Chapter 4: Integumentary System Flashcards
What percentage of our body weight is exclusively skin?
7%
What are the two layers of skin?
Epidermis and Dermis
What is the deepest layer of the skin called?
Hypodermis
What are the types of cell in the epidermis?(4)
Keratinocytes, merkel cells, langerhans/dentritic cells, melanocytes
What is the most abundant type of cell in the epidermis?
Keratinocytes
What type of cell is the epidermis?
keratinized stratified squamous epithelial
What is the Pacinian corpuscle?
Sensory organ
What is the functions of keratinocytes?
Produce keratin
What is the function of merkel cells?
Detection of light touch and pressure
Where is the Merkel cells found?
At the dermo epidermal junction
What are the Langerhans/dentritic cells?
Phagocytic cells
What is the function of melanocytes? (2)
Production of pigment melanin
Protects against UV radiation
What are the five layers of epidermis? Name them from deep to superficial
- Stratum basale (mitotic layer) [stratum germinativum]
- Stratum spinosum (spiny layer)
- Stratum granulosum
- Stratum lucidum (clear layer)
- Stratum corneum (horny layer)
What is the function of stratum basale?
Contain stem cells that undergo mitosis to form keratinocytes which form the more superficial layers of epidermis
What cells do stratum basale contain?
Merkel cells and Melanocytes
Which layer contains some amount of mitotic cell activity?
Stratum spinosum
Why is the stratum spinosum called the spiky layer?
Cells are held together with spiny projections
What cells does stratum spinosum contain?
langerhans cells
What does Stratum granulosum consist of?
Keratinocytes with deep staining granules
What are the two types of granules in stratum granulosum?
keratohyalin granules and lamellated granules
What is the function of keratohyalin granules?
help form keratin
What is the function of lamellated granules?
Contain a waterproofing glycolipid
What is the stratum lucidum layer composed of?
a few rows of flat, dead, keratinocytes
Where is stratum lucidum layer seen?
only in thick skin
Which layer is not seen on every surface of the body?
stratum lucidum
What is the stratum corneum composed of?
thick layer if dead keratinocytes and thickened plasma membranes
What is the function of stratum corneum?
protects skin against dehydration, abrasion and penetration by microbes
What are the extensions of the dermis called?
Dermil papillae
What are the extension/depressions of the epidermis into the dermis called?
epidermal ridges
What does the dermis contain? (4)
Blood vessels, sweat, sebaceous glands and lamellar corpuscles
What is the dermis composed of? Name them from superficial to deep
- Papillary layer
- Reticular layer
What is the papillary layer composed of?
areolar CT
Which layer produces sweat that leaves fingerprints in hands and feet?
papillary layer
How much of the dermal layer is reticular layer?
80%
What is the reticular layer composed of?
dense irregular CT
What is another name for hypodermis?
superficial fascia or subcutaneous layer
What tissues does hypodermis contain?
contains areolar and adipose connective tissues
What is the function of hypodermis? 3
anchors skin to underlying structures, thermal insulator, acts as shock absorber
What is alibinism?
A genetic disorder with inability if melanocytes to produce melanin, which affects coloring of skin hair and nails
What is vitiligo?
The melanocytes in certain areas lose their ability to produce melanin, possible due to an autoimmune reaction. This leads to a loss of color in patches
What are the accessory skin structures (appendages) 3
Hair, glands, nails
Where is hair not found? 6
palms, soles, lips, nipples, parts of external genitalia, and distal segments of fingers and toes
What type of glands are included in the skin? 3
sebaceous (oil) glands
sweat glands
mammary glands
What is hair made of?
Flexible type of dead, keratinizes epithelial structure
What are the main parts of the hair?
root and shaft
What is the root?
the part of hair that is imbedded in the skin and enclosed in a sheath (hair follicle)
What is the shaft?
Part of the hair that projects above the skin surface
What is the three concentric layers of keratinized cells?
medulla (central core), cortex (surrounds medulla), cuticle (outermost layer)
What is a hair follicle made up of?
hair bulb and root plexus
What is the hair bulb?
deep, expanded end of the hair follicle
What is the root plexus?
knot of sensory nerves around the hair bulb
What is the hair bulb composed of?
Hair follicle, wall of hair follicle and arrector pilli muscle
What is the wall of hair follicle made of?
inner connective tissue root sheath and outer epithelial root sheath
What is the arrector pilli muscle and what does it do?
It is a bundle of smooth muscle that connects hair follicle to dermal tissue and contracts to erect hair
Where are sebaceous glands found?
everywhere in the body
What type of glands are sebaceous glands?
exocrine glands
What do sebaceous glands secrete?
sebum, an oily substance
How does sebaceous glands secrete sebum?
Holocrine secretion - entire cell breaks up to form secretion
What type of exocrine glands is sebaceous glands?
simple branched alveolar gland
What is the function of sebum? 2
Softens and lubricated hair and skin
prevents bacterial infection
What is another name for sweat gland?
sudoriferous glands
What is sweat made up of?
99% water with some salts and traces of metabolic wastes
What are the two types of sweat glands?
eccrine glans and apocrine glans
Which gland produces true sweat?
Eccrine gland
How does sweat from eccrine gland reach skin surface?
through a duct that open externally through sweat pore
What is the most numerous sweat gland?
eccrine gland
Where is apocrine sweat gland found? 3
axillary, anal and genital areas
What is the larger sweat gland?
aprocrine gland
What does apocrine gland produce?
special kind of sweat
How does the sweat from apocrine gland move to the surface?
their ducts empty into hair follicle
What are nails made of?
hard dead keratin
Where do nails grow from?
nail matrix
What are the parts of nails?
free edge, body and root
How are burns classified?
By area and depth (degree) of burn
How is first degree burn classified?
only epidermis is damaged (ex. sunburn)
How is second degree burn classified?
upper part of dermis is also damaged. Blisters appear bur skin heals with little scarring
How is third degree burn classified?
consumption of all thickness of skin (dermis and epidermis), are turns white, red or blackened. Heals with scarring but needs skin grafting
How is fourthdegree burn classified?
Full thickness burns but extend to deeper tissues
What is the rule of 9?
Ant. and pos. head and neck = 9%
Ant. and pos. upper limbs 18%
Ant. and posterior trunk 36%
Anterior and post. low limb 36%
Perinum = 1%
Define neoplasms
An abnormal mass of tissue that forms when cells grow and divide more than they should or do not die when they should
What is an example of a benign neoplasm?
Warts (HPV virus)
What is the least malignant neoplasm?
basal carcinoma
What is the most malignant neoplasm?
malignant melanoma
What is the another type of malignant neoplasm?
squamous cell carcinoma
What is most common malignant neoplasm?
basal cell carcinoma
Where and how does squamous cell carcinoma arise?
UV exposure, arises in stratum spinosum
Which cell is malignant melanoma arised from?
melanocytes
How does malignant melanoma arise?
accumulated DNA damage in a skin cell