touch ad pressure
- Thermoreeptors(Cold and warmth)-Free nerve endings
- Nociceptors(pain) -free nerve endings.
3 basic layers of skin
- Epidermis
- Dermis
- Hypodermis
Epidermis properties/function/origin
4-5 cell layers- constantly shed and get replaced
- have free nerve endings
- Derived from ectoderm
Dermis properties/function/origin
CT w/ collagen and elastin fibers
- Has blood vesses, nerve endings, hair follicles and glands
- Majo rle in formation and adhesion of epithelial cells
- derived from meso derm
Hypodermis
- Called the superficial fascia
- loose CT w/ adipose cells
Rete Apparatus
-At where the dermis and epidermis meer there are dermal and epidermal ridges that interdigitate
Type of epithelium in epidermis
Stratified squamous keratinized epithelium
Types of cells in epidermis
- Keratinocytes
- Melanocytes
- Langerhans cells
- Merkel cells
Keratinocytes
- largest cell population in skin
- Produce keratin and lipoporteins
Five zones/layers of keratinocytes
(from base to surface)
- Stratum Basal(germinativum)
- Stratum spinosum
- stratum granulosum
- stratum lucidum(not always there)
- Stratum corneum
What attaches the stratum basal to everything else?
Desmosomes bind the startum basal cells to each other and to the cells of the stratum spinosum.
While hemidesmosomes attach them to the basal lamina
Stratum basale (keratin production)
They begin production of tonofilaments
Lower Stratum spinosum (keratin production)
Tonofilaments merge to form tonofibrils
Upper stratum spinosum (keratin production)
Cells begin to produce keratohylin granules
Stratum granulosum (keratin production)
Substance from the keratohyalin granules(non-membrane bound) combine with the tonofibrils to form keratin
Stratum corneum(keratin production)
Cytoplasm of the cells replaced by keratin
Lamellar bodies
- Made by keratinocytes
- membrane bound
- contain glycophospholipids
- serve to waterproof skin
- released into intercellular space in the stratum granulosum
Melanocytes(location/function)
- Stratum basale
- Formation of pigment in skin
Pigment formation process
- Tyrosine(Amino Acid) is transported into teh cell and converted to melanin by tyrosinase(enzyme)
- Melanocytes have processes that go inbetween keratinocytes
- Melanin is then transferred to keratinocytes via melanosomes
Langerhans cells( Dendritic cells) function
- Contain Birbeck granules(unknown function)
- Phagocytosis and Antigen presenting cell(APC)
Merkel Cells
- Associaed with sensory nerves which traverse basal lamina of teh epidermis
- Mechanoreceptors( respond to light touch)
Free nerve ending
-Thermoreceptors and nociceptors
Dermis layers
- Papillary layer
- Reticular layer
Papillary layer contain…
- Type III collagen
- Elastic fibers
- Anchoring fibrils(VII)
- Capillary loops
- CT cells
Reticular layer
- Type I collagen
- lastic fibers
- Sweat glands
- Sebaceous glands
- Hair follicles
- Smooth muscle cells
Type of glands and how they work
- Holocrine- The whole cell is disintegrated and secreted
- Merocrine- released through exocytosis of vesicles
- Apocrine- Parts of the cells are pinched off
Sweat gland secretion types
- Eccrinee(merocrine)
- apocrine
Myoepithelial cells (function/location)
- they surround acini of exocrin glands (e.g. eccrine sweat glands)
- Are of epthelial origin but have smooth muscle like properties.
- They contact and help with releasing secretions.
Apocrine sweat glands
- Found only in the armpit, areola of the nipple and the anal regions
- Ducts open int the canal of hair follicles
Sebaceous glands
- Found throughout the body except palm of hands, sole and side of feet.
- Embedded in the dermis
- Secretes sebum, a wax-like, oily mixture of cholesterol, triglycerides, etc
- holocrine secretion
- associated with hair follicles
Arrrector pili muscles
-Make hair stand up and move.
Receptors in the dermis
- Meissners corpuscle(light touch)
- Pacinian corpuscle(deep pressre/vibration)
- Ruffini organ(Stretch)
Receptors in the epidermis
- Merkel disks
- Free nerve endings
