Bio Lecture 4 Flashcards
1
Q
skin accounts for __% of the body weight
A
15
2
Q
functions of skin (6)
A
resistance to trauma and infection
water retention
vitamin d
sensation
thermoregulation
nonverbal communication
3
Q
resistance to trauma and infection (3)
A
- epidermal cells are packed with keratin
- resists and recovers from injury better than other organs
- bacteria and fungi may live on the skin surface, but the relative dryness and slight acidity of the skin keeps numbers down
4
Q
water retention (2)
A
- prevents the body from absorbing too much water from the outside
- prevents the body from losing excess water
5
Q
vitamin d (2)
A
- necessary for bone development and maintenance
- the first step in synthesis occurs in the skin
6
Q
sensation (1)
A
- the skin is equipped with nerve endings that react to heat, cold, touch, texture, pressure, vibration, and tissue injury
7
Q
thermoregulation (2)
A
- in response to chilling, the skin helps to retain heat through vasoconstriction
- in response to overheating, the skin helps to cool the body through vasodilation
8
Q
nonverbal communication (1)
A
- complex skeletal muscle inserts on dermal collagen fibers and pulls on the skin to create subtle and varied facial expressions
9
Q
____ _____ - undifferentiated cells that undergo mitosis and give rise to keratinocytes.
only in the stratum basale
A
stem cells
10
Q
_______ - cells that synthesize melanin. they are found in the stratum basale
A
melanocytes
11
Q
_______ - cells that make up most of the epidermal cells and that are named for their role in synthesizing keratin
A
keratinocytes
12
Q
_____ cells - cells that are receptors for the sense of touch. they are found in the stratum basale
A
tactile
13
Q
_____ cells - cells that are macrophages that “stand guard” against pathogens that penetrate the skin and alert the immune system if such invaders are detected.
They are found in the stratum spinosum and in the stratum granulosum
A
dendritic
14
Q
layers of the epidermis (5)
A
stratum basale
stratum spinosum
stratum granulosum
stratum lucidum
stratum corneum
15
Q
stratum _____ - bottom layer of the epidermis
A
basale
16
Q
stratum _____ - mainly single layer of cuboidal to low columnar stem cells and keratinocytes on the basement membrane
A
basale
17
Q
stratum _____ - some melanocytes and tactile cells are scattered here
A
basale
18
Q
stratum _____ - stem cells undergo mitosis and give rise to keratinocytes that migrate toward the skin surface
A
basale
19
Q
stratum _____ many layers of keratinocytes above the stratum basale
A
spinosum
20
Q
stratum _____ - deepest cells are capable of mitosis, but cells closer to the surface stop dividing and produce more keratin which causes the cell to flatten
A
spinosum
21
Q
stratum _____ - dendritic cells may be found
A
spinosum
22
Q
stratum _____ - cells here have a spiny appearance, but only after preservation techniques
A
spinosum
23
Q
stratum _____ - three to five layers of flat keratinocytes and some dendritic cells
A
granulosum
24
Q
stratum _____ - the keratinocytes in this layer produce keratohyalin granules
A
granulosum
25
stratum _____ - a thin transparent layer seen only in thick skin
lucidum
26
stratum _____ - cells here have no organelles, so the zone appears featureless
lucidum
27
stratum _____ - up to 30 layers of dead, scaly, keratinized cells
corneum
28
stratum ____ - forms a durable, water-resistant surface layer
corneum
29
Layers of the dermis (2)
papillary layer
reticular layer
30
_____ layer - thin zone of areolar tissue in and near the dermal papillae
loosely organized tissue allows for mobility of leukocytes and other defenses against organisms introduced through breaks in the dermis
papillary
31
_____ layer - deeper and thicker layer of the dermis consisting of dense irregular connective tissue
Reticular
32
stretching of the skin in obesity or pregnancy can tear the collagen fibers producing _____ (stretch marks)
striae
33
The _______ - the layer below the reticular layer of the dermis has more areolar and adipose tissue
hypodermis
34
The _____ layer - binds the skin to the underlying muscle and pads the body
is highly vascular (injections here)
contains subcutaneous fat
hypodermis
35
fat serves as an _____ reservoir and thermal insulator
energy
36
_____ - pigment produced by the melanocytes which accumulate in keratinocytes of the stratum basale and stratum spinosum
Melanin
37
_____ - brownish-black pigment
_____ - reddish-yellow pigment
Eumelanin
Pheomelanin
38
_____ - red pigment of blood, which makes the skin look reddish or pink
Hemoglobin
Skin is redder in areas such as the lips, where blood comes closer to the surface
39
_____ - yellow pigments acquired from egg yolks and yellow and orange vegetables
It can become concentrated in the stratum corneum and subcutaneous fat
Carotene
40
Abnormal coloration (6)
Albinism
Bronzing
Cyanosis
Erythema
Jaundice
Pallor
41
_____ - blueness of the skin resulting from the deficiency of oxygen
cyanosis
42
_____ - abnormal redness of the skin, caused by increased blood flow in dilated cutaneous blood vessels
Erythema
43
_____ - pale or ashen color when there is little blood flow through the skin. White color of the dermal collagen shows
Pallor
44
_____ - genetic lack of melanin, resulting in white hair, pale skin
Albinism
45
_____ - yellowing of the skin and whites of the eyes
Jaundice
46
_____ - golden-brown skin color that results from Addison disease
Bronzing
47
_____ ____ - marking on the fingertips that leave distinctive oily fingerprints
friction ridges
48
_____ ____ - lines on the flexor surfaces of the digits, palms, wrists, elbows, etc
skin folds during flexion of the joints
flexion lines
49
_____ - flat melanized patches that vary with heredity and exposure to the sun
freckles
50
_____ - elevated patches of melanized skin
moles
51
____ - slender filament of keratinized cells that grows from an oblique rube in the skin called a hair follicle
hair
52
glabrous skin - lips, nipples, palms, soles, parts of genitals, and parts of fingers
extremities and trunk have about 55-70 hairs per square cm
30k hairs on a man's bears and 100k on scalp
53
_____ - fine downy, unpigmented fetal hair
lanugo
54
_____ - fine, unpigmented hair replaces lanugo
Vellus
55
_____ hair - longer, courser, pigment hair that forms the eyebrows, eyelashes, scalp hair, facial hair, axillar hair, pubic hair
terminal
56
____ - portion of the hair below the skin
_____ - portion of the hair above the skin
root
shaft
57
_____ - rounded portion at the lower end of the root
_____ _____ - bud of vascular connective tissue surrounding the bulb, provides hair with nutrition
bulb
dermal papilla
58
____ _____ - the hair's growth center, above the papilla, where the cells are mitotically active
hair matrix
59
_____ - a core of loosely arranged cells and air spaces found in thick hairs only
medulla
60
_____ - a layer of keratinized cuboidal cells
cortex
61
_____ - a surface layer of scaly cells that overlap each other like roof shingles
cuticle
62
_____ ____ _____ - an extension of the epidermis
it lies immediately adjacent to the hair root
epithelial root sheath
63
______ ____ _____ - derived from the dermis
surrounds the epithelial sheath
connective tissue root
64
____ ______ - nerve fibers that entwine each follicle and respond to hair movements
hair receptors
65
________ _____ (arrector pili) - a bundle of smooth muscle cells extending from dermal collagen fibers to the connective tissue root sheath of the follicle
when these muscles contract the hair stands up
piloerector muscle
66
_____ - due to differences in cross-sectional shape
texture
67
______ hair - circular in cross-section
______ hair - oval in cross-section
______ hair - relatively flat in cross-section
straight
wavy
tightly curly
68
_____ - due to pigment granules in the cells of the cortex
color
69
_____ - rich in eumelanin
_____ - less eumelanin, high in pheomelanin
_____ - intermediate pheomelanin, very little
eumelanin
_____ - little or no melanin in the medulla
brown and black hair
red hair
blonde hair
Grey or white hair
70
_____ clear, hard derivatives of the stratum corneum
Nail
71
Nail _____ - growth zone beneath the skin at the proximal edge of the nail
matrix
72
Nail _____ - the visible portion of the nail, covering the tip of the finger or toe
Plate
73
Nail ____ - the skin on which the nail plate rests
bed
74
_____ the dead epidermis which covers the proximal end of the nail
eponychium
75
_____ - the epithelium of the nail bed
hyponychium
76
_____ _____ also known as sudoriferous glands
sweat glands
77
_____ sweat glands - the most numerous type, produces watery perspiration
merocrine
78
_____ sweat glands are scent glands that secrete pheromones
thicker and milkier than merocrine sweat
apocrine
79
______ glands - produce oily secretions
they're holocrine glands
sebaceous
80
sebaceous glands secretion consists of broken-down cells that are replaced ______
their secretion, sebum, keeps the skin and hair from drying
mitosis
81
______ glands - produce cerumen, which is earwax
found only in the external
keep the eardrum pliable, and waterproof the canal, kill bacteria
ceruminous
82
_____ glands - milk-producing glands that develop within the breasts under conditions of pregnancy and
mammary
83
_____ of sebaceous glands leaves the skin and hair drier
atrophy
84
Aged skin has less _____ due to loss of elastic fibers
Aged skin has fewer _____ _____ and those that remain are fragile
elasticity
blood vessels
85
thermoregulation can be a problem because of _____ of blood vessels, sweat glands, and subcutaneous fat
atrophy
86
skin cancer (3)
basal cell carcinoma
squamous cell carcinoma
malignant melanoma
87
_____ ___ _____ - most common type but least dangerous
arises from stratum basale
lesion first appears as a small, shiny, bump, then develops depression as it enlarges
basal cell carcinoma
88
_____ ___ _____ - arises from keratinocytes in stratum basale
can be treated through surgical removal
recovery is good if treated quickly
squamous cell carcinoma
89
_______ _______ - arises from melanocytes of a pre-existing mole
metastasizes quickly
often fatal if not treated immediately
malignant melanoma
90
___ degree burn - involved only the epidermis
redness and pain
first
91
_____ degree burn - involves the epidermis and part of the dermis
blisters and pain
second
92
_____ degree burn - the complete destruction of epidermis and dermis
skin is blacked or charred, and nerve damage may occur
often requires skin grafts
third
