Flashcards in Chapter 5 Integumentary System Deck (60)
What are dermal ridges?
Found in areas where the dermal papillae are more prominent (like the palms and soles of feet) thick collagen fibers. This structure indents the overlying epidermis creating epidermal ridges. Enhances gripping ability. The sweat excreted on dermal ridges makes fingerprints.
How is skin color determined? And where is this substance produced?
by various amounts of the orange-red to black protein pigment melanin, is produced by melanocytes in the stratum basale of the epidermis.
The reticular layer is also associated with which types of skin markings?
Tension, aka cleavage lines, and flexure lines.
The special vesicle in which the enzymatic reaction that produces melanin is?
What is the primary function of melanin?
to protect the DNA of neighboring keratinocytes from UV induced mutations that cause cancer. A secondary function of melanin is it decreases the synthesis of vitamin D in response to UV radiation because too much vitamin D can lead to kidney failure. This is why climates with less sun have whiter skin than climates with more sun.
What is the immediate response to UV radiation? What is the secondary response?
1.immediate: oxidize the melanin already formed within the keratinocytes, which causes the melanin to darken.
2. secondary: UV radiation damages the DNA of the melanocytes, which increases the production of more melanin (about 72 hours later).
what is a freckle?
what is a mole/nevus?
1. an area of increased pigmentation resulting from an increase of melanin production in a concentrated spot.
2. a local proliferation of melanocytes.
What is carotene, and where is it found?
a yellow-orange lipid soluble pigment that accumulates, and is slightly visible in the stratum corneum of thick skin.
What is hemoglobin, and how does it affect skin color?
hemoglobin is an iron containing protein that binds to and transports oxygen through the body in the blood. It is responsible for blood's red color because it oxidizes iron when in contact with oxygen. It can be seen through the epidermis of fair skinned people, giving the skin a faint pinkish hue.. In areas of thinner skin, like the lips, the pink color appears darker.
What is erythema, and why does it happen?
when a person becomes more red because of increased blood flow through the dermis. Reasons for this are is a person is exercising and the body needs to cool off, or at the site of an injury, like a broken bone.
What is pallor, and why does it happen?
when the skin becomes white due to lack of blood flow to an area. Reasons for this include the body trying to conserve heat.
What is cyanosis, and why does it happen?
cyanosis is when a person turns bluish due to low levels of hemoglobin binding to oxygen. A person with cyanosis needs immediate med attn.
Hair grows between 1 - 1.5cm /month, but varies between individuals. Describe the growth phase, and the resting phase.
1. Mitosis occurs within the cells of the matrix in the root. As cells divide, the cells above them are pushed away from the blood supply, keratinize and die (much like the epidermis). Lasts from 1 month in eyelashes to 6 years in the scalp.
2. During the resting phase, the cells stop dividing and start to die. The follicle shortens and the hair is pushed up to the surface of the follicle, which remains dormant for 1 to several months. The hair may fall out, or be pushed out when a new one comes in.
Name and describe the 3 types of hair.
1. Laguno: a fetus is covered in this. It is non-pigmented, and falls out around the time of birth, and is replaced by one of the following...
2. Terminal hair: thicker, coarser, and pigmented. Found on scalp, and around eyes
3. Vellus hair: thinner, and non-pigmented. Found all over the body. After puberty, much of the vellus hair is replaced by terminal hair (about 90% for males, and 35% for females).
What produces hair color?
melanin in the matrix by melanocytes. Blond has little melanin, whereas black has a lot. Red is special, containing iron. As we age, we produce less melanin, so hair turns grey or white.
What are nails made of? What is the most visible component? Now name each other structure of the nail.
Nails are made of stratified squamous epithelia full of hard keratin. The most visible part is the nail plate, which rests on the nail bed. The nail plate is divided into the nail body, and the nail root (under the skin). This is where the nail matrix actively divides new cells.
name the folded regions of skin around the nail.
proximal nail fold, medial nail fold, and lateral nail fold. They reinforce the nail.
Nails do not contain melanocytes so are mostly translucent except at a region called the...
lunula (the 1/2 moon shaped region close to the nail root). Represents an accumulation of keratin.
What are the functions of nails?
1. protect the finger and toe tips from trauma. Nails can be used as tools, enabling better gripping when picking things up.
The skin contains two basic types of glands both derived from epithelial cells in the epidermis but located deeper in the dermis. What are they?
1. Sweat glands
2. Sebaceous glands
What are the 4 types of sweat glands and what is their function?
1. Eccrine: most prevalent. Found in dermis, sweat exits through a sweat pore. Primary function is thermoregulation
2. Apocrine: Found in axillae, anus, and areola. Large glands that release protein-rich secretion into hair follicles. Can stink when bacteria comes in contact. Influenced by sex hormones after puberty.
3. Ceruminous: modified apocrine glands that release earwax into ears. Function is to lubricate tympanic membrane and trap incoming particles.
4. Mammary glands: highly specialized. Produce a sweat product, milk.
Sebaceous glands empty into a hair follicle or a small pore that makes and secretes...
Where are sebaceous glands located? And what body parts lack them?
most numerous in face and scalp, but found everywhere in the body except the palms and soles.
Describe the composition and release of sebum. What does sebum contain?
it is a waxy, oily mixture that contains lipids. It is excreted by holocrine secretion. For this reason it contains cell fragments and debris. it inhibits the growth of certain bacteria.
What is a wound? What is a burn?
A wound is defined as any disruption in the skin’s integrity and include the following more specific injuries: lacerations or cuts, burns, and skin cancers. A burn is a wound caused by heat, extreme cold, electricity, chemicals, or radiation.
Explain the rule of nines and why its used
The rule of nines divides the body into 11 different regions each equaling 9% of the surface of the body plus the genital area equaling 1%. This rule is important because it is used to predict the complications associated with the burn, the patients level of dehydration, and their prognosis.
Describe the three levels of burns
1. first degree: only epidermis is damaged. No blisters. May be red and painful. no Dr. needed.
2. Second degree: partial thickness. Involve epidermis, and part or all of the dermis. Very painful, blistering, scarring. Dr. usually needed.
3. Third degree: Full thickness burns. Involve epidermis, dermis, hypodermis, and maybe more. Loss of tissue. Possible grafting needed. Dehydration is a danger.
Where does basal cell carcinoma arise from? Describe its appearance
most common type of skin cancer, arises from the keratinocytes of the stratum basale. It looks like a nodule with a crater in the middle. Easy to resolve w/ surgery.
Where does squamous cell carcinoma arise from? What does it look like?
second most common type of skin cancer. Arises from the keratinocytes of the stratum spinosum. Looks like scaly plaques that bleed. Found mainly on head and neck. More likely to metastasize than basal, but still possible to manage by removal.