The Layers of the Anatomy Flashcards
What are the 5 layers of the anatomy?
- Skin
- Subcutaneous tissue
- Subcutaneous Musculoaponeurotic System
- Retaining ligaments
- Periosteum
Describe the Epidermis:
- Outermost layer
- Protective barrier
- Consists of keratinocytes
How are keratinocytes produced and where?
- By the mitosis of stem cells in the stratum basale and in the deepest layer of the stratum spinosum
How long does the process of new skin development to flaking off take?
30-40 days
What are the 5 identified layers of the epidermis?
- Stratum Corneum
- Stratum Lucidum
- Stratum Granulosum
- Stratum Spinosum
- Stratum Basale
Stratum Corneum
- Top layer of dermis
- Dead, scaly, keratinized cells (durable layer)
- Resistent
Stratum Lucidum
- Thin layer (only in thick skin)
- Keratinocytes do nothave nuclei or other organelles
Stratum Granulosum
- Keratinocytes have coarse granules
Stratum Spinosum
- Deepest cells are capable of mitosis
- Cells pushed upward are flat and can not
- Contains Langerhan cells
Stratum Basale
- Single layer of cuboidal to low columnar stem cells and keratinocytes
- Cells divide and push formed cells into higher layers
What is the second layer of the skin caller?
Dermis
What 3 substances makes up the dermis?
- Collagen
- Elastin fibers
- Hyaluronic acid
What does collagen provide?
- Tensile strength to the dermis
- Forms a framework
- Allows new cells to grow
What is the % of collagen and elastic fibers in healthy skin?
80% collagen
4% elastic fiber mesh network
What is Hyaluronic acid?
Polysaccharide
What does hyaluronic acid do?
Attracts water
Why is water an essential part of a person’s dermis?
It keeps the skin plump and moisturized
What are the 2 layers of the dermis?
- Papillary
- Reticular layers
Describe the papillary layer?
- Upper layer
- Thin arrangement of collagen fibers
- 1/5th of the dermis
Describe the reticular layer
- Lower layer
- Thicker
- Made of thick collagen fibers that are arranged parallel to the surface
Where are dermal fillers normally injected?
Lower 4ths of the dermis
What are 6 specialized cells and structures are contained in the dermis?
- Hair follicles with the erector pili
- Sebaceous glands
- Apocrine glands
- Eccrine glands
- Blood vessels
- Nerves
What are the nerves in the dermis responsible for?
Transmitting sensations of pain, itch, and temperature
Describe the subcutaneous tissue
- Layer of fat and connective tissue
- Houses larger blood vessels and nerves
- Attaches to dermis by the collagenous and elasticfibers
What is this layer important for?
Temperature regulation
What isSMAS?
Superficial Musculoaponeurotic System (SMAS)
What does SMAS contain?
- Intrinsic muscles od the cheek that have extensive attachment to the soft tissues when they move
What happens when the SMAS approaches a mimetic muscle?
(orbicularis oculi, orbicularis oris or zygomatic muscle)
- Splits into a superficial and deep layer to surround the muscle
- Transverses the face until it reaches anouth mimetic muscle
In the neck, what is the SMAS known as?
Platysmal fascia
In the cephalad, what is the SMAS known as?
Superficial temporal fascia
When the SMAScrosses thetemporal fusion line and enters the forehead, what is it known as?
Galea aponeurotica
What are retaining ligaments?
- Strong and deep fibrous attachments thatoriginate from the periosteum ordeep facial fascia
- Travel perpendicularilythrough facial layers to insert on to the dermis
What do retaining ligaments act as when they retain and stabilize the skin and the superficial fascia (SMAS) to the underlying deep fascia and facial skeleton?
Anchor points
What is the periosteum?
A membrane that covers the outer surface of the bones
What is inside the cellular layer of the periosteum?
Osteogenic layer that attaches the periosteum to the bone (perforating fibers)
