Integumentary System Flashcards
What are the two distinct layers of your skin?
- epidermis
2. dermis
What is the epidermis? What is it composed of?
the outermost protective shield; composed of epithelial cells
What is the dermis? What is it composed of?
tough, leathery layer, making up the bulk of the skin; dense connective tissue
Only the […] is vascularized. Nutrients reach the […] layer via diffusion.
dermis; epidermis
Subcutaneous tissue:
tissue just deep to the skin
consists of adipose plus some areolar connective tissue
also called hypodermis or superficial fascia
What are the functions of the subcutaneous tissue(4)?
- storing fat
- anchors tissue to the underlying structures (mostly muscles)
- it is loose enough to allow skin to slide
- shock absorber
- insulator (reduces heat loss)
What is the importance of the skin being able to slide?
protects the body by ensuring everyday bumps often glance off our bodies
How many cell types, how many cell layers consist of the epidermis?
four distinct cell types; four or five distinct layers
What are the four cells that populate the epidermis?
- keratinocytes (majority)
- melanocytes
- dendritic cells
- tactile epithelial cells
Keratinocytes produce […]. A fibrous […] that helps give the epidermis […]
keratin; protein; protective properties
How are keratinocytes put together?
tied together by desmosomes (strength), and in some layers tight junctions (hinder water movement)
The deepest part of the epidermis form keratinocytes, the […].
stratum basale
What induces the stratum basale to go through continuous replication?
an epidermal growth factor– a peptide produced by various cells
What is the condition of the keratinocytes at the top?
the cells are already dead, flat sacs filled with keratin
What is the rate of newly formed epidermis?
every 25 to 45 days
When the skin experiences friction […] and […] are accelerated.
cell production; keratin formation
Persistent friction causes…
thickening of the epidermis called a callus
Melanocytes description:
spider-shaped epithelial cells
Melanocyte synthesize […] which are found on the […] layer of the epidermis.
melanin; deepest
How is melanin synthesized? Where does it go after production?
melanin is made in membrane-bound granules called melanosomes
transferred through cell processes “spider legs” to nearby keratinocytes
[…] contain more melanin than do melanocytes
basal keratinocytes
What is the location and purpose of the melanin clusters within keratinocytes?
“sunny side” of keratinocytes
pigment shield protects the nucleus from the damaging effects of UV radiation in the sunlight
Dendritic cells arise from […] and migrate to the […] .
bone marrow; epidermis
Dendritic cells are also called […].
Langer cells
Where can you find tactile epithelial cells?
at the epidermal-dermal junction
Each tactile epithelial cell is intimately associated with a disc-like […] , the combination functions as a […] to touch.
sensory nerve ending; sensory receptor
Thick skin epidermis consists of… (list)
five layers/strata
stratum basale, stratum spinosum, stratum, granulosum, stratum lucidum, stratum corneum
What layer is absent in the thin skin?
stratum lucidum
Where can you find thick skin?
areas subject to abrasion– palms, fingertips, soles of the feet
The stratum basale, the […] layer, is also called the […] layer
deepest epidermal; germinating
What happens to the daughter cells that divide at the basal layer?
one daughter is pushed to the next layer to begin specialization into a mature keratinocyte
one daughter cell remains in the basal layer to continue the process of producing
The stratum spinosum is microscopically prickly because…
during tissue preparation there is a shrinkage of the cell, filaments hold tightly at their many desmosomes
The stratum spinosum layer contains thick bundles of […] which consists of […]-resisting protein […].
intermediate filaments; pre-keratin
Intermediate filaments […] in the cell and are anchored to the […].
resist tension; desmosomes
What process occurs in the stratum granulosum layer?
keratinization: cells fill with keratin
What happens to the cell shape during keratinization?
cells flatten, nuclei and organelles begin to disintegrate
The granular layer accumulates what 2 granules?
- keratohyalin granules
2. lamellar granules
[…] help to form keratin in the upper layers.
keratohyalin granules
[…] contain a water resistant […] that is secreted into the extracellular space.
lamellar granules; glycolipids
What plays a major part in slowing water loss across the epidermis?
glycolipid and tight junctions
[…] within the keratinocytes and […] deposited outside make these cells tough and water resistant.
protein; lipids
What happens to the layers above the stratum granulosum? Why?
the cells die
- the epidermal cells are too far away from the connective tissue
- glycolipids cut them off from from nutrients
Stratum lucidum is also known as the…
clear layer
The clear layer consists of…
a few rows of dead keratinocytes, identical to those in the layer above
The outermost layer is known as […] or the […] layer and accounts for […] of the epidermal thickness.
stratum corneum; horny layer; 3/4
Keratin consists of the […] filaments embedded in a glue from the […] granules.
pre-keratin intermediate; keratohyalin
What two things accumulate within the cells of the horny layer to protection from abrasion and penetration?
- proteins
2. keratin
What helps keep the outermost layer water resistant?
glycolipids between its cells
The dermis is made up of […], […] connective tissue.
strong; flexible
What cells make up the dermis layer?
fibroblasts, macrophages, mast cells, white blood cells
*what you would find in connective tissue proper
What two layers does the dermis have?
- papillary
2. reticular
T/F: The two layers of the dermis lie next to each other.
true
Thin, superficial papillary dermis is […] tissue.
areolar connective
How is the papillary dermis structured:
the connective tissue loosely interlaces collagen and elastic fibers with many small blood vessels
What is the benefit of the papillary dermis being loose?
allows phagocytes and other defensive cells to wander freely and patrol for bacteria
What are the indentions on the epidermis from?
dermal papillae
Dermal papillae contain…
capillary loops and free nerve endings (pain receptors) and tactile corpuscles (touch receptors)
Tactile corpuscles also known as […].
Meisnner’s corpuscles
On thick skin (palms/soles) papillae lie atop larger mounds called […], which in turn cause the overlying epidermis to form […].
dermal ridges; epidermal ridges
What are the skin ridges known as? What is their purpose?
friction ridges
enhance the ability to grip certain surfaces and contribute to sense of touch
How to friction ridges aid our sense of touch?
enhance vibrations detected by the large lamellar corpuscles (receptors) in the dermis
Friction ridge patterns have […] along their crests which leave unique […].
sweat pores; fingerprints
What kind of connective tissue lies in the reticular dermis?
dense irregular connective tissue
How is the reticular dermis nourished?
underlying network of blood vessels that sits between the dermis and the subcutaneous tissue–known as the dermal vascular plexus
The extracellular matrix of the reticular dermis contains thick bundles of interlacing […].
collagen fibers
T/F: The reticular dermis implies the abundance of reticular fibers.
False; it refers to the network of collagen fibers (reticulum = network)
Most collagen within the reticular dermis run […] to the skin surface.
parallel
What is formed between the bundles where there is separations (less dense region)?
cleavage tension lines in the skin
Cleavage lines run […] in the skin of the limbs and in […] around the neck and trunk.
longitudinally; circular patterns
Why are cleavage lines important?
Surgery incisions are made parallel to these lines, allowing the skin to gape less and heal more readily.
Collagen fibers of the dermis give skin […] and […] that prevent minor jabs and scrapes from penetrating the dermis.
strength; resiliency
Elastic fibers provide the […] and […] properties.
stretch; recoil
What are the dermal folds that occur at or near joints?
flexure lines
Why do flexure lines appear?
the dermis is tightly secured to deeper structures to accommodate joint movement
Dendritic cells are […] cells that engulf […], migrate to […], and present the […] to T cells, causing them to activate and mount an […] response.
protective; antigens; lymph nodes; antigens; immune
