Integument

Question 1

What is basal lamina?

Answer 1

Epithelial derivative; makes up extracellular matrix between epidermis and dermis that contains lamina densa and lucida. This forms a net made of type 4 collagen, type 7 collagen (fibrillin), glycoproteins, hemidesmosomes, and perlecan that link epithelium to underlying tissue.

Question 2

What is epidermolysis?

Answer 2

This is when there is malformation of the hemidesmosomes, so the basal membrane is not linked as tightly which leads to blistering of the epithelium from the basement membrane.

Question 3

What lateral (intracellular) junctions are found in epithelium from basal to apical layer?

Answer 3

gap junctions, desmosomes (macula adherens) with intermediate pins, zonula adherens (form terminal web on top of cell to resist abrasion). and zonula occludens (tight junctions against leakiness).

Question 4

what is epidermis, connective tissue, and melanocytes derived from?

Answer 4

epidermis is derived from epithelium (specifically ectoderm), connective tissue is derived mesoderm, and melanocytes are derived from neural crest cells.

Question 5

what kind of cells make up the epithelium?

Answer 5

cell classification is determined based on most superficial cell type. In the case of epithelium, it is stratified squamous keratinized.

Question 6

what are hair, glands, and nails derived from?

Answer 6

epithelium derivatives. The hair invaginates into dermal papillae where nourished, and the hair root is extends to the capillary of hypodermis. The nail plate and cuticle are stratum corneum, while the bed is stratum basal/spinosum.

Question 7

what’s adermatoglyphia?

Answer 7

Patients with lack of ridges to skin, on thick skin; caused by dysplasia.

Question 8

what are the layers of epidermis (deep to superficial) and some characteristics of each layer?

Answer 8

1. Stratum basal (germativum) - made up of simple mitotic cuboidal cells. Has melanocytes attached here.
2. Stratum spinosum - this is thickest layer (5-10 layers). Here the cells flatten a little and develop these spines called tonofilaments which are bundles of keratin that pin through a desmosome.
3. Stratum granulosum - keratohyalin and tonofilaments mainly make up this region along with some SPRs that crosslink with the keratin, desmosomes, and loricin. Those proteins help make up the inner membrane of cell envelope. The outer lipid membrane is made of tonofilaments with ceramide budding vesicles; 2-3 layers.
4. Stratum lucidem - cell organelles begin to die here. Not always visible but exist; 2-3 layers.
5. Stratum corneum - about 15 layers. More shredded like in thin skin. This keratinocytes are anucleate, and stratum corneum sheds every 24 hours.

Question 9

What’s a melanocyte and how does it work?

Answer 9

A cell attached to basal layer and stays between keratinocytes. This cell produces melanin. Melanocyte cell membrane vesicles are budded and the phagocytosed by melanosome. This budding is stimulated by UV. The melanocytes absorb the UV while the melanin protects the nuclei.

Question 10

What are some determinants of an individual’s skin color?

Answer 10

Melanin degraded quicker in lighter people, UV exposure increases # of melanocytes, proteins like hemoglobin/bilirubin/ and carotene can change color too. There’s also 2 types of melanin: eumelanin: brown/black, and pheomelanin: reddish/yellow.

Question 11

What are two melanocyte disorders?

Answer 11

1. Vitiligo: is when melanocytes are attacked and leads to patches of color.
2. Albinism: altered tyrosine (essential for producing melanin) leads to no melanin production.

Question 12

what are langerhan cells?

Answer 12

they’re antigen presenting cells that are bone marrow derived; you can find in epidermis and dermis

Question 13

What is the papillary layer?

Answer 13

Layer where dermal papillae project to the epidermis. This is made up of loose connective tissue, and you can find Meissner’s corpuscles, lymphocytes, and reticular lamina here. These papillae have one branch artery, and one lymphatic plexus.

Question 14

What are functions of the skin (there’s 6)?

Answer 14

prevent desiccation, protect against UV, communication, thermoregulation, expansion, and dermatoglyphs (fingerprint)

Question 15

What are characteristics of reticular layer in the integument?

Answer 15

Located under dermal papillae, dense irregular connective tissue, and has elastic fibers (branched)

Question 16

How are epidermal cells replaced?

Answer 16

there’s mitosis of stratum basal, differentiation, programmed cell death in stratum lucidum, that they are exfoliated off.

Question 17

What are the buds made of from the stratum granulosum ?

Answer 17

These buds are keratohyalin granules and lamellar bodies that eventually become the stratum corneum.

Question 18

What’s function of venous plexus?

Answer 18

get rid of heat

Question 19

What are the types of free nerve endings (there’s 6)

Answer 19

1. Merkel - found in epidermis; mechanical and produces hormones.
2. Ruffini - encapsulated; detect stretch
3. Peritrichial nerve - attached to hair follicle
4. Pacinian - encapsulated; deep hypodermis; deep pressure
5. Krause - encapsulated; cold
6. Meissner’s - encapsulated; in dermal papillae; fine touch

Question 20

What are some differences between sebaceous gland and sweat gland?

Answer 20

Sebaceous is acinar shaped (cloud shaped), secretes sebum (oil), secretes via holocrine (cell death), and under a microscope has larger lumen and thinner layer of stratified cuboidal than sweat gland. A sweat gland is coiled or tubular, secretes via merocrine (vesicle fusion) or apocrine (top of cell pinches off to release), and have thicker stratified cuboidal. Also both glands are wrapped with myoepithelial to help squeeze.

Question 21

What is rule of 9’s in burn victims?

Answer 21

Body is divided into 9’s (legs), 4.5 (arms), and 18’s back. This determines % of body burned.

Question 22

What are types of burns?

Answer 22

1st = just stratum corneum; blister. 2nd = width of epidermis, 3rd =goes into dermis; need a skin graft, and 4th = goes to the bone.

Question 23

What are ABCDE’s in identifying a melanoma?

Answer 23

A = asymmetry of mark, B = border irregular shape, C = color is mixed, D = diameter greater than 6mm, and E = evolves (becomes larger)

Question 24

Pacinian

Answer 24

Question 25

rectoanal junction (apocrine gland)

Answer 25

Question 26

Sebaceous, eccrine (spiral sweat gland), and apocrine (less coiled sweat gland)

Answer 26

Question 27

3 layers of skin:

Answer 27

Epidermis = stratified squamous., keratinized. Dermis = dense irregular connective. Hypodermis (not part of integument) = loose connective to help anchor skin

Question 28

5 layers of epidermis

Answer 28

Question 29

Different cell types found in thick skin

Answer 29

Question 30

Thick skin cross section

Answer 30