Integumentary System (Ch. 5) Flashcards
What are the 4 primary types of cells found in the epidermis?
- Keratinocytes
- Melanocytes
- Tactile cells
- Dendritic cells (protective from microbes)
What are the 3 steps of keratinocyte growth and development before they get sloughed off and replaced?
- Cells divide in the basal layer and are pushed towards the surface
- Cells become keratinized as they go up
- Apoptosis (programmed cell death)
Then dead cells are sloughed off and replaced
What are the strata (developmental layers) of keratinocytes/the epidermis? 4-5 depending on thin or thick skin
Deep –> superficial
Stratum basale Stratum spinosum Stratum granulosum Stratum lucidum (in thick skin) Stratum corneum
What does the word “integument” mean?
Covering
Is the hypodermis technically a part of the skin?
No
What are the 2 regions of the skin?
Epidermis and dermis
What kind of tissue is the dermis primarily made of? Epithelial? Connective? Muscle?
Connective
Is the dermis vascularized or avascularized?
Vascularized (it’s where the epidermis gets its nutrients and blood flow from)
What are the 2 layers of the dermis?
- Papillary layer
2. Reticular layer
Which layer (hypodermis or dermis) attaches the skin to the underlying muscle?
Hypodermis
What kind of cell junctions attach keratinocytic cells to each other?
Desmosomes
How do melanocytes make melanin? What prompts your body to produce more melanin?
an enzyme (tyrosinase) converts tyrosine to melanin. Enzyme activity increases with exposure to UV radiation.
Keratinocyte layers: Stratum basale
What level is it?
What’s deep and superficial to it?
Deepest layer
Keratinocyte synthesis
Anchored to basement membrane
Superficial to it is the stratum spinosum
Keratinocyte layers: Stratum spinosum
What level is it?
What’s deep and superficial to it?
2nd layer
Deep to it: basale
Superficial to it: granulosum
Spiny protein fibers attach to desmosomes
Keratinocyte layers: Stratum granulosum
What level is it?
What’s deep and superficial to it?
3rd layer
Cells undergoing apoptosis
Protein granules dehydrate the dying cells, and staining makes the granules dark.
Deep to it: spinosum
Superficial to it: in thick skin, stratum lucidum. In thin skin, just stratum corneum.
Keratinocyte layers: Stratum lucidum
What level is it?
What’s deep and superficial to it?
4th layer in thick skin only Deep to it: granulosum Superficial to it: corneum Clear flat dead cells Lots of keratin
Keratinocyte layers: Stratum corneum
What level is it?
What’s deep and superficial to it?
4th layer in thin skin 5th layer in thick skin Top (outermost) layer Deep to it: lucidum in thick skin, granulosum in thin skin Superficial to it: nothing Continuously shed and replaced
Papillary layer of the dermis - what kind of connective tissue is it made of?
Areolar connective tissue
Loose so that phagocytes can patrol and remove bacteria
What do dermal papillae adhere to on the epidermis?
Epidermal ridges
What do epidermal ridges adhere to on the dermus?
Dermal papillae
What part of skin causes fingerprints to exist?
Dermal papillae (and their interaction with the epidermal ridges)
Which layer of skin has the sensory innervation?
Papillary layer of the dermis
Tactile corpuscles (touch receptors)
Free nerve endings including lamellated corpuscles
What does “papillae” mean? (dermal papillae)
Nipple
What are lamellated corpuscles? Where are they found?
In the dermis.
Deep pressure receptors
What kind of connective tissue is the reticular layer of the dermis made of?
Dense irregular connective tissue