Chapter 5 Integumentary system Flashcards
What is the integumentary system?
Organs that include skin, hair, nails, sudoriferous glands, and sebaceous glands
What is dermatology?
The medical specialty for the diagnosis and treatment of disorders of the integumentary system
What are the two types of skin?
- Thin (hairy) skin
- Thick (hairless) skin
What is Thin (hairy) skin?
Covers all body regions except the palms, palmer surfaces of digits, and soles
What is thick (hairless) skin
Covers the palms, palmer surfaces of digits, and soles
What are the functions of the skin?
- regulate body temperature
- blood reservoir
- protection
- cutaneous sensations
- excretion and absorption
- synthesis of vitamin D
What is the cutaneous membrane?
The skin which covers the body and is the largest organ of the body by surface area and weight
What are the major layers of the skin?
- Outer
- Inner
What is the outer layer of the skin?
Called the epidermis, which consists of epithelial tissue and is the thinner layer
What is the inner layer?
Thicker layer called the dermis
What is the subcutaneous (sub Q) layer?
Also called the hypodermis and is located underneath the dermis.
What does the subcutaneous layer do?
Attaches the skin to the underlying tissues and organs
What is the epidermis composition?
Four layers of thin skin and five layers of thick skin
What are the layers of the epidermis?
- Stratum Basale
- Stratum Spinosum
- Stratum Granulosum
- Stratum lucidum
- Stratum Corneum
What is the Stratum Basale?
Deepest layer of the epidermis where continuous cell division occurs which produces all the other layers
What is the Stratum Spinosum?
The layer of the epidermis where 8-10 layers of keratinocytes occur
What is the Stratum Granulosum?
Area of the epidermis which includes the keratohyalin and lamellar granules
What is the Stratum Lucidum?
Area of the epidermis present only in thick skin (the skin of the fingertips, palms, and soles)
What is the stratum corneum?
Area of the epidermis composed of many sublayers of flat, dead keratinocytes that are continuously shed and replaced by cells from a deeper strata
What are keratinocytes?
90% of the cells which produce keratin which is a tough fibrous protein that provides protection
What are Melanocytes?
Produce the pigment melanin that protects against damage by ultraviolet radiation, found in the deepest layers of the epidermis
What are Langerhans Cells?
Cells found in the epidermis which are involved in immune response and arise from red bone marrow
What are Merkel Cells?
Cells found in the epidermis which function in the sensation of touch along with the adjacent tactile discs
What is keratinization?
Accumulation of more and more protective keratin, which occurs as cells move from the deepest layer to the surface layer.
What is dandruff?
An excess of keratinized cells shed from the scalp
What are characteristics of the dermis?
Composed of connective tissue containing collagen and elastic fibers
What are the two layers of the dermis?
- Papillary region
- Reticular layer
What is the papillary region?
Superficial layer of the dermis which consists of connective tissue containing thin collagen and elastic fibers, projections called papillae which forms a distinct patter (fingerprints).
What is the reticular layer?
Layer of the dermis which consists of dense irregular connective tissue containing collagen and elastic fibers, adipose cells, hair follicles, nerves, sebaceous (oil) glands, and sudoriferous (sweat) glands
What is the structural basis of skin color?
Based on variations in the amount of three pigments
1. melanin
2. carotene
3. hemoglobin
What is melanin?
A yellow- red or brown-black pigment produced by melanocytes
Where are the melanocytes located?
Mostly in the epidermis, where it absorbs UV radiation
What does the melanin do in terms of skin color?
causes the skin color to vary from pale yellow to red to tan to back
Are the amount of melanocytes the same in everyone?
Yes, they are about the same. However, Differences in skin color is due to the amount pigment produced
What is carotene?
A yellow-orange pigment found in vegetables and builds up in the stratum corneum and fatty areas of the dermis
What are Hemoglobin?
reddish pigment in the red blood cells, not in skin cells.
What is the color of oxygenated blood?
Pinkish color
What is the color of deoxygenated blood?
Blue color
What is albinism?
An inherited inability to produce melanin
What is vitiligo?
Partial or complete loss of melanocytes from patches of skin
What is carotene?
Yellow-orange pigment, usually found in the stratum corneum, dermis, and subcutaneous layer
What is hair?
present on most surfaces except the palms, anterior surfaces of fingers, the soles of the feet and toes, nipples and some areas of genitalia.
What is hair composed of?
Dead, keratinized epidermal cells, genetics determines thickness and distribution.
What is hair also called?
Pili
What is the main function of hair?
protection. Hair also helps with touch sensation and protects the body against the harmful effects of the sun and against heat loss.
What are the two main groups of exocrine glands?
- Sebaceous (oil) glands
- Sudoriferous (sweat) glands
Between the two main exocrine glands which are connected to hair follicles and which are found in the dermal region of the skin
Sebaceous are connected to the hair follicles and sudoriferous glands are found in the dermal region of the skin
What are the two types of sweat glands?
- Eccrine sweat glands
- Apocrine sweat glands
What are the eccrine sweat glands?
Most numerous and secrete a watery solution that helps cool the body and eliminates small amounts of waste
What are the Apocrine sweat glands?
Located mainly in the skin of the axilla, groin, areole, and bearded facial regions of adult males. They secrete slightly viscous sweat
What causes the eccrine sweat glands to release sweat?
Emotional stress such as fear or embarrassment. (cold sweat)
What causes the apocrine sweat glands to release sweat?
emotional stress and sexual excitement. Much of the body odor is due to apocrine sweat.
What are ceruminous glands?
modified sweat glands located in the ear canal, which are involved in producing a waxy secretion called cerumen (earwax) which provides a sticky barrier that prevents entry of foreign bodies into the ear canal.
What are nails?
Composed of hard, keratinized epidermal cells located over the dorsal surfaces of the ends of the fingers and toes.
What are nail structures?
Free edge (white part) and nail root (embedded in the fold of skin)
two kinds of wound healing processes can occur depend on the depth of injury, what are they?
- Epidermal wound healing
- Deep wound healing
What is epidermal wound healing?
Occurs following superficial wounds that affect only the epidermis (return to normal function rule)
What is deep wound healing?
Occurs when an injury extends to the dermis and subcutaneous layer. (loss of some function and development of scar tissue is the rule)
What are the four phases of wound healing?
- inflammation
- migration
- proliferative phase
- maturation phase
What is inflammation?
Blood clot forms in wound and loosely unites wound edges. Vasodilation and increased permeability of blood vessels enhance delivery of helpful cells
What is migration?
Clot becomes scab, fibroblasts migrate along fibrin threads and synthesize scar tissue
What is proliferative phase?
Extensive growth of epithelial cells beneath scab and deposition of fibroblasts of collagen fibers
What is maturation?
Scab sloughs off once epidermis has restored to normal thickness
What is a burn?
When tissue is damaged by excessive heat, electricity, radioactivity, or corrosive chemicals that denature (break down) the proteins in the skin cells
What does burns do to homeostasis?
destroys skins important contributions to homeostasis- protection against microbial invasion and desiccation, and thermoregulation
How are burns graded?
According to their severity
What is a first degree burn?
involves only the epidermis.
How is a first degree burn characterized?
mild pain and erythema (redness) but no blisters on skin and functions remain intact
What is a second degree burn?
Destroys the epidermis and part of the dermis- some skin functions are lost.
What are characterizations of second degree burns?
Redness, blister formation, edema, and pain result
What is a third degree burn?
full thickness burn (destroys the epidermis, dermis, and subcutaneous layer)
What are the characterizations of a third degree burn?
Most skin functions are lost, and the region is numb because sensory nerve endings have been destroyed
What is considered a major burn?
- 3rd degree over 10% of body surface area
- 2nd degree over 25% of the body surface area
- 3rd degree burns on the face, hands, feet, or perineum (which includes anal and urogenital regions)
