Integumentary System

Question 1

What is the Epidermis, and what kind of cells is it composed of?

Answer 1

The Epidermis is the outermost protective shield of the body, and is composed of epithelial cells. Note it is also stratified.

Question 2

What is the Dermis and what kind of cells is it composed of?

Answer 2

The Dermis makes up most of the skin, and is a tough, leathery layer composed mostly of dense connective tissue.

Question 3

How do nutrients reach the dermis and epidermis?

Answer 3

The dermis is vascularized, but the epidermis only gains nutrients from diffusion from nearby blood vessels.

Question 4

What tissues are Subcutaneous Tissue composed of and what is another name for it?

Answer 4

It is composed of adipose tissue and some areolar connective tissue. It can also be referred to as the hypodermis.

Question 5

What are the 3 purposes of Subcutaneous Tissue besides storing fat? How does it attach to the underlying structures?

Answer 5

Shock Absorption, Insulation, and Anchoring. It is attached loosely so it can slide over.

Question 6

What is the purpose of a keratinocyte and where are they located?

Answer 6

Keratinocytes produce keratin, and skin is composed mostly of keratinocyte cells.

Question 7

What holds keratinocytes together for strength, and why are they waterproof?

Answer 7

Desmosomes hold together keratinocytes, and tight junctions between cells make them waterproof.

Question 8

List the five layers of the epidermis in thick skin in order of deepest to most superficial. Which layer is not present in thin skin?

Answer 8

Stratum Basale, Stratum Spinosum, Stratum granulosum, stratum lucidum, stratum corneum. The stratum lucidum is not found in thin skin.

Question 9

In the stratum Basale, what types of cells can be found, and what cellular process occurs?

Answer 9

Stem cells can be found undergoing mitosis into keratinocytes, some dendritic cells and melanocytes can be found there as well.

Question 10

In the stratum spinosum, what cells are present, and what tension-resisting protein can be found?

Answer 10

Keratinocytes can be found containing bundles of filaments with pre-keratin inside of them. Dendritic cells are also most abundant in this layer.

Question 11

In the stratum granulosum, what two types of granules are found and what are their purposes? What process is the most important in this layer?

Answer 11

Keratohyalin granules help form keratin in the keratinization of the keratinocytes. Lamellar granules also secretes glycolipids into the extracellular space that is water resistant.

Question 12

In the stratum lucidum, what cells are found? What clear protein is found here?

Answer 12

It is filled with dead keratinocytes that are translucent. Eleidin is found here which gives the layer its translucent property.

Question 13

How many layers of keratinocytes are found in the stratum corneum? What does the keratin found here consist of?

Answer 13

20-30 layers of dead keratinocytes are found here. The keratin found consists of the pre-keratin filaments bound together by the keratohyalin granules.

Question 14

What 2 layers compose the dermis? What tissues compose these layers?

Answer 14

The papillary layer consists of areolar connective tissue and is thin and superficial. The reticular layer is composed of coarse, dense, irregular connective tissue.

Question 15

What is a dermal papilla? What do they contain?

Answer 15

They are small projections of the papillary layer of the dermis into the epidermis. They contain capillary loops to bring nutrients to the epidermis, or nerve endings/touch receptors (tactile corpuscles).

Question 16

What fibers identify the reticular dermis?

Answer 16

Collagen Fibers

Question 17

What are flexure lines?

Answer 17

Dermal folds that occur at/near joints. They are where the dermis is well anchored to the underlying structure.

Question 18

What tears when striae are formed?

Answer 18

The dermis is torn.

Question 19

Where do blisters occur? What happens?

Answer 19

Fluid fills the space between the dermis and epidermis.

Question 20

Melanin is found in which layers of the skin? Why?

Answer 20

Melanin is found in keratinocytes closer to the dermis, as lysosomes break down melanin in dying cells closer to the top.

Question 21

Which enzyme triggers the production of melanin?

Answer 21

Tyrosinase

Question 22

Where does carotene store to pigment the skin?

Answer 22

The subcutaneous tissue and the stratum corneum.

Question 23

What pigment in the dermal capillaries causes fair-skinned people to have a pinkish hue?

Answer 23

Hemoglobin

Question 24

What are the advantages of having hard keratin for hair over regular keratinocytes?

Answer 24

It is tougher, and cells do not slough off.

Question 25

What are the 3 layers of the hair from the deepest to superficial?

Answer 25

Medulla, cortex, cuticle

Question 26

What is differentiating about the medulla? In which hairs is it not found?

Answer 26

It has larger cells and has air spaces in between the cells. It is absent in fine hair (vellus hair).

Question 27

What is contained within the cortex?

Answer 27

It is comprised of several layers of keratinocytes with pigmented melanin.

Question 28

What is the organization of keratinocytes in the cuticle of a hair?

Answer 28

Keratinocytes are shingled together to provide strength and prevent matting.

Question 29

What is replaced by what when hair turns grey/white?

Answer 29

Melanin is replaced with air bubbles.

Question 30

What is the protrusion into a hair bulb?

Answer 30

A dermal papilla protrudes into each hair bulb.

Question 31

What is the knot of nerve endings around the hair bulb called?

Answer 31

A hair follicle receptor.

Question 32

What sheath of the hair follicle derives from the dermis and is the external layer of the follicle wall? What membrane is it superficial to?

Answer 32

The peripheral connective tissue sheathe or fibrous sheath is adjacent to the glassy membrane.

Question 33

What sheath derives from the epidermis and how are its two components derived?

Answer 33

The epithelial root sheathe is comprised of the external root sheathe, which is a continuation of the epidermis, and the internal root sheathe, which is a derivation from the hair matrix.

Question 34

What part of the hair bulb is responsible for the growth of the hair?

Answer 34

The hair matrix.

Question 35

What cells does the hair matrix contain? Where do they come from?

Answer 35

The hair matrix contains stem cells that specialize into hair matrix cells. These stem cells come from a region closer to the skin surface called the hair bulge.

Question 36

What is the arrector pili? What is its function?

Answer 36

It is a bundle of smooth muscle associated with the hair follicle. It can pull the hair upright and dimple the skin.

Question 37

Where is vellus hair found?

Answer 37

The body hair of women and children.

Question 38

Where is terminal hair found?

Answer 38

The hair of the eyelashes, eyebrows, and scalp.

Question 39

What abnormality is characterized by high testosterone in women leading to the growth of facial hair?

Answer 39

Hirsutism

Question 40

What general unit of measurement is used often for the growth cycle of hair?

Answer 40

Years.

Question 41

What is the difference between general balding and male-pattern balding?

Answer 41

General balding is the conversion of coarse terminal hairs to vellus hairs. Male Pattern Balding is a hereditary condition that causes the hair follicles to go through very shortened hair cycles.

Question 42

What is another name for the nail cuticle?

Answer 42

The Eponychium

Question 43

What is the location of the nail matrix?

Answer 43

It is wrapped around the bottom of the nail plate.

Question 44

What structure is the lunule distal to?

Answer 44

The cuticle (eponychium)

Question 45

Where is the hyponychium located?

Answer 45

Adjacent to the most distal part of the nail bed.

Question 46

What fold is located above the cuticle?

Answer 46

The proximal nail fold.

Question 47

Why is the lunule white?

Answer 47

It lays over the thick part of the nail matrix, which is not heavily capillarized.

Question 48

What is the more common type of sweat gland? Where are they concentrated?

Answer 48

The eccrine sweat glands are concentrated on the palms, forehead, and soles of the feet.

Question 49

What is sweat composed of?

Answer 49

Mostly water, some salt, some vitamins, dermcidin, and some metabolic waste.

Question 50

What is dermcidin?

Answer 50

It is a microbe killing peptide found in sweat.

Question 51

What is the major role of sweating?

Answer 51

Heat distributes outside of the body to prevent overheating.

Question 52

What is the less common type of sweat gland? Where are they located? Where do their ducts empty?

Answer 52

The Apocrine glands are located in the armpit and anogenital region. Their ducts empty into hair follicles.

Question 53

What is added to apocrine secretion as opposed to eccrine secretion?

Answer 53

Some fatty substances and proteins.

Question 54

What is the function of general apocrine glands?

Answer 54

Unknown, hypothesized to be linked to mating pheromones (sexual scent glands).

Question 55

What are the two types of modified apocrine glands and what are their functions?

Answer 55

Ceruminous glands secrete earwax, and mammary glands secrete milk.

Question 56

What do sebaceous glands secrete?

Answer 56

An oily substance called sebum.

Question 57

What structure are sebaceous glands mostly attached to?

Answer 57

Hair follicles.

Question 58

What is sebum's purpose in hair follicles?

Answer 58

Lubrication and moisturization, some bactericidal purpose.

Question 59

What are the 6 functions of the skin?

Answer 59

Protection, Temperature regulation, sensation, metabolic action, blood reservation, and excretion.

Question 60

What two corpuscles are involved in sensation, an what kind of sensory input do they sense?

Answer 60

Tactile corpuscles (Meissner's) record the feelings of things against the skin. Lamellar corpuscles are deeper in the subcutaneous tissue or deeper dermal tissue gives sensation deeper in the tissue.

Question 61

How much of the body's blood is held in the skin?

Answer 61

5%

Question 62

What tissues are damaged in a first-degree burn?

Answer 62

Epidermal Tissue

Question 63

Which layers of the skin are damaged in a second degree burn?

Answer 63

The epidermis and the upper region of the dermis are injured.

Question 64

What characterizes a third degree burn?

Answer 64

A third degree burn is characterized by damage to the full extent of the epidermis and dermis.

Question 65

What are the first and second main threats of burn victims?

Answer 65

The first is loss of fluid, and the second is infection.

Question 66

What is the vernix caseosa?

Answer 66

The thick coating of a baby when it is born to protect its skin.

Question 67

As one ages, what happens to the rate of cell replacement? What does this lead to?

Answer 67

The rate decreases which leads to thinner skin and more bruises and superficial injury.

Question 68

What happens to collagen fibers when one ages?

Answer 68

They stiffen and clump.