Integumentary System

Question 1

What are the two main layers of the skin and what are they made of?

Answer 1

The epidermis (superficial layer of the skin, composed of epithelial tissue) and the dermis (connective tissue)

Question 2

What is the hypodermis, what is it composed of and what is it function?

Answer 2

The hypodermis is the layer deep to the dermis, it is made of areolar and adipose tissue, and it serves to connect the skin to the underlying fascia.

Question 3

List the layers of epidermis from superficial to deep

Answer 3

stratum corneum, stratum lucidum (only in hands and soles), stratum granulosum, stratum spinosum, stratum basale

Question 4

Describe the structure and function of stratum basale

Answer 4

It is the deepest layer of the skin, composed of highly miotic stem cells. It attaches the epidermis to the basal lamina (dermis)

Question 5

Describe the structure and function of stratum spinosum

Answer 5

Made of keratinocytes attached with desmosomes, provides strength and flexibility to the skin

Question 6

Describe the structure and function of stratum granulosum

Answer 6

It is made of keratinocytes, and it marks the transition between metabolically active layers and layers of dead cells. A water reppellent scealent forms in this layer.

Question 7

Describe the structure and function of stratum lucidum

Answer 7

Present only in fingers, palms and soles, it is a thin layer of transparent dead cells

Question 8

Describe the structure and function of stratum corneum

Answer 8

Composed of dead cells and lamellar granules making it water repellent (increased keratinization). Helps prevention of microbes.

Question 9

What is a callus?

Answer 9

An increase in depth of the corneum due to abnormal friction.

Question 10

How many types of cells are contained in the epidermis?

Answer 10

4

Question 11

What are the principal types of cells in the epidermis?

Answer 11

keratinocytes, melanocytes, Langerhans cells and Merkel cells

Question 12

Describe keratinocytes, where they are located and their function

Answer 12

They produce the protein keratin, which helps protect the skin from heat, microbes and chemicals. Keratin produces lamellar granules which release a waterproof sealant. They are located in the spinosum and granulosum layers of the skin.

Question 13

What is keratinazation and how long does it take to occur?

Answer 13

The replacement of a cell contents with the protein keratin, which occurs when cells move to the skin surface over a period of 2 to 4 weeks.

Question 14

What are melanocytes and where are they located?

Answer 14

Cells that produce melanin, a pigment which contributes to our skin colour and absorbs UV light. They are in the stratum basale layer.

Question 15

What are Langerhans cells and where are they located?

Answer 15

They are cells that participate in immune response (macrophage) in the stratum spinosum layer.

Question 16

What are Merkel cells and where are they located?

Answer 16

The Merkel cells touch a sensory structure called a tactile disc and function in the sensation of touch. They are in the stratum basale.

Question 17

What is the dermis made of and what is its function?

Answer 17

It is the layer underneath the epidermis, it contains two layers of connective tissue containing collagen and elastic fibers, as well as blood, lymph vessels, nerves, etc. It is the core of the integumentary system.

Question 18

What are the layers of the dermis called ?

Answer 18

The papillary layer and the reticular layer.

Question 19

What is the connective tissue type of the papillary layer?

Answer 19

Areolar connective tissue (collagen and elastic fibers form a loose mesh)

Question 20

Describe the papillary layer’s structure

Answer 20

It projects unto the stratum basale to form finger-like dermal papillae.

Question 21

What structures are included in the papillary layer?

Answer 21

corpuscules of touch (Meissner’s corpuscules) and free nerve endings for sensation of heat, cold, pain, tickle, etc.

Question 22

What is the reticular layer made of?

Answer 22

Dense irregular connective tissue with bundles of collagen fibers and some elastic fibers

Question 23

What are epidermal ridges, what it their use and origin?

Answer 23

They come from the underlying contours of the dermis, they increase friction for better grasping ability, and provide the basis for fingerprints and footprints.

Question 24

What are the three pigments that cause skin color?

Answer 24

Melanin, carotene and hemoglobin.

Question 25

What are the cellular vesicules transporting melanin into the keratinocytes called?

Answer 25

Melanosomes

Question 26

What are the three parts of a hair ?

Answer 26

A shaft above the surface of the skin, a root that penetrates the dermis and ends in a hair bulb, and a hair follicle, which consists of two epidermal layers surrounding the root.

Question 27

What are the parts composing the non-living hair shaft and the living hair root?

Answer 27

The outer cuticle, the inner medulla and the innermost cortex.

Question 28

What are the different parts of the hair follicle?

Answer 28

The enlarged base called the hair bulb, a hair papilla (brings blood and nutrients), and a hair matrix (miotically active cells)

Question 29

What are the functions of hair papilla and hair matrix?

Answer 29

Hair papilla has many blood vessels to nourish the growing hair, and the hair matrix contains miotically active cells to produce new hair.

Question 30

What are the functions of hair?

Answer 30

Protection, thermal insulation, sensing light touch.

Question 31

What are the skin gland types?

Answer 31

Sebaceous, sudoriferous and ceruminous

Question 32

What are sebaceous glands, where are they found and what is their function?

Answer 32

They are a type of oil gland, they are mostly connected to hair follicules. They are everywhere in the body except the hands and feet. They produce sebum, which moistens hairs, softens and waterproofs the skin and inhibits bacterial growth.

Question 33

What are the types of sudoriferous glands?

Answer 33

Ecrine and apocrine sweat glands

Question 34

What are eccrine sweat glands and where are they located?

Answer 34

They are a type of merocrine glands that produce sweat for thermoregulation through evaporation, and eliminate waste such as urea. They are located everywhere on the body.

Question 35

What are apocrine sweat glands and where are they located?

Answer 35

They are merocrine sweat glands limited to the skin of the axilla, pubis and areolar, their ducts open into hair follicules.

Question 36

What are cerumeneous glands and where are they found?

Answer 36

They are modified sudoriferous glands that produce a waxy substance called cerumen. They are found in the external auditory meatus.

Question 37

Name the functions of the skin

Answer 37

1. Thermoregulation 2. Protection through physical, chemical and biological barriers 3. Cutaneous sensations including: touch, pressure, vibration, tickle, heat, cold, pain 4. Excretion and absorption 5. Synthesis of vitamin D