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
The hair root stops and the hair shaft usually begins where…
you find the sebaceous gland
When arrector pili contracts, what happens?
- It pulls the follicle and forces the hair to stand erect (goose bumps too)
- Squeezes lipids and oily fluids out of sebaceous gland and go onto hair
Nerves and blood vessels go into/out of what part of the hair?
The hair papilla
In comparison to the layers of epidermis, the matrix of the hair is the “same” as…
The stratum germinativum (basale)
The waxy, protective layer on the outside of your hair is…
the cuticle
After the cuticle of the hair, the next outer portion is…
the hair follicle (not part of the hair)
The external root sheath:
an extension of the epidermis
After the external root sheath, the next outer portion is the…
glassy membrane
The glassy membrane is the derivative of…
the basal lamina
Concerning a basal lamina connected to epithelial tissue, what’s on the other side?
connective tissue
Inner part of the nail that is “buried” in your tissues is…
the nail root
The nail is germinating (growing) from…
the nail matrix
The white crescent part at the base of your nail is called…
the lunula
The lunula is white because…
no blood vessels
The eponychium and hyponychium are really just extensions of…
stratum corneum
The “cuticle” of your nail is called
the eponychium
The technical term for sweat glands is…
sudoriferous glands
2 basic types of sudoriferous (sweat) glands and description:
Eccrine/merocrine sweat glands: merocrine secretion method; regular sweat/perspiration
Apocrine sweat glands: merocrine secretion method; develops in combination with hair follicles of armpit, around nipples and pubic
Mammary glands:
- “Modified” sweat glands
- Apocrine secretion method
Sebaceous glands:
- Holocrine secretion method
- Associated with hair follicle
Sebaceous follicle:
Collection of sebaceous glands which are not associated with hair follicles
Ceruminous glands:
- Modified sweat gland inside the ear
- Secrete cerumen (earwax)
Where are the germinative cells in the hair located?
hair matrix
