Integumentary System Flashcards
What does the integumentary system consist of?
- Skin
- Hair, nails, glands
- Sensory receptors
- Muscles
What are the layers of skin?
Epidermis (Upper) aka Superficial
Dermis (Lower) aka Deep
Below skin = Hypodermis (Deep to)
What are the characteristics of Epidermis?
- Stratified Squamous Epithelium
- Avascular
- Separated into 4 to 5 layers based on cell types
What are the cell types of Epidermis?
- Stratum Basale
- Stratum Spinosum
- Stratum Granulosum
- Stratum Lucidum
- Stratum Corneum
What is stratum basale?
Single row of cells with 2 cell types.
- Keratinocytes
- Melanocytes
Keratinocytes make up 90% of these cells and undergo mitosis to make keratin. As new cells are produce, the old ones surface
Melanocytes make up 10% and produce pigment (melanin) for UV light protection.
How does different skin color and thin skin relate to melanocytes?
Everyone has the same amount of melanocytes, but cells make different shades of melanin. Some have no melanin = Albinism. In thin skin, blood can be seen as a pinkish color.
Characteristics of stratum granulosum?
Has dark staining granules.
Characteristics of Stratum Lucidum?
- Flat, dead cells b/c they are too far from blood supply and only visible in thick skin.
Characteristics of stratum corneum?
20 - 30 layers of flat, dead cells filled with keratin and surrounded by waterproofing glycolipids (prevents water loss). These cells are shed and replaced from below.
What does the dermis contain?
Blood vessels
Nerves
Glands
Hair follicles
What are the two sublayers of the dermis?
Papillary layer and Reticular Layer.
What are the characteristics of the papillary layer?
Areolar CT
Vascular
Has projections in to the epidermis called dermal papillae.
In thick skin, these form dermal ridges = fingerprints that improve grip
What are the characteristics of the reticular layer?
Makes up most of the dermis and has dense irregular CT.
What is the hypodermis?
It is the subcutaneous layer and it has superficial fascia (CT layers that surround and support organs) and as well as adipose CT below the skin. Stores half the body’s adipose tissue (for insulation)
Hypodermis is not part of the skin.
What are the differences between thin and thick skin?
Thin skin does not have a lucidum and has hair follicles, sebaceous glands, arrector pili muscles.
Thick skin is only found on the palm and the soles. Lucidum is visible and has no hair follicles, sebaceous glands or arrector pili muscles.
What are the derivatives of the epidermis?
Hair, nails and exocrine glands.
What is hair and its parts?
Hair is dead cells that derive from basale cells and their parts are:
- Root = below surface
- Shaft = above surface
- Hair follicle = Surrounds the root
The hair follicle contains a epithelial root sheath which extend into the dermis, a bulb which is the expanded region at base of root.
The hair matrix is the site of hair growth and melanin for color.
What is associated with each hair follicle?
Dermal root sheath
- CT that holds follicle in place
Hair papilla
- Extends upward beneath matrix and has a blood supply for growing hair and signals for regulation
Root hair plexus
- Sensory nerve
Sebaceous gland
- Opens into follicle
Arrector pili muscle
- Smooth muscle and causes goosebumps
What are nails and what do they consist of?
Nails are heavily keratinized epidermal cells. They consist of the nail root (buried in skin), the body (visible) and the free edge.
What are the 4 skin exocrine glands and their details?
Sebaceous glands
-Secrete sebum which lubes hair
Sudoriferous glands
- Sweat glands and secretory portions of thick and thin skin. These ducts open on to skin surface.
Sweat is antibiotic and removes wastes
Ceruminous
- Modified sweat glands found in the ear canal
- Produce ear wax
Mammary glands
- Modified sweat glands that produce milk
What are cutaneous sense receptors and their 4 major types?
These receptors are specialized to respond to stimuli and their 4 types are:
Touch receptors
Pressure receptors
Thermoreceptors
Nociceptors
What are touch receptors used for?
Three types of touch receptors are free nerve endings, root hair plexuses and Meissner’s Corpuscles. Meissner’s’ corpuscles are in dermal papillae and corpuscles are CT capsule surrounding nerve ending.
What are the characteristics of pressure receptors?
Types of pressure receptors are free nerve endings in the dermis and Pacinian corpuscles which are deep in dermis or hypodermis.
What Thermoreceptors used for?
Temperature.
