Integument Flashcards
How big is the integumentary organ system?
1.2-2.2 meters squared in area
What is the largest organ system?
The integumentary system
What percent of body weight is made up by the integumentary system?
7%
What are the two parts of the integument?
The cutaneous membrane (skin) and accessory structures (hair, nails, etc)
What are the parts of the cutaneous membrane?
The outer membrane (superficial epithelium) and the inner dermis
What is the outer membrane?
The superficial epithelium/ epithelial tissues of the cutaneous membrane
What is the inner dermis?
The connective tissues of the cutaneous membrane
Where do accessory structures originate?
They originate in the dermis
What are accessory structures?
A part of the integument that originates in the dermis and extends through the epidermis to the skin surface
What are some examples of accessory structures?
Hair, skin, nails, and multicellular exocrine glands
What are the functions of the skin?
Protect, excrete, maintain temperature, synthesize, store, adn detect
What does the skin protect?
The underlying tissues and organs
What does the skin excrete?
The skin excretes salt, water, and organic wastes (through glands)
How does the skin maintain body temperature?
Through insulation and evaporation
What does the skin synthesize?
Vitamin D3
What does the skin store?
Lipids
What does the skin detect?
Touch, pressure, pain, and temperature
What types of cells make up the epidermis?
Avascular stratified squamous epithelial cells
How do cells in the epidermis get nutrients and oxygen?
Nutrients and oxygen diffuse form the capillaries in the dermis
What types of cells make up the epidermis?
Avascular stratified squamous epithelial cells
How do cells in the epidermis get nutrients and oxygen?
Nutrients and oxygen diffuse form the capillaries in the dermis
What are the types of cells in the epidermis?
Keratinocytes, melanocytes, langerhans cells, and corneocytes
What are keratinocytes?
Found in the epidermis, keratinocytes contain large amounts of keratin, and they’re the most abundant cells in the epidermis
What are the most abundant cells in the epidermis?
Keratinocytes
What are melanocytes?
Found in the epidermis, melanocytes produce a yellow-brown or black pigment
What are langerhans cells?
Found in the epidermis, langerhans cells support the immune system
What are corneocytes?
Found in the epidermis, corneocytes are non-living keratinized cells, and comprise the top layer of the epidermis.
What makes up the top layer of the epidermis?
Corneocytes
What is the mnemonic for the layers of the epidermis?
Come, Let’s Get SunBurnt
What are the 5 layers of the epidermis?
[Stratum] Corneum, lucidum granulosum, spinosum, basale
What is the stratum basale?
The germative layer of the epidermis
What is unique about the stratum basale in the epidermis?
It has many stem cells and is the only layer to have mitosis
How is the stratum basale attached, and to what?
The stratum basale is attached to basal lamina by hemidesmosomes
What are hemidesmosomes?
The anchors that keep the stratum basale attached to the basal lamina; keeps the stratum basale from falling off. Creates a strong bond between the epidermis and dermis
Where are melanocytes found?
In the stratum basale
What percent of the stratum basale layer is made up by melanocytes?
10-25% of the cells in the stratum basale layer are melanocytes
What layer are epidermal ridges found in?
The stratum basale
What are epidermal ridges?
Like fingerprints
What are dermal papillae?
Tiny mounds found in the stratum basale layer of the epidermis
What do dermal papillae do?
They increase the surface area of the basal lamina, and strengthen the attachment between the epidermis and dermis.
How is the stratum spinosum produced?
It’s produced by the division of the stratum basale
What makes up the stratum spinosum?
8-10 layers of keratinocytes bound to each other by desmosomes
What is unique about the stratum spinosum?
It has langerhans cells
What are langerhans cells?
Cells that defend against pathogens as an immune response
What is a possible use for langerhans cells?
Attacking skin cancers
Where are langerhans cells made?
They’re made in the bone marrow/ spongy bone
What makes up the stratum granulosum?
3-5 layers of keratinocytes
Does the stratum spinosum produce keratin?
The spinosum layer has keratinocytes but doesn’t produce a lot of keratin
What layer starts producing a significant amount of keratin?
The stratum granulosum starts producing keratin
What is keratin?
It’s a tough, fibrous protein that makes up the hair and nails
What layer is the clear layer?
The stratum lucidum
Where is the stratum lucidum found?
In thick skin
What is the stratum lucidum?
A clear layer found only in thick skin that has cells filled with keratin
What is the stratum corneum?
It’s the exposed surface of the skin that’s water resistant and is shed and replaced every 2 weeks
What makes up the stratum corneum?
15-30 layers of keratinized cells (corneocytes)
What are corneocytes?
Kaeratinized cells, often found in the stratum corneum
What is keratinization?
The formation of a layer of dead, protective cells filled with keratin
What layer is the exposed surface of the skin?
The stratum corneum
What layer does keratinization take place in?
The stratum corneum
Where does keratinization occur?
On all exposed skin surfaces except eyes
What is insensible perspiration?
It’s the loss of interstitial fluid via evaporation
What are the two types of perspiration?
Insensible and sensible perspiration
How much water is lost through insensible perspiration every day?
About 1 pint, or 500 mL
What is sensible perspiration?
Water excreted by sweat glands
What is dehydration caused by?
Damage to the stratum corneum, insensible perspiration, or immersion in a hypertonic solution
**What causes hydration?
Immersion in a hypotonic solution, which then causes the stretching and wrinkling of skin
What is carotene?
A orange-yellow pigment in the epidermis
What causes red skin?
Blood vessels dialate from heat, and skin reddens
What causes pale skin?
Blood vessels constrict blood flow, so the skin pales
What is cyanosis?
A blue skin tint, which is sometimes caused by a lack of oxygen
Where is the dermis located?
Between the epidermis and the subcutaneous layer
What does the dermis do?
It anchors the epidermal accessory structures?
What are the two components of the dermis?
The outer papillary layer and the inner reticular layer
What does the papillary layer consist of?
Areolar tissue
What does the papillary layer contain?
It contains smaller capillaries, lymphatics, and sensory neurons
How are fingerprints created?
In the papillary layer of the dermis, dermal papillae project between the epidermal ridges, creating fingerprints
In what layer do the fingerprints originate?
In the papillary layer of the dermis
What makes up the reticular layer of the dermis?
Dense irregular connective tissue
What does the reticular layer contain?
Larger blood vessels, lymph vessels, nerve fibers, collagen, and elastic fibers.
What is dermatitis?
An inflammation of the papillary layer
How is inflammation created?
There’s an increased blood flow to the area to bring white blood cells
What causes dermatitis?
Infection, radiation, mechanical irritation, or chemicals (like poison ivy)
What characterizes dermatitis?
Itching or pain
What are the characteristics of the dermis?
It’s strong, elastic, flexible, and over time can get saggy and wrinkled and get stretch marks
Why is the dermis strong, elastic, and flexible?
It has collagen fibers to make it strong, elastic fibers to make it elastic, and has skin turgor to make it flexible
What can cause sagging and wrinkles in the dermis?
Dehydration, age, hormonal changes, and UV
What causes stretch marks in the dermis?
Excessive stretching of the skin
What are the lines of cleavage made of?
Collagen and elastic fibers in the dermis
How are the collagen and elastic fibers that make up the lines of cleavage arranged?
They’re arranged in parallel bundles
How do cuts heal according to the lines of cleavage?
Parallel cuts remain shut and heal well, perpendicular cuts/ cuts across/ right angle cuts pull open and scar
What do nerve fibers under the skin control?
Blood flow, gland secretions, and sensory receptors
What does the subcutaneous layer of the hypodermis do?
It stabilizes the skin, allows separate movement, and is the site of subcutaneous injections using hypodermic needles.
What does hair do?
It protects by gathering dust, insulates, guards openings against particles and insects, and is sensitive to very light touch
Where is the hair follicle located?
Deep in the dermis
What is the hair follicle wrapped in?
A dense connective tissue sheath
What is the base of the hair follicle surrounded by?
Sensory nerves called the root hair plexus
What is the root hair plexus?
The sensory nerves that surround the hair follicle deep in the dermis
What are the two parts of hair?
The root (below skin) and the shaft (above skin)
What is the muscle near the hair root called)
The arrector pili muscle
About how many hairs do you lose a day?
About 50 hairs are lost every day
What can hair testing be useful for and why?
Because nutrients are incorporated into hair, the hair can be tested for chemicals like mercury
What part of the body can be tested for chemicals like mercury and why?
The hair, because nutrients are incorporated into hair
What is hair color produced by and why?
Hair color is produced by melanocytes at the hair papilla
What is hair color determined by?
Genes
What are the two types of hairs?
Vellus and terminal hairs
What are vellus hairs?
They’re soft and fine, and they cover the body’s surface
What are terminal hairs?
They’re heavy and pigmented, and they make up the hair on your head and eyebrows. They also cover other parts of the body after puberty.
What are sebaceous glands?
Oil glands that secrete a lipid called sebum
What do sebaceous glands secrete?
A lipid called sebum
What do sebaceous glands and sebum do?
They lubricate the hair, control bacteria, and maintain keratinized cells from drying out
What are the two types of sweat glands?
Apocrine glands and merocrine glands
What are apocrine glands?
They secrete sticky stuff that has proteins and fats
What are merocrine glands?
They have water salty secretions that contain vitamins and drugs
Where are merocrine glands found?
All over the body, but especially on the palms, soles, and forehead
Where does nail production occur?
Deep in the epidermis fold near the bone called the nail root
What is the main part of the nail called?
The nail body
What is the nail body?
The visible portion of the nail that covers the nail bed
Where does the nail grow from?
The eponychium/ cuticle
What is the first step of repairing localized injuries to the skin?
First bleeding occurs, and mast cells trigger an inflammatory response
What is the second step of repairing localized injuries to the skin?
A scab stabilizes and protects the area
What happens during the inflammatory response when localized injuries to the skin are being repaired?
Germinative cells migrate around the wound, microphages clean the area, and fibroblasts and endothelial cells move in and produce granulation tissue
What do macrophages do in the inflammatory response when healing a skin injury?
They clean the area
What do fibroblasts and endothelial cells do in the inflammatory response when healing a skin injury?
They move in and produce granulation tissue
What is the third step of repairing localized injuries to the skin?
Fibroblasts produce scar tissue, inflammation decreases, and the clot disintegrates
What is the fourth step of repairing localized injuries to the skin?
Fibroblasts strengthen scar tissue, and a raised keloid forms
