Module 4

Question 0

What type of tissue is the epidermis made of and how does it receive nutrients and oxygen?

Answer 0

Epithelial tissue
It is avascular since it is not directly supplied by blood vessels but rather receives nutrients from the dermis layer and oxygen via diffusion with the outside environment.

Question 1

Hypodermis aka subcutaneous tissue

Answer 1

Loose connective tissue and adipose tissue allow it to connect with bones & muscle. Fatty tissue provides protection to internal tissues. Injections go to the hypodermis because the dermis and epidermis would push it out.

Question 3

What is a keratinocyte?

Answer 3

95% of EPIDERMAL cells are kertinocytes. The most superficial layer layer are deceased and provide a barrier for H20 loss, UV damage, heat & harmful pathogens. The deepest layer process the nutrients received from the dermis.

Question 4

What do keratinocytes produce?

Answer 4

Keratin- a fibrous protein. It hardens cells & is found in nails, hair and hooves. Found in Spinosum

Question 5

What do melanocytes do?

Answer 5

A type of cell found in the epidermis Stratum Basale layer, produces the pigment melanin (black or dark) light exposure increases proaction of melanin and darkens existing melanin

Question 6

What are langerhans cells?

Answer 6

Found in the epidermis all layers but mostly spinosum and work in conjunction with the immune system to protect against bacteria.

Question 6

Describe desquamate

Answer 6

5 layers in the epidermis, produced in the deepest layer & pushed upward as new cells are created. Once dead, are shed.
As cells move upward keratin is incorporated by keratinocytes to harden cells (keratinization) & form a strong durable skin layer to protect against abrasion

Question 7

What are merkel cells?

Answer 7

Special type of cell that works with the nervous system to detect touch and pressure. Found in basale

Question 8

Psoriasis

Answer 8

A skin condition in which the process of keratinization occurs too quickly causing the skin to become scaly

Question 9

Stages of keratinization in order and how they vary

Answer 9

Deepest Stratum Basale
Stratum Spinosum
Stratum Granulosum
Stratum Lucidum
Superficial Stratum Corneum
Vary in # of cells and not all regions of the skin possess all 5 skin stages

Question 10

Stratum Basale

1 layer thick

Answer 10

Deepest layer of the epidermis where skin cells are created. Made up of cuboidal or columnar cells and anchored by hemidesomsomes. Desmosomes are responsible for anchoring the keratinocytes together for structure. Kerotinocytes are replenished through mitosis
Melanlocytes are found in the stratum basale, where pigment is created to protect against UV rays

Question 12

Stratum Spinosum

just superficial to the Stratum Basale

Answer 12

Shorten cells are flattened/stacked 8-10 layers. Desmosomes from basale layer break down during division but reform in this layer
Living

Question 13

Stratum Granulosum

Superficial to Spinosum

Answer 13

Cells flatten out further and become long & pinched at ends. 5 layers deep. Organelles inside these cells perish due to the ever increaseing distance between their location and the vascular dermis. Keratin & keratohyalin begin to harden, initiating their role as water proofers.
Start to die

Question 14

Stratum Lucidum

Superficial to the Granulosum

Answer 14

2-6 layers deep and become very flattened and thin. Keratohyalin begins to disappear & keratin continues to fill & harden the cells. Cells lose their organells and boundaries. Thick skin: palms, soles of feet.
Not present in THIN skin

Question 15

Stratum Corneum
Superficial to Lucidum
Most superficial layer of epidermis

Answer 15

25-30 cells layered deep of deceased cells completely flattened. Filled with keratin (keratin fibers & keratinocytes). Extremely hard for protection. Soft: cells of skin. Hard: nails & hair. Lipids surrounding these cells are constantly being broken apart which leads these cells being desquamated and replaced by underlying cells
Most protein-keratin

Question 16

Thick skin

Answer 16

Does NOT contain hair follicles, sebaceous glands, or arrector pili muslces. Covers the majority of our body. has all 5 strata and outside cells are highly cornified

Question 17

Thin skin

Answer 17

covers majority of our body and only 1st 3 strata layers and the stratum granulosum is less developed. Does contain hair follicles, sebaceous glands, or arrector pili muslces

Question 18

Callus

Answer 18

forms due to friction from the stratum corneum. If occurs over a boney area its called corn and can be painful

Question 19

Tyrosinase

Answer 19

An enzyme inside melanocytes converts amino acid tyrosine into dopaquinone that eventually converts it to the pigment melanin.

Question 20

Albinism

Answer 20

A genetic disorder in which the body cannot produce the enzyme tyrosinase which means a lack of melanin in skin, hair and eyes

Question 21

Cholasma

Answer 21

Estrogen and melanocyte stimulating hormone (MSH)increase during pregnancy and splotchy skin is due to production of melanin.

Question 22

Erythema

Answer 22

Red skin color caused by hyperemia (increased blood flow) to the capillaries loaded in the skin-sunburn, bug bites, rashes, infections, allergic reactions may cause inflammation and erythema.

Question 23

Cyanosis

Answer 23

Opposite erythema. Blue, decrease in oxygen in skin

Question 24

Carotene

Answer 24

yellow pigment found in plants, carrots, pumpkins, sweet potatoes, corn. Beta-carotene is an important dietary compound as it is a precursor to vit. A = vision, immune sys, growth/development. Overconsumption may cause yellow pigment to deposit in the stratum corneum and in cells of the dermis leading to orange skin tone.

Question 25

Bruise

Answer 25

a rupturing of capillaries under the skin which allows blood to scape and see into the surrounding tissue. Nerve ending can become sensitized and the area will be painful.
Bruises can change color due to the breakdown of the protein hemoglobin in RBC’s. Can turn green, brown, yellow. Tissue will repair before bruise disappears.

Question 26

Functions of skin

Answer 26

Protection from UV rays, dehydration, foreign invaders
Sense of contact & temp. & pressure
Temperature regulation: cold our pores and hair follicles constrict to trap heat. Hot relaxes and sweat
Skin makes Vit D when exposed to UV rays of sunlight. Vit. D then helps the liver and kidneys in calcium production
Rid body of waste products by excretions through skin.

Question 27

Dermis

Answer 27

Collegen: protein made by cells for cushion & strength. Leather

Question 28

Non-Keratinized

Answer 28

GI tract, mouth

Question 29

Skin color

Answer 29

Genetic characteristics, level of sun exposure, amount of blood flowing through skin, pigment-melanin- hair, skin and irises

Question 30

Dermis

Answer 30

2 layers: Papillary layer & reticular layer
Collegen fibers, elastin & reticular fibers
Thicker than epidermis

Question 31

Papillary layer of dermis

Answer 31

Superficial layer gets its name from the dermal papillae protrusions that extend up into the epidermis. These papillae become more abundant and organized in certain areas prone to high levels of friction such as hands and feet. Creates waves and ridges (fingerprints) improve grip for additional friction. Fine loosely arranged fibers of loose connective tissue. Due to contact with epidermis, the papillary layer provides nutrients from its vasculature as well in temp regulation and excretion

Question 32

Reticular layer of dermis

Answer 32

More dense than papillary. Compact fibers of dense connective tissue gives strength and elasticity. Orientation of fibers produce cleavage or Langer Lines. Stitches should be made parallel to hold skin together. If overly stretched= stretch marks, tearing of dermis

Question 33

Hypodermis, subcutaneous layer

Answer 33

Is not technically part of the integumentary sys. It provides a strong anchor for dermis to sit on and attachment site for underlying muscles and bones. Loose connective tissue, fibroblasts, adipose cells, & macrophages.
50% body fat is stored in the hypodermis for insulation, energy & cushioning.