The Integument Flashcards
1
Q
Define the integument
A
a tough outer protective layer, especially that of animal or plant
2
Q
What are the layers of the epidermis?
A
- stratum corneum
- stratum lucidum (only found in thick skin)
- stratum granulosum
- stratum spinosum
- stratum basale
- all are found in thin skin except lucidum ?
3
Q
stratum basale
A
- deepest layer
- single layer of cuboidal cells that rests on basal lamina
- keratinocytes, merkel cells (sensory cells), and melancytes live here
- layer = always going thru mitosis in order to produce new cells
4
Q
stratum spinosum
A
- maturing keratinocytes w/ cytoplasmic (spiny) processes
- spines joined by desmosomes
- spines appear as “intercellular bridges”
5
Q
stratum lucidum
A
- clear zone of matted cells with no apparent cell structure
- found only in thick skin Ex: heel of foot, palm of hand
- looks translucent
6
Q
stratum corneum
A
- stratified squamous keratinized epithelium
- flattened, dead cells (top layer)
- filled with keatin filaments but no organelles or nucleus
- abrupt transition btw nucleated cells of stratum granulosum and those of stratum
- keratin makes it tough and allows protection and water-proofing
- cells get filled with keratin filaments so much that they kill all other organelles in the cell
- organelles can’t access nutrients, so they just wither and die
7
Q
Cells of the Epidermis: Keratinocytes
A
- highly specialized epithelial cells that participate in the epidermal water barrier
- most abundant cell type in the epidermis
- main cells in the epidermis
- won’t find a keratinocyte anywhere else in the body
8
Q
Cells of the Epidermis: Melanocytes
A
- found only in stratum basale
- produce and secrete melanin (pigment in our skin)
- have arms that project up into the other layers
9
Q
Cells of the Epidermis: Langerhans’ Cells
A
- antigen presenting cells of the epidermis
- catch antigens as they enter the body and then present them to the immune system so we can have abys
10
Q
Cells of the Epidermis: Merkel Cells
A
- sensory cells found in the stratum basale
11
Q
how to produce keratinocytes thru the process of keratinization?
A
- basal layer cells divide to produce new keratinocytes (mitosis)
- new keratinocytes migrate up into the spinous layer and start to produce keratin and keratohyalin
- keratinocytes in the granular layer continue to form keratin and keratohyalin
- fully mature keratinocytesare filled with keratin, and lack a nucleus and organelles
- keratinocytes are continuously shed and replaced
12
Q
pigment donation by melanocytes
A
- vesicles containing pre-melanin emerge from golgi
- melanin is produced in response to melanocyte-stimulating hormone, and accumulates in melanosomes
- mature melanosomes have lots of melanin and accumulate in “arms” of melanocytes
4-6. keratinocytes “eat” tips of melanocyte that contain melanosomes (cytocrine secretion) - melanosomes released into the cytoplasm of keratinocyte (membrane dissolves and releases those melanosomes into keratinocytes)
- melanin protects nucleus from UV radiation -> so DNA in nucleus doesn’t mutate too much
13
Q
does everyone have the same number of melanocytes?
A
yes. some ppl just have more active ones
14
Q
know how to label the cells of the epidermis
A
- pink = keratinocytes
- melanocytes = orange
- blue = langerhans’ cells
- merkel cells = not pictured
15
Q
layers of the dermis: papillary layer
A
- narrow zone of loose connective tissue beneath epidermis
- invaginates btw grooves of epithelium
- contains capillaries and nerve endings for epidermis
- cushion and shock absoprtion
- epidermis gets nourishment from the dermis -> particularly the papillary layer
16
Q
layers of the dermis: reticular layer
A
- broad, dense layer of connective tissue
- contains interlacing (reticulated) bundles of collagen
19
Q
hair follicles
A
- shaft of hair extends from root out
- root extends from bulb to shaft
- hair bulb is the epithelium surrounds papillae (capillaries and nerves)
- root and hair bulb pictured
20
Q
hair follicles: arrector pilli
A
- smooth muscle associated with hair follicles
- contract to raise hair in respone to cold or sympathetic stimulation
- run btw hair follicle and papillary dermis
21
Q
Sebaceous glands
A
- produce sebum: waxy holocrine section (get in our pores)
- antibacterial and waterproof properties (keeps our skin from getting too dry)
- coats hair and skin surrounding gland (prevents bacterial infxn)
22
Q
Acne vulgaris
A
- Excess sebum production (in response to androgens) -> when you hit puberty
- Colonization of follicle by bacteria (cutibacterium aches excess production can lead to bacterial infxn)
- Follicular plugging (keratin plug)
- Release of inflammatory mediators -> what causes skin to look red
23
Q
Eccrine (merocrine) sweat glands
A
- produce thin, watery sweat (serous)
- distributed over the entire body surface
- thermoregulation, excretion, protection
24
Q
Apocrine Sweat Glands
A
- secrete stinky sweat into hair follicles in armpits and groin
- limited to axilla, areola, and nipple of breast, skin around anus and external genitalia
25
Q
Nails
A
- found on the dorsal surface of fingers and toes
- nail root: nail production occurs
- eponychium (cuticle): is extra stratum corneum
- nail body sits on nail bed
- nail matrix: purple section under the nail body
26
Q
Second half of the pictures of the nail
A
