lecture 6

Question 1

the components and primary functions of the integumentary system

Answer 1

• Protection – gives the barrier to protect the body from water loss, invading pathogens, UV radiation, and physical issues
• Temperature regulation – if too cold, the body’s temp is maintained through skin and hair. If too hot the body releases sweat
• Sensory reception – allows us to feel things
• Vitamin D synthesis

Question 2

the process and importance of vitamin D synthesis

Answer 2

• When sunlight hits the skin, modified cholesterol molecules are converted to a vitamin D receptor.
• Vitamin D is necessary for calcium absorption
• Lack of vitamin D during development can cause rickers

Question 3

the two main layers of the skin, and the one just deep to skin

Answer 3

• Epidermis – superficial -> the thin wavy base. Is stratified squamous
• Dermis – the deeper layer -> where we see the nerves, follicles, and parts.
• Hypodermis – the subcutaneous layer -> in charge of insulation, energy storage, and adipose tissues

Question 4

the tissue types of the epidermis

Answer 4

stratified squamous epithelium

Question 5

the tissue type of the dermis

Answer 5

dense irregular connective tissue

Question 6

the tissue type of the hypodermis

Answer 6

loose connective tissue and adipose tissue (fat cells)

Question 7

the functions of the four main cell types in the epidermis

Answer 7

• Keratinocytes – the most abundant cell type, produce keratin and a tough fibrous protein. (as cells fill with keratin they die)
• Melanocytes – found in the deepest layer of the epidermis and produce melanin. When in contact with the skin more melanin is produced to protect the lower skin tissues
• Dendritic (Langerhans) cells – like macrophages; help fight of pathogens, has pathogens that help kill things by invading the skin
• Tactile (merkel) cells – they are between the epidermis and dermis, allows you to feel light touches on the skin. Fingertips are an area with a lot of these

Question 8

the 5 layers of the epidermis

Answer 8

• Stratum corneum – the top layer made of dead keratinocytes (is the thickest)
• Stratum lucidum – (only found in thick skin), the clear layer, is 2-3 layers, and is on the hands and feet
• Stratum granulosum – has 1-5 layers, is where keratin building begins
• Stratum spinosum – the spiny layer – living keratinocytes (has desmosomes). This is where squamous cell carcinoma occurs.
• Stratum basale – is the bottom layer. The layer of the base of the dermis. Where stem cells rapidly divide and create new ones. This layer is avascular and relies on capillaries (where the keratinocytes of the epidermis are generated)

Question 9

cell types of the epidermis

Answer 9

keratinocytes
melanocytes
dendritic (langerhans) cells
tactile (merkel) cells

Question 10

cell types of the dermis

Answer 10

The primary cell type in the dermis is the fibroblast, which produces collagen and elastin, while other cell types present include macrophages, mast cells, adipocytes, Schwann cells, and occasional immune cells like lymphocytes and dendritic cells

Question 11

cell types of the hypodermis

Answer 11

adipocytes (fat cells)
fibroblasts
macrophages

Question 12

describe the changes in cells chapes and function that occur as cells travel through the layers

Answer 12

As cells move through different layers of a tissue, their shape and function often change significantly due to variations in their environment, signaling molecules, and interactions with neighboring cells, leading to specialization and adaptation to the specific role required in that layer; this process is called cellular differentiation, where a cell’s gene expression is altered to produce different proteins and structures, ultimately modifying its shape and function.

Question 13

basal cell carcinoma

Answer 13

makes up about 80% of cases, is most commonly seen on the face, is a proliferation of the stratum basale cells, is the least malignant and most common one, 99% of these can be surgically removed

Question 14

squamous cell carcinoma

Answer 14

on the head, face; and nails. Is proliferation of keratinocytes in the stratum spinosum. The 2nd most common form, can metastasize if not treated in time

Question 15

melanoma

Answer 15

the most dangerous type and is 2-3% of all cases. The proliferation of melanocytes is highly metastatic and resistant to chemo. Early detection is key

Question 16

describe the function and structural characteristics of the two dermal layers

Answer 16

• Papillary dermis
• Areolar connective tissue where the fine interlacing collage and elastic fibers form a loosely woven may with many small blood vessels.
• Allows phagocytes and other defensive cells to wander freely as they patrol the area for bacteria that may have penetrated the skin.
• Has dermal papillae on the surface, which house capillary loops and/or nerve endings and touch receptors.
• Friction ridges -> may enhance our ability to grip certain kinds of surfaces
• Reticular dermis
• Accounts for about 80% of the thickness of the dermis, and is coarse, dense irregular connective tissue. The blood vessels nourish this layer
• Reticular = network
• Has cleavage (tension) lines -> externally visible lines that tend to run longitudinally in the skin of the limbs and in circular patterns around the neck and trunk.
• Has flexure lines -> dermal folds that occur at or near joints, where the dermis is tightly secured to deeper structures.

Question 17

hemoglobin

Answer 17

is localized in the dermis

Question 18

sebaceous glands

Answer 18

microscopic exocrine glands found in the skin that produce and secrete an oily substance called sebum, primarily functioning to lubricate the skin and hair by creating a protective barrier against drying out; they are most concentrated on the face and scalp, and are typically associated with hair follicles, with the exception of certain areas like the eyelids where they open directly onto the skin surface.

Question 19

sweat glands

Answer 19

also known as sudoriferous glands, are small tubular structures located in the skin that produce sweat, primarily functioning to regulate body temperature through evaporative cooling by releasing water onto the skin’s surface
apocrine
eccrine

Question 20

apocrine sweat glands

Answer 20

secretes a viscous milky or yellowish sweat
begins functioning at puberty (may act as a sexual scent glands)

Question 21

eccrine sweat glands

Answer 21

secretes sweat, which helps regulate body temperature (thermoregulation) and disposes of metabolic wastes

Question 22

sweat glands

Answer 22

in the sweat glands are epidermal ridges and sweat pores that are primarily responsible for fingerprints

Question 23

melanin

Answer 23

dark pigment formed by cells called melanocytes; imparts color to the skin and hair

Question 24

carotene

Answer 24

yellow to orange pigment that accumulates in the stratum corneum epidermal layer and in fatty tissue of the subcutaneous tissue

Question 25

the three types of burns

Answer 25

1st degree - effects the epidermis
2nd degree - effects the epidermis and dermis
3rd degree - effects all layers

Question 26

hair

Answer 26

flexible strands produced by hair follicles and consist largely of dead, keratinized cells

Question 27

hair shaft

Answer 27

the part that projects above the skin’s surface

Question 28

hair root

Answer 28

the part of the hair that is embedded into the skin

Question 29

hair follicle

Answer 29

structure with outer and inner root sheaths extending from the epidermal surface into the dermis and from which new hair develops

Question 30

arrector pilli muscle

Answer 30

tiny, smooth muscles attached to hair follicles; contraction causes the hair to stand upright

Question 31

the basic structure and function of the nails

Answer 31

• The nail forms a clear protective covering on the dorsal surface of the distal part of a finger or toe. The nail normally appears pink because of the rich bed of capillaries in the underlying dermis.
• Each nail has a proximal root, a nail plate of body, and a free ridge. The nail rests on a bed of the epidermis which is called the nail bed.
• The nail itself corresponds to the superficial keratinized layers
• The nail matrix – responsible for nail growth.
• The proximal and lateral borders of the nail are overlapped by skin folds called nail folds. The proximal nail fold projects onto the nail body as the cuticle. The thickened area where debris may collect is called the hyponychium.

Question 32

define burn

Answer 32

tissue damage caused by heat, electricity, radiation, or certain chemicals, which result in denaturation or protein and cell death