Structure of the skin (U2)

ALL ABOUT THE SKIN

Describe the 3 types of epithelial membranes: cutaneous, mucous, serous.

Cutaneous membrane - your skin – it has a superficial epidermis layer and covers the body surface. It is exposed to air and is a dry membrane.

Mucous membranes – these membranes line body cavities and are open to the exterior (e.g. mouth, esophagus, lungs, urinary tract, reproductive tract.) Mucosa comes in 2 types of cellular make-up: squamous epithelium and simple columnar epithelium. They are wet or moist membranes that are continually bathed in secretions.

Serous membranes – these line body cavities and are closed to the exterior. There is a parietal layer (lines the body cavity) and the visceral layer (covers the outside of the organs). E.g. the pleura that surrounds the lungs and the pericardium which surrounds the heart.

Where would one find the synovial membrane?

These membranes line the fibrous capsules surrounding joints. They provide a

smooth surface and secrete a lubrication fluid. E.g. knee joint. They also help to

cushion organs moving against each other during muscle activity. REDUCE FRICTION

4. What are the functions of the integumentary system?

The integumentary system does the following:

protects deeper tissues from mechanical bumps, chemical damage, bacterial damage, UV radiation, thermal damage, desiccation (drying out), aids body heat loss or heat retention, aids in

excretion of urea and uric acid, synthesizes vitamin D, blood storage.

5. What cell type is most abundant in the epidermis?

The epidermis is made up of mostly keratinocytes (keratin cells) which produce keratin, the fibrous protein that makes the epidermis a tough protective layer. Carries out a process called keratinzation when skin cells get filled with keratin and move to the surface and shed.

6. Which layer of skin produces new epidermal cells?

The stratum basale or stratum germinativium which is the layer closest to the dermis produces new cells constantly (germinating layer).

Name the factors that determine skin colour and describe the function of melanin.

Melanin – produced by melanocytes —> the amount and kind (yellow, reddish brown or black) of melanin in the epidermis.

Carotene – pigment that is deposited in the stratum corneum and subcutaneous tissue. Skin tends to take on a yellow-orange cast when you eat large amounts of carotene rich food.

Hemoglobin – also a pigment, the carrier for oxygen in our blood.

How do emotions affect skin colour?

Redness or erythema – reddened skin may indicate embarrassment (blushing), fever, hypertension, inflammation or allergy.

Pallor or blanching – in some people emotions like fear, anger, etc. cause their skin to pale. Pale skin may also indicate anemia, low blood pressure or impaired blood flow.

Jaundice – usually indicates a liver disorder in which excess bile pigments areabsorbed into the blood and then deposited in body tissues.

Bruises or black and blue marks – aka hematomas could indicate a deficiency in Vitamin C or hemophilia.

10. Which of the cutaneous gland types can make your hair limp and oily?

The sebaceous or oil glands release a substance called sebum which can make

your hair limp and oily.

Define what sebum is

This is a mixture of oily substances and fragmented cells. It is a lubricant that

keeps skin soft and moist and prevents hair from becoming brittle. It also

contains substances that kill bacteria.

Compare and contrast sebaceous glands and sweat glands

These are the 2 types of cutaneous glands.

Sebaceous glands or oil glands are found all over the skin with the exception of palms of the hands and soles of the feet

They secrete sebum and help to keep hair soft, skin moist and kill bacteria.

Sweat glands or sudoriferous glands are widely distributed and there are about 2.5 million per person. They release sweat which is mostly water and some vitamin C, salts and metabolic wastes. This helps to regulate body temperature.

Differentiate between first, second and third degree burns (superficial, partial thickness, full thickness).

Superficial (formerly First degree burns) – only the epidermis is damaged. The area is red and swollen and only temporary discomfort is experienced. Will generally heal without special attention.

Partial Thickness (formerly Second degree burns) – injury to the epidermis and the upper region of the dermis. Skin is red and painful and blisters appear. If care is taken to prevent infection then no permanent scarring will result.

Full Thickness (Third degree burns) – these destroy the full thickness of the burn. The area becomes blanched or blackened and nerves are destroyed so the pain is actually less. Skin regeneration is not possible – skin grafting must be used.

What are 2 life-threatening consequences of a severe burn?

A severe burn can result in dehydration and shock – the kidneys may shut down.

Infection is a huge concern because pathogens can easily invade areas where

skin has been destroyed and multiply rapidly in the dead tissues.

What name is given to the rule for recognizing the signs of melanoma? Explain how to use it

ABCD rule – Asymmetry, Border irregularity, Colour, Diameter. (E or Evolving)

• A – Asymmetry: One half of the mole does not match the other.

• B – Border: Edges are irregular, ragged, notched, or blurred.

• C – Color: The mole has varying shades of brown, black, tan, red, white, or blue.

• D – Diameter: The spot is larger than 6 mm across (the size of a pencil eraser).

• E – Evolving: The mole changes in size, shape, color, or begins to itch or bleed.

What is most common skin cancer risk factor?

Overexp to UV radiation

What cells do no skin cancers develop in?

Stratum corneum cells

Top most layer of epidermis are made of these cells. They are dead so they no longer undergo mitosis (cell div)

What change in aging skin accounts for wrinkles and cold intolerance in older adults?

The amount of subcutaneous tissue decreases, this dries the skin out as less oil

is produced and the skin is thinner so intolerance to cold may result.

What is vernix caseaosa and what is the source? Where do we see it?

Milky white cheese like substance that appears on babies skin forms protective barrier during fetal development

Due to seb glands from baby and protects bebe from damage during constant exp to amniotic fluid

What is cyanosis? If a patient is cyanotic, what does its presense indicate?

This is when the blood, skin, nail beds can appear blue. This is common during heart

failure and severe breathing disorders. and cold temps

Skin is orange, this is called carotenemia, what is this? explain

Eating large amounts of vegetables that are high in carotene can result in an

orange colour to the skin. (e.g. carrots, orange peppers, sweet potato).

Liver cannot process fast enough then deposits into stratum corneum and subcut fat turning skin orangish

List 3 functions of your skin

Protection: phys and chem barrier against germs, bacteria

Temp regu: helps keep bodys internal temp stable, cools body by releasing sweat, adj blood flow through blood vessels in dermis

sensory perception: contains specialized nerve endings that detect touch, pressure, vib, and temp (hot/cold

skin creates vit D when exp to UV. ess for calcium absorption

Compare+contrast epiderm and derm

Sims: Protective barriers, constant interaction (epid relies on dermis for nutrients through blood flow)

Diffs: Epi: Outermost layer, primary tissue type is epithelial tissue (stratified squamous keratinocytes), Avascular (NO blood vessels so relies on dermis for nutrients), contains melanocytes and pores, high regenration rate (4-6 weeks sheds/renews)

Diffs: Derm: middle layer direcrly under, thick (makes up most of skin), dense connective tissue, vascular, contains specialized receptors, conatins hair fols. sweat glands, sebacous oil glands, regen ratw is slow forms scars when damaged

List 2 potential caused of erythema:

-Temp changes hot/cold, causes blood vessels near face to dilate—> increased blood flow

-Mood change also changes that

2 potential causes for pallor/blanching

Mood change —> Fear, anxiety causes blood vessel to narrow and redirect blood flow away from face to vital organs

Infections: Same thing

Compare.contrast cuatneous and mucuos mebranes

Both EPITHELIAL MEMBS made of epithelial on top of connective, protective barriers

-Cutaneous membrane: outer layer (skin), covers body surf exposed to air, made of epi on top and dermis underneath, protective barrier, technical term for skin, made of epithelial tissue, keeps things dry

-Mucous mems; comes in 2 types of cellular make-up squamous epithelium and simple columnar, keep things moist, line pathways to the outside of body, in digestive tract, urinary body tracts

Whats the serous memb—> exaples:?

-lines body cavs closed to exterior, theres pariertal layer (lines bod cavs) and the visceral layer (cobvers outside of orgs)

EXAMPLES: Pleura: surrounds lungs

Pericardium: surrounds heart

Compare/contrast : abrasion and laceration

Both skin injuries

Abrasion: Top layer scrape by friction, minimal bleeding, affects epidermis

Laceration: break into skin below epidermis, deeper tear, significant bleeding, jagged edged wounds

what are some uses for wound dressing and provide two examples

wound dressing stop bleeding, protect against infections, absorb fluids, remove dead tissue, provide moist environ that promote healing

Gauze: small cuts abrasions

Hydrogel dressings: great for dry wounds since they have moist components for pressure ulcers, diabetic ulcers