Chapter 6 Flashcards
Integumentary System
The integument (skin) is the
largest organ of the body composed of all the tissue types that function to protect the internal structures of the body.
The skin accounts for ____ of the total body weight.
7-8%
The skin consists of two distinct layers:
Epidermis
Dermis
epidermis is made of
keratinized stratified squamous epithelium
dermis is made of
both areolar and dense irregular connective tissue
under the dermis lies the
hypodermis (subcutaneous layer)
hypodermis is made of
both areolar and adipose connective tissue.
five layers of the epidermis
Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale
which layers of the epidermis are made of living cells?
Stratum granulosum
Stratum spinosum
Stratum basale
which layer of the epidermis is only found in thick skin?
stratum lucidum
where is thick skin found?
palms of hands
soles of feet
three cell types that reside in the stratum basale?
keratinocytes
melanocytes
merkel cells
keratinocyte stem cell function
divide to replace dead keratinocytes that are shed from the surface.
what does keratin do for the skin?
provides water resistance
melanocyte function
store and produce melanin in response to UV light to protect DNA from damage.
merkel cell function
tactile cells that are sensitive to touch and release chemicals that act on nerves to send touch impulses to the brain.
The keratinocytes in the stratum spinosum layer are
highly specialized and do not continue cell division.
specialty cell that resides in the stratum spinosum
epidermal dendritic cells (Langerhans)
langerhans cell function
help to provide immune protection for the epidermis.
Cells are not fully keratinized until
they reach the superficial most layer
fully keratinized cells have
no nucleus or organelles
what is keratinization?
where the cells begin synthesis of large amounts of keratin
what does keratinization lead to?
disintegration of the nucleus and organelles, leading to cell death.
where does keratinization occur in the epidermis?
stratum granulosum
The stratum lucidum is a (color)
clear, thin layer roughly 2-3 keratinocytes thick
where does the translucency of the stratum lucidum come from?
protein eledin
the stratum corneum is the
most superficial layer of the epidermis
the stratum corneum consists of
20 to 30 layers of dead, interlocking, keratinized cells
keratinized cells of the stratum corneum are also considered
cornified
thick skin contains
all five layers of epidermal tissue and has sweat glands (no hair follicles or oil glands)
thin skin contains
4 epidermal layers sweat glands, hair follicles, and oil (sebaceous) glands.
three molecules that contribute to skin color
hemoglobin, melanin, and carotene.
hemoglobin is ____ and does what?
a protein in red blood cells that binds to oxygen, and upon binding, it exhibits a bright red color, giving blood vessels in the dermis a reddish tint.
two forms of melanin
eumelanin
pheomelanin
eumelanin produces
shades of brown and black
pheomelanin produces
lighter shades of tan, yellow, and red.
carotene is ____ and comes from where?
yellow-orange pigment that is acquired from similar colored vegetables like carrots, corn, and squashes
one example of the many forms of carotene
beta-carotene
how is skin color influenced?
genetics and UV exposure of the skin. These affect the color of melanin and melanocyte activity, affecting skin color.
everyone has roughly the same number of melanocytes
Albinism is
an inherited condition where the enzyme tyrosinase (to produce melanin) is nonfunctional, therefore no melanin is produced from melanocytes.
Nevus/nevi are
harmless, localized overgrowth of melanocytes. Rarely, moles can become cancerous resulting from excessive UV exposure.
Freckles are
spots that represent localized areas of increased melanocyte activity, not an increase in melanocyte quantity.
Hemangiomas are
anomalies that result in skin discoloration from blood vessels that proliferate and form a benign tumor
Individuals with albinism have
white hair, pale skin, and pink irises of the eyes.
Capillary hemangiomas are
present at birth and disappear into childhood