1. The Integumentary System
-the skin and its various accessory structures,
and the membranes
-functions to protect the body against
infection, physical damage, and temperature
changes
-the largest organ in the body
I. Epidermis

2. Epidermis

3. The Integumentary System
-the skin and its various accessory structures,
and the membranes
-functions to protect the body against
infection, physical damage, and temperature
changes
-the largest organ in the body
I. Epidermis
-protects the body against infection and ultraviolet radiation
-cells have about 40-day life cycle, shortest-lived cells
A. Stratum corneum
-“horny layer”
-made up entirely of dead, flattened, highly-
keratinized (tough, waterproof) keratinocytes
-cells contain carotene, yellow/orange pigment
most evident in palms and soles, calluses

4. Stratum corneum
Epidermis

5. The Integumentary System
-the skin and its various accessory structures,
and the membranes
-functions to protect the body against
infection, physical damage, and temperature
changes
-the largest organ in the body
I. Epidermis
-protects the body against infection and ultraviolet radiation
-cells have about 40-day life cycle, shortest-lived cells
A. Stratum corneum
-“horny layer”
-made up entirely of dead, flattened, highly-
keratinized keratinocytes
-cells contain carotene, yellow/orange pigment
most evident in palms and soles, calluses
B. Stratum lucidum
-“clear layer”
-extra layer found in palms and soles
C. Stratum granulosum
-site of deposition of keratin granules
D./E. Stratum germinativum

6. Stratum corneum
Epidermis
Stratum lucidum
Stratum granulosum

7. D. Stratum spinosum
-“spiny layer”
-thick layer where keratinocytes are pushed
farther from the nourishing blood supply of
the dermis, progressively die and flatten out
E. Stratum basale
-produces keratinocytes
-also contains melanocytes, which produce
melanin to deposit in deeper layers of the
Stratum spinosum

8. Epidermis Stratum corneum Stratum lucidum Stratum granulosum
Stratum spinosum
Stratum basale

9. D. Stratum spinosum
-“spiny layer”
-thick layer where keratinocytes are pushed
farther from the nourishing blood supply of
the dermis, progressively die and flatten out
E. Stratum basale
-produces keratinocytes
-also contains melanocytes, which produce
melanin to deposit in deeper layers of the
Stratum spinosum
Rx—Basal Cell Carcinoma
-cancer of the keratinocyte-producing cells of
the stratum basale
1. Melanocytes
-produce melanin, a brown pigment which
absorbs visible and ultraviolet (UV) light
-all people have about the same number of
melanocytes, but differ in the amount of
melanin produced by each cell, which is
gentically determined, lighter skin thought to
be an adaptation for survival against Ricketts
and osteomalacia in temperate zones

10. Rx—Malignant Melanoma -cancer of the melanocytes, very quickly
metastasizing and deadly form of skin cancer
1. Melanocytes
-keratinocytes further pigmented with
carotene (orange)
Rx—Albinism
-recessive genetic disorder in which melanoctyes are
unable to synthesize melanin ♂ ♂ A A A a ♀ ♀
Carrier
Carrier
Carrier a Aa Aa A AA Aa
Normal
Normal
Normal
Normal
Carrier
Carrier
Carrier a a Aa Aa Aa aa
Normal
Normal
Normal
Albino

11. An individual who produces as much melanin
as humanly possible has genotype MMLLNN.
That person’s phenotype would be to have very
dark skin, so brown as to almost appear black.
MMLLNN
During meiosis, the diploid (2n) genotype, MMLLNN,
Is reduced to the haploid genotype. As the alleles are
segregated from each other, the only possibility for the
sperm or egg is MLN.
MLN
MLN

12. Section 15-1
The union of one genetic half-cell, the sperm, with the other genetic half-cell, the egg, results in one genetically whole cell, the zygote
MLN
sperm +
MLN
egg
MMLLNN
zygote
fertilization

13. Add the alleles from the sperm (MLN) and the alleles from the egg (MLN) to determine the genotype of the zygote (and the new individual), (MMLLNN)

14. The genotype of all the offspring, (1 out of 1, or 1/1), is MMLLNN,
so all the offspring have the same phenotype—very dark skin.

15. An individual who produces as little melanin
as humanly possible has genotype mmllnn.
That person’s phenotype would be to have very
light skin, so as to appear so white that the pink
of the blood shows through.
mmllnn
mln
mln
During meiosis, the diploid (2n) genotype, mmllnn,
is reduced to the haploid genotype. As the alleles are
segregated from each other, the only possibility for the
sperm or egg is mln.

16. Add the alleles from the sperm (mln) and the alleles from the egg (mln) to determine the genotype of the zygote (and the new individual)

17. The genotype of all the offspring, (1 out of 1, or 1/1), is mmllnn,
so all the offspring have the same phenotype—very light skin.
In both examples, when the very dark mate with the very dark
and when the very light mate with the very light, the crosses
result in no variation.
What happens if the very dark mate with the very light?

18. Add the alleles from the sperm (MLN) and the alleles from the egg (mln) to determine the genotype of the zygote (and the new individual)

19. The genotype of all the offspring, (1 out of 1, or 1/1), is MmLlNn,
so all the offspring have the same phenotype—medium skin.
In all three examples, when the very extreme mate with the
very extreme, the crosses result in no variation.
What happens if the medium-skinned mate with the medium skinned? If
Melvin, who has genotype MmLlNn for shade of skin color, and Melanie, who has
genotype MmLlNn for shade of skin color, have 10 children, how many, according
to the odds, should have the same shade of skin color as their parents?

20. During meiosis, the diploid (2n) genotype, MmLlNn
is reduced to the haploid genotype. As the alleles
segregate and assort
independently, maximum
diversity results.
mln
MLN
MLn
mlN
MmLlNn
mLn
MlN
mLN
Mln

21. Add the alleles from the sperm (MLN) and the alleles from the egg (MLN) to determine the genotype of the zygote (and the new individual), (MMLLNN)

22. Now do the same for the other possible combinations of sperm and eggs, filling in the boxes of the Punnet square

29. Now, fill in the rest of the squares

30. If you count up the number of alleles represented by capital letters, you get the number of alleles that code to make a person’s hair, eyes, or skin darker, because each allele represented by a capital letter causes skin cells to make more melanin (brown pigment)

31. The number of alleles coding for the cells to make melanin determine how genetically dark the individual’s hair, skin, or eyes will be. Count up the alleles and total them in the first square

32. The number of alleles coding for the cells to make melanin determine how genetically dark the individual’s hair, skin, or eyes will be. Count up the alleles and total them in the first square

33. Now, count up the alleles coding for melanin production and total them in each square of the Punnet square

34. Now, count up the alleles coding for melanin production and total them in each square of the Punnet square

35. Now, fill in the rest of the squares in the Punnet square
Now, fill in the rest of the squares in the Punnet square. Notice there is a pattern to the numbers.

36. Count how many sixes, fives, fours, threes, twos, ones, and zeroes, out of 64, and write the totals in the data table on the next slide.

37. Now, plot the data on the graph, with the numbers of alleles on the x-axis and the number of individuals on the y-axis. 1 6 15 20 15 6 1

38. Now, plot the data on the graph, with the numbers of alleles on the x-axis and the number of individuals on the y-axis. 1 6 15 20 15 6 1

39. Now, plot the data on the graph, with the numbers of alleles on the x-axis and the number of individuals on the y-axis. 1 6 15 20 15 6 1

40. II. Dermis
-protects body from changes in temperature by housing blood
vessels, glands, and producing hair
-made from collagen and elastin form elasticity
A. Hair
-can be elevated to trap air for further insulation
-offers some physical protection (padding)
-axillary and pubic hair linked to apocrine glands
-protects against pathogens entering eyes, ears, nose, etc.
B. Sebaceous (Oil) Glands
-produce sebum (oil) to lubricate skin and
protect it from drying out
-provide sebum as food source for
mutualistic bacteria (Staphylococcus
epidermidis) which compete biologically
with pathogens (Staphylococcus aureus)
Rx—Acne
-infection of a sebaceous gland or hair follicle by S. aureus, or
other bacteria which feed on oil and produce toxic by-products
which damage cells; attack of white blood cells (neutrophils)
create pain, swelling, redness, pus

41. hair
Epidermis
Sebaceous (oil) gland
Dermis

42. II. Dermis
C. Sudoriferous (Sweat) Glands
-produce sudor (sweat) as
protection against heat by
evaporative cooling
-protect from pathogens by uric
acid, which lowers pH of skin
1. Eccrine glands
-most numerous and widespread sweat
glands, especially concentrated in palms,
soles, forehead
2. Apocrine glands
-less numerous, large, high volume sweat
glands associated with hair, especially
concentrated in axillary and anogenital
areas
-secretions sometimes associated with
stress or sexual arousal

43. hair
Epidermis
Sebaceous (oil) gland
Dermis
Sudoriferous (sweat) gland

44. II. Dermis
C. Sudoriferous (Sweat) Glands
3. Ceruminous glands
-produce cerumin (earwax) in ear canal
to protect tympanic membrane
(eardrum) and inner ear
4. Mammary glands
-modified sweat glands which produce
milk in mammals to nourish young
D. Dermal Blood Vessels
-regulate body temperature by dilating
(cooling) or constricting (preventing
cooling)
-along with faster heart rate, speeds
cooling, transfer of heat from outside to
inside of body

45. E. Nerve Endings
-protect by sending sensory information about
skin to cerebral cortex
1. Free Nerve Ending
-sense pain, temperature
2. Tactile (Meissner’s) Corpuscle
-sense light touch
3. Lamellated (Pacinian) Corpuscle
-sense deep pressure
III. Subcutaneous Layer (Hypodermis)
-stored adipose (fat) provides
protection by cushioning and
thermal insulation
-Swedish bikini team?

46. Lamellated (Pacinian)
hair
Tactile (Meissner’s)
Corpuscle
Epidermis
Papillary
Layer
Dermal blood vessels
Sebaceous (oil) gland
Dermis
Free nerve ending
Reticular
Layer
Sudoriferous (sweat) gland
Subcutaneous
Layer
(Hypodermis)
Lamellated (Pacinian)
Corpuscle

47. Rx—Burns
-cell damage by heat, electricity, radiation, acids, and bases
-loss of fluids and electrolyte imbalance (leading to renal
shutdown and circulatory shock)
-open up body to infections
1. First degree
-only damage to epidermis
-sunburn
-redness, swelling, pain (localized)
2. Second degree
-epidermis and papillary layer of dermis
-same symptoms as first degree, plus blistering
3. Third degree
-all epidermis, papillary and reticular layer of dermis
-skin gray or blackened
-no pain or blistering
-prevent circulatory shock, prevent infection
-treated with pig or cadaver skin as temporary graft
-skin grafts (autografts), grown outside of body in tubes
-artificial skin grafts made from plastic, collagen from cattle,
or ground cartilage from sharks