Integumentary System Flashcards
What are the 2 components of the cutaneous layer?
- Epidermis 2. Dermis
True or false the hypodermis is part of the cutaneous layer.
False
What are the 6 functions of the skin?
1. Thermoregulation
- sweat and increased capillary blood flow for cooling,
- hair for retaining heat
2. Protection from external enviroment
3. Cutaneous sensation
-pain, touch, pressure, temp
4. Excretion
5. Vit D synthesis
6. Absorbing certain substances
What are the 4 major types of cells found in the epidermis, and what are thier characteristics/fxns?
1. Keratinocytes- most numerous formed when new cells become filled with keratin
2. Melanocytes- cells contain a melansome, that produces
3. Langerhans cells- Dendritic cells of skin
4. Merkel Cells- responsible for sensation of touch, Found in the basal layer of the epidermis, where they are in contact w/ Merkel discs (type of sensory neuron)
How is melanine produced?
From Tyrosine in the prescence of tyrosinase.
What are the 5 layers of the epidermis, and breifly describe them.
Come, Lets Get Some Beer (superficial to deep)
1. Stratum Corneum = most superficial layer, dead keratinocytes, continously sloughed off.
2. Startium Lucidum= only found on palms, fingertips, and soles. composed of dead keratinocytes
3. Stratium Granulosum = Transition between deeper living cells and dead superficial cells. Filled with granules of keratin. Lamellar granules release waterproofing lipids.
4. Startium Spinosum= layer just superficial to basale layer. Cells are still alive, some dividing but some starting to flatten out
5. Stratim Basale= deepest layer, living keratin cells undergoing continous mitosis.
How is keratin produced?
produced from tonofilaments (type of intermediate filaments) which contain a protein precusr to keratin.
What types of connective tissues make up the dermis?
Dense irregular tissue, collagen tissue, and elastic connective tissues.
What are the 2 components of the dermis
1. Papillary region
2. Reticular region
Describe the papillary region of the dermis?
More superiorficial. Contain dermal papilllae for better adhesions and diffision to apidermis. Contains: meissner corpuscles (touch/light touch) and free nreve endings for warmth, pain, tickle, itch
Describe the reticular region of the dermis?
Deeper of the 2 regions. Spaces betwen fibers filled with adipose tissues, hair follicles nerves, sebaceous and sudoriferous glands.
What are epidermal ridges?
Finger tips, formed by the dermal papillary. Important for increasing grip by increasing friction.
What type of tissues mainly compose the subcutaneous/hypodermis
- Areolar and adipose tissues, containing larger bloos vessels.
- Contains Pacinain corpuscles (sense pressure)
What 3 pigments affect skin color
- melanin= dark brown, genetically determined how much you usually produce (all races have ! the same # of melanoctyes)
- carotene= yellow-orange pigment that is a precusor to Vit A. Genetically determined
- hemoglobin =pinkness of skin
What is hair composed of?
Dead keratinized cells bonded by proteins
Where is the root of the hair located?
The dermis
Where does the germinal layer of cells in the hair bulb arises from?
The startum basale of the epidermis, so cells from epidermis physically located in the dermis d/t external root sheath.
What are the 3 layers of the of the hair shaft and root?
- Medulla
- Cortex
- Cuticle
Describe hair growth
The division of cells at the base of the hair follicles whereby new cells produced in the matrix push the growing hair through the pilary canal.
What structures are associated w/ hair?
- Sebaceous glands
- Arrector pili muscle (goos bumps)
- Hair root plexus= dendrites and nerve endigs around hair follicle that generate nerve pulses when hairs are moved