Topic 9: Integumentary System Flashcards by Zenah Large

what does the integumentary system consist of?

-skin
-hair
-nails
-glands
-nervous sense receptors
-hypodermis
-muscles surrounding

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how many layers does the skin have? what are these layers called?

-2 layers
-epidermis (superficial layer)
-dermis (deep layer)

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what is the layer below the skin?

-hypodermis

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is the hypodermis considered to be apart of the skin?

-NO

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what are the characteristics of the epidermis?

-stratified squamous epithelium (from ectoderm)
-avascular
-seperated into 4-5 strata (sub-layers) depending on the cell type

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what are the 5 layers of the epidermis?

-stratum basale
-stratum spinosum
-stratum granulosum
-stratum lucidum
-stratum corneum

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what is the stratum basale composed of?

-single row of cells
-two cell types (keratinocytes + melanocytes)

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what are the abundances of the two cell types present in the stratum basale?

-keratinocytes (90%)
-melanocytes (10%)

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what are the basics of keratinocytes?

-undergo mitosis
-make keratin (a very tough protein)

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what happens when new cells are produced in the stratum basale?

-keratinocytes are pushed to the surface

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what are the basics of melanocytes?

-produce pigment (melanin) for UV light protection
-protects from sunburns, wrinkles (collagen damage), and cancer (DNA damage)

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why do humans differ in skin colour?

-we all have the same relative number of melanocytes
-cells will produce different amounts/shades of melanin
-albinism is a lack of melanin produced by melanocytes
-blood (hemoglobin) in the dermis can give fair skinned people a pinkish tinge (areas of thin skin)

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what is the stratum spinosum?

-above the stratum basale
-has low levels of mitosis

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what is within the stratum granulosum?

-dark staining granules that help to produce keratin and begin to produce waterproofing glycolipids
-last layer of living cells
-no mitosis occuring

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what is contained in the stratum lucidum?

-flat, dead cells
-they are too far away from the blood supply

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in what type of skin is the stratum lucidum?

-thick skin

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what is the stratum corneum composed of? what happens to this layer?

-many layers of flat dead cells filled with keratin which are surrounded by waterproofing glycolipids
-shed and replaced from below

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what is the purpose of the glycolipids surrounding the dead cells in the stratum corneum?

-to prevent water loss

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what does the dermis layer of the skin contain?

-blood vessels
-nerves
-glands
-hair follicles
-arrector pili muscles

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what are the two sub-layers of the dermis?

-papillary layer
-reticular layer

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what is the papillary layer of the dermis?

-directly beneath the epidermis
-made of areolar CT
-vascular (lots of blood flow)
-has projections into the epidermis called dermal papillae

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what do the dermal papillae form in thick skin?

-fingerprints
-improved grip

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what is the reticular layer of the dermis?

-majority of the dermis
-made of dense irregular CT

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what is the hypodermis?

-subcutaneous layer (lies under the skin)
-superficial fascia
-composed of adipose CT

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what is fascia?

-connective tissue layers that surround and support organs

how much adipose tissue does the hypodermis store?

-half of the bodies total -used for insulation

what differentiates thin skin?

-lucidum is absent -has hair follicles, sebaceous glands, and arrector pili muscles -covers most of the body

what differentiates thick skin?

-found on palms of hands and soles of feet -lucidum is present -no hair follicles, sebaceous glands, or arrector pili muscles

what structures are formed by the epidermis?

-hair -nails -skin exocrine glands

what cells make up our hair?

-dead cells

what are the parts of hair?

-root -shaft -hair follicle

what is the hair root?

-part of the hair embedded within the skin

what is the hair shaft?

-visible part of the hair that is above the surface of the skin

what is the hair follicle?

-surrounds the hair root -contains the epithelial root sheath, bulb, and matrix -also contains the outer CT sheath, hair papilla, root hair plexus, sebaceous gland, arrector pili muscle

what is the epithelial root sheath?

-several epidermal layers that extend into the dermis

what is the bulb of the hair follicle?

-expanded region at the base of the root

what is the matrix of the hair follicle?

-single layer of cells (derived from basale cells) -site of hair growth and melanin for hair colour -not associated with the extracellular matrix

what is the outer CT sheath?

-formed from the dermis -holds the follicle in place

what is the hair papilla?

-extends upwards, beneath the matrix -contains blood supply for hair growth (blood vessels) -formed from the dermis

what is the hair root plexus?

-free nerve endings (touch) -why pulling of hair hurts -generates nerve impulses if the hair shafts are moved

what is a sebaceous gland?

-oil gland (exocrine) -opens into the follicle -secretes sebum -prevents hair from becoming dry and brittle by coating the surface of hairs -also lubricates skin -antibiotic function as well

what are arrector pili muscles?

-smooth muscle tissue -causes goosebumps

what do our nails consist of?

-heavily keratinized epidermal cells -has a nail root (buried in the skin) -body (visible portion) -free edge (end of nail)

what are sudoriferous glands?

-sweat glands -have secretory portions in the dermis of thick and thin skin -ducts open onto the skin surface

what is the purpose of sudoriferous glands?

-temp. regulation (cools the body) -antibiotic (acidic) -removes small amounts of waste (urea)

what are ceruminous glands?

-modified sweat glands -in the ear canal -produce ear wax (ex: prevents insects from entering)

what is the most active layer of the epidermis?

-stratum basale -constantly undergoing mitosis

what epidermis layers contain living cells?

-stratum basale -stratum spinosum -stratum granulosum

what epidermis layers contain dead cells?

-stratum lucidum -stratum corneum

what are mammary glands?

-modified sweat glands -produce milk

what are the skin exocrine glands?

-sebaceous glands -sudoriferous glands -ceruminous glands -mammary glands

what is the tissue type of the exocrine glands in the skin?

-glandular epithelium

why are nails heavily keratinized?

-they need to be strong -stops them from breaking and being brittle

what are cutaneous sense receptors?

-sensory neurons part of the nervous system (long in order to pass signals) -specialized cells that respond to stimuli (touch, temp,pain) -have 4 major types

what are the 4 major types of cutaneous sense receptors?

-touch receptors -pressure receptors -thermoreceptors -nociceptors

what are touch receptors?

-free nerve endings that branch into the epidermis -root hair plexuses -meissner's corpuscles (dermal papillae) -all need little pressure to fire

what is a corpuscle?

-connective tissue capsule that surrounds nerve endings

what are the types of pressure receptors?

-free nerve endings that branch in the dermis -lamellar (pacinian) corpuscles -these need more pressure to fire

where are pacinian (lameller) corpuscles located?

-deep in the dermis or in the hypodermis

what are thermoreceptors?

-free nerve endings that respond to temperature

what are nociceptors?

-free nerve endings that respond to pain

what degree of burn destroys the nociceptors?

-3rd degree -cant feel the pain

do all sensory receptors contain pain? or just nociceptors?

-all contain pain reactions -nociceptors are more prominent/general

what composes sebum?

-mix of fats, salts, and proteins

what is psoriasis?

-autoimmune disorder -causes accelerated mitosis of keratinocytes in the stratum basale which delays maturation and differentiation -immature keratinocytes accumulate in the epidermis -stratum corneum fails to shed -thick scaly layer on the surface of the skin (plaque)

Topic 9: Integumentary System Flashcards

(65 cards)