THE INTEGUMENTARY SYSTEM Flashcards
What is the Integumentary System
The covering of skin and accessory structures (sweat & oil glands, hair and nails)
What are the 3 main areas of the skin
Epidermis, Dermis, Hypodermis
What does the Subcutaneous layer do?
It helps with the framework for the skin using fats. (not truly skin)
What are the sublayers of the Dermis
Papillary and Reticular
What are the 4 types of Epidermal Cells
Keratinocytes, Melanocytes, Dendritic (Langerhans), Tactile (Merkel)
What is the Function of Keratinocytes
It gives the skin; waterproofing, strength, and sturdiness to withstand trauma.
Keratinocytes (life cycle)
come from stem cells that sit by dermal papillae, and actively divide. They have a life span of 25-45 days and will move up throughout that time.
What hormone will help stimulate keratinocyte production?
EGF, will stimulate mitotic activity
What is the function of a Melanocytes
to produce melanin for UV radiation protection
How do Melanocytes work?
Once melanin is produced it is packed into melanosomes, which will branch numerous times until transferring to adjacent cell
Linking between Keratinocytes and Melanocytes
Keratinocytes collect the product of melanocytes (melanin) before moving upwards. This is done in order to protect us against UV radiation
How often does our skin shed
The skin turns over once a month, we lose 1.6 pounds of shed skin a day
(slower when older -> wrinkles)
What is the function of Dendritic (Langerhans) cells
Very first line of defence of immune system, and will signal rest of immune system of bacteria, virus, or fungi within the body (from particular area)
What is the function of Tactile (Merkel) cells
Are the touch receptors of the body, and will give information to the CNS (certain areas are more sensitive.
What is the proper order of Epidermal cells and layers of the epidermis? (Superficial to deep) - THICK
Stratum Corneum, Stratum Lucidum, Stratum Granulosum, Stratum Spinosum, Stratum Basale
What layer isn’t in thin skin? (Epidermal Cells and layers of epidermis)
Stratum Lucidum
Why does thick skin have more layers than thin skin?
Because it is found in higher-abrasion areas such as hand and feet
What is the dermis?
A strong, flexible connective tissue, thats embedded with collagen, elastic, and reticular fibers. It contains nerves, BV, lymphatic vessels, hair follicles, oil and sweat glands
What types of Cells are found in the dermis?
Fibroblasts, dermal, macrophages, and sometimes mast cells (histamine), and WBCs
Define the Papillary Layer
interwoven mat of areolar CT fibers interspersed with BV
Define the Dermal Papillae
Superficial region of the dermis that indents the overlying epidermis, it supplies the epidermis with nutrients and allows for tactile receptors
What are Friction Ridges
On the palms of hands (fingers), soles of feet, dermal papillary lie on top of dermal ridges, which give rise to epidermal ridges
What do Epidermal Ridges (friction ridges) do?
enhance gripping ability, contribute to sense of touch, sweat pores in ridges leave unique finger patterns
Fun Facts about Friction Ridges
Pre-birth development Can only disappear if scarring, all are different
Define the Reticular Layer
deeper + thick dense irregular CT, source of lines of cleavage (tension) lines, collagen fibers give strength & resiliency & maintain skin hydration, elastic fibers provide stretch-recoil
What is a Cleavage (tension) Lines
Indicate the direction of orientation of the underlying collagen fibers
Going with cleavage line vs going against cleavage limes
With: not subjected to stress, won’t gap, will heal and scar nicely
Against: subjected to stress, will cause gapping, will heal poorly, and scar
