1
Q
Functions of the Skin
A
1) Protection
2) Thermoregulation
3) Touch
4) Vitamin D and Melanin Production
5) Stores blood
6) Absorbs and excretes
2
Q
Layers of the Skin
A
1) Epidermis
2) Dermis
3) Hypodermis/Subcutaneous
3
Q
Name Types of Epidermal Cells
A
1) Keratinocytes 2) Melanocytes 3) Langerhan cells 4) Merkel cells
4
Q
Keratinocytes
A
- 90% of your skin cells
- produce the protein keratin: tough and protects
- Produce lamellar granules: make the skin waterproof
5
Q
Melanocytes
A
- cuboidal cells with projections linking them to keratinocytes
- creates melanin (Found in skin and mucous membranes)
- 1) Pheomelanin - yellow-red
- 2) Eumelanin - brown-black
- contains melanin caps for nuclei = protects DNA from UV rays
6
Q
Langerhan cells
A
- cells with projections among keratinocytes
- born in the bone marrow and then migrate to the epidermis when they mature
- immunity
7
Q
Merkel cells
A
- deep cells in epidermis
- in contact with sensory neurons
- Merkel + tactile disk + neuron = sense touch
8
Q
Layers of the epidermis (Top to Bottom)
A
1) Stratum Corneum 2) Stratum Lucidum 3) Stratum Granulosum 4) Stratum Spinosum 5) Stratum Basale
9
Q
Stratum Basale
A
- epidermal basement (cellular division occurs)
- Cuboidal cells make new keratinocytes
- Melanocytes and Merkel cells and neurons
- Stratum germinativum (means the layer that germinates/grows) = mitosis occurs
10
Q
Stratum Spinosum
A
- Looser and rounder cells anchored by proteins (but not a strong anchor)
- Langerhans cells - immunity
11
Q
Stratum Granulosum
A
- Apoptosis = programmed cell death happening so the above layer can be created (they lose the nucleus when they die and become sacs of keratin)
- Flattened
- Lamellar granuoles work here(make skin waterproof)
- Form layer up above
12
Q
Stratum Lucidum
A
- Fingertips and Palms and soles of the feet
- Dead Keratinocytes
- Contain lots of keratin
13
Q
Stratum Corneum
A
- most prevalent in thick skin
- Scales or squames
- Contain more keratin than stratum lucidum
- Are shed constantly
14
Q
FUN FACTS ABOUT THE SKIN THAT MAY OR MAY NOT BE IMPORTANT
A
*If you rub off too much of the stratum corneum rubs off you get a callus*
*If you rub down into the live skin cells, the stratum spinosum cells pop and release interstitial fluid and form a blister*
*Every four weeks you have a new set of skin*
15
Q
The dermis contains two regions….
A
1) Papillary region
2) Reticular region
16
Q
Papillary region
A
- Dermal papillae - vary in size depending on skin thickness
- Thin = fewer papillae/irregular
- Thick = numerous/regular
- Capillary loops: blood and nutrients!
- Meissner corpuscles: touch receptors = nerve endings
17
Q
Reticular region
A
- -thick bundles of collagen in rectangular net with irregular connective tissue with fibroblast (coarse elastic fibers)
18
Q
The structural basis of skin color depends on 3 things…..
A
1) Melanocytes
2) UV exposure
3) Vitamin D
19
Q
UV exposure
A
Melanin acts as protection
20
Q
Vitamin D
A
- UVB rays react with chemicals in the skin to produce Vitamin D
- Purposes:
- Bone growth and repair
- Calcium absorption
- Immunity
21
Q
Hypodermis
A
- contains thick vessels
- Fat (adipose) and CT dominate
- Fat storage
- Pacinian corpuscles: pressure sense
- insulates the body and provides protective padding around internal organs and stores energy
22
Q
Accessories
A
- Nails
- Hair (made of keratin and protein): protection, heat loss, UV blocking, sensation
23
Q
Tattoos!
A
- The ink of a tattoo is inserted into the dermis which is not subject to regeneration by new skin cells, so the tattoo remains even as the epidermis sheds dead skin cells.
24
Q
A
25
arrector pili musscle
smooth muscle that makes hair stand erect
26
sebaceous gland
oil producing gland
27
dendritic cell
cell with long branches involved in protection against pathogens
28
sudoriferous gland
sweat producing gland
29
tactile cell
touch receptor
30
epidermis
* protects the body from the elements (ex: wind and radiation)
* barrier that keeps bacteria and viruses out and water in
* some gases such as O2 can pass though easily produces Vitamin D
31
dermis
* supplies epidermis with O2 and nutrients from blood
* regulates body temperature
* when it's hot, vessels in the dermis expand to radiate ecess heat
* when it's cold, they constrict to retain heat
* liquid sweat compelled frotm sweat glands also cools the body as it evaporates oil glands, secretes lipds, and lubricates and waterproofs the skin
32
what is the connection between skin, sunlight, and vitamin D?
UVB radiation from the sun starts the process that converts the inactive form of vitamin in the skin to the active form circulating in the blood.
33
describe the life cycle of keratinocytes
New keratinocytes form at the bottom of the epidermis from dividing stem cells. As they migrate to the top, they increase keratin production and eventually stop dividing. The top layer of the epidermis consists of tightly packed dead keratinocytes.
34
what advantage did sweat glands and less body hair provide in our ancestors' environment?
having sweat glands and less hair would have helped keep bodies cool when running
35
how does a melanocyte's shape relate to its function?
they look like nerve cells with their long projections, whcih serve to deliver melanosomes to keratinocytes
36
explain how the amount of eumelanin and umber of melanosomes differ between a person with lighter color skin and a person with darker color skin
Skin with mostly pheomelanin appears a light pinkish color, and skin with mostly eumelanin appears brown. The more eumelanin that is present, the darker a person's skin color. More eumelanin producing melanosomes will result in darker shades.
37
name two molecules in the body that UV radiation can damage
DNA and molecules in the blood
38
How does melanin protect these molecules from UV damage?
Some melanosomes form a sort of cover, known as a supra nuclear cap, above a keratinocyte's nucleus. This cap shields the DNA inside of the keratinocyte from harmful UV rays.
39
What are pyrimidine dimers, what causes them, and why are they dangerous?
When two adjacent pyrimidine bases link together abnormally, this causes a pyrimidine dimer. They are very dangerous because if they are not repaired, the DNA cannot transcribe itself and the cell will die. Even if the cell attempts to remove the pyrimidine dimer and replace it with the proper sequence of nucleotides, it is possible for the cell to replace the dimer with the incorrect sequence of nucleotides, leading to a mutation.
40
How can pyrimidine dimers lead to cancer?
When cells attempt to replace a pyrimidine dimer with the correct sequence of nucleotides, they sometimes replace the dimer with the wrong sequence of nucleotides. This leads to a mutation in the genes that are crucial to cell division which can cause unregulated cell reproduction or cancer. This type of mutation is one of the causes of skin cancer.
41
pos and neg effects of UVB exposure
Positive: UVB radiation is necessary for producing Vitamin D in the body.
Negative: UVB radiation causes DNA mutations and destroys folate in the blood.
42
explain how the relationship between skin color and UV radiation provides evidence that this trait evolved by natural selection
The closer to the equator, the higher and more consistent the radiation level and the darker the skin color. This darker skin offeres protection from the higher radiation level.
43
What causes skin to tan? What causes skin to sunburn?
* Sunburn occurs when an inflammatory response happens in the skin that causes the keratinocytes to undergo apoptosis (cell death) when exposed to too much UVB radiation.
* Tanned skin is a response to DNA damage which causes an increase in eumelanin and thickness of the epidermis. This occurs in preparation for more sun exposure in the future.
Anatomy MIDTERM
flashcards
Decks in class (12)
# Cards
-
Describing the Anatomic Position25
-
Anatomical Body Cavities14
-
Anatomical Planes of the Body8
-
Types of Movement17
-
Levels of Organization5
-
Types of Tissue18
-
Integumentary System43
-
Thermoregulation & Extreme Conditions and Regulation26
-
Skeletal System57
-
Muscles65
-
Nervous System90
-
Nervous System COPY90
