Integumentary (4) Flashcards
Functions of the integumentary system
-protection
-excretion
-maintenance of body temperature
-production of melanin
-production of keratin
-synthesis of vitamin D
-storage of lipids
- detection of touch, pressure, pain, and temperature stimuli
what are the 3 protection barriers the skin has
-chemical
-physical
-biological
Chemical barriers
include skin secretions and melanin
The low pH of skin acts as an ACID MANTLE which
retards BACTERIAL MULTIPLICATION
DERMICIDIN in sweat……
and BACTERIAL SUBSTANCES in sebum kill many bacteria
Skin cells secrete NATURAL ANTIBIOTICS called
DEFENSINS
Injured skin cells produce PROTECTIVE PEPTIDES called
CATHELICIDINS
Physical Barriers
provided by interlocking continuity and KERATINIZATION of epithelial cells
Melanin
(physical barrier)
provides a chemical pigment shield to prevent UV damage to skin cells
Dendritic Cells
(Biological barrier)
active elements of the immune system
Dermal macrophages (biological barrier)
dispose of viruses and bacteria
DNA
(biological barrier)
an effective biologically based sunscreen; electrons in DNA molecules absorb UV radiation
Body temperature regulation
dermal blood vessels and sweat glands help regulate body temperature
When the body temperature rises the nervous system stimulates
Vasodilation and sweat glands get into vigorous secretory activity
In cold environment it causes vasoconstriction which
helps conserve body heat
Exteroceptors
Skin is richly supplied with cutaneous sensory receptors
Meissner’s corpuscles and tactile discs
for light touch
Merkel disks
touch
Krause end bulbs
touch
root hair plexus
touch
ruffini endings
pressure
pacinian corpuscles
deep pressure
free nerve ending
for pain
Metabolic functions
a modified cholesterol in the skin is converted to a VITAMIN D precursor through the action of sunlight
Blood reservoir
The dermal vascular supply is extensive and can hold about 5% of the body entire blood flow
Excretion
Eliminates limited amounts if Nitrogen containing wastes and salts in the sweat
what is excreted
-Urea
-Uric acid
-Ammonia
-NaCl in sweat
The skin is composed of the two layers ___
-Epidermis
- Dermis
and sometimes Hypodermis
Epidermis
composed of epithelial cells (outermost protective shield of the body)
Dermis
The bulk of the skin, tough and leathery mostly composed of dense connective tissue
Hypodermis
Subcutaneous tissue also called Subcutaneous fat
-shock absorber and insulator to reduce heat loss
The most important cell population of the epidermis are
Keratinocytes
Keratinocytes
produces keratin, the fibrous protein that gives the epidermis its protective properties
Melanocytes
Synthesize the pigment melanin
Melanin
produced by the melanocyte is primarily made from amino acid tyrosine
Thick skin
covers areas subject to abrasions such as palms, finer and toes, sole of the feet
- contains stratum lucidum
The epidermis consists of five layers what are they from deep to superficial (base to top most)
- Stratum basale
-stratum spinosum
-stratum granulosum
-stratum lucidum
-stratum corneum
Thin skin
covers the rest of the body
- does not have
stratum lucidum
stratum means
layer
stratum basale
deepest epidermal layer
stratum spinosum
(prickly layer)
keratinocytes in this layer appear to have spines and cause them to be called prickle cells
stratum granulosum
(granular layer)
-one to five cell layers thick
-process of keratinization begins
stratum lucidum
(clear layer)
-visible only in thick skin
-consists of 2 or 3 rows of clear, dead keratinocytes
Stratum corneum
(horny layer)
- 20-30 layers thick accounts for at least 3/4 of the epidermal thickness
-Keratin in these cells protect the skin from abrasion and penetration and waterproofs it
Cells of the dermis are
fibroblasts, macrophages, and occasional mast cells and white blood cells
Dermis has two layers called
-Papillary layer
- reticular layer
Papillary layer
(upper dermal region)
has peg-like projections from its surface called DERMAL PAPILLAE that indent the overlaying epidermis
In thick skin these dermal papillae cause
the overlying epidermis to form epidermal ridges or friction ridges
Our fingertips leave identifying films of sweat called
fingerprints
Blood flows to dermis and epidermis through the
papillary plexus and the vascularity is reflected in the skin color
cyanosis
the surface of the skin has a bluish color
more blood flow to region results in
red color
less blood flow to region results in
pale color
lower oxygen levels makes hemoglobin
darker red
Oil (sebaceous glands)
produce oile (sebum) a lipid substance
what is acne
when glands get blocked and infected
What are the two types of sweat glands
Eccrine and Apocrine glands
Eccrine or Merocrine Glands
The duct opens on the skin surface in sweat pores
Apocrine sweat glands
-numerous in the axillary and anogenital areas
-larger than eccrine glands, but their ducts empty into hair follicles
Ceruminous glands
Produce cerumen (earwax)
Mammary glands
a type of modified sweat glands that secrete milk
The part of the hair above the skin surface is called the
shaft
the part of the hair below the skin surface is called the
root
structure of the nail
-free edge
-body
-root
-cuticle
-lunula
What are the types of burns
-Thermal
-electrical
-chemical
-radiation
In adults volume of fluid loss can be estimated by computing the percentage of body surface burned using the
RULE OF NINES
For RULE OF NINES the body is divided into
11 areas
Burns are classified according to their
severity or depth
first-degree burns
only epidermis is damaged
-sunburn
second-degree burns
epidermis and upper dermis are damages
-Blisters form
1st and 2nd degree burns are referred to as
partial thickness burns
Third-degree burns
destroys entire thickness of skin
- referred to as full-thickness burns
Burns are considered critical if
-Over 25% of the body has 2nd degree burns
-over 10% of the body has 3rd degree burns
Facial burns are particularly dangerous due to
Laryngeal edema which lead to swelling of larynx and suffocation due to obstruction to the passage of air
Cancer is classified in two ways
benign or malignant
benign
does not metastasize
malignant
metastasizes to other parts of the body
Basal cell carcinoma
-least malignant and most common type (80%)
-occurs most often in sun exposed areas of the face
squamous cell carcinoma
-2nd most common skin cancer
-scalp, ears, dorsum of hands
Key to survival is early detection
ABCDE rule
ABCDE rule
A= asymmetry
B= Border irregularity
C=different colors in pigmented area
D= diameter
E= elevation above skin surface
