Human Anatomy - The integumentary system Flashcards
The skin is our _______ organ composed of all 4 ____ types.
Largest
tissue
What are the four tissue types?
- Nervous tissue
- Muscle Tissue
- Connective Tissue
- Epithelial Tissue
The skin is divided into what two layers?
Epidermis and Dermis
What is the epidermis?
Keratinized stratified squamous epithelium
What is the dermis?
Connective tissue
Where is the hypodermis located relative to the dermis?
Deep
What constitutes the hypodermis?
Adipose tissue and connective tissue (areolar)
What are the functions of the skin?
PREAPS P - Protection R - Regulation of body temperature E - Excretion A - Absorption P - Production of vitamin D S - Sensory reception
What are the two cell types in the epidermis?
Keratinocytes and melanocytes.
Where are keratinocytes located?
Stratum spinosum
What do keratinocytes do?
Produce keratin (protection)
At the skin surface, what is the state of keratinocytes?
Dead
Where are melanocytes located?
Stratum basale
What do melanocytes do?
Manufacture and secrete melanin
What are the layers of the epidermis (superficial to deep) and which is only present in thick skin?
Stratum corneum Stratum lucidum - only in thick skin Stratum granulosum Stratum spinosum Stratum basale
What is a callus?
Thickening of the epidermis due to repeated friction.
What is a blister?
Separation of the epidermis from dermis by a fluid-filled pocket.
What is the stratum basale?
- Deepest layer of the epidermis
- Attached to underlying dermis
- Cells actively divide (single row of youngest keratinocytes)
- Also contains melanocytes
What is the stratum spinosum (spiny layer)?
- 8-10 cells layers thick
- small amount of mitosis
- contains thick bundles of intermediate filaments
- contains star-shaped Langerhans cells (macrophage)
- 2nd deepest layer
What is the stratum granulosum?
1-5 layers of flat, dying keratinocytes
- contains lamellar granules that release waterproofing glycolipid
What is the stratum lucidum?
Only appear in thick skin on palms and soles of feet
- composed of a few rows of flat, dead keratinocytes
What is the stratum corneum (horny layer)?
25-30 cell layers thick of dead keratinocytes containing only keratin
- continuously shed
- protects skin against abrasion and penetration
______ cells divide to produce keratinocytes.
Stem
As keratinocytes are pushed upwards towards the surface, they fill with what?
Keratin
The typical journey of a keratinocyte last how long? What can modify this?
4 weeks. Can be modified by abrasion of the outer layers.
What is psoriasis?
Autoimmune, chronic disorder.
Caused by keratinocytes that divide and move more rapidly than normal through the epidermis.
This causes cells to pile up on the skin surface. These resembles flaky silvery, scales.
What is the dermis?
The second major layer of the skin.
What characterizes the dermis?
- Strong, flexible connective tissue
- Richly supplied with blood vessels and nerves
- Holds the body together like a body stocking - animal hide
What are the two layers of the dermis?
Papillary and reticular
The papillary layer consists of the top __% of the dermis.
20
The papillary layer is composed of _______ _______ tissue.
Areolar connective
The papillary layer is named due to what?
Its finger like projections called dermal papillae.
What are the functions of dermal papillae?
- Anchors epidermis to dermis (reduce blister formation)
- contains capillaries that feed the epidermis
- increase surface area for exchange of gases, nutrients, wastes
The reticular layer has what kind of tissues and fibres?
Dense irregular connective tissue with thick interlacing collagen and elastic fibres
The tissue and fibres of the reticular layer function for what?
Provide strength, extensibility and elasticity to the skin. This gives stretch-recoil properties to the skin,
Extreme stretching due to pregnancy or obesity lead to tearing of _______ in the dermis resulting in ______ ______.
Collagen; stretch marks
What three pigments contribute to skin colour?
Melanin
Carotene
Hemoglobin
Which of the skin pigments is the most important?
Melanin
What are the colour ranges of melanin?
yellow-red-brown-black
What colour is carotene and where does it come from?
Yellowish pigment obtained from carrots and tomatoes
Where does carotene accumulate?
Stratum corneum and hypodermis
Caucasian skin has contains little ________; epidermis is nearly ________. This allows the crimson colour of ______ to show through.
melanin
transparent
Blood
What is the hypodermis?
Deep to the skin
contains areaolar and adipose connective tissue
anchors skin to underlying structures
helps insulate the body and protect against skin infections
What is another word for hypodermis?
Superficial fascia
What is a first degree burn?
Epidermis is damaged
What is a second degree burn?
Upper part of dermis is also damaged
What is a third degree burn
Consumes thickness of skin
What are the three common forms of skin cancer?
Basal cell carcinoma
Squamous cell carcinoma
Malignant melonoma
Basal cell carcinoma _____ metastasizes.
rarely
Squamous cell carcinoma _____ metastasize.
May
Malignant melanoma _______ metastasizes.
Rapidly
_______ is the most common cancer in young women. This cancer arises from ________. The key to treatment is ______ _______. Risk factors include ____ colour, ___ exposure, _____ history, ___ and ___________ status.
Malignant melanoma Melanocytes Early detection Skin Sun Family Age Immunological status
The _________ thins as the germinative cell activity declines.
epidermis
Why does the epidermis thin?
Due to decline in germinative cell activity.
As we age, _____ activity decreases.
Melanocyte.
What is the basis of wrinkles?
As we age, the dermis thins, we lose elastic fibres and collagen production slows down.
As we age, skin _____ slows.
repair
