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62 Cards in this Set
- Front
- Back
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What is the largest organ of the body?
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SKIN, it makes up ~ 16% of body weight
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What are the functions of integument?
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- protection
- excretion -regulation -sensation -metabolism - immune -endocrine |
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What does integument protect against?
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dessication (impermeable to water)
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Integument is excretion is through?
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glands of the skin
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What are some components of of regulation within integument?
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temp., water balance, i.e. homeostasis
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Some sensation felt by integument includes?
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touch, pressure, pain, & temp.
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Integument metabolism includes?
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fat storage, vitamin D synthesis
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Does integument provide immune info to the lymphatic system?
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YES
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What is the endocrine function of integument?
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secretion of hormones, cytokines, growth factors
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Integument is attached to what two layers?
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(1) epidermis
(2) dermis |
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Epidermis is characterized as what?
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-outer layer (avascular)
- keratinized stratified squamous epithelium (keratinocytes) |
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The dermis consists of?
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- deep layer (vascular)
- dense irregular connective tissue |
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Hypodermis
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- underlies skin (i.e. subcutaneous tissue)
- consists of loose areolar connective tissue - superficial fascia of gross anatomy - permits movement of skin |
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There are two types of skin: thick and thin, what characterizes thick skin?
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-it is found in on the palms of hands and soles of feet
-thick epidermis with a thick outer layer of keratin -high dermal papillae enhance adhesion of dermis and epidermis -ridges and grooves present- responsible for finger prints -numerous sweat glands |
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Thin skin can be decribed in the following terms:
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- covers the majority of the body not taken over by thick skin
- thin epidermis and keratin layer - contains hair follicles - fewer sweat glands and no ridges and grooves |
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What are the five layers for thick skin?
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(1) stratum basale
(2) statum spinosum (3) stratum granulosum (4) stratum lucidum (5) stratum corneum |
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stratum corneum
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-several layers of flat, dead cells containing keratin
-outer layers are continually desquamated -cells lost and replaced continually |
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stratum lucidum
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- thin layer, appears as a clear bright line in thick skin, often absent in thin skin
- granules, nuclei and organelles absent or indistinct |
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stratum basale
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- 1 layer of basophilic columnar cells
- anchored by desmosomes & hemi-desmosomes - intermediate filaments aka cytokeratins are produced (tonofilaments) - contain stem cells from which keratinocytes arise i.e. germinal layer |
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stratum spinosum
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- polyhedral cells bearing processes (spines)
- spines from adj. cells attached by desmosomes - tonofibrils ( bundles formed from intermediate filaments) - project into spines & desmosomes - maintain cohesion between cells, resist effects of abrasion - mitotic figures common in basale and spinosum (i.e. Malpighian layer) |
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Epidermis is characterized as what?
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-outer layer (avascular)
- keratinized stratified squamous epithelium (keratinocytes) |
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The dermis consists of?
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- deep layer (vascular)
- dense irregular connective tissue |
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Hypodermis
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- underlies skin (i.e. subcutaneous tissue)
- consists of loose areolar connective tissue - superficial fascia of gross anatomy - permits movement of skin |
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There are two types of skin: thick and thin, what characterizes thick skin?
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-it is found in on the palms of hands and soles of feet
-thick epidermis with a thick outer layer of keratin -high dermal papillae enhance adhesion of dermis and epidermis -ridges and grooves present- responsible for finger prints -numerous sweat glands |
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Thin skin can be decribed in the following terms:
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- covers the majority of the body not taken over by thick skin
- thin epidermis and keratin layer - contains hair follicles - fewer sweat glands and no ridges and grooves |
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What are the five layers for thick skin?
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(1) stratum basale
(2) statum spinosum (3) stratum granulosum (4) stratum lucidum (5) stratum corneum |
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stratum corneum
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-several layers of flat, dead cells containing keratin
-outer layers are continually desquamated -cells lost and replaced continually |
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stratum lucidum
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- thin layer, appears as a clear bright line in thick skin, often absent in thin skin
- granules, nuclei and organelles absent or indistinct |
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stratum basale
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- 1 layer of basophilic columnar cells
- anchored by desmosomes & hemi-desmosomes - intermediate filaments aka cytokeratins are produced (tonofilaments) - contain stem cells from which keratinocytes arise i.e. germinal layer |
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stratum spinosum
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- polyhedral cells bearing processes (spines)
- spines from adj. cells attached by desmosomes - tonofibrils ( bundles formed from intermediate filaments) - project into spines & desmosomes - maintain cohesion between cells, resist effects of abrasion - mitotic figures common in basale and spinosum (i.e. Malpighian layer) |
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stratum granulosum can be described as?
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~ 3 rows of flattened keratinocytes
- either keratohylalin granules or epidermal water barrier |
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During keratinization of Keratohyalin Granules what happens?
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1. granules are released into the cytoplasm
2. they form a homogeneous matrix 3. then through aggregation of intermediate filaments they form soft keratin 4. outter layers breakdown which are made of granulosum nucleus and organelles break down - become embedded in heratohyalin homogenous matrix - matrix also infiltrates remnants of nucleus & organelles keratin therefore formed from transformation of cellular constitutents |
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Epidurmal Water Barrier is
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- granulosum cells produce lamellar bodies or granules
--lamellar disks formed by lipid bilayers --lamellar bodies released by exocytosis- form lipid containing sheets --lipid seals skin between granulosum and corneum -insoluble proteins deposited on inner surface of plasmalemma -creates cell envelope which enhances water barrier and mechanical props - 80% of cell envelope protein is loricrin |
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Thin skin can be described as...
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thin and simple epidermins with no stratum lucidum
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A person gets pigmentation due to what factors?
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1. blood
2. carotene 3. melanin 4. tanning |
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Melanocytes
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-the precursor cells originate in neural crest, migrate to dermal- epidermal junction
-located beneath or between basal cells of epidermis -melanocyte processes extend between epidermal cells - melanocytes produce melanin granules (melanosomes) - granules released from processes- enter epidermal cells via processes |
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Tanning
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-caused by exposure to UV rays
-physicochemical reaction occurs when: melanin darkens and is rapidly released into keratinocytes and the rate of melanin synthesis increases -melanin granules in keratinocytes accumulate in the supranuclear region -protect the nuclei of dividing cells from solar radiation |
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Langerhan Cells
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-stellate, dendritic cells throughout epidermis
-present in lymphatic organs -antigens that pass through skin take these up & present them to lymphoid cells in lymph nodes - referred to as antigen presenting cells -mediate contact allergic responses in skin & delayed hypersensitivity reactions |
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Dermis
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-pretty much the same in thick & thin skin
-thickness varies -protrusions of this into epidermis is called papillae - has 2 layers: papillary & reticular |
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Papillary layer
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includes papillae, thin c.t. fibres, nerve endings, capillaries
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Reticular layer
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-deeper main portion
-denser c.t., muscle fibres, fat cells close to hypdermis |
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Epidurmal Water Barrier is
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- granulosum cells produce lamellar bodies or granules
--lamellar disks formed by lipid bilayers --lamellar bodies released by exocytosis- form lipid containing sheets --lipid seals skin between granulosum and corneum -insoluble proteins deposited on inner surface of plasmalemma -creates cell envelope which enhances water barrier and mechanical props - 80% of cell envelope protein is loricrin |
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Thin skin can be described as...
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thin and simple epidermins with no stratum lucidum
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A person gets pigmentation due to what factors?
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1. blood
2. carotene 3. melanin 4. tanning |
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Melanocytes
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-the precursor cells originate in neural crest, migrate to dermal- epidermal junction
-located beneath or between basal cells of epidermis -melanocyte processes extend between epidermal cells - melanocytes produce melanin granules (melanosomes) - granules released from processes- enter epidermal cells via processes |
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Tanning
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-caused by exposure to UV rays
-physicochemical reaction occurs when: melanin darkens and is rapidly released into keratinocytes and the rate of melanin synthesis increases -melanin granules in keratinocytes accumulate in the supranuclear region -protect the nuclei of dividing cells from solar radiation |
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There are 2 blood vessel networks in integument what are they? They also have what type of shunts?
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(1) b/w papillary & reticular layers (subpapillary plexus)
(2) b/w dermis & hypodermis (cutaneous plexus) - have arteriorvenous shunts which bypass capillaries, they play role in thermoregulation |
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subpapillary plexus
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-b/w papillary & reticular layers
-thin branches loop upwards into papillae |
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cutaneous plexus
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-b/w dermis & hypodermis
- supply glands, hair follicles |
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Nerves in the the integument include what?
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- motor nerves to vessels, muscles, & glands
- sensory nerves in all layers - sensory receptors |
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Sensory receptors in integument include what?
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- meissner corpuscles
- merkel cell - free endings - peritrichial endings |
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meissner corpuscles
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- in dermal papillae- tactile receptor
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Merkel cell
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- neural crest derived cell in basale- tactile receptor
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free endings
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- no myelin or schwann cells- pain & temp.
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peritrichial endings
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- around hairs- stimulated by movement of hair
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There are 2 types of sweat glands found in the integument, what are they?
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-eccrine
- apocrine |
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Eccrine Sweat Glands
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the most common type
- undergo merocrine secretion, i.e. no cytoplasm is lost - secretory portion: *deep in dermis or hypodermis *simple columnar or cuboidal ep. -3 *cell types, dark cells, clear cells, *myoepithelial cells *myoepithelial cells are contractile *aid in emptying gland - excretory duct: *double layer of cuboidal cells - no *myoepithelial cells *duct loses wall and spirals through *epidermis |
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Apocrine Sweat Glands
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-confined to axilla, pubic region, areola of the breasts
- ducts connect with hair follicles - begin functioning at puberty, secretion more viscous - undergo apocrine secretion - a fraction of the cytoplasm is lost & becomes part of the secretory product |
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Sebaceous Glands
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- located in dermis adjacent to hair follicles
- empty oily secretion (sebum) into hair follicles via ducts - several sacs (alveoli) empty into each duct - gland is made up of a stratified epithelium with small basal and larger central cells - central cells degenerate and become the secretory product, i.e. holocrine secretion |
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Age Changes in Skin
Fetal to Adult: |
- collagen fibres thicken, collagen synthesis decreases
- elastic fibres increase in number and thickness - elastin in adult is five times the amount in fetus |
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Age Changes in Skin
Adult to Old Age: |
- cross linking of collagen fibres, loss of elastic fibres
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Solar Elastosis:
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-caused by excessive exposure to sun
- skin becomes fragile, loses suppleness, develops wrinkles |
