Integumentary System

Question 1

What are the two main layers of the skin?

Answer 1

Epidermis and Dermis

Question 2

What is the deepest layer of the integumentary system?

Answer 2

Hypodermis

Question 3

What is the epidermis composed of?

Answer 3

keratinzed, stratified squamous epithelium

Question 4

How many layers are in the epidermis?

Answer 4

4 or 5 depending on location in the body

Question 5

What are the layers of the epidermis?

Answer 5

Stratum corneum
Stratum lucidum (only in thick skin)
Stratum granulosum
Stratum basale
(melanocytes)

Question 6

What is the Stratum Basale (stratum germinativum)?

Answer 6

Lowest layer of the epidermis; is a single layer if cuboidal mitotic stem cells that give rise to keratinocytes.
10-25% are melanocytes
some tactile and epidermal dendritic cells

Question 7

What layer of the epidermis forms the patterns for fingerprints?

Answer 7

Stratum Basale

Question 8

What is the Stratum Spinosum?

Answer 8

The prickly layer of the skin above the stratum basale.
Has 8-10 layers of keratinocytes
Melanin granules and dendritic cells are most abundant here

Question 9

What is the Stratum Granulosum?

Answer 9

Also known as the Granular layer, this is the third deepest layer of the epidermis.
Only has 3-5 rows of flattened cells
Cells undergo keratinization in this layer due to its distance from the dermis.

Question 10

What is keratinization?

Answer 10

Flattening of cells and disinegration of nuclei and organelles.

Question 11

What do keratohyaline granules aid in?

Answer 11

Cell dehydration, crosslinking keratin (intermediate) filaments, and kertanization.

Question 12

What do keratohyaline granules aid in?

Answer 12

Cell dehydration, crosslinking keratin (intermediate) filaments, and kertanization.

Question 13

What is the Stratum Lucidum?

Answer 13

Thin, transparent band above the stratum granulosum.
Consists of 2-3 rows of dead keratoncytes.
Clear appearance due to eledin.

Question 14

What is the Stratum Corneum?

Answer 14

AKA the horny layer; has 20-30 cell layers of horny scales made up of dead keratinocytes.
Offers biological, chemical, and physical protection

Question 15

Why is the Stratum Corneum water resistant?

Answer 15

Glyco protiens

Question 16

What are the cells of the epidermis?

Answer 16

Keratinocytes
Merkel Cells
Langerhans Cells
Melanocytes

Question 17

What are Melanocytes?

Answer 17

Produce brown pigment (melanin) in response to UVB light.
Located b/w cells of stratum basale

Question 18

What is albinism?

Answer 18

Lack of melanin, leaving individuals defenseless against sun cancer.
Can be caused by defect in enzyme used to make melanin.

Question 19

What is vitiligo?

Answer 19

When Melanocytes die or unable to function
Often caused by autoimmune reasons
Can be treated by transplanting melanocytes.

Question 20

What is bronze diabetes?

Answer 20

When there is too much iron in the body associated with hemochromatosis

Question 21

What are the layers of the dermis?

Answer 21

Papillary and Reticular

Question 22

What is the papillary layer of the dermis?

Answer 22

Superior surface contains peg like projections called dermal papillae

Question 23

What are Merkel Cells?

Answer 23

touch receptors, membranes intact with free nerve endings.

Question 24

What are Langerhans Cells

Answer 24

dendritic cells, epidermal macrophages.

Question 25

What are Cleavage (tension) lines?

Answer 25

Important skin patterns to how the body heals. A parallel cut remains shut and heals well, a cut across pulls open and scars

Question 26

How are cleavage (tension) lines formed?

Answer 26

by the collagen and elastic fibers in the dermis that are arranged in parallel bundles and resist force in a specific direction.

Question 27

What composes the reticular layer of the dermis?

Answer 27

Dense connective tissue Collagen fibers add strength and resiliency to skin Elastin fibers provide stretch and recoil properties.

Question 28

What is the Hypodermis?

Answer 28

Mainly adipose tissue; its a shock absorber, insulator, and stores energy. It is a subcutaneous layer that is deep in the skin (superficial fascia) Areolar tissue connects skin to underlying structures (muscle)

Question 29

How does the integumentary system provide protection?

Answer 29

Chemically - low pH secretions retard bacterial activity (sebum and sweat), melanin provides UV protection. Physically - keratin and glycolipids prevent entry and loss of fluids. Biological - immune cells attack foreign substances (dendritic cells)

Question 30

How does the skin sense temperature?

Answer 30

Thermoreceptors aka ruffini

Question 31

How does skin sense touch?

Answer 31

Merkel discs Meissners corpiuscles (light touch) hair follicules.

Question 32

How does skin detect pressure?

Answer 32

Pacinian Corpuscles (deep pressure and adapts quickly)

Question 33

How does skin detect pain?

Answer 33

Free nerve endings

Question 34

What is the metabolic function of the skin?

Answer 34

Produces vitamin D precursor Activates steroid hormones