Chapter 4 -
Integumentary System Functions
Protects from environmental hazards
Synthesizes and stores lipids
Coordinates immune response to pathogens & cancers in skin
Senses information
Synthesizes vitamin D3
Excretes
Thermoregulation (regulates body temp)
Epidermis
Synthesizes vitamin D3
The integument contains all four primary tissue type:
An epithelium covers its surface
Underlying connective tissues make it strong and resilient
Smooth muscle tissue within the integument controls the diameters
of the blood vessels & adjusts the positions of the hairs that
project above the body surface.
Nervous tissue controls these smooth muscles and monitors sensory
receptors that provide the sensations to touch, pressure,
temperature, and pain.
Deep to the dermis, the loose connective tissue of the subcutaneous
layer, also known as the hypodermis or superficial fascia, separates
the integument from deep fascia around other organs, such as muscles
and bones.
The epidermis, the most superficial layer of the skin, is
composed of stratified squamous epithelium.
There are four cell types in the epidermis: keratinocytes,
melanocytes, merkel cells, and Langerhans cells.
Keratinocytes: are the most numerous cells within epidermis.
Merkel cells have a role in detecting sensation, and Langerhans cells
(dendritic) are wandering phagocytic cells that are important in the
body’s immune response. Melanocytes, Merkel cells, and Langerhans
cells are scattered among keratinocytes.
From deep to superficial, the epidermal layers of thick skin are
that stratum basale, stratum spinosum, stratum granulosum,
stratum lucidum, and stratum corneum.
, The epidermis has five thick layers: beginning at the basal lamina and
traveling superficially toward the epitheial surface, we find the
stratum basal, stratum spinosum, stratum granulosum, stratum lucidum,
and stratum corneum.
The brown tones of the skin result from the pigment-producing cells
called melanocytes. Melanocytes are scattered among the basal cells of
the stratum basale. They have numerous cytoplasmic processes that
inject melanin – a black yellow-brown, or brown pigment – into the
basal cells in this layer and into the keratinocytes of more
superficial layers. The ratio of melanocytes to stem cells ranges
between 1:4 and 1:20 depending on the region examined. Melanocytes are
most abundant in the cheeks, forhead, nipples, and genital area.
Albinism: is an inherited disorder characterized by deficient melanin
production; individuals with this condition have a normal distribution
of melanocytes.
Skin surfaces that lack hair contain specialized epithelial cells
known as Merkel cells.
Merkel cells are sensitive to touch and when compressed, release
chemicals that stimulates sensory nerve endings, providing information
about objects touching skin.
Each keratinocyte in the stratum spinosum contains bundles of protein
filaments that extend from one side of the cell to the other. These
bundles called tonofibrils, begin and end at a desmosome that connects
the keratinocyte to its neighbors.
Langerhans cells, which account for 3-8 percent of the cells in the
epidermis, are most common in the superficial portion of the stratum
spinosum. These cells play an important role triggering an immune
response against epidermal cancer cells and pathogen that have
penetrated the superficial layers of epidermis.
Stratum granulosum: The most superficial layer of the epidermis in
which all the cells still possess a nucleus.
Stratum Basale:
is the deepest, basal layer.
Attachment to basal lamina
Contains epidermal basal (stem) cells, melanocytes, and Merkel
cells.
Keratohyalin: accumulates in electrodense keratohyalin granules. These
granules form an intracellular matrix that surrounds the keratin
filaments.
Integumentary System Functions
Protects from environmental hazards
Synthesizes and stores lipids
Coordinates immune response to pathogens & cancers in skin
Senses information
Synthesizes vitamin D3
Excretes
Thermoregulation (regulates body temp)
Epidermis
Synthesizes vitamin D3
The integument contains all four primary tissue type:
An epithelium covers its surface
Underlying connective tissues make it strong and resilient
Smooth muscle tissue within the integument controls the diameters
of the blood vessels & adjusts the positions of the hairs that
project above the body surface.
Nervous tissue controls these smooth muscles and monitors sensory
receptors that provide the sensations to touch, pressure,
temperature, and pain.
Deep to the dermis, the loose connective tissue of the subcutaneous
layer, also known as the hypodermis or superficial fascia, separates
the integument from deep fascia around other organs, such as muscles
and bones.
The epidermis, the most superficial layer of the skin, is
composed of stratified squamous epithelium.
There are four cell types in the epidermis: keratinocytes,
melanocytes, merkel cells, and Langerhans cells.
Keratinocytes: are the most numerous cells within epidermis.
Merkel cells have a role in detecting sensation, and Langerhans cells
(dendritic) are wandering phagocytic cells that are important in the
body’s immune response. Melanocytes, Merkel cells, and Langerhans
cells are scattered among keratinocytes.
From deep to superficial, the epidermal layers of thick skin are
that stratum basale, stratum spinosum, stratum granulosum,
stratum lucidum, and stratum corneum.
, The epidermis has five thick layers: beginning at the basal lamina and
traveling superficially toward the epitheial surface, we find the
stratum basal, stratum spinosum, stratum granulosum, stratum lucidum,
and stratum corneum.
The brown tones of the skin result from the pigment-producing cells
called melanocytes. Melanocytes are scattered among the basal cells of
the stratum basale. They have numerous cytoplasmic processes that
inject melanin – a black yellow-brown, or brown pigment – into the
basal cells in this layer and into the keratinocytes of more
superficial layers. The ratio of melanocytes to stem cells ranges
between 1:4 and 1:20 depending on the region examined. Melanocytes are
most abundant in the cheeks, forhead, nipples, and genital area.
Albinism: is an inherited disorder characterized by deficient melanin
production; individuals with this condition have a normal distribution
of melanocytes.
Skin surfaces that lack hair contain specialized epithelial cells
known as Merkel cells.
Merkel cells are sensitive to touch and when compressed, release
chemicals that stimulates sensory nerve endings, providing information
about objects touching skin.
Each keratinocyte in the stratum spinosum contains bundles of protein
filaments that extend from one side of the cell to the other. These
bundles called tonofibrils, begin and end at a desmosome that connects
the keratinocyte to its neighbors.
Langerhans cells, which account for 3-8 percent of the cells in the
epidermis, are most common in the superficial portion of the stratum
spinosum. These cells play an important role triggering an immune
response against epidermal cancer cells and pathogen that have
penetrated the superficial layers of epidermis.
Stratum granulosum: The most superficial layer of the epidermis in
which all the cells still possess a nucleus.
Stratum Basale:
is the deepest, basal layer.
Attachment to basal lamina
Contains epidermal basal (stem) cells, melanocytes, and Merkel
cells.
Keratohyalin: accumulates in electrodense keratohyalin granules. These
granules form an intracellular matrix that surrounds the keratin
filaments.
