The Integumentary System Flashcards
What is the integumentary system?
*Skin is the largest organ in the body
*Makes up ~10-15% of body weight
What is the function of skin?
- Barrier
- Immunologic
- Temperature regulation
- Protection from Radiation
- Nerve sensation
- Injury repair
- Appearance & Quality of Life
- Excretion & Vitamin D synthesis
what is the function of the skin barrier?
*Physical barrier
* Regulates water loss
(desiccation)
*Dysfunction
functions of the Immunologic
- Senses and responds to pathogens
- Dysfunction
what is hyperthermia?
overheating
what is hypothermia?
very cold temp
what is Raynaud phenomenon?
it’s the episodes of reduced blood flow, particularly to the fingers and toes.
Excretion?
small amounts of waste produced from the body via sweat
what is vitamin D required for?
for the small intestine to absorb calcium ions, which are important for
* Nerve function
* Muscle contraction
* Building and maintaining bone, etc
what are the phases of the wound repair?
- Coagulation
– Inflammatory
– Proliferation-migratory
– remodeling
what are the clinical importance of skin colour?
yellow = jaundice
blue-gray = cyanosis (CV/Respiratory)
pale (pallor) = anemia
-ex: shock (low blood pressure), and emotional stress
red (erythema) = fever
- ex: Infection, rash, Allergies, hypertension, embarrassment
Bruises (black and blue marks) = blood escapes circulation and
coagulates under the skin.
3 layer of the skin?
- Epidermis
– outer layer composed
of stratified squamous
epithelium. - Dermis
– layer primarily
composed of dense
and loose irregular
connective tissue - Hypodermis
– AKA subcutis,
subcutaneous tissue,
superficial fascia
– Loose connective
tissue/adipose tissue
Epiderms is contained of
keratinized stratified squamous epithelium AKA: keratinocytes
what are the layer of the skin?
– stratum basale
– stratum spinosum
– stratum granulosum
– stratum lucidum**
– stratum corneum
what are the cells found in the epidermis
–Keratinocytes
– Dendritic (Langerhans) cells
– Tactile epithelial (Merkel) cells
– Melanocytes
the stratum basale?
Stem cells divide and give rise to keratinocytes that migrate toward skin surface to replace lost cells.
Also contains a few melanocytes and tactile cells deepest epidermal layer
Synthesis in melanocyte
(inside melanosome)
The stratum spinosum
L: spinous; spine, thorn
* polyhedral cells (called
prickle cells)
Several layers of keratinocytes joined together by desmosomes and tight junctions
Named for appearance of cells after histological preparation (spiny)
Also contains some dendritic cells
what do the small neurons in dermis do
– Detect light touch and discriminate
shapes and textures
– Large numbers in regions specialized
for touch fingertips, lips, and at
base of hairs
Stratum Granulosum
L. granulum; grain
Cells of the stratum
granulosum begin to fill
with keratin (keratinization)
* Cells flatten, nuclei and
other organelles begin to
disintegrate and two types
of granules accumulate
– Keratohyaline granules
(keratin)
– Lamellar granules
(lipids)
* Cells begin to die
Stratum Lucidum
- L. lucidum; clear
- Thin, translucent layer
- Cells appear pale,
indistinct boundaries - Found only in thick skin
stratum corneum
- Cells are dead
- 15-30 cells thick
Keratinocyte life cycle
New keratinocytes push older ones toward the surface
Over time, keratinocytes flatten, produce more keratin and membrane-coating vesicles that release lipids that waterproofs the cell.
take about 40-50 days
The function of dermis
Provides blood supply for epidermis
* Contains sensory receptors
* Anchors epidermis in place
* Composed of two distinct layers:
– Stratum papillarosum (papillary layer)
– Stratum reticularosum (reticular layer)
Describe the papillary layer of the dermis?
Most superficial layer of the dermis
Thin zone of areolar tissue in and near the dermal papilla
Anchors epidermis to dermis
Rich in small blood vessels
Contains Tactile (Meissner) corpuscles (touch) and free nerve endings (pain and temperature)
