Chapter 5 - Integumentary System

Question 1

The organs of the **integumentary system **include?

Answer 1

**skin **& accessory structures including hair, nails, glands, blood vessels, muscles and nerves

Question 2

Dermatology

Answer 2

medical specialty for the diagnosis and treatment of disorders of the **integumentary system. **

Question 3

**Skin **

aka?

location?

size?

Answer 3

subcutaneous membrane

covers body

largest organ of body by surface area & weight

Question 4

**Skin **

area & weight

% of body weight

Answer 4

2 square metres (22 sq. feet)

4.5-5 kg (10-11 lb)

7%

Question 5

**Skin **thickness

range & average

Answer 5

0.5-4.0 mm thick

thinnest on eyelids

thickest on heels

average = 1-2 mm

Question 6

SKIN

(2) major layers

Answer 6

1) **epidermis - **outer, thinner layer; consists of epithelial tissue
2) **dermis - **inner, thicker layer

Question 7

Beneath the dermis is?

Answer 7

a **subcutaneous (subQ) layer **(also called hypodermis)

which attaches the skin to underlying tissues & organs.

Question 8

Important characteristics of the Epidermis

**(2) **

Answer 8

• composed of **keratinized **stratified squamous epithelium

contains 4 major types of cels

Question 9

Epidermis

(4) major types of cells

Answer 9

1) keratinocytes
2) melanocytes
3) Langerhans cells
4) **Merkel cells **

Question 10

Major cells of the epidermis: Keratinocytes

Answer 10

(90% of the cells)

**- **produce keratin (a tough fibrous protein that provides protection)

Question 11

Major cells of the epidermis: Melanocytes

Answer 11

produce the pigment melanin that protects against damage by UV radiation

Question 12

Major cells of the epidermis: **Merkel cells **

Answer 12

involved in immune responses, arise from red bone marrow

Question 13

major cells of the epidermis: Merkel cells

Answer 13

function in sensation of touch along with adjacent tactile discs

Question 14

The epidermis contains how many layers?

Answer 14

four major layers (thin skin)

five major layers (thick skin)

Question 15

(5) layers of the epidermis

Answer 15

1) stratum corneum
2) stratum lucidum
3) stratum granulosum
4) stratum spinosum
5) stratum basale

Question 16

Stratum Basale

Answer 16

aka stratum germinativum

deepest layer

continuous cell division occurs which **produces all other layers **

Question 17

Stratum Spinosum

Answer 17

8-10 layers of keratinocytes

Langerham cells & projections of melanocytes present

Question 18

Stratum Lucidum

Answer 18

present **only in thick skin **

(the skin of the fingertips, palms, and soles)

Question 19

Stratum granulosum

Answer 19

includes keratohyalin and lamellar granules

consists of 3 to 5 layers of flattened keratinocytes undergoing apoptosis

marks transition between deeper metabolically active strata & dead cells of superficial strata

Question 20

Stratum corneum

Answer 20

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 21

Formation of a callus

Answer 21

constant friction

Question 22

Keratinization

Answer 22

the accumulation of more and more protective keratin, occurs as cells move from the deepest layer to surface layer

Question 23

Dandruff

Answer 23

• an excess of keratinized cells shed from the scalp

Question 24

Important characteristics of the Dermis

Answer 24

composed of connective tissue containing collagen & elastic fibers

contains 2 layers

Question 25

(2) layers of the **dermis**

Answer 25

1) **Papillary **region 2) **Reticular **region

Question 26

**Papillary **region consists of? containing?

Answer 26

outer region, consists of **areolar** (soft) **connective** **tissue** containing **thin** **collagen**, **elastic fibers**, **dermal** **papillae** (including **capillary** **loops**), **corpuscles** of **touch** & **free** **nerve endings **

Question 27

**Reticular **region

Answer 27

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

Question 28

**Striae **

Answer 28

stretch marks - appear if the skin is stretched too much

Question 29

**Lines of Cleavage**

Answer 29

## Footnote tension lines” in the skin indicate the predominant direction of underlying collagen fibers

Question 30

**Epidermal ridges** function?

Answer 30

## Footnote reflect **contours** of the **underlying** **dermal papillae** & form the basis for fingerprints (and footprints); **function**: to increase firmness of grip by increasing friction.

Question 31

**Subcutaneous **(subQ) Layer

Answer 31

aka **hypodermis\** not part of the skin but attaches to skin to underlying tissue

Question 32

The **Subcutaneous **Layer (and sometimes the dermis) contains?

Answer 32

**lamellated (pacinian) corpuscles **which detect external pressure applied to the skin

Question 33

**Accessory ****structures **of the skin

Answer 33

include **hair, skin glands **& **nails**

Question 34

**Hair ** aka? (3) important functions

Answer 34

Pili 1) protection 2) reduction of heat loss 3) sensing light tough

Question 35

**Hair ** composed of?

Answer 35

## Footnote composed of **dead, keratinized epidermal cells **

Question 36

**Hair **consists of?

Answer 36

**shaft **- mostly projects above **root** - penetrates into dermis **hair follicle **- surrounds root of hair, made up of external & internal root sheath referred together as the **epithelial root sheath ** **dermal root sheath - **dense dermis surrounding hair follicle

Question 37

(3) different **types of hair**

Answer 37

1) **lanugo ** 2) **vellus **haira 3) **terminal **hairs

Question 38

Lanugo

Answer 38

fine, non-pigmented downy hairs on body

Question 39

Vellus hairs

Answer 39

replace lanugo short, fine, pale hairs barely visible

Question 40

terminal hairs

Answer 40

long, course, heavily pigmented replace lanugo of eyebrows, eyelashes & scalf

Question 41

## Footnote Hair color is determined by ?

Answer 41

the amount and type of **melanin**

Question 42

s**ebaceous (oil) glands** connected to? secrete?

Answer 42

hair follicles oily substance called **sebum**

Question 43

**Sebum**

Answer 43

an oily substance secreted by **sebaceous glands **to prevent *dehydration of hair & skin* and *inhibit growth* of certain bacteria

Question 44

(3) Types of **Skin Glands**

Answer 44

1) **Sebaceous **glands 2) ** Sudoriferous (sweat)** glands 3) **Ceruminous **glands

Question 45

**Sudoriferous (sweat) **glands (2) types

Answer 45

1) **Eccrine (merocrine) **sweat glands 2) **Apocrine **sweat glands

Question 46

**Dermatoglyphics**

Answer 46

the sutdy of the pattern of **epidermal ridges**

Question 47

**Eccrine (merocrine) **sweat glands function? location?

Answer 47

helps to **cool** body by **evaporating**, & **eliminates small amounts of wastes** distributed throughout skin of most regions especialy in skin of **forehead**, **palms** & **soles ** - located mostly in **deep dermis** (*sometimes* in **subQ layer**)

Question 48

**Apocrine **sweat glands located? function?

Answer 48

located mainly in the skin of the **axilla**, **groin**, **areolae**, and **bearded facial regions** of adult males. - their **excretory ducts** open into **hair follicles ** - sweat secreted during **emotional stress **& **sexual excitement**

Question 49

**Ceruminous **Glands ## Footnote **what** are they & where are they **located**? **function**?

Answer 49

Modified sweat glands located in the **external auditory (ear)** **canal** ## Footnote secretary portion lie in subQ layer, deep to sebaceous glands 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 ear canal.*

Question 50

Functions of Nails (3)

Answer 50

1) **protect distal end** of **digits ** 2) provide **support** & **counterpressure** to palmar surface to **enhance touch perception** & **manipulation** 3) allow us to **grasp & manipulate small objects** + **scratch** & **groom**

Question 51

What are **Nails?** Where are they located?

Answer 51

composed of **hard, keratinized epidermal cells** located over **dorsal surfaces **of the **ends of fingers & toes**

Question 52

Each **nail **consists of? (6)

Answer 52

1) **free edge ** 2) transparent **nail body ** 3) whitish **lunula ** 4) **eponychium** (**cuticle**) 5) **nail root** 6) **hyponychium **(**nail bed**)

Question 53

**Free Edge **of Nail

Answer 53

part of nail body that may extend past distal end of digit

Question 54

**Nail Body** aka?

Answer 54

(**plate**) transparent whitish **lunula at its base ** comparable to stratum corneum of general epidermis

Question 55

**Lunula**

Answer 55

whitish crescent-shaped area at base of **nail body (plate) ** white b/c vascular tissue underneath does not show through thickened region of epithelium

Question 56

**Nail Root**

Answer 56

embedded in a fold of skin

Question 57

**Hyponychium**

Answer 57

**nail bed** thickened region of stratum corneum that secures nail to fingertip

Question 58

**Eponychium **

Answer 58

**cuticle** **narrow band of epidermi** consists of stratum corneum extends from & adheres to margin (lateral border) of nail wall - occupies proximal border

Question 59

(2) major types of **skin**

Answer 59

1) **thin (hairy) **skin 2) **thick (hairless) **skin

Question 60

**thin** (**hairy**) skin covers what body regions?

Answer 60

all body regions **EXCEPT **palms, palmar surfaces of digits & soles

Question 61

**thick** (**hairless**) skin covers what body regions?

Answer 61

**palms**, **palmar surfaces** of **digits** & **soles**

Question 62

**Integumentary System **- functions? (6)

Answer 62

1) **regulate** body **temp** 2) **store blood** 3) **protection** from external environment 4) **detect** cutaneous sensations 5) **excrete**/**absorb** substances 6) **synthesize** vitamin D

Question 63

(5) **Hair **functions

Answer 63

1) protection from injury (scalp) 2) protection from sun's rays 3) sensing light touch 4) decreasing heat loss 5) protect eyes from foreign particles

Question 64

Main Organ of the **Integumentary System**

Answer 64

skin

Question 65

(3) associated structures in the **Integumentary system**

Answer 65

1) nails 2) hair 3) glands

Question 66

Most** superficial **region of the dermis

Answer 66

**papillary** region

Question 67

Most common **connective tissue** **fibre** found in the **dermis **

Answer 67

collagen

Question 68

**Which layer** of the integument **releases** the **heat** from the body **via the blood vessels?**

Answer 68

dermis

Question 69

What material makes the **epidermis** tough?

Answer 69

keratin

Question 70

Distinguish between **Pacinian** corpuscles, **Meissner’s** corpuscles and **pain receptors** in the skin

Answer 70

**Pacinian - **located deep in dermis & hypodermis ## Footnote - function to recieve sensation of **deep pressure** **Meissner's - **located just underneath epidermis - function to percieve **light tough** **Pain Receptors - **in the dermis - **respond** to numerous **pain stimuli**

Question 71

Approximately how long does it take for the epidermis to renew itself?

Answer 71

4-6 weeks

Question 72

**Piloerector Muscle** What is it? What does it do?

Answer 72

smooth muscle that extends from superficial dermis to dermal root sheath contracts which pulls hair shaft perpendicular to skin surface (upright)

Question 73

What is the **outermost portion **of the **hair?**

Answer 73

**cuticle**