MICROBIAL DISEASES OF THE EYES AND SKIN(2) Flashcards
is a physical barrier against microorganisms.
skin
_____areas of the skin support larger populations of
bacteria than dry areas.
Moist
Structure and Function of the Skin
- Epidermidis
- Dermis
- Subcutaneous
- Adipose tissue/ fats
Components:
➔ Keratin
➔ Sebum
➔ Perspiration
waterproofing of the skin
➔ Keratin
oil that moisturizes the skin
➔ Sebum
regulates body temp
➔ Perspiration
● The outer portion of the skin
● Composed of several layer of epithelial cells
EPIDERMIDIS
The outermost layer, the stratum corneum, consists of
many rows of dead cells that contains a waterproofing
protein called keratin
EPIDERMIDIS
Effective physical barrier against mo
EPIDERMIDIS
● The inner, relatively thick portion of skin
● Composed mainly of connective tissue
DERMIS
DERMIS
● The _____,_____,____, in the dermis provide passageways through which
microorganisms can enter the skin and penetrate deeper
tissues.
hair follicles, sweat gland ducts, and oil gland
ducts
● Provides moisture and some nutrients for microbial
growth
● Also contains salt which inhibits many microorganisms
PERSPIRATION
PERSPIRATION
Contains the enzyme _______, which is capable of
breaking down the cell walls of certain bacteria; and
antimicrobial peptides.
lysozyme
● Secreted by oil glands
● A mixture of lipids (unsaturated fatty acids), proteins,
and salts
● Prevents skin and hair from drying out
SEBUM
MUCOUS MEMBRANE
● a.k.a.
Mucosa
● Lines the body cavities that open to the exterior, i.e.
gastrointestinal, respiratory, urinary, and genital tracts
MUCOUS MEMBRANE
● Consists of sheets of tightly packed epithelial cells
attached at their bases to a layer of extracellular material
called basement membrane
MUCOUS MEMBRANE
Membranes of the eyes are mechanically washed by
_____, and the _____ in tears destroys the cell walls
of certain bacteria
tears
lysozymes
Microorganisms that live on skin are resistant to
desiccation and high concentrations of salt.
predominate on the skin.
Gram-positive cocci
Members of the genus ______ metabolize oil
from the oil glands and colonize hair follicles.
Cutibacterium
______yeast grows on oily secretions and
may be the cause of dandruff.
Malassezia furfur
The majority (90%) of skin microbiota consist of
coagulase-negative_____
Staphylococcus epidermidis
dandruff:
Seborrheic dermatitis
are small fluid-filled lesions
Vesicles
are vesicles larger than 1 cm
Bullae
are flat, reddened lesions
Macules
are raised lesions
Papules
are raised lesions containing pus
Pustules
are spherical gram-positive bacteria that
form irregular grape-like clusters
Staphylococci
● Coagulase-positive:
● Coagulase-negative:
S. aureus
S. epidermidis
Localized infections (____) result
from entry of _____ through openings in the skin.
sties, pimples, and boils
S. aureus
is a furuncle which extensively damages
neighboring tissues
Carbuncle
Produce a hard, round deep inflammation of
tissue under the skin
Carbuncle
occurs when toxins enter the bloodstream
Toxemia
staphylococcal toxemias include :
scalded skin
syndrome and toxic shock syndrome
is also characteristic of the late
stages of toxic shock syndrome (TSS).
● Scalded skin syndrome
Potential life-threatening condition, fever,
vomiting, and a sunburn-like rash
Scalded skin syndrome
Scalded skin syndrome
Caused by a staphylococcal toxin called
TSST-1
● Very common on the skin
● Generally pathogenic only when the skin barrier is
broken or is invaded by medical procedures, e.g.
insertion and removal of catheters into veins
Staphylococcus epidermidis
● Resident microbiota of the nasal passage
-produce
coagulase
Staphylococcus aureus “gold”