Chapter 5 Flashcards
What causes the decrease of speed and efficiency of tissue repair with age?
Caused by:
• Slower rate of energy consumption (metabolism)
• Hormonal alterations
• Reduced physical activity
the largest system of the body
Integument
Two parts that make up the itegument
- Cutaneous membrane
(skin) - Accessory structures
Two components of the cutaneous membrane
Outer epidermis and inner dermis
Structures that originate in the dermis and extend through the epidermis to skin surface
Accessory Structures
Consists of loose connective tissue and found below the dermis
Hypodermis
(Superficial Fascia or
Subcutaneous
Layer)
What are the functions of skin?
• Protection of underlying tissues and organs
• Excretion of salts, water, and organic wastes (glands)
• Maintenance of body temperature (insulation and
evaporation)
• Production of melanin
• Production of keratin
• Synthesis of vitamin D3
• Storage of lipids
• Detection of touch, pressure, pain, and temperature
avascular stratified squamous epithelium
Epidermis
Contain large amounts of keratin and are the most abundant cells in the epidermis
Keratinocytes
Covers most of the body and has four layers of keratinocytes
Thin Skin
Covers the palms of the hands and soles of the feet
and has five layers of keratinocytes
Thick Skin
What are the five
strata of keratinocytes in thick skin?
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum lucidum
- Stratum corneum
Stratum that is attached to basement membrane by
hemidesmosomes (junctional anchoring proteins) and forms epidermal ridges; it has many basal or germinative cells
Stratum Basale
Function to increasethe area of basement membrane and strengthen the attachment between epidermis and dermis
Dermal papillae
Specialized cell of stratum basale that are found in hairless skin and respond to touch
Merkel cells
Specialized cell of stratum basale that contain the pigment melanin and are scattered throughout stratum basale
Melanocytes
Stratum that is produced by division of stratum basale and has eight to ten layers of keratinocytes bound by
desmosomes; their cells shrink until cytoskeletons stick out
Stratum Spinosum
— the “spiny layer”
What cells are present in stratum spinosum that are active in immune response?
dendritic (antigen presenting) cells
Stratum that stops dividing, and starts producing keratin and keratohyalin
Stratum Granulosum
— the “grainy layer”
A tough, fibrous protein that makes up hair and nails
Keratin
Dense granules that cross-link keratin fibers
Keratohyalin
Stratum that is found only in thick skin and covers stratum granulosum
Stratum Lucidum
— the “clear layer”
Stratum that is the exposed surface of skin and has
15 to 30 layers of keratinized cells; it is water resistant and sheds and is replaced every 2 weeks
Stratum Corneum
— the “horn layer”
This is the formation of a layer of dead, protective cells filled with keratin that occurs on all exposed skin surfaces except eyes
Keratinization
Type of perspiration where the interstitial fluid lost by evaporation through the stratum corneum
Insensible perspiration
Type of perspiration where water is excreted by sweat glands
Sensible perspiration
Where does dehydration results from?
• From damage to stratum corneum (e.g., burns and
blisters
[insensible perspiration])
• From immersion in hypertonic solution (e.g.,
seawater [osmosis])
Where does hydration results from?
Results from immersion in hypotonic solution (e.g.,
freshwater [osmosis]) which causes swelling of epithelial cells
Pigments that influence skin color
- Carotene
2. Melanin
Orange-yellow pigment that is found in orange vegetables and accumulates in epidermal cells and fatty tissues of the
dermis; it can be converted to vitamin A
Carotene
Yellow-brown or black pigment that are produced by melanocytes in stratum basale; they are stored in transport vesicles (
melanosomes and are transferred to keratinocytes
Melanin
What is the function of melanocytes?
Produces melanin which protects skin from sun damage/UV radiation
How does oxygenated blood contribute to skin color?
- Blood vessels dilate from heat, skin reddens
* Blood flow decreases, skin pales
Bluish skin tint caused by severe reduction in blood flow or oxygenation
Cyanosis
Illness caused by buildup of bile produced by liver and produces a yellow skin color
Jaundice
Illness caused by the Excess Melanocyte Stimulating Hormone (MSH)
Pituitary tumor
A disease of the pituitary gland (insufficient ster
oid hormones) that causes skin darkening and other nonspecific symptoms
Addison’s disease
Disease caused by loss of melanocytes, resulting to loss of color
Vitiligo
Illness caused by insufficient vitamin D3
rickets
Liver and kidneys convert vitamin D3 into what?
calcitriol
Function of calcitriol
Aids absorption of calcium and phosphorus
Powerful peptide growth factor that produced by glands (salivary and duodenum); they are used in laboratories to grow skin grafts
Epidermal Growth Factor (EGF)
Functions of EGF
- Promotes division of germinative cells
- Accelerates keratin production
- Stimulates epidermal repair
- Stimulates glandular secretion
Located between epidermis and subcutaneous layer and anchors epidermal accessory structures
Dermis
two components of the dermis
- Outer papillary layer
2. Deep reticular layer
Layer that consists of areolar tissue and contains smaller capillaries, lymphatics, and sensory neurons; it has dermal papillae projecting between epidermal ridges
Papillary Layer
Layer that consists of dense irregular connective tissue and contains larger blood vessels, lymphatic vessels,
nerve fibers, collagen and elastic fibers and connective tissue proper
Reticular Layer
An inflammation of the papillary layer caused by infection, radiation, mechanical irritation, or chemicals (e.g., poison ivy); it is characterized by itch or pain
Dermatitis
Two types of fibers in the dermis that permit strength and elasticity
Collagen fibers and elastic fibers
Fibers that are very strong, resist stretching but bend easily and provide flexibility
Collagen fibers
Fibers that permit stretching and then recoil to original length and
limit the flexibility of collagen fibers to prevent damage to tissue
Elastic fibers
A network of arteries along the reticular layer
Cutaneous plexus
Capillary network from small arteries in papillary
layer
Papillary plexus
Capillary return deep to the papillary plexus
Venous plexus
Damage to blood vessels resulting in “black-and-blue” bruising
Contusion
Where are the tactile corpuscles located at?
dermal papillae
Where are the
lamellated corpuscles located at?
reticular layer
Layer that lies below the integument stabilizes the skin and allows separate movement; it is made of elastic areolar and adipose tissues
Hypodermis
Subcutaneous Layer
The human body is covered with hair,
except for which areas?
- Palms
- Soles
- Lips
- Portions of external genitalia
Functions of hair
- Protects and insulates
* Guards openings against particles and insects
Located deep in dermis and
produces nonliving hairs; they are wrapped in a dense connective tissue sheath where the base is surrounded by sensory nerves
Hair Follicle
Lower part of the hair that is attached to the integument
Hair root
Upper part of the hair that is
not attached to the integument
Hair shaft
produces hair matrix
hair bulb
A layer of dividing basal cells that produces hair structure and pushes hair up and out of skin
hair matrix
The central core of the hair shaft
Medulla
The middle layer of the hair shaft
Cortex
The surface layer of the hair shaft
Cuticle
Medulla contains flexible
________ keratin while cortex and cuticle contain __________ keratin
soft, stiff hard
Type of hair that is soft, fine
and covers body surface
Vellus hairs
Type of hair that is heavy and pigmented and found in head, eyebrows, and eyelashes
Terminal hairs
Holocrine glands that secrete sebum
Sebaceous Glands
oil glands
Two types of sweat glands
- Apocrine glands
2. Merocrine (eccrine) glands
Sweat glands found in armpits, around nipples, and groin; they secrete products into hair follicles and produce sticky, cloudy secretions; they break down and cause odors
Apocrine sweat glands
cells that surround the apocrine gland and squeeze apocrine gland secretions onto skin surface
myoepithelial cells
Sweat glands Widely distributed on body surface especially on palms and soles; they are coiled, tubular glands that discharge directly onto skin surface; produces sensible perspiration
Merocrine (Eccrine) Sweat Glands
Functions of merocrine sweat gland activity
- Cools skin
- Excretes water and electrolytes
- Flushes microorganisms and harmful chemicals from skin
integumentary gland that produce milk
Mammary glands
integumentary gland that produce cerumen (earwax)
Ceruminous glands
Nervous system that controls sebaceous and apocrine sweat glands and
works simultaneously over entire body
Autonomic nervous system (ANS)
What is the main function of sensible perspiration?
Thermoregulation
Structure that is made of dead cells packed with keratin and protect fingers and toes
Nails
Where does nail production occurs?
nail root
The visible portion of the nail that covers the
nail bed
Nail body
The pale crescent at the base of the nail
Lunula
How is the integument repaired following an injury?
- Bleeding occurs
- Mast cells trigger inflammatory response
- A scab stabilizes and protects the area
- Germinative cells migrate around the wound
- Macrophages clean the area
- Fibroblasts and endothelial cells move in, producing granulation tissue
Which cells produce scar tissue?
Fibroblasts
