BIO-201 Exam 2
What structures make up the integumentary system? - ANS-skin, hair, nails, sweat
glands and sebaceous glands
What are the 6 main functions of skin? Briefly explain each function. - ANS-Protection:
creates chemical, physical and biological barrier between the outside world and inside
body
Body Temp. Regulation: ex. sensible perspiration cools body down, dermal blood
vessels constrict to preserve body heat
Cutaneous Sensations: respond to stimuli like touch, pain, temp.
Metabolic Functions: skin can synthesize vitamin D
Blood reservoir: Skin can hold up to 5% of body's total blood volume
Excretion: skin can secrete limited amounts of nitrogenous wastes
What are the 3 main layers of the skin? How would you describe each layer? -
ANS-Epidermis: most superficial region
Dermis: connective tissue layer below epidermis
Hypodermis: adipose tissue layer that connects dermis to underlying structures
What 4 types of cells can be found in the epidermis? - ANS-1) Keratinocytes
2) Melanocytes
3) Dendritic cells
4) Tactile cells
What are the layers of the epidermis and where do you find each (deep to superficial)?
What is the function of each layer? Where are keratinocytes produced? - ANS-Most
Superficial
--------------------
,stratum corneum: 20-30 rows of dead skin cells, though dead provide protection
Stratum lucidum: found only in thick skin (palms and soles of feet)
Stratum granulosum: thin layer that preservers water in body (last layer of living cells
Stratum spinosum: several layers thick with keratinocytes, dendritic cells and
melanosomes
Stratum basale: composed of stem cells that produce new daughter cells, 10 - 25%
melanocytes (keratinocytes produced)
-------------------
deepest layer
What is the difference between thick and thin skin? Where is each found?* - ANS-Thick:
contains stratum lucidum (ex. palms and soles of feet)
Thin: does not have stratum lucidum, (ex. everywhere else)
What are the layers of the dermis? - ANS-papillary and reticular
What forms your fingerprints? - ANS-Sweat pores in epidermal ridges
What is the importance of cleavage lines?* - ANS-incisions parallel to cleavage lines
heal quicker
What are the functions of the hypodermis? - ANS-Insulation, shock absorbing cushion,
serves as a reserve for energy storage
What are the 3 main pigments that determine skin color? What is the color of each? -
ANS-1) Melanin: brown
2) Carotene: yellow to orange
3)Hemoglobin: pinkish
What is the relationship between UV exposure and melanin? - ANS-Melanin protects
from overexposure to UV light
, Explain the importance of skin color for indicating different diseases (include: cyanosis,
pallor, erythema, jaundice and bruises).* - ANS-Cyanosis: blue skin color from lack of
oxygen and hemoglobin
Pallor: pale color from anemia, low blood pressure, fear or anger
Erythema: redness from allergies, hypertension, inflammation
Jaundice: yellow from liver disorders (bile)
Bruises: hematoma, blood clotting under skin
What are the 4 functions of hair? - ANS-1. Protection
2. Sensation
3. Temperature regulation
4. Shielding from sunlight
What is the structure of the hair shaft (3 layers)? - ANS-Medulla: central core
Cortex: several layers of flattened cells surrounding medulla
Cuticle: outer layer consisting of overlapping layers of single cells
Describe the components of a hair follicle and their functions. - ANS-Hair bulb:
expanded area at deepest end of follicle
Hair follicle receptor: sensory nerve ending around bulb
Hair matrix: area of bulb that produces hair cells
Arrector pilli: small band of smooth muscle attached to follicle to raise hair
Where are fingernails derived from? What are they made of? - ANS-Derived from nail
matrix. Made of keratin
Describe the structures of the nail and their functions. - ANS-Nail matrix: responsible for
nail growth
Nail folds: skin folds that overlap the border of nail
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