Chapter 5 Flashcards
What are the two parts of the skin?
Epidermis and dermis
What kind of tissue is the epidermis?
Epithelial Tissue
What type of tissue is the dermis?
Connective tissue (supplies nutrients to the epidermis)
What kind of cells are found in the epidermis?
Keratinized stratified squamous epithelium
What is another name for the hypodermis?
Superficial fascia
Where is the hypodermis located?
deep to the skin
NOT part of the skin
What kind of tissue is found in the hypodermis?
Adipose tissue
What does the hypodermis do for the skin?
It anchors the skin to underlying structures such as muscle
It acts a shock absorber an insulator (adipose-fat)
What are the 4 types of cells found in the skin?
Keratinocytes
Melanocytes
Dendritic (Langerhans) cells
Tactile (Merkel) cells
What do keratinocytes do for the skin?
Produce fibrous (structural) keratin
What connects keratinocytes in the epidermis and why is this important?
Desmosomes (tightly connected) Allows stretch (velcro) Keeps moisture in to avoid dehydration
What do melanocytes do for the cell?
Produce pigment melanin (protect against UV)
Why are dendritic cells important in the skin and what is an example of one?
Macrophages
Important for warding off infections
What do tactile cells for the skin?
Allow sensations of touch (Merkel)
There are deep and light touches
What is apoptosis?
Controlled cellular suicide
What are the 5 layers of the epidermis and what layer is only found in thickened skin like the palms and heels?
Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum Basale
Lucidum is only in tough areas (think lucid=white/clear and the heals and calyces are white)
What is the deepest layer of the epidermis and what does it do?
Stratum basale
Site of mitosis (production of new live cells - it is closest to the nourishment)
Think of a basement= basale and basements are the lowest part of the house
What layer of the epidermis has the highest concentration of dendritic cells?
Stratum spinosum
(spiny looking layers- spin/spine)
Dendritic cells help with immune protection
Also has melanosomes as well
What layer in the epidermis do cells start to change and become more tough and flat?
Stratum granulosum (contains keratinocytes and keratin is important for the tough structure of the skin)
What layer of the epidermis contains many rows dead keratinocytes?
The stratum corneum
(this layer is important for the first line of defense against assaults and is important for keeping the deeper layers from loosing water)
What is the dermis made up of?
Connective tissue
Fibroblasts,macrophages, and other immune cells
Nerve fibers
Blood and lymphatic vessels
Epidermal hair follicles, oil and sweat glands
What are the two layers of the dermis?
Papillary and reticular
What layer of the dermis gives rise to fingerprints?
The thin papillary layer (dermal papillae to be specific)
What kind of connective tissue is found in the papillary layer?
Areolar connective tissue with collagen and elastic fibers and blood vessels
(Allows for stretch and recoil while also having structure and strength and is vascularized so nourished)
What does the dermal papillae allow for in the fingers and toes?
Friction ridges
Enhance grip, contribute to sense of touch (Merkel cells)
What layer of the dermis accounts for 80% of its thickness?
The reticular layer
What connective tissue is the reticular layer made up of?
Dense fibrous connective tissue (elastic and collagen -strength and stretch/recoil)
What are cleavage lines and what are they formed by?
Formed by collagen fibers that run parallel to the skin surface (surgeons use these lines so that the person heals faster)
What skin marking is formed by dermal folds at or near joints (like palm reading lines)
Flexure lines (where there is alot of range of motion)
What skin marking is referred to as stretch marks?
Striae (silvery-white scars)
What skin marking is a fluid filled pocket that separates the epidermal and dermal layer and what might cause this?
Blisters (2nd degree burn/ when your sunburn bubbles up)
What are the three pigments that contribute to skin color?
Melanin (brown hue or reddish yellow hue)
Carotene (orange hue)
Hemoglobin (red hue)
Where is melanin formed?
In melanocytes
What marking is formed by local accumulations of melanin?
freckles or moles
What stimulates melanin production?
Sun exposure
What are fungal infections that look like white dots on the skin?
Sunspots (tinea versicolor- not related to melanin production)
What are the two forms of melanin?
Reddish-yellow
Brownish-black
What pigment does carotene cause?
Yellow to orange pigment (carrots and carotene)
What can carotene be converted into and what is this used for?
Vitamin A - vision and epidermal health
What hue is given off from hemoglobin and in what type of skin?
Pinkish hue of fair skin
What diagnosis can come from cyanosis?
Hypoxia/ low oxygenation of hemoglobin
Blue hue of skin