The Integumentary System

Question 1

What does epidermis and dermis lay on?

Answer 1

Lays on a supportive hypodermis

Question 2

What is epidermis composed of?

Answer 2

It is composed of keratinized stratified squamous epithelium

Question 3

What are keratinocytes?

Answer 3

They produce proteins to provide protection

Question 4

What are melanocytes?

Answer 4

They produce pigment melanin which protects against UV radiation.

Question 5

What are langerhans cells?

Answer 5

They are involved in immune responses and formed in red bone marrow.

Question 6

What are merkel cells?

Answer 6

They function in sensation of touch with tactile discs.

Question 7

What are the layers of epidermis?

Answer 7

Stratum basale (deepest layer) or stratum germinativum, where continuous cell division occurs which produces all the other layers
• Stratum spinosum, 8-10 layers of keratinocytes
• Stratum granulosum, which includes keratohyalin and lamellar
granules
• Stratum lucidum is present only in thick skin (the skin of the fingertips,
palms, and soles)
• Stratum corneum: composed of many sublayers of flat, dead keratinocytes called corneocytes or squames that are continuously shed and replaced by cells from deeper strata; constant friction can stimulate formation of a callus.

Question 8

What is dermis composed of?

Answer 8

Dermis is composed of connective tissue containing collagen and elastic fibers. It also contains two layers; outer papillary region and deeper reticular region.

Question 9

What is outer papillary region?

Answer 9

The outer papillary region consists of areolar connective tissue containing thin collagen and elastic fibers, dermal papillae (including capillary loops), corpuscles of touch and free nerve endings.

Question 10

What is deeper reticular region?

Answer 10

The deeper reticular region consists of dense irregular connective tissue containing collagen and elastic fibers adipose cells, hair follicles, nerves, sebaceous (oil) glands, and sudoriferous (sweat) glands.

Question 11

What causes variations in skin?

Answer 11

Variations in skin color arise from variations in the amounts of three pigments: melanin, carotene, and hemoglobin

Question 12

Where is melanin found?

Answer 12

Melanin - a yellow-red or brown-black pigment produced by melanocytes (located mostly in the epidermis, where it absorbs UV radiation)

Question 13

What is a nevus?

Answer 13

A benign localized overgrowth of melanocytes is a nevus or mole

Question 14

Where is carotene found?

Answer 14

Carotene - yellow-orange pigment (found in the stratum corneum, dermis, and subcutaneous layer)

Question 15

Where is hemoglobin found?

Answer 15

Hemoglobin - red color (located in erythrocytes flowing through dermal capillaries)

Question 16

What are the functions of hair?

Answer 16

Hairs (pili) have a number of important functions:
– protection
– reduction of heat loss
– sensing light touch

Question 17

Hair is composed of?

Answer 17

Hair is composed of dead, keratinized epidermal cells

Question 18

Structure of hair?

Answer 18

.shaft which mostly projects above the surface of the skin
• root which penetrates into the dermis
• hair follicle
• epithelial root sheath
• dermal root sheath

Question 19

How many types of hair?

Answer 19

lanugo, vellus hairs and terminal hairs

Question 20

How many types of sudoriferous glands?

Answer 20

– Eccrine sweat glands
– Apocrine sweat glands

Question 21

What are eccrine glands?

Answer 21

Numerous eccrine (or merocrine) sweat glands helps to cool the body by evaporating, and also eliminates small amounts of wastes

Question 22

Where is apocrine glands found?

Answer 22

Apocrine sweat glands, located mainly in the skin of the axilla, groin, areolae, and bearded facial regions of adult males.
– their excretory ducts open into hair follicles

Question 23

What are ceruminous glands?

Answer 23

Modified sweat glands located in the ear canal
• Along with nearby sebaceous glands, they are involved in producing a waxy secretion called cerumen (earwax) which provides a sticky barrier that prevents entry of foreign bodies into
the ear canal.

Question 24

What are nails composed of?

Answer 24

Nails are composed of hard, keratinized epidermal cells located over the dorsal surfaces of the ends of fingers and toes
• Each nail consists of:
• free edge
• transparent nail body (plate) with a whitish lunula at its base
• nail root embedded in a fold of skin

Question 25

Functions of the skin?

Answer 25

• Regulation of body temperature
• Blood reservoir
• Protection
• Cutaneous sensations
• Excretion and absorption
• Synthesis of vitamin D