Chapter 6: The Integumentary System

Question 1

What is the Integumentary System?

Answer 1

A fancy name for the SKIN; It consists of the skin and accessory organs such as hair, nails and cutaneous glands

Question 2

Why is the skin the most vulnerable organ?

Answer 2

B/c it is exposed to radiation, trauma, infection and injurious chemicals

Question 3

What are the Three Layers of Skin?

Answer 3

1) Epidermis
- stratified squamous epithelium
2) Dermis
- Deeper connective tissue layer
3) Hypodermis
- connective tissue layer below dermis (not part of skin, but associated with it

Question 4

What is Thick Skin?

Answer 4

• Type of Skin that covers the front of hands, bottoms of feet
• Has sweat glands, but no hair follicles or sebaceous (oil) glands
• The epidermis is 0.5mm thick
• contains five strata

Question 5

What is Thin Skin?

Answer 5

• Type of Skin that covers most of the body
• Has hair follicles, sebaceous (oil), and sweat glands
• The epidermis is about 0.1mm thick
• Contains four strata

Question 6

What are some functions of the Skin?

Answer 6

• Resistance to trauma and infection, (Keratin, Dermacidin and defensins, Acid Mantle)
• It is the our first line of defense and barrier from water, UV radiation and harmful chemicals
• Helps with Vitamin D synthesis (first step)
• Sensation (receptors for temperature, touch, pain ect.)
• Thermorgulation (Perspiration)
• Nonverbal communication (Facial expression)

Question 7

What are some characteristics of the Epidermis?

Answer 7

• It is keratinized stratified squamous epithelium
• dead cells at skin surface with though keratin protein
• Lacks blood vessels
• contains sparse nerve endings for touch and pain

Question 8

What are the five Epidermal Cell Types?

Answer 8

1) Stem Cells
2) Keratinocytes cells
3) Melaocytes cells
4) Tactile cells
5) Dendritic cells

Question 9

What are Stem Cells?

Answer 9

• Type of Epidermal cell
• Undifferentiated cells that give rise to keratinocytes
• It is in the deepes layer of the epidermis (stratum basale)

Question 10

What are Keratinocytes

Answer 10

• Type of Epidermal Cell
• It is the majority of epidermal cells
• responsible for synthesizing keratin

Question 11

What are Melanocyte cells?

Answer 11

• Type of Epidermal Cell
• It syntesizes pigment melanin (coloring of hair and eyes) that shields DNA from ultraviolet radiation
• Occurs only in stratum basale but have branched processes that spread among keratinocytes and distribute melanin

Question 12

What are Tactile Cells?

Answer 12

• Type of Epidermal cell
• Has touch receptor cells associated with dermal nerve fibers
• Located in basal layer of epidermis

Question 13

What are Dendritic Cells?

Answer 13

• Type of Epidermal cell
• Macrophages originating in bone marrow that guard against pathogens
• found in stratum spinosum and granulosum

Question 14

How are Keratinocytes produced?

Answer 14

• They are produced by mitosis of stem cells in stratum basale or mitosis of keratinocytes in the deepest part of stratum sqinosum

Question 15

What is the Stratum Basale?

Answer 15

• Deepest layer of the epidermis
• It is a single layer of stem cells and keratinocytes resting on the basement membrane
• stem cells divide and give rise to keratinocytes that migrate toward skin surface to replace lost cells

Question 16

What is the stratum spinosum?

Answer 16

• Layer of the Epidermis
• It is several layers of keratinocytes joined together by desmosomes and tight junctions
• named for appearance of cells after histrological preparation

Question 17

What is the Strarum Granulosum?

Answer 17

• layer of the epidermis
• Three to five layers of flat keratinocytes
• Cells contain dark- staining keratohyalin granules

Question 18

What is the Stratum Lucidum?

Answer 18

• Layer of the Epidermis
• Thin, pale layer found only in Thick Skin
• Keratinocytes packed with clear protein eleidin

Question 19

What is the Stratum Corneum (surface layer)

Answer 19

• Layer of the Epidermis
• Several layers (up to 30 layers) of dead, scaly, keratinized cells
• Resists abrasion, penetration, water loss

Question 20

What are calluses/ corns?

Answer 20

• Thick accumulations of dead keratinocytes on hands or feet?

Question 21

What are the four important events that occur in the Stratum Granulosum?

Answer 21

1) Keratohyalin granules release filaggrin (a protien that binds keratin into tough bundles)
2) Cells produce tough envelope proteins beneath their membranes
3) Membrane- coating vesicles release lipid mixture that spreads out and waterproofs it
4) Keratinocytes’ organelles degenerate and the cells die

Question 22

What is the Epidermal Water Barrier?

Answer 22

• It is tught junctions between skin cells and waterproofing that occurs in the stratum granulosum

Question 23

What are some functions of the Epidermal Water Barrier?

Answer 23

• water retention
• Helps prevent dehydration
• Does not prevent the absorption of water by stratus corneum

Question 24

What are some characteristics of the Dermis?

Answer 24

• It is the connective tissue layer beneath epidermis
• Contains a lot of blood vessels, sweat glands, sebaceous glands and nerve endings
• Is the tissue of the facial skin to which skeletal muscles attach and cause facial expressions and emotions
• Houses hair follices and nail roots

Question 25

What is the Dermal Papillae

Answer 25

• Type of wavy, dermal boundary that is upwards, finger-like extensions of the dermis

Question 26

What is the Epidermal Ridges?

Answer 26

• downward waves of epidermis