Lecture 3 (FIRST MIDTERM) Flashcards
Functions of the integument and descriptions:
Protection: physical and against desiccation
Excretion: ions, water, organic waste
Temp. maintenance: insulation and cooling
Vitamin D3 synthesis: calcium balance
Lipid storage
Sensation: touch, pressure, pain, temperature
Layers of the integument:
Cutaneous membrane Superficial fascia (or hypodermis or subcutaneous layer)
Layers of the cutaneous membrane:
Epidermis and dermis
Layers of the dermis:
Papillary and reticular
Dermal papillae connect with…
Epidermal ridges
Fingerprints are made from…
Epidermal ridges
Layers of the epidermis from top to bottom:
Stratum corneum (dead) Stratum lucidum Stratum granulosum Stratum spinosum Stratum germinativum
Stratum germinativum layer:
- Also called stratum basale
- Contains hemidesmosomes that attach to the basal lamina
- Basal cells divide through mitosis and replace (differentiate into) more superficial keratinocytes
- Contains melanocytes (pigment cells)
Stratum spinosum layer:
- Cells pushed from stratum germinativum
- Cells start to differentiate to keratinocytes, which have multiple layers, still dividing
- Participate in immune response
Stratum granulosum layer:
- Darker layer because of granules inside cells
- Cells pushed up from stratum spinosum
- Keratinocytes of multiple layers but less now; not dividing (still alive)
- Granules are made of vesicles with heratohyalin inside - helps cells further differentiate into keratin (start to dehydrate)
Stratum lucidum layer:
- Not always there; thick skin has it (hands/feet), thin skin does not
- covers stratum granulosum
- flattened and densely packed cells filled with keratin
How can peel off sheets of skin when you get sunburnt?
The dead cells in each layer of the stratum corneum are tightly connected by desmosomes
Stratum corneum layer:
- Most superficial
- 15-30 layers of keratinized cells, tightly connected with desmosomes
- Important for water retention
- Karatinization (or cornification) is the hardening of cells
Papillary layer:
- Consists of areolar tissue
- Contains capillaries, lymphatics, sensory neurons
Reticular layer:
- Dense irregular connective tissue
- stretchy but tough
- elastin + collagen fibers
Hypodermis (or superficial fascia or subcutaneous layer):
- Consists of areolar and adipose tissues
- Lots of blood vessels
Origins of…
Epidermis
Dermis
Hypodermis
- Epidermis: ectodermal - stratified squamous epithelium
- Dermis: mesodermal - collagen, elastic fibers, papillary layer, and reticular layer
- Hypodermis: mesodermal
Hair is what kind of structure?
accessory
The hair follicle surrounds what?
The hair itself
The hair grows from…
the hair bulb
The hair papilla contains:
Vasculature
Innervation
The tip of the hair papilla is…
The hair matrix
Where in the hair are the germinative cells located?
The hair matrix
Layers of the hair (from inner to outer):
Medulla of hair
Cortex of hair
Cuticle of hair
