Anatomy & Physiology
Chapter 2: the integumentary system
Unit 2: the layers of the integumentary system
The functions of the integumentary system
o functions of the integumentary system consist of:
o protection: the skin protects against microorganism invasion,
water loss, abrasion and other mechanical damage, and
ultraviolet light.
o temperature regulation: sweat glands located in the skin,
along with the amount of blood flow to capillaries in the skin,
help regulate body temperature.
o vitamin D PRODUCTION: SEVERAL PROTIENS ARE
MANUFACTURED IN THE SKIN, AND WHEN EXPOSED TO
ULTRAVIOLET LIGHT, A MOLECULE IS MADE THAT CAN BECOME
VITAMIN d.
o SENSATION: MANY SENSORY RECEPTORS ARE LOCATED IN THE
SKIN THAT DETECT TOUCH, PRESSURE, PAIN, HEAT, AND COLD,
o EXCRETION: SWEAT GLANDS EXCRETE SMALL AMOUNTS OF
WASTE PRODUCTS IN SWEAT.
o SKIN COMPOSED OF Two KINDS OF TISSUE LAYERS
o The outermost layer is the epidermis. It is made of epithelial
tissue.
o The epidermis layer rests on the dermis, which is made of
irregular connective tissue.
o The skin rests on the hypodermis, a subcutaneous tissue that is a
loose connective tissue, it is primarily composed of adipose.
The layers of the epidermis
o An epidermis is composed of up to five layers.
o Stratum corneum: the most superficial layer of the epidermis,
it is the thickest layer, and the dead cells here are completely
filled with keratin.
o Stratum lucidum: as the dead cells leave the stratum
granulosum, they form the transparent stratum lucidum.
o Stratum granulosum: the next layer up is the stratum
granulosum. In this layer, the cell organelles, including the
nucleus, degenerate, which causes the cells to die.
o Stratum spinosum: as the new epidermal cells move up, they
become part of the stratum spinosum.
, o Stratum Basale: the deepest cell layer, it is also called the
stratum germinativum.
The layers of the dermis
o Dermis contains nerve endings, smooth muscles, hair follicles,
lymphatic vessels, sebaceous (oil) glands, and blood vessels. The
dermis is divided into two regions called the papillary layer and the
reticular layer.
o The upper papillary layer gets its name from the dermal papillae.
Which are upward projections toward the epidermis.
Unit 2.2: the roles and functions of melanin and keratin
The functions of melanin
o Melanocytes found in the stratum Basale, produce a group of pigments
called melanin. Melanin production is controlled by:
o Genetics: many different genes determine the amount and type
of melanin an individual produces,
o Exposure to light: ultraviolet light from the sun stimulates the
production of melanin. This results in what we call a “tan.”
o Hormones: an increase in hormones can stimulate the
production of more melanin. This is common during pregnancy
when surges in hormones may produce dark spots on the face
known as melasma.
The functions of keratin
o The deepest layer of the epidermis, the stratum Basale, has stem cells
that continually produce new epithelial cells.
o As the cells move toward the surface, they fill with keratin. The cells
that produce this keratin are called keratinocytes. This process is called
keratinization.
Unit 2.3: accessory structures of the integument
Hair follicles in the skin
o Hair is an epithelial structure that forms from stratum Basale epithelial
cells that make up the hair follicle. Just like skin, hair forms as new cells
develop and push older cells to the surface. Older cells become
keratinized and die.
The factors affecting hair growth.
o The main factors affecting hair growth are:
Chapter 2: the integumentary system
Unit 2: the layers of the integumentary system
The functions of the integumentary system
o functions of the integumentary system consist of:
o protection: the skin protects against microorganism invasion,
water loss, abrasion and other mechanical damage, and
ultraviolet light.
o temperature regulation: sweat glands located in the skin,
along with the amount of blood flow to capillaries in the skin,
help regulate body temperature.
o vitamin D PRODUCTION: SEVERAL PROTIENS ARE
MANUFACTURED IN THE SKIN, AND WHEN EXPOSED TO
ULTRAVIOLET LIGHT, A MOLECULE IS MADE THAT CAN BECOME
VITAMIN d.
o SENSATION: MANY SENSORY RECEPTORS ARE LOCATED IN THE
SKIN THAT DETECT TOUCH, PRESSURE, PAIN, HEAT, AND COLD,
o EXCRETION: SWEAT GLANDS EXCRETE SMALL AMOUNTS OF
WASTE PRODUCTS IN SWEAT.
o SKIN COMPOSED OF Two KINDS OF TISSUE LAYERS
o The outermost layer is the epidermis. It is made of epithelial
tissue.
o The epidermis layer rests on the dermis, which is made of
irregular connective tissue.
o The skin rests on the hypodermis, a subcutaneous tissue that is a
loose connective tissue, it is primarily composed of adipose.
The layers of the epidermis
o An epidermis is composed of up to five layers.
o Stratum corneum: the most superficial layer of the epidermis,
it is the thickest layer, and the dead cells here are completely
filled with keratin.
o Stratum lucidum: as the dead cells leave the stratum
granulosum, they form the transparent stratum lucidum.
o Stratum granulosum: the next layer up is the stratum
granulosum. In this layer, the cell organelles, including the
nucleus, degenerate, which causes the cells to die.
o Stratum spinosum: as the new epidermal cells move up, they
become part of the stratum spinosum.
, o Stratum Basale: the deepest cell layer, it is also called the
stratum germinativum.
The layers of the dermis
o Dermis contains nerve endings, smooth muscles, hair follicles,
lymphatic vessels, sebaceous (oil) glands, and blood vessels. The
dermis is divided into two regions called the papillary layer and the
reticular layer.
o The upper papillary layer gets its name from the dermal papillae.
Which are upward projections toward the epidermis.
Unit 2.2: the roles and functions of melanin and keratin
The functions of melanin
o Melanocytes found in the stratum Basale, produce a group of pigments
called melanin. Melanin production is controlled by:
o Genetics: many different genes determine the amount and type
of melanin an individual produces,
o Exposure to light: ultraviolet light from the sun stimulates the
production of melanin. This results in what we call a “tan.”
o Hormones: an increase in hormones can stimulate the
production of more melanin. This is common during pregnancy
when surges in hormones may produce dark spots on the face
known as melasma.
The functions of keratin
o The deepest layer of the epidermis, the stratum Basale, has stem cells
that continually produce new epithelial cells.
o As the cells move toward the surface, they fill with keratin. The cells
that produce this keratin are called keratinocytes. This process is called
keratinization.
Unit 2.3: accessory structures of the integument
Hair follicles in the skin
o Hair is an epithelial structure that forms from stratum Basale epithelial
cells that make up the hair follicle. Just like skin, hair forms as new cells
develop and push older cells to the surface. Older cells become
keratinized and die.
The factors affecting hair growth.
o The main factors affecting hair growth are:
